Materials and Methods

Ethical approval. collection, processing, and analysis of phytogens. The experiment's standards and criteria for animal and animal protocol were accepted by the Research and Ethics Committee of the Department of Animal Production and Health, the Federal University of Technology, Akure (FUTA), Nigeria. The experiment took place in February and March of 2021, with an average ambient temperature of 27.77±0.4 degrees Celsius and relative humidity of 74.5 %. Osowe et al. (2021)Osowe, C.O., Olowu, O.P.A., Adu, O.A., Oloruntola, O.D. & Chineke, C.A. 2021. "Proximate and mineral composition, phytochemical analysis, and antioxidant activity of fig trees (Ficus spp.) leaf powder". Asian Journal of Biochemistry, Genetics and Molecular Biology, 9(1): 19-29, ISSN: 2582-3698. https://doi.org/10.9734/ajbgmb/2021/v9i130206. described the procedure for gathering, preparing, and analyzing Ficus exasperata leaf powder (FELP).

Vitamin C and ingredients for experimental feed. Local markets in Akure, Nigeria, were used to obtain Vitamin C powder (Avondale Laboratories Limited, Banbury, England) and other feed ingredients such as maize, maize bran, rice bran, soybean meal, soy oil, fish meal, limestone, bone meal, common salt, broiler premix, methionine, and lysine.

Experimental diets, experimental design, and the birds’ living environment. To address the dietetic requirements of the experimental broiler starter and finisher chickens (crude protein: 22.18 % and 20.03 %; crude fibre: 3.51 % and 3.59 %; crude fat: 4.22 % and 2.39 %; metabolizable energy: 12.61 kJ/kg and 12.99.1 kJ/kg), a basic experimental diet was compounded for the starting phase (0 to 21 days) and the finishing phase (21-42 days) (table 1). The crude protein, crude fat, and crude fat content of the experimental diets were determined (AOAC 2016AOAC (2016). Association of Official Analytical Chemistry. Official methods of analysis of AOAC. International (20th ed.). Rockville, MD: AOAC International.).

The baseline diet was divided into eight equal portions and called diets 1 to 8 for each phase. Diets 1 and 2 were fed to Arbor acre and Cobb 500, respectively, with no supplements; Diets 3 and 4 were fed to Arbor acre and Cobb 500, respectively, and were supplemented with 200 mg/kg Vitamin C powder; Diets 5 and 6 were fed to Arbor acre and Cobb 500, respectively, and were supplemented with 1 % FELP; while diets 7 and 8 were fed to Arbor acre and Cobb 500, respectively and were supplemented with 200 mg/kg Vitamin C and 1% FELP, respectively.

The feeding trial took place at the FUTA Teaching and Research Farm in Nigeria. For this experiment, a total of 480 broiler chickens (240 Arbor acre; 240 Cobb 500) were used. Specifically, 240 Arbor acre broiler chicks were randomly assigned to diets 1, 3, 5, and 7 in a completely randomised arrangement; while 240 one-day-old Cobb 500 were also allocated to diets 2, 4, 6, and 8 at random. Six times, each diet was repeated with ten birds each time (10 birds/repeat). Wood flakes were used to blanket the floor (2m x 1m) of the experimental pen that housed each replicate to a depth of 3 cm. To keep the chicks warm, heat lamps were positioned above the brooder. The temperature in the experimental house was maintained at 31±2 degrees Celsius for the earliest week, then dropped by 2 degrees Celsius each subsequent week until it reached 26±2 degrees Celsius. On the first day, the lights were left on for 24 hours, and on subsequent days, it was left on for 23 hours.

Performance characteristics. The body weight (BW) and feed intake (FI) of the experimental broiler birds were examined and measured every seven days. The average body weight gain (BWG) was calculated using the difference between the birds’ initial and final BW. The feed conversion ratio was computed by dividing the amount of feed consumed by the amount gained in weight.

Blood samples. On day 42 of the feeding study, 24 birds (3/replications) from each dietary group were randomly selected and bled using a syringe and needle via the wing vein. For serum proteins (total protein, albumin, globulin), biochemical components (creatinine, and cholesterol), enzyme activities (aspartate aminotransferase, and alanine transaminase) a portion of the blood sample (4 mL) was poured into a plain blood sample vial. The blood sample in each of the sample bottles was spun before analysis, and the serum was decanted into another plain bottle before freezing at -20 °CA Reflectron ^®Plus 8C79 (Roche Diagnostic, GombH Mannheim, Germany) and kits were used to detect serum proteins, biochemical components, and enzyme activity. For the measurement of haematological indices, the leftover blood (2 mL) was put into an Ethylenediaminetetraacetic acid blood sample collection tube. The standard procedures for determining haematological indices were followed (Cheesbrough 2000Cheesbrough, M. 2000. District Laboratory Practice in Tropical Countries (1st ed.). Cambridge University Press, UK.).

Statistical data evaluation. The data was analysed using the SPSS version 20 General Linear Model procedure for a complete randomized design with 2x2x2 factorial arrangements. The data were tested for the main effects (breeds, Vitamin C, and FELP inclusion) and their interactions.

The P<0.05 was used to determine significance. Means were separated using Duncan multiple range test using SPSS.

Results

Performance. The growth performance response of different breeds of broiler chickens to Ficus exasperata leaf powder and Vitamin C dietary supplementation is shown in table 2. At the starter phase (1-3 weeks), FELP significantly (P<0.05) reduced the FI. This results in the reduced (P<0.05) FI recorded in treatments 5, 6, 7, and 8 compared to the control treatments (1 and 2). The feed conversion ratio (FCR) improved (P<0.05) by breed and FELP supplementation; consequently, the FCR was better (P<0.05) in the AB breed, compared to the CO breed, and in FELP supplemented treatment (5, 6, 7 and 8) compared to no FELP supplemented treatments (1, 2, 3, and 4).

At the finisher phase (4-6 weeks), the body weight gain (BWG), FI, and FCR were affected (P<0.05) by the dietary treatments. The BWG of CO was greater (P<0.05) than AB, the vitamin C supplementation improved (P<0.05) the BWG; while the FELP supplementation reduced (P<0.05) the BWG. Consequently, the best (P<0.05) BWG was recorded in treatments 2 and 4. The Breed x FELP and vitamin C x FELP were significant (P<0.05) for BWG. The vitamin C supplementation significantly (P<0.05) reduced the FI; while the FELP supplementation increased (P<0.05) the FI. The Vitamin C x FELP improved the FCR. The FCR was improved (P<0.05) by breed and Vitamin C supplementation; while FELP impaired the FCR.

At the overall phase (1-6 weeks), the breed and Vitamin C supplementation improved (P<0.05) the BWG; while the FELP retards the BWG. Consequently, the BWG recorded in treatments 2, and 4 were higher (P<0.05), compared to the rest of treatments 1, 3, 5, 6, 7, and 8. The Vitamin C x FELP was significant (P<0.05) for FI. Vitamin C supplementation reduced the FI. The Vitamin C x FELP was significant (P<0.05) for FCR. Vitamin C supplementation improved (P<0.05) FCR; while the FELP impaired the FCR. Accordingly, there was improved (P<0.05) FCR in treatments 2 and 4, compared to treatments 1, 3, 5, 6, 7, and 8.

Haematological indices. All the haematological indices in this study were significantly (P<0.05) affected by the treatment effects, except (P>0.05) for the mean cell haemoglobin concentration (MCHC), granulocytes, and monocytes (table 3). The packed cell volume (PCV) was significantly (P<0.05) affected by breed x Vitamin C, Vitamin C x FELP, and breed x Vitamin C x FELP. In addition, the Vitamin C and FELP supplementations improved (P<0.05) the PCV level. In consequence, the PCV was highest (P<0.05) in treatments 6 and 7, compared to treatments 1, 2, 3, 4, 5, and 8. The red blood cell (RBC) counts were significantly (P<0.05) affected by Vitamin C x FELP and breed x Vitamin C and FELP. The RBC count of CO was lower (P<0.05) than AB; while the Vitamin C and FELP independently improved (P<0.05) the RBC count. Thus, the RBC count of birds in treatment 7 was higher (P<0.05) compared to the rest treatments.

The haemoglobin concentration (HBc) was significantly (P<0.05) affected by breed x Vitamin C, Vitamin C x FELP, and breed x Vitamin C and FELP. The Vitamin C and FELP supplementation independently improved (P<0.05) the HBc of the broiler chickens. Hence, the significantly (P<0.05) highest HBc was recorded in treatment 7, compared to the controls, and the rest treatments. The MCV and MCH were affected (P<0.05) by the interaction of Vitamin C and FELP. Additionally, the MCV and MCH were improved (P<0.05) by the breed but impaired (P<0.05) by Vitamin C supplementation. Accordingly, the best (P<0.05) MCV and MCH values recorded in treatment 6 were similar (P>0.05) to treatment 2, but significantly (P<0.05) higher than treatments 1, 3, 4, 6, 7, and 8.

The white blood cell (WBC) counts were increased (P<0.05) by FELP supplementation. Consequently, the highest (P<0.05) WBC counts recorded in treatments 6, and 7 were similar (P>0.05) to treatments 5 and 8 but were higher (P<0.05) than in the rest treatments. The breed x Vitamin C and FELP were significant (P<0.05) for lymphocyte counts. The highest (P<0.05) lymphocyte counts were recorded in AB; while the Vitamin C and FELP supplementations independently improved the lymphocyte count. So, the lymphocyte counts were highest (P<0.05) in treatment 7, compared to the control and other treatments.

Serum Chemistry. The serum biochemical profiles of different breeds of broiler chicken fed Ficus exasperata leaf powder and Vitamin C supplemented diets are shown in table 4. The vitamin C x FELP supplements were significant (P<0.05) for serum aspartate aminotransferase (AST). The vitamin C supplementation reduced (P<0.05) the AST concentration, so the least (P<0.05) AST concentration recorded in treatments 3, 4, and 8 was similar (P>0.05) to 7, but was significantly (P<0.05) lower than treatments 1, 2, 5, and 6. The vitamin C and FELP independently reduced (P<0.05) the serum creatinine concentration. Consequently, the lowest creatinine concentration recorded in treatments 3, 4, 7, and 8 reported, though similar to treatments 5 and 6, was significantly higher (P<0.05) than in treatments 1 and 2. The FELP supplementation reduced (P<0.05) the serum cholesterol concentration. So, the serum cholesterol level was significantly (P<0.05) lower in treatments 5, 6, 7, and 8, compared to the rest treatments. Vitamin C supplementation increased the serum total protein and albumin concentration. The FELP improved (P<0.05) the globulin concentration, hence the highest (P<0.05) globulin concentration was recorded in treatments 5, 6, 7, and 8, compared to treatments 1, 2, 3, and 4.

Discussion

When birds are grown outside of the thermo-neutral zone (18 ºC -24 ºC), they perform poorly, so they re-organize their energy and protein supplies to cope with heat stress, but at the cost of reduced reproductive efficiency and growth (Park and Kim 2017Park, S.O. & Kim, W.K. 2017. "Effects of betaine on biological functions in meat-type ducks exposed to heat stress". Poultry Science, 96(5): 1212-1218, ISSN: 1525-3171. https://doi.org/10.3382/ps/pew359. ). The observed variation in the performance characteristics response of the broiler chickens to the dietary treatments at the starter and finisher phase of production could be due to differences in the management, physiological status and nutritional factors between the starter and finisher phase (Oloruntola et al. 2018Oloruntola, O.D., Agbede, J.O., Ayodele, S.O. & Oloruntola, D.A. 2018. "Neem, pawpaw, and bamboo leaf meal dietary supplementation in broiler chickens: Effect on performance and health status". Journal of Food Biochemistry, 43(2): e12723, ISSN: 1745-4514. https://doi.org/10.1111/jfbc.12723.). The improved BWG in CO breed fed the non-supplemented diets (treatment 2) and 200 mg/kg Vitamin C supplemented diet (treatment 4) in this study during the finisher and overall phases, depict the effects of breed, FELP, and vitamin C supplementation on the body weight gain of broiler chickens. Improved growth performance in broiler chickens has been attributed to genetics and breeding, nutrition, and management practices (Tavarez and Solis de los Santos, 2016Tavarez, M.A. & Solis de los Santos, F. 2016. "Impact of genetics and breeding on broiler production performance: a look into the past, present, and future of the industry". Animal Frontiers, 6(4): 37-41, ISSN: 1424-8247. https://doi.org/10.2527/af.2016-0042. ).

During the finisher and overall stages of this study, the superior BWG reported in CO breed compared to AB breed illustrates the variation in incremental improvement by genetic selection for growth rate across the two broiler chicken breeds under consideration. This finding demonstrates that genetics is one of the most important factors influencing broiler growth (Rance et al. 2002Rance, K., McEntee, G. & McDevitt, R. 2002. "Genetic and phenotypic relationships between and within support and demand tissues in a single line of broiler chicken". British Poultry Science, 43(4): 518-527, ISSN: 1466-1799. https://doi.org/10.1080/0007166022000004426. and Tavarez and Solis de los Santos 2016Tavarez, M.A. & Solis de los Santos, F. 2016. "Impact of genetics and breeding on broiler production performance: a look into the past, present, and future of the industry". Animal Frontiers, 6(4): 37-41, ISSN: 1424-8247. https://doi.org/10.2527/af.2016-0042. ). In addition, the observed improved BWG by Vitamin C supplementation supports the earlier report of Al-Masad (2012)Al-Masad, M. 2012. "Effects of Vitamin C and zinc on broilers performance of immunocompetence under heat stress". Asian Journal of Animal Science, 6(2): 76-84, ISSN: 0976-8963. https://doi.org/10.3923/ajas.2012.76.84. , who recorded higher body weight in broilers fed diets supplemented with Vitamin C and reared under high ambient temperature, compared to those fed un-supplemented diets.

Since heat exposure produces oxidative stress in broilers, which reduces their growth performance (Shakeri et al. 2019Shakeri, M., Cottrell, J. J., Wilkinson, S., Le, H. H., Suleria, H. A. R., Warner, R. D., & Dunshea, F. R. 2019. "Growth Performance and characterization of meat quality of broiler chickens supplemented with betaine and antioxidants under cyclic heat stress". Antioxidants, 8(9): 336, ISSN: 2076-3921. https://doi.org/10.3390/antiox8090336. ), the possible causes of better BWG documented in the experimental birds could be Vitamin C’s activity as an antioxidant that can inhibit growth performance decline owing to heat stress (Al-Masad 2012Al-Masad, M. 2012. "Effects of Vitamin C and zinc on broilers performance of immunocompetence under heat stress". Asian Journal of Animal Science, 6(2): 76-84, ISSN: 0976-8963. https://doi.org/10.3923/ajas.2012.76.84. ). In biological systems, ascorbic acid acts as a free radical scavenger and reducer, scavenging oxidising free radicals and harmful oxygen-derived species such as hydrogen peroxide, hydroxyl radicals, and singlet oxygen (Hacışevki, 2009Hacışevki, A. 2009. "An overview of ascorbic acid biochemistry". Journal of Faculty of Pharmacy of Ankara University, 38(3): 233-255, ISSN: 2564-6524. https://doi.org/10.1501/Eczfak_0000000528. ). The lower BWG in the experimental birds due to FELP supplementation in this study suggests a possible compromise of nutritive quality and impairment of feed acceptability by the birds, because some phytochemicals and phytogenics may interfere with nutrient bioavailability in the birds, especially when present at levels above the tolerable concentration in their diets (Dhama et al. 2014Dhama, K., Tiwari, R., Khan, R. U., Chakraborty, S., Gopi, M., Karthik, K., Saminathan, M., Desingu, P. A. & Sunkara, L. T. 2014. "Growth promoters and novel feed additives improving poultry production and health, bioactive principles and beneficial applications: The trends and advances- A Review". International Journal of Pharmacology, 10(3): 129-159, ISSN: 1812-5700. https://doi.org/10.3923/ijp.2014.129.159. and Oloruntola, 2021 Oloruntola, O.D., Adu, O.A., Gbore, F.A., Falowo, A.B. & Olarotimi, O.J. 2021. "Performance of broiler chicken fed diets supplemented with Irvingia gabonensis kernel powder and Ocimum gratissimum leaf powder". Slovakia Journal of Animal Science, 54(1): 7-20, ISSN: 1338-0095.).

Multiple studies have demonstrated a decline in feed consumption due to the high inclusion level (>1500 mg/kg) of phytochemical feed supplements and the inherent properties of some compounds, such as a strong flavour and odour (Yan et al. 2011Yan, L., Meng, Q. W. & Kim, I. H. 2011. "The effect of an herb extract mixture on growth performance, nutrient digestibility, blood characteristics and fecal noxious gas content in growing pigs". Livestock Science, 141: 143-147, ISSN: 1871-1413. http://dx.doi.org/10.1016/j.livsci.2011.05.011. , Oloruntola et al. 2016 aOloruntola, O.D., Ayodele, S.O., Agbede, J.O, Oloruntola, D.A, Ogunsipe, M.H. & Omoniyi, I.S. 2016a. "Effect of Alchornea cordifolia leaf meal and enzyme supplementation on growth, haematological, immunostimulatory and serum biochemical response of rabbits". Asian Journal of Biological and Life Sciences, 5(2): 190-195, ISSN: 2278-5957., bOloruntola, O.D., Ayodele S.O., Agbede J.O. & Oloruntola, D.A. 2016b. "Effect of feeding broiler chicken with diets containing Alchornea cordifolia leaf meal and enzyme supplementation". Archivos de Zootecnia, 65(252): 489-498, ISSN: 0004-0592. and Valenzuela-Grijalva et al. 2017Valenzuela-Grijalva, N. V., Pinelli-Saavedra, A., Muhlia-Almazan, A., Domínguez-Díaz, D. & González-Ríos, H. 2017. "Dietary inclusion effects of phytochemicals as growth promoters in animal production". Journal of Animal Science and Technology, 59: 8, ISSN: 2055-0391. https://doi.org/10.1186/s40781-017-0133-9. ). Although FELP was not consumed at a high dietary level in this trial, its bioactive components may have contributed to the reduced feed intake at the starter phase by activating the release of satiety hormone (cholecystokinin) by the cells of the upper small intestine, delaying stomach emptying, and increasing feelings of satiety and anorexia (Tucci 2010Tucci, S. A. 2010. "Phytochemicals in the Control of Human Appetite and Body Weight". Pharmaceuticals (Basel), 3(3): 748-763, ISSN: 1424-8247https://doi.org/10.3390/ph3030748.). Furthermore, the usage of feed supplements can affect an animal’s willingness to eat a given feed (Valenzuela-Grijalva et al. 2017Valenzuela-Grijalva, N. V., Pinelli-Saavedra, A., Muhlia-Almazan, A., Domínguez-Díaz, D. & González-Ríos, H. 2017. "Dietary inclusion effects of phytochemicals as growth promoters in animal production". Journal of Animal Science and Technology, 59: 8, ISSN: 2055-0391. https://doi.org/10.1186/s40781-017-0133-9. ). This is in tandem with the interactive effects of the breed with FELP (at the finisher phase) and vitamin C with FELP (at the overall phase) in this study. Previous studies reported improved FI in broiler chickens as a result of interaction between thyme and cinnamon (Al-Kassier 2009Al-Kassie, G.A. 2009. "Influence of two plant extracts derived from thyme and cinnamon on broiler performance". Pakistan Veterinary Journal, 29: 169-173, ISSN: 2074-7764. ) and CrPic and vitamin C (Adebayo et al. 2022Adebayo, F.A., Adu, O.A., Chineke, C.A., Oloruntola, O.D., Omoleye, O.S., Adeyeye, S.A. & Ayodele S.O. 2022. "The performance, antioxidant status, blood chemistry analysis and tissue histology of broiler birds fed a diet containing Chromium picolinate and vitamin C". Iranian Journal of Applied Animal Science, 12(1): 129-142, ISSN: 2251-631X. ). However, during the finisher and overall periods of the experimental birds, the FI was consistent across treatment groups. This observation suggests that the birds’ FI intake capacity changes or improves as they grow older and is consistent with increased FI in broiler chickens on day 22 compared to day 14, being reported by Babatunde et al (2019)Babatunde, O.O., Cowieson, A.J., Wilson, J.W. & Adeola, O. 2019. "The impact of age and feeding length on phytase efficacy during the starter phase of broiler chickens". Poultry Science, 98(12): 6742-6750, ISSN: 1525-3171. https://doi.org/10.3382/ps/pez390. . The reduction in the FI recorded in the FELP treated groups (5, 6, 7, and 8) and the significant effect of FELP supplementation in this study suggest the negative effects of the FELP on the feed acceptability and consumption by the birds during the early stage of their life (the starter phase). The reduced FI in the affected treatment groups could be due to the phytoconstituents of the FELP. For instance, tannin, when present at high levels in diets reduces voluntary feed intake and nutrient digestibility (Hassan et al. 2020Hassan, Z. M., Manyelo, T. R., Salaledi, L. & Mabelebele, M. 2020. "The effects of tannins in monogastric animals with special reference to alternative feed ingredients". Molecules, 25(20): 4680, ISSN: 1420-3049. https://dx.doi.org/10.3390/molecules25204680. and Osowe et al. 2021Osowe, C.O., Olowu, O.P.A., Adu, O.A., Oloruntola, O.D. & Chineke, C.A. 2021. "Proximate and mineral composition, phytochemical analysis, and antioxidant activity of fig trees (Ficus spp.) leaf powder". Asian Journal of Biochemistry, Genetics and Molecular Biology, 9(1): 19-29, ISSN: 2582-3698. https://doi.org/10.9734/ajbgmb/2021/v9i130206. ).

The feed conversion ratio (FCR) is a proxy for efficiency in terms of performance and shows the amount of feed required to gain one unit of body weight on a live bird over a given period. As revealed in this study, breed, Vitamin C and FELP supplementation have varying noticeable effects on the FCR of the broiler chickens. The effects of the interaction of vitamin C and FELP on FCR in this study agreed with earlier studies that a blend of feed supplements could synergise and complement each other to produce noticeable effects on performance characteristics such as FCR (Al-Kassier 2009Al-Kassie, G.A. 2009. "Influence of two plant extracts derived from thyme and cinnamon on broiler performance". Pakistan Veterinary Journal, 29: 169-173, ISSN: 2074-7764. and Adebayo et al. 2022Adebayo, F.A., Adu, O.A., Chineke, C.A., Oloruntola, O.D., Omoleye, O.S., Adeyeye, S.A. & Ayodele S.O. 2022. "The performance, antioxidant status, blood chemistry analysis and tissue histology of broiler birds fed a diet containing Chromium picolinate and vitamin C". Iranian Journal of Applied Animal Science, 12(1): 129-142, ISSN: 2251-631X. ).

The improved FCR recorded in the CO breed over the AB breed during the starter phase (1-3 weeks) of this study shows that improved genetics and breeding are among the factors behind the improved performance and in particular the feed efficiency in broiler chickens production (Tavarez and Solis de Los Santos 2016Tavarez, M.A. & Solis de los Santos, F. 2016. "Impact of genetics and breeding on broiler production performance: a look into the past, present, and future of the industry". Animal Frontiers, 6(4): 37-41, ISSN: 1424-8247. https://doi.org/10.2527/af.2016-0042. ). In actuality, broiler chicken production performance is always changing as a function of genetics and breeding (Zuidhof et al. 2014Zuidhof, M.J., Schneider, B. L., Carney, V. L., Korver, D. R. & Robinson, F. E. 2014. "Growth, efficiency, and yield of commercial broilers from 1957, 1978, and 2005". Poultry Science, 93: 2970-2982, ISSN: ISSN: 1525-3171. http://dx.doi.org/10.3382/ps.2014-04291. ). In addition, the improved FCR recorded in the broiler chickens as a result of vitamin C supplementation in this study negates the earlier report of Abudabos et al (2018)Abudabos, A.M., Al-Owaimer, A.N., Hussein, E.O.S. & Ali, M.H. 2018. "Effect of natural Vitamin C on performance and certain haemato-biochemical values on broiler chickens exposed to heat stress". Pakistan Journal of Zoology, 50(3): 951-955, ISSN: 0030-9923., who recorded similar FCR in broiler chickens fed the control and vitamin C supplemented diets. However, the addition of 250 mg/kg of Vitamin C to broiler chicken feed has been demonstrated to improve body weight gain and feed efficiency. Increased performance, such as FCR, may be attributable to thyroid activity and increased oxygen consumption in the presence of ascorbic acid, especially when the ambient temperature is high (Kassim and Norziha 1995Kassim, H. & Norziha, I., 1995. "Effects of ascorbic acid (Vitamin C) supplementation in layer and broiler diets in the tropics". Asian-Australasian Journal of Animal Science, 8(6): 607-610, ISSN: 1976-5517. https://doi.org/10.5713/ajas.1995.607. and Khan et al. (2012a)Khan, R.U., Naz, S., Nikousefat, Z., Selvaggi, M., Laudadio, V. & Tufarelli, V., 2012a. "Effect of ascorbic acid in heat-stressed poultry". World’s Poultry Science Journal, 68(3): 477- 490, ISSN: 1743-4777. https://doi.org/10.1017/S004393391200058X. . The negative effects of FELP on FCR in this study suggest the phytogens have some phytochemicals at concentrations above the tolerable level for the birds (Valenzuela-Grijalva et al. 2017Valenzuela-Grijalva, N. V., Pinelli-Saavedra, A., Muhlia-Almazan, A., Domínguez-Díaz, D. & González-Ríos, H. 2017. "Dietary inclusion effects of phytochemicals as growth promoters in animal production". Journal of Animal Science and Technology, 59: 8, ISSN: 2055-0391. https://doi.org/10.1186/s40781-017-0133-9. ).

Haematological measures can be used to identify an animal’s pathogenic, physiological, and nutritional status (Adeyeye et al. 2020Adeyeye, S.A., Oloruntola, O.D., Ayodele, S.O., Falowo, A.B. & Agbede J.O. 2020. "Wild sunflower and goat weed composite-mix supplementation in broiler chicken: effects on performance, health status and meat". Acta Fytotechnica et Zootechnica, 23(4): 205-212, ISSN: 1336-9245. https://doi.org/10.15414/afz.2020.23.04.205-212. ). Blood has an important function in thermoregulation in birds in a typical tropical climate. The wattles, comb, and skin’s blood vessels dilate to transport internal body heat to the skin surface, causing convective, radiative, and conductive heat loss (Kpomasse et al. 2021Kpomasse, C.C., Oke, O.E., Houndonougbo, F.M. & Tona, K. 2021. "Broiler production challenges in the tropics: A review". Veterinary Medicine and Science, 7(3): 831-842, ISSN: 2053-1095. https://doi.org/10.1002/vms3.435. ). The fact that factors such as vitamin C, FELP, and breed; and the interactions: breed x vitamin C; vitamin C x FELP and breed x vitamin C x FELP increased PCV, RBC, and HB in this study suggests that these nutrients are important in increasing the proportion of total erythrocyte mass to total blood volume, the number of erythrocytes, and the concentration of protein molecules in the red blood cells that carry oxygen to the lungs.

Therefore, leveraging on this finding, broiler chickens with anaemia could be treated by adding vitamin C and FELP to their diets, either independently or combined. The improved PCV, RBC, and HB by the vitamin C, FELP, breed x vitamin C x FELP could be the antioxidant activity or properties of these supplements synagising with the breed factor (Yadav et al. 2016Yadav, S.S., Kolluri, G., Gopi, M., Karthik, K., Malik, Y.S. & Dhama, K. 2016. "Exploring alternatives to antibiotics as health-promoting agents in poultry- A review". Journal of Experimental Biology and Agricultural Sciences, 4(3S): 368-383, ISSN: 2320-8694. http://dx.doi.org/10.18006/2016.4(3S).368.383. and Osowe et al. 2021Osowe, C.O., Olowu, O.P.A., Adu, O.A., Oloruntola, O.D. & Chineke, C.A. 2021. "Proximate and mineral composition, phytochemical analysis, and antioxidant activity of fig trees (Ficus spp.) leaf powder". Asian Journal of Biochemistry, Genetics and Molecular Biology, 9(1): 19-29, ISSN: 2582-3698. https://doi.org/10.9734/ajbgmb/2021/v9i130206. ). Furthermore, FELP’s contribution to the broiler diet’s essential mineral profile (Osowe et al. 2021Osowe, C.O., Olowu, O.P.A., Adu, O.A., Oloruntola, O.D. & Chineke, C.A. 2021. "Proximate and mineral composition, phytochemical analysis, and antioxidant activity of fig trees (Ficus spp.) leaf powder". Asian Journal of Biochemistry, Genetics and Molecular Biology, 9(1): 19-29, ISSN: 2582-3698. https://doi.org/10.9734/ajbgmb/2021/v9i130206. ), as well as the possible complementary role of supplemental vitamin C in assisting the breakdown of amino acids and aiding in the absorption of minerals, particularly iron, by keeping them in a reduced ferrous state, could be responsible for the improved erythrogram caused by these supplements (Yadav et al. 2016Yadav, S.S., Kolluri, G., Gopi, M., Karthik, K., Malik, Y.S. & Dhama, K. 2016. "Exploring alternatives to antibiotics as health-promoting agents in poultry- A review". Journal of Experimental Biology and Agricultural Sciences, 4(3S): 368-383, ISSN: 2320-8694. http://dx.doi.org/10.18006/2016.4(3S).368.383. ). The higher RBC counts in the AB breed compared to the CO breed suggest that genetic variables may influence erythrocyte count. Previous research has shown that genetic variables influence haematological parameters such as PCV, RBC, HBC, mean cell haemoglobin, and mean cell haemoglobin concentration, among others (Chineke et al. 2006Chineke, C. A., Ologun, A. G. & Ikeobi, C. O. N. 2006. "Haematological parameters in rabbit breeds and crosses in humid tropics". Pakistan Journal of Biological Sciences, 9(11): 2102-2106, ISSN: 1812-5735. https://doi.org/10.3923/PJBS.2006.2102.2106. and Etim et al. 2014Etim, N. N., Williams, M. E., Akpabio, U. & Offiong, E.A. 2014. "Haematological parameters and factors affecting their values". Agricultural Science, 2(1): 37-47, ISSN: 2690-4799. https://doi.org/10.12735/as.v2i1p37. ). The PCV, RBC, and HB values in this study are all within normal ranges (PCV: 22-35 %, RBC: 2.5-3.5 x 106/L, and HB: 7-13 g/dL) reported by Bounous and Stedman (2000)Bounous, D. & Stedman, N. 2000. Normal avian hematology: chicken and turkey. In: Feldman BF, Zinkl JG, Jain NC, editors. Schalm’s veterinary hematology. New York: Wiley; 2000. p.1147-1154..

The interaction of vitamin C and FELP producing reduction of the MCV and MCH indicates the presence of microcytic anaemia, which is frequently associated with the iron shortage. Furthermore, the increased MCV and MCH levels in CO breeds indicate macrocytic anaemia, which is defined by excessively large red blood cells and implies that red blood cells are fewer and transport less haemoglobin, meaning that the blood is not as oxygen-rich as it should be (Aslinia et al. 2006Aslinia, F., Mazza, J. J. & Yale, S. H. 2006. "Megaloblastic anemia and other causes of macrocytosis". Clinical Medicine and Research, 4(3): 236-241, ISSN: 1554-6179. https://doi.org/10.3121/cmr.4.3.236. ). However, the levels observed in this study are within the normal range (MCV: 90 - 140 fl; MCH: 33-47 pg/cell) as reported by (Bounous and Stedman 2000Bounous, D. & Stedman, N. 2000. Normal avian hematology: chicken and turkey. In: Feldman BF, Zinkl JG, Jain NC, editors. Schalm’s veterinary hematology. New York: Wiley; 2000. p.1147-1154.); therefore the raised MCV values induced by breeds or reduced MCV values produced by Vitamin C supplementation may not be of health concern (Bounous and Stedman 2000Bounous, D. & Stedman, N. 2000. Normal avian hematology: chicken and turkey. In: Feldman BF, Zinkl JG, Jain NC, editors. Schalm’s veterinary hematology. New York: Wiley; 2000. p.1147-1154.).

The body is protected by leukocytes and its differentials from harmful or foreign organism infiltration, as well as antibody production and dispersion (Oloruntola et al. 2016aOloruntola, O.D., Ayodele, S.O., Agbede, J.O, Oloruntola, D.A, Ogunsipe, M.H. & Omoniyi, I.S. 2016a. "Effect of Alchornea cordifolia leaf meal and enzyme supplementation on growth, haematological, immunostimulatory and serum biochemical response of rabbits". Asian Journal of Biological and Life Sciences, 5(2): 190-195, ISSN: 2278-5957.). Furthermore, several phytogens have immunomodulatory properties (Dashputre and Naikwade 2010Dashputre, N. L., & Naikwade, N. S. 2010. "Preliminary Immunomodulatory activity of aqueous and ethanolic leaves extract of O. basilicum Linn in mice". International Journal of PharmTechn Research, 2(2): 1342-1349, ISSN: 2455-9563. and Oloruntola et al. 2016 aOloruntola, O.D., Ayodele, S.O., Agbede, J.O, Oloruntola, D.A, Ogunsipe, M.H. & Omoniyi, I.S. 2016a. "Effect of Alchornea cordifolia leaf meal and enzyme supplementation on growth, haematological, immunostimulatory and serum biochemical response of rabbits". Asian Journal of Biological and Life Sciences, 5(2): 190-195, ISSN: 2278-5957.,bOloruntola, O.D., Ayodele S.O., Agbede J.O. & Oloruntola, D.A. 2016b. "Effect of feeding broiler chicken with diets containing Alchornea cordifolia leaf meal and enzyme supplementation". Archivos de Zootecnia, 65(252): 489-498, ISSN: 0004-0592.). This explains the increased WBC counts as a result of FELP supplementation, compared to the control in this study The immunomodulatory properties of phytogens could be linked to dietary substances like phytoestrogens, which, when ingested, can mimic the effects of the hormone oestrogen, (Cady et al. 2020Cady, N., Peterson, S.T., Freedman, S.N. & Mangalam, A.K. 2020. "Beyond metabolism: The complex interplay between dietary phytoestrogens, gut bacteria, and cells of nervous and immune systems". Frontier in Neurology, 11: 1-15, ISSN: 1664-2295. https://doi.org/10.3389/fneur.2020.00150. ) oestrogen controls immune response by suppressing the negative selection of high-affinity auto-reactive B cells, influencing B cell function, and triggering the Th2 response (Taneja 2018Taneja V. 2018. "Sex Hormones Determine Immune Response". Frontiers in Immunology, 9: 1931, ISSN: 1664-3224. https://doi.org/10.3389/fimmu.2018.01931 ). The increased lymphocyte counts observed in this study as a result of interactions (breed x vitamin C x FELP), vitamin C supplementation, and FELP supplementation highlight the potential impact of vitamin C (Shojadoost et al. 2021Shojadoost, B., Yitbarek, A., Alizadeh, M., Kulkarni, T. T., Astill, J., Boodhoo, N. & Sharif S. 2021. "Centennial Review: Effects of vitamins A, D, E, and C on the chicken immune system". Poultry Science, 100 (4): 1-17, ISSN: 1525-3171. https://doi.org/10.1016/j.psj.2020.12.027. ), FELP (Dashputre and Naikwade 2010Dashputre, N. L., & Naikwade, N. S. 2010. "Preliminary Immunomodulatory activity of aqueous and ethanolic leaves extract of O. basilicum Linn in mice". International Journal of PharmTechn Research, 2(2): 1342-1349, ISSN: 2455-9563. and Oloruntola et al. 2016 aOloruntola, O.D., Ayodele, S.O., Agbede, J.O, Oloruntola, D.A, Ogunsipe, M.H. & Omoniyi, I.S. 2016a. "Effect of Alchornea cordifolia leaf meal and enzyme supplementation on growth, haematological, immunostimulatory and serum biochemical response of rabbits". Asian Journal of Biological and Life Sciences, 5(2): 190-195, ISSN: 2278-5957.,bOloruntola, O.D., Ayodele S.O., Agbede J.O. & Oloruntola, D.A. 2016b. "Effect of feeding broiler chicken with diets containing Alchornea cordifolia leaf meal and enzyme supplementation". Archivos de Zootecnia, 65(252): 489-498, ISSN: 0004-0592.) and their interactions with breed factors (Zahoor et al. 2018Zahoor, I., Ghayas, A. & Basheer, A. 2018. "Genetics and genomics of susceptibility and immune response to necrotic enteritis in chicken: a review". Molecular Biology Reports, 45(1) 31-37, ISSN: 1573-4978. http://dx.doi.org/10.1007/s11033-017-4138-8. ) on the immunological condition of birds. Additionally, the higher lymphocyte count in the AB breed compared to the CO breed in this study suggests a difference in the birds’ immune response capabilities and the impact of genetic makeup on the experimental birds’ immune response (Zahoor et al. 2018Zahoor, I., Ghayas, A. & Basheer, A. 2018. "Genetics and genomics of susceptibility and immune response to necrotic enteritis in chicken: a review". Molecular Biology Reports, 45(1) 31-37, ISSN: 1573-4978. http://dx.doi.org/10.1007/s11033-017-4138-8. ).

The transaminase enzyme, aspartate aminotransferase (AST) catalyzes the transformation of aspartate and alpha-ketoglutarate to oxaloacetate and glutamate. Except for bone, AST may be detected in all tissues, with the highest amounts in skeletal muscle and the liver. The concentration of AST rises after injury, bruising, necrosis, neoplasm, or infection of the liver or muscle (Washington and Van Hoosier, 2012Washington, I. M. & Van Hoosier, G. 2012. Clinical Biochemistry and Hematology. In: The Laboratory rabbit, guinea pig, hamster, and other rodents. Edited by Mark A. Suckow, Karla A. Stevens and Ronald P. Wilson. Academic Press, USA. pp 1247-1268. https://doi.org/10.1016/C2009-0-30495-X. ). Therefore, the reduction of the serum AST concentration by interaction (vitamin C x FELP) and vitamin C concentration in this study shows the antioxidative properties and protective role of vitamin C and the interaction effects of vitamin C with the phytogenic supplement (FELP) against liver or muscle damage. Vitamin C protects proteins from alkylation by electrophilic lipid peroxidation products, oxidative stress-induced cellular damage by rummaging reactive oxygen species, and vitamin E-dependent neutralisation of lipid hydroperoxyl radicals (Traber and Stevens, 2011Traber, M. G. & Stevens, J. F. 2011. "Vitamins C and E: beneficial effects from a mechanistic perspective". Free Radical Biology and Medicine, 51(5): 1000-1013, ISSN: 1873-4596. https://doi.org/10.1016/j.freeradbiomed.2011.05.017. ). In addition, Vitamin C helps endothelial nitric oxide synthase (eNOS) functions by recycling the eNOS cofactor tetrahydrobiopterin, which is important for arterial elasticity and blood pressure management (Miranda et al. 2009Miranda, C. L., Reed, R. L., Kuiper, H.C., Alber, S. & Stevens, J. F. 2009. "Ascorbic acid promotes detoxification and elimination of 4-hydroxy-2(E)-nonenal in human monocytic THP-1 cells". Chemical Research in Toxicology, 22(5): 863-874, ISSN: 1520-5010. https://doi.org/10.1021/tx900042u. , Chavez et al. 2010Chavez, J., Chung, W.G., Miranda, C.L., Singhal, M., Stevens, J.F. & Maier, C.S. 2010. "Site-specific protein adducts of 4-hydroxy-2(E)-nonenal in human THP-1 monocytic cells: protein carbonylation is diminished by ascorbic acid". Chemical Research in Toxicology, 23(1): 37-47, ISSN: 1520-5010. https://doi.org/10.1021/tx9002462. and Traber and Stevens 2011Traber, M. G. & Stevens, J. F. 2011. "Vitamins C and E: beneficial effects from a mechanistic perspective". Free Radical Biology and Medicine, 51(5): 1000-1013, ISSN: 1873-4596. https://doi.org/10.1016/j.freeradbiomed.2011.05.017. ).

Creatinine is a nitrogen waste product that is not protein-based, and its measurement can be used to assess renal function (Salazar 2014Salazar, J.H. 2014. "Overview of Urea and Creatinine". Laboratory Medicine, 45(1): e19-e20, ISSN: 0007-5027. https://doi.org/10.1309/LM920SBNZPJRJGUT. ). The reduction of serum creatinine concentration by the Vitamin C and FELP supplementation as recorded in this study also elucidates the health benefits of Vitamin C and FELP dietary supplementation in preserving the physiological and anatomical functions of the kidney, which may owe to the antioxidant properties of Vitamin C (Traber and Stevens 2011Traber, M. G. & Stevens, J. F. 2011. "Vitamins C and E: beneficial effects from a mechanistic perspective". Free Radical Biology and Medicine, 51(5): 1000-1013, ISSN: 1873-4596. https://doi.org/10.1016/j.freeradbiomed.2011.05.017. ) and FELP (Osowe et al. 2021Osowe, C.O., Olowu, O.P.A., Adu, O.A., Oloruntola, O.D. & Chineke, C.A. 2021. "Proximate and mineral composition, phytochemical analysis, and antioxidant activity of fig trees (Ficus spp.) leaf powder". Asian Journal of Biochemistry, Genetics and Molecular Biology, 9(1): 19-29, ISSN: 2582-3698. https://doi.org/10.9734/ajbgmb/2021/v9i130206. ).

Serum cholesterol is produced in the liver and is derived from the diet. A high cholesterol level is a sign of heart disease. Reduced serum cholesterol levels can be caused by a low-fat diet, a decrease in cholesterol uptake, or intestinal mal-absorption (Adegbeye et al. 2020 Adegbeye, M.J., Oloruntola, O.D., Asaniyan, E.K., Agunbiade, B., Oisagah, E.A. & Ayodele, S.O 2020. "Pawpaw, black cumin, and mustard seed meal dietary supplementation in broiler chickens: Effect on performance, gut microflora, and gut morphology". Journal of Agricultural Science and Technology, 22(5): 1235-1246, ISSN: 2345-3737. ). In this study, the phytogens’ hypocholesterolemic capabilities are revealed by the broiler chickens’ reduced blood cholesterol levels after being fed FELP supplemented diets. The hypocholesterolemic effect reported may be owing to the phytosterols in FELP limiting cholesterol absorption in the intestine due to the structural similarities of cholesterol and phytosterol (Adegbeye et al. 2020 Adegbeye, M.J., Oloruntola, O.D., Asaniyan, E.K., Agunbiade, B., Oisagah, E.A. & Ayodele, S.O 2020. "Pawpaw, black cumin, and mustard seed meal dietary supplementation in broiler chickens: Effect on performance, gut microflora, and gut morphology". Journal of Agricultural Science and Technology, 22(5): 1235-1246, ISSN: 2345-3737. and Ayodele et al. 2021Ayodele S.O., Oloruntola O.D., Ayeyeye S.A., Jimoh O.A., Falowo A.B. & Omoniyi I.S. 2021. "Supplementation value of Mucuna seed powder on performance, antioxidant enzymes, meat cholesterol and peroxidation, and serum metabolites of broiler chickens". Malaysian Journal of Animal Science, 24(1): 11-22, ISSN: 2550-2123. ). Furthermore, one of the phytochemicals in FELP, saponins, is known to modulate blood lipids (Osowe et al. 2021Osowe, C.O., Olowu, O.P.A., Adu, O.A., Oloruntola, O.D. & Chineke, C.A. 2021. "Proximate and mineral composition, phytochemical analysis, and antioxidant activity of fig trees (Ficus spp.) leaf powder". Asian Journal of Biochemistry, Genetics and Molecular Biology, 9(1): 19-29, ISSN: 2582-3698. https://doi.org/10.9734/ajbgmb/2021/v9i130206. ).

Haemo-concentration, increased globulin production, lipaemia, and haemolysis are the most common causes of elevated serum total protein. However, the observed increase in the serum total protein and albumin, due to Vitamin C supplementation may not be pathological because, the serum total protein levels (53.30 -69.42 g/L) and albumin level (23.03-34.05 g/L) recorded in this study are within the normal range for total protein (52-69 g/L) and albumin (21 - 34.5 g/L) reported by Mitruka and Rawnsley (1977)Mitruka, B. M. & Rawnsley, H. M 1977. Clinical biochemical and hematological reference values in normal experimental animals. Masson Publishing USA, Inc. pp. 134-139. and Oloruntola et al. (2016a)Oloruntola, O.D., Ayodele, S.O., Agbede, J.O, Oloruntola, D.A, Ogunsipe, M.H. & Omoniyi, I.S. 2016a. "Effect of Alchornea cordifolia leaf meal and enzyme supplementation on growth, haematological, immunostimulatory and serum biochemical response of rabbits". Asian Journal of Biological and Life Sciences, 5(2): 190-195, ISSN: 2278-5957. for chickens. Vitamin C supplementation has been shown to raise blood protein levels (Karakilcik et al. 2004Karakilcik, A. Z., Zerinm. K., Arslanm, B., Nazligul, L. & Vural, F. 2004. "Effects of vitamin C and E on liver enzymes and biochemical parameters of rabbits exposed to aflatoxin B1". Veterinary and Human Toxicology, 46(4): 190-192, ISSN: 0145-6296. and Nayila 2020Nayila, I. 2020. "Effect of Vitamin C supplementation on serum ascorbic acid level and liver function profile in healthy individuals". Asian Journal of Medicine and Health, 18(9): 28-39, ISSN: 2456-8414. https://doi.org/10.9734/ajmah/2020/v18i930235. ). Globulins are a diverse collection of large serum proteins that do not include albumin (Odunitan-Wayas et al. 2018Odunitan-Wayas, P., Kolanisi, U., & Chimonyo M. 2018. "Haematological and serum biochemical responses of Ovambo chickens fed Provitamin A Biofortified maize". Brazilian Journal of Poultry Science, 20(3): 425-433, ISSN: 1806-9061 http://dx.doi.org/10.1590/1806-9061-2016-0444. ). In addition to the aforementioned variables that cause an increase in total protein, an increase in alpha, beta, or gamma globulin can cause an increase in serum globulin. By implication, the increased globulin concentration observed in this study because of FELP supplementation suggests the phytogens stimulated the increased globulin production in the serum. This agrees with Ghazalah and Ali (2008)Ghazalah, A. A. & Ali, A.M. 2008. "Rosemary leaves as a dietary supplement for growth in broiler chickens". International Journal of Poultry Science, 7: 234-239, ISSN: 1994-7992 ., who recorded increased serum protein and globulin concentration in broiler chickens fed a 5g/kg rosemary leaves supplemented diet. Phytogenics can stimulate the intestinal walls, increasing the secretion of digestive enzymes, as well as enhancing the absorption of more nutrients and, as a result, an improved protein profile (Abudabos et al. 2016Abudabos, A.M., Alyemni, A.H., Dafallah, Y.M. & Khan, R.U. 2016. "The effect of phytogenic feed additives to substitute in-feed antibiotics on growth traits and blood biochemical parameters in broiler chicks challenged with Salmonella typhimurium". Environmental Science and Pollution Research, 23: 24151-24157, ISSN: 1614-7499. https://doi.org/10.1007/s11356-016-7665-2. ).

Conclusions

In conclusion, to achieve optimal body weight gain in broiler chickens, breed selection (CO) and 200 mg/kg Vitamin C supplementation are recommended, especially in a typical tropical environment. However, for better immunity and hypocholesterolemia in the birds, 1 % FELP dietary supplementation is indicated. As a nutritional supplement, 1 % FELP might be coupled with 200 mg/kg of vitamin C to enhance feed consumption, red blood cell count, packed cell volume, and haemoglobin concentration; to prevent liver and tissue damage and protect renal cells from damage in broiler chickens.

Materiales y Métodos

Aprobación ética. Recolección, procesamiento y análisis de fitógenos. Los estándares y criterios del experimento para animales y protocolo animal fueron aceptados por el Comité de Ética e Investigación del Departamento de Producción y Salud Animal de la Federal University of Technology, Akure (FUTA), Nigeria. El experimento se llevó a cabo en febrero y marzo de 2021, con una temperatura ambiente promedio de 27,77±0,4ºC y humedad relativa de 74,5 %. Osowe et al. (2021)Osowe, C.O., Olowu, O.P.A., Adu, O.A., Oloruntola, O.D. & Chineke, C.A. 2021. "Proximate and mineral composition, phytochemical analysis, and antioxidant activity of fig trees (Ficus spp.) leaf powder". Asian Journal of Biochemistry, Genetics and Molecular Biology, 9(1): 19-29, ISSN: 2582-3698. https://doi.org/10.9734/ajbgmb/2021/v9i130206. describieron el procedimiento para recolectar, preparar y analizar el harina de hojas de Ficus exasperata (PHFE).

Vitamina C e Ingredientes para Piensos Experimentales. Los mercados locales en Akure, Nigeria, se utilizaron para obtener polvo de vitamina C (Avondale Laboratories Limited, Banbury, Inglaterra) y otros ingredientes para piensos como maíz, salvado de maíz, salvado de arroz, harina de soja, aceite de soja, harina de pescado, piedra caliza, harina de huesos, sal común, premezcla para pollos de engorde, metionina y lisina.

Dietas experimentales, diseño experimental y el entorno de vida de las aves. Para atender los requerimientos dietéticos de los pollos de engorde experimentales de iniciación y finalización (proteína bruta: 22.18 % y 20.03 %; fibra bruta: 3.51 % y 3.59 %; grasa bruta: 4.22 % y 2.39 %; energía metabolizable: 12.61 kcal/kg y 12.99.1 KJ/kg), se compuso una dieta experimental básica para la fase inicial (0 a 21 días) y la fase final (21-42 días) (tabla 1). Se determinó el contenido de proteína bruta y grasa bruta de las dietas experimentales (AOAC 2016AOAC (2016). Association of Official Analytical Chemistry. Official methods of analysis of AOAC. International (20th ed.). Rockville, MD: AOAC International.).

La dieta base se dividió en ocho porciones iguales y se denominó dietas 1 a 8 para cada fase. Las dietas 1 y 2 se suministraron a Arbor acre y Cobb 500, respectivamente, sin suplementos; las dietas 3 y 4 se suministraron a Arbor acre y Cobb 500, respectivamente, suplementadas con 200 mg/kg de vitamina C en polvo; las dietas 5 y 6 se suministarron a Arbor acre y Cobb 500, respectivamente, y se suplementaron con 1 % de PHFE; mientras que las dietas 7 y 8 se suministraron a Arbor acre y Cobb 500, respectivamente, suplementadas con 200 mg/kg de vitamina C y 1 % de PHFE, respectivamente.

La prueba de alimentación se llevó a cabo en la Granja de Enseñanza e Investigación de FUTA en Nigeria. Para este experimento, se utilizaron un total de 480 pollos de engorde (240 Arbor acre; 240 Cobb 500). Específicamente, se asignaron aleatoriamente 240 pollos de engorde Arbor acre a las dietas 1, 3, 5 y 7 en un arreglo completamente aleatorizado; mientras que 240 Cobb 500 de un día también se asignaron a las dietas 2, 4, 6 y 8 al azar. Seis veces, cada dieta se repitió con diez aves cada vez (10 aves/repetición). Se usaron virutas de madera para cubrir el piso (2m x 1m) del corral experimental que alojaba cada réplica a una profundidad de 3 cm. Para mantener calientes a los pollitos, se colocaron lámparas de calor encima de la incubadora. La temperatura en el área experimental se mantuvo a 31±2 ºC durante la primera semana, luego bajó 2 ºC cada semana hasta alcanzar los 26±2ºC. El primer día se dejó encendida la luz durante 24 horas y los días siguientes durante 23 horas.

Características del comportamiento. El peso corporal (PC) y el consumo de alimento (CA) de las aves de engorde experimentales se examinaron y midieron cada siete días. La ganancia de peso corporal promedio (GPC) se calculó utilizando la diferencia entre el peso corporal inicial y final de las aves. La tasa de conversión alimentaria se calculó dividiendo la cantidad de alimento consumido por la cantidad ganada en peso.

Muestras de sangre. El día 42 del estudio de alimentación, se seleccionaron al azar 24 aves (3/repeticiones) de cada grupo dietético y se les extrajo sangre usando una jeringa y una aguja a través de la vena del ala. Para proteínas séricas (proteína total, albúmina, globulina), componentes bioquímicos (creatinina y colesterol), actividades enzimáticas (aspartato aminotransferasa y alanina transaminasa; una porción de la muestra de sangre (4 mL) se vertió en un frasco de muestra de sangre simple. La muestra de sangre en cada uno de los frascos de muestra se centrifugó antes del análisis y el suero se decantó en otro frasco simple antes de congelarse a -20°CA Reflectron ^®Plus 8C79 (Roche Diagnostic, GombH Mannheim, Alemania) y se usaron kits para detectar proteínas séricas, componentes bioquímicos y actividad enzimática. Para la medición de los índices hematológicos, la sangre sobrante (2 mL) se colocó en un tubo de recolección de muestras de sangre con ácido etilendiaminotetraacético. Se siguieron los procedimientos estándar para determinar los índices hematológicos (Cheesbrough 2000Cheesbrough, M. 2000. District Laboratory Practice in Tropical Countries (1st ed.). Cambridge University Press, UK.).

Evaluación de datos estadísticos. Los datos se analizaron utilizando el procedimiento SPSS versión 20 General Linear Model para un diseño completamente aleatorizado con arreglo factorial 2x2x2. Los datos se probaron para los efectos principales (razas, vitamina C e inclusión de PHFE) y sus interacciones.

Se usó P<0.05 para determinar la significación. Las medias se separaron usando la prueba de rango múltiple de Duncan usando SPSS.

Resultados

Comportamiento. La respuesta del comportamiento del crecimiento de diferentes razas de pollos de engorde al harina de hoja de Ficus exasperata y la suplementación dietética con vitamina C se muestra en la tabla 2. En la fase inicial (1-3 semanas), PHFE redujo significativamente (P<0.05) el CA. Esto da como resultado el CA reducido (P<0.05) registrado en los tratamientos 5, 6, 7 y 8 en comparación con los tratamientos de control (1 y 2). La tasa de conversión alimentaria (TCA) mejoró (P<0.05) por raza con la suplementación de PHFE; por consiguiente, la TCA fue mejor (P<0.05) en la raza AB, en comparación con la raza CO, y en el tratamiento suplementado con PHFE (5, 6, 7 y 8) en comparación con los tratamientos de PHFE sin suplemento (1, 2, 3 y 4).

En la fase final (4-6 semanas), la ganancia de peso corporal (GPC), CA y TCA se vieron afectados (P<0.05) por los tratamientos dietéticos. La GPC de CO fue mayor (P<0.05) que AB, la suplementación con vitamina C mejoró la (P<0.05) GPC; mientras que la suplementación con PHFE redujo (P<0.05) la GPC. En consecuencia, la mejor (P<0.05) GPC se registró en los tratamientos 2 y 4. La Raza x PHFE y la vitamina C x PHFE fueron significativas (P<0.05) para la GPC. La suplementación con vitamina C redujo significativamente (P<0.05) el CA; mientras que la suplementación con PHFE incrementó (P<0.05) el CA. La Vitamina C x PHFE mejoró la TCA. La TCA mejoró (P<0.05) con la raza y la suplementación con vitamina C; mientras que el PHFE afectó la TCA.

En la fase general (1-6 semanas), la raza y la suplementación con vitamina C mejoraron (P<0.05) la GPC; mientras que el PHFE retarda la GPC. En consecuencia, la GPC registrada en los tratamientos 2 y 4 fue mayor (P<0.05), en comparación con el resto de los tratamientos 1, 3, 5, 6, 7 y 8. La Vitamina C x PHFE fue significativa (P<0.05) para el CA. La suplementación con vitamina C redujo el CA. La vitamina C x PHFE fue significativa (P<0.05) para la TCA. La suplementación con vitamina C mejoró (P<0.05) TCA; mientras que el PHFE afectó la TCA. Por consiguiente, hubo una mejorra de la TCA (P<0.05) en los tratamientos 2 y 4, en comparación con los tratamientos 1, 3, 5, 6, 7 y 8.

Índices hematológicos. Todos los índices hematológicos de este estudio se vieron afectados significativamente (P<0.05) por los efectos del tratamiento, excepto (P>0.05) para la concentración media de hemoglobina celular (CMHC), granulocitos y monocitos (tabla 3). El volumen de células empaquetadas (VCE) se vio significativamente afectado (P<0.05) por la raza x vitamina C, la vitamina C x PHFE y la raza x vitamina C x PHFE. Además, la suplementación con vitamina C y PHFE mejoró (P<0.05) el nivel de VCE. En consecuencia, el VCE fue más alto (P<0.05) en los tratamientos 6 y 7, en comparación con los tratamientos 1, 2, 3, 4, 5 y 8. Los conteos de glóbulos rojos (GR) se vieron afectados influidos significativamente (P<0.05) por la vitamina C x PHFE y la raza x vitamina C y PHFE. El conteo de GR de CO fue más bajo (P<0.05) que AB; mientras que la vitamina C y PHFE mejoraron de forma independiente (P<0.05) el conteo de glóbulos rojos. Por lo tanto, el conteo de glóbulos rojos de las aves en el tratamiento 7 fue mayor (P<0.05) en comparación con los tratamientos restantes.

La concentración de hemoglobina (CH) fue significativamente afectada (P<0.05) por la raza x vitamina C, vitamina C x PHFE y raza x vitamina C y PHFE. La suplementación con vitamina C y PHFE mejoró de forma independiente (P<0.05) la CH de los pollos de engorde. Por lo tanto, la CH significativamente más alta (P<0.05) se registró en el tratamiento 7, en comparación con los controles y el resto de los tratamientos. El VCM y HCM fueron influidos (P<0.05) por la interacción de la vitamina C y PHFE. Además, el VCM y HCM mejoraron (P<0.05) por la raza, pero se vieron afectados (P<0.05) por la suplementación con vitamina C. Por lo tanto, los mejores (P<0.05) valores de VCM y HCM registrados en el tratamiento 6 fueron similares (P>0.05) al tratamiento 2, pero significativamente (P<0.05) más altos que los tratamientos 1, 3, 4, 6, 7 y 8 . Los conteos de glóbulos blancos (GB) aumentaron (P <0,05) con la suplementación de PHFE.

Por consiguiente, los conteos de GB más altos (P<0.05) registrados en los tratamientos 6 y 7 fueron similares (P>0.05) a los tratamientos 5 y 8 pero fueron más altos (P<0.05) que en el resto de los tratamientos. La raza x vitamina C y PHFE fueron significativos (P<0.05) para los conteos de linfocitos. Los conteos de linfocitos más altos (P<0.05) se registraron en AB; mientras que los suplementos de vitamina C y PHFE mejoraron de forma independiente el conteo de linfocitos. Por tanto, los conteos de linfocitos fueron los más altos (P<0.05) en el tratamiento 7, en comparación con el control y los otros tratamientos.

Química del suero. Los perfiles bioquímicos séricos de diferentes razas de pollos de engorde alimentados con polvoharina de hojas de Ficus exasperata y dietas suplementadas con vitamina C se muestran en la tabla 4. Los suplementos de vitamina C x PHFE fueron significativos (P<0.05) para la aspartato aminotransferasa sérica (AST). La suplementación con vitamina C redujo (P<0.05) la concentración de AST, por lo que la menor (P<0.05) concentración de AST registrada en los tratamientos 3, 4 y 8 fue similar (P>0.05) a 7, pero fue significativamente (P<0.05 ) inferior a los tratamientos 1, 2, 5 y 6. La vitamina C y PHFE redujeron de forma independiente (P<0.05) la concentración de creatinina sérica. Por consiguiente, la concentración de creatinina más baja registrada en los tratamientos 3, 4, 7 y 8 reportada, aunque similar a los tratamientos 5 y 6, fue significativamente mayor (P<0.05) que en los tratamientos 1 y 2. La suplementación con PHFE redujo (P<0.05) la concentración de colesterol sérico. Así, el nivel de colesterol sérico fue significativamente (P<0.05) más bajo en los tratamientos 5, 6, 7 y 8, en comparación con el resto de los tratamientos. La suplementación con vitamina C aumentó la concentración sérica de proteína total y albúmina. El PHFE mejoró (P<0.05) la concentración de globulina, por lo que la mayor concentración de globulina (P<0.05) se registró en los tratamientos 5, 6, 7 y 8, en comparación con los tratamientos 1, 2, 3 y 4.

Discusión

Cuando las aves se crían fuera de la zona termoneutral (18 ºC -24 ºC), se desempeñan mal, por lo que reorganizan sus suministros de energía y proteínas para hacer frente al estrés caloríco, pero a costa de una menor eficiencia reproductiva y crecimiento ( Parque y Kim 2017Park, S.O. & Kim, W.K. 2017. "Effects of betaine on biological functions in meat-type ducks exposed to heat stress". Poultry Science, 96(5): 1212-1218, ISSN: 1525-3171. https://doi.org/10.3382/ps/pew359. ). La variación observada en la respuesta de las características de rendimiento de los pollos de engorde a los tratamientos dietéticos en la fase de inicio y finalización de la producción podría deberse a diferencias en el manejo, estado fisiológico y factores nutricionales entre la fase de inicio y finalización (Oloruntola et al. 2018Oloruntola, O.D., Agbede, J.O., Ayodele, S.O. & Oloruntola, D.A. 2018. "Neem, pawpaw, and bamboo leaf meal dietary supplementation in broiler chickens: Effect on performance and health status". Journal of Food Biochemistry, 43(2): e12723, ISSN: 1745-4514. https://doi.org/10.1111/jfbc.12723.). La GPC mejorada en la raza CO alimentados con las dietas no suplementadas (tratamiento 2) y con una dieta suplementada con 200 mg/kg de vitamina C (tratamiento 4) en este estudio durante las fases final y general, muestran los efectos de la raza con la suplementación de PHFE y vitamina C en la ganancia de peso corporal de los pollos de engorde. El comportamiento del crecimiento mejorado en pollos de engorde se ha atribuido a la genética y las prácticas de reproducción, nutrición y manejo (Tavarez y Solis de los Santos, 2016Tavarez, M.A. & Solis de los Santos, F. 2016. "Impact of genetics and breeding on broiler production performance: a look into the past, present, and future of the industry". Animal Frontiers, 6(4): 37-41, ISSN: 1424-8247. https://doi.org/10.2527/af.2016-0042. ).

Durante las etapas final y general de este estudio, la GPC superior informada en la raza CO en comparación con la raza AB muestra la variación en la mejora incremental por selección genética para la tasa de crecimiento en las dos razas de pollos de engorde. Este resultado demuestra que la genética es uno de los factores más importantes que influyen en el crecimiento de los pollos de engorde (Rance et al. 2002Rance, K., McEntee, G. & McDevitt, R. 2002. "Genetic and phenotypic relationships between and within support and demand tissues in a single line of broiler chicken". British Poultry Science, 43(4): 518-527, ISSN: 1466-1799. https://doi.org/10.1080/0007166022000004426. y Tavarez y Solis de los Santos 2016Tavarez, M.A. & Solis de los Santos, F. 2016. "Impact of genetics and breeding on broiler production performance: a look into the past, present, and future of the industry". Animal Frontiers, 6(4): 37-41, ISSN: 1424-8247. https://doi.org/10.2527/af.2016-0042. ). Además, la GPC mejorada por la suplementación con vitamina C respalda lo anteriormente expuesto por Al-Masad (2012)Al-Masad, M. 2012. "Effects of Vitamin C and zinc on broilers performance of immunocompetence under heat stress". Asian Journal of Animal Science, 6(2): 76-84, ISSN: 0976-8963. https://doi.org/10.3923/ajas.2012.76.84. , quien registró mayor peso corporal en pollos de engorde alimentados con dietas suplementadas con vitamina C y criados a temperatura ambiente alta, en comparación con aquellos alimentados sin dietas suplementadas.

La exposición al calor produce estrés oxidativo en los pollos de engorde, lo que reduce su rendimiento de crecimiento (Shakeri et al. 2019Shakeri, M., Cottrell, J. J., Wilkinson, S., Le, H. H., Suleria, H. A. R., Warner, R. D., & Dunshea, F. R. 2019. "Growth Performance and characterization of meat quality of broiler chickens supplemented with betaine and antioxidants under cyclic heat stress". Antioxidants, 8(9): 336, ISSN: 2076-3921. https://doi.org/10.3390/antiox8090336. ), las posibles causas de la mejor GPC documentado en las aves experimentales podrían ser la actividad de la vitamina C como antioxidante que puede inhibir la disminución del comportamiento de crecimiento debido al estrés calórico (Al-Masad 2012Al-Masad, M. 2012. "Effects of Vitamin C and zinc on broilers performance of immunocompetence under heat stress". Asian Journal of Animal Science, 6(2): 76-84, ISSN: 0976-8963. https://doi.org/10.3923/ajas.2012.76.84. ). En los sistemas biológicos, el ácido ascórbico actúa como buscador y reductor de radicales libres, eliminando los radicales oxidados libres oxidantes y las especies nocivas derivadas del oxígeno, como el peróxido de hidrógeno, los radicales hidroxilo y el oxígeno “singlete” (Hacışevki 2009Hacışevki, A. 2009. "An overview of ascorbic acid biochemistry". Journal of Faculty of Pharmacy of Ankara University, 38(3): 233-255, ISSN: 2564-6524. https://doi.org/10.1501/Eczfak_0000000528. ). La GPC más baja en las aves experimentales debido a la suplementación con PHFE en este estudio sugiere un posible equilibrio de la calidad nutritiva y un deterioro de la aceptabilidad del alimento por parte de las aves, porque algunos fitoquímicos y fitogénicos pueden interferir con la biodisponibilidad de nutrientes en las aves, especialmente cuando están presentes en niveles superiores a la concentración tolerable en sus dietas (Dhama et al. 2014Dhama, K., Tiwari, R., Khan, R. U., Chakraborty, S., Gopi, M., Karthik, K., Saminathan, M., Desingu, P. A. & Sunkara, L. T. 2014. "Growth promoters and novel feed additives improving poultry production and health, bioactive principles and beneficial applications: The trends and advances- A Review". International Journal of Pharmacology, 10(3): 129-159, ISSN: 1812-5700. https://doi.org/10.3923/ijp.2014.129.159. y Oloruntola, 2021 Oloruntola, O.D., Adu, O.A., Gbore, F.A., Falowo, A.B. & Olarotimi, O.J. 2021. "Performance of broiler chicken fed diets supplemented with Irvingia gabonensis kernel powder and Ocimum gratissimum leaf powder". Slovakia Journal of Animal Science, 54(1): 7-20, ISSN: 1338-0095.).

Múltiples estudios han demostrado una disminución en el consumo de alimento debido al alto nivel de inclusión (>1500 mg/kg) de suplementos alimenticios fitoquímicos y las propiedades inherentes de algunos compuestos, como un fuerte sabor y olor (Yan et al. 2011Yan, L., Meng, Q. W. & Kim, I. H. 2011. "The effect of an herb extract mixture on growth performance, nutrient digestibility, blood characteristics and fecal noxious gas content in growing pigs". Livestock Science, 141: 143-147, ISSN: 1871-1413. http://dx.doi.org/10.1016/j.livsci.2011.05.011. , Oloruntola et al. 2016 aOloruntola, O.D., Ayodele, S.O., Agbede, J.O, Oloruntola, D.A, Ogunsipe, M.H. & Omoniyi, I.S. 2016a. "Effect of Alchornea cordifolia leaf meal and enzyme supplementation on growth, haematological, immunostimulatory and serum biochemical response of rabbits". Asian Journal of Biological and Life Sciences, 5(2): 190-195, ISSN: 2278-5957., bOloruntola, O.D., Ayodele S.O., Agbede J.O. & Oloruntola, D.A. 2016b. "Effect of feeding broiler chicken with diets containing Alchornea cordifolia leaf meal and enzyme supplementation". Archivos de Zootecnia, 65(252): 489-498, ISSN: 0004-0592. y Valenzuela-Grijalva et al. 2017Valenzuela-Grijalva, N. V., Pinelli-Saavedra, A., Muhlia-Almazan, A., Domínguez-Díaz, D. & González-Ríos, H. 2017. "Dietary inclusion effects of phytochemicals as growth promoters in animal production". Journal of Animal Science and Technology, 59: 8, ISSN: 2055-0391. https://doi.org/10.1186/s40781-017-0133-9. ). Aunque el PHFE no se consumió a un nivel alto en la dieta en este ensayo, sus componentes bioactivos pueden haber contribuido a la reducción del consumo de alimento en la fase inicial al activar la liberación de la hormona de la saciedad (colecistoquinina) por las células del intestino delgado superior, lo que retrasa el vaciamiento del estómago y aumenta la sensación de saciedad y anorexia (Tucci 2010Tucci, S. A. 2010. "Phytochemicals in the Control of Human Appetite and Body Weight". Pharmaceuticals (Basel), 3(3): 748-763, ISSN: 1424-8247https://doi.org/10.3390/ph3030748.). Además, el uso de suplementos alimenticios puede afectar la disposición de un animal a comer un alimento determinado (Valenzuela-Grijalva et al. 2017Valenzuela-Grijalva, N. V., Pinelli-Saavedra, A., Muhlia-Almazan, A., Domínguez-Díaz, D. & González-Ríos, H. 2017. "Dietary inclusion effects of phytochemicals as growth promoters in animal production". Journal of Animal Science and Technology, 59: 8, ISSN: 2055-0391. https://doi.org/10.1186/s40781-017-0133-9. ). Esto está en conjunto con los efectos interactivos de la raza con PHFE (en la fase de finalización) y la vitamina C con PHFE (en la fase general) en este estudio. Estudios previos reportaron un CA mejorado en pollos de engorde como resultado de la interacción entre el tomillo y la canela (Al-Kassier 2009Al-Kassie, G.A. 2009. "Influence of two plant extracts derived from thyme and cinnamon on broiler performance". Pakistan Veterinary Journal, 29: 169-173, ISSN: 2074-7764. ) y CrPic y la vitamina C (Adebayo et al. 2022Adebayo, F.A., Adu, O.A., Chineke, C.A., Oloruntola, O.D., Omoleye, O.S., Adeyeye, S.A. & Ayodele S.O. 2022. "The performance, antioxidant status, blood chemistry analysis and tissue histology of broiler birds fed a diet containing Chromium picolinate and vitamin C". Iranian Journal of Applied Animal Science, 12(1): 129-142, ISSN: 2251-631X. ). Sin embargo, durante los períodos de finalización y general de las aves experimentales, el CA fue constante en todos los grupos de tratamiento. Esta observación sugiere que la capacidad de ingesta de las aves cambia o mejora e la medida que envejecen y es consistente con el aumento del CA en pollos de engorde el día 22 en comparación con el día 14, informado por Babatunde et al. (2019)Babatunde, O.O., Cowieson, A.J., Wilson, J.W. & Adeola, O. 2019. "The impact of age and feeding length on phytase efficacy during the starter phase of broiler chickens". Poultry Science, 98(12): 6742-6750, ISSN: 1525-3171. https://doi.org/10.3382/ps/pez390. . La reducción en el CA registrado en los grupos tratados con PHFE (5, 6, 7 y 8) y el efecto significativo de la suplementación con PHFE en este estudio sugieren los efectos negativos del PHFE en la aceptabilidad y el consumo de alimento por parte de las aves durante la primera etapa de su vida (la fase inicial). El reducido CA en los grupos de tratamiento afectados podría deberse a los fitoconstituyentes del PHFE. Por ejemplo, el tanino, cuando está presente en niveles altos en las dietas, reduce el consumo voluntario del alimento y la digestibilidad de los nutrientes (Hassan et al. 2020Hassan, Z. M., Manyelo, T. R., Salaledi, L. & Mabelebele, M. 2020. "The effects of tannins in monogastric animals with special reference to alternative feed ingredients". Molecules, 25(20): 4680, ISSN: 1420-3049. https://dx.doi.org/10.3390/molecules25204680. y Osowe et al. 2021Osowe, C.O., Olowu, O.P.A., Adu, O.A., Oloruntola, O.D. & Chineke, C.A. 2021. "Proximate and mineral composition, phytochemical analysis, and antioxidant activity of fig trees (Ficus spp.) leaf powder". Asian Journal of Biochemistry, Genetics and Molecular Biology, 9(1): 19-29, ISSN: 2582-3698. https://doi.org/10.9734/ajbgmb/2021/v9i130206. ).

La tasa de conversión alimenticia (TCR) es un indicador de la eficiencia en términos de rendimiento y muestra la cantidad de alimento necesaria para ganar una unidad de peso corporal en un ave viva durante un período determinado. Como se reveló en este estudio, la raza, la vitamina C y la suplementación con PHFE tienen efectos notables variables en la TCA de los pollos de engorde. Los efectos de la interacción de la vitamina C y PHFE en la TCA en este estudio coincidieron con estudios anteriores de que una mezcla de suplementos alimenticios podría crear sinergias y complementarse entre sí para producir efectos notables en las características de comportmiento como la TCA (Al-Kassier 2009Al-Kassie, G.A. 2009. "Influence of two plant extracts derived from thyme and cinnamon on broiler performance". Pakistan Veterinary Journal, 29: 169-173, ISSN: 2074-7764. y Adebayo et al. 2022Adebayo, F.A., Adu, O.A., Chineke, C.A., Oloruntola, O.D., Omoleye, O.S., Adeyeye, S.A. & Ayodele S.O. 2022. "The performance, antioxidant status, blood chemistry analysis and tissue histology of broiler birds fed a diet containing Chromium picolinate and vitamin C". Iranian Journal of Applied Animal Science, 12(1): 129-142, ISSN: 2251-631X. ).

La TCA mejorada registrada en la raza CO sobre la raza AB durante la fase inicial (1-3 semanas) de este estudio muestra que la genética y la reproducción mejoradas se encuentran entre los factores detrás del comportmiento mejorado y, en particular, la eficiencia alimentaria en la producción de pollos de engorde ( Tavarez y Solis de Los Santos 2016Tavarez, M.A. & Solis de los Santos, F. 2016. "Impact of genetics and breeding on broiler production performance: a look into the past, present, and future of the industry". Animal Frontiers, 6(4): 37-41, ISSN: 1424-8247. https://doi.org/10.2527/af.2016-0042. ). En realidad, el comportmiento de la producción de pollos de engorde siempre cambia en función de la genética y la crianza (Zuidhof et al. 2014Zuidhof, M.J., Schneider, B. L., Carney, V. L., Korver, D. R. & Robinson, F. E. 2014. "Growth, efficiency, and yield of commercial broilers from 1957, 1978, and 2005". Poultry Science, 93: 2970-2982, ISSN: ISSN: 1525-3171. http://dx.doi.org/10.3382/ps.2014-04291. ). Además, la TCA mejorada registrada en los pollos de engorde como resultado de la suplementación con vitamina C en este estudio niega el informe anterior de Abudabos et al. (2018)Abudabos, A.M., Al-Owaimer, A.N., Hussein, E.O.S. & Ali, M.H. 2018. "Effect of natural Vitamin C on performance and certain haemato-biochemical values on broiler chickens exposed to heat stress". Pakistan Journal of Zoology, 50(3): 951-955, ISSN: 0030-9923., quienes registraron una TCA similar en pollos de engorde alimentados con dietas de control y suplementadas con vitamina C. Sin embargo, se ha demostrado que la adición de 250 mg/kg de vitamina C al alimento para pollos de engorde mejora la ganancia de peso corporal y la eficiencia alimentaria. El aumento del rendimiento, como la TCA, puede atribuirse a la actividad de la tiroides y al aumento del consumo de oxígeno en presencia de ácido ascórbico, especialmente cuando la temperatura ambiente es alta (Kassim y Norziha 1995Kassim, H. & Norziha, I., 1995. "Effects of ascorbic acid (Vitamin C) supplementation in layer and broiler diets in the tropics". Asian-Australasian Journal of Animal Science, 8(6): 607-610, ISSN: 1976-5517. https://doi.org/10.5713/ajas.1995.607. y Khan et al. (2012a)Khan, R.U., Naz, S., Nikousefat, Z., Selvaggi, M., Laudadio, V. & Tufarelli, V., 2012a. "Effect of ascorbic acid in heat-stressed poultry". World’s Poultry Science Journal, 68(3): 477- 490, ISSN: 1743-4777. https://doi.org/10.1017/S004393391200058X. . Los efectos negativos del PHFE en la TCA en este estudio sugieren que los fitógenos tienen algunos fitoquímicos en concentraciones por encima del nivel tolerable para las aves (Valenzuela-Grijalva et al. 2017Valenzuela-Grijalva, N. V., Pinelli-Saavedra, A., Muhlia-Almazan, A., Domínguez-Díaz, D. & González-Ríos, H. 2017. "Dietary inclusion effects of phytochemicals as growth promoters in animal production". Journal of Animal Science and Technology, 59: 8, ISSN: 2055-0391. https://doi.org/10.1186/s40781-017-0133-9. ).

Las medidas hematológicas se pueden utilizar para identificar el estado patogénico, fisiológico y nutricional de un animal (Adeyeye et al. 2020Adeyeye, S.A., Oloruntola, O.D., Ayodele, S.O., Falowo, A.B. & Agbede J.O. 2020. "Wild sunflower and goat weed composite-mix supplementation in broiler chicken: effects on performance, health status and meat". Acta Fytotechnica et Zootechnica, 23(4): 205-212, ISSN: 1336-9245. https://doi.org/10.15414/afz.2020.23.04.205-212. ). La sangre tiene una función importante en la termorregulación de las aves en un clima tropical típico. Las barbas, la cresta y los vasos sanguíneos de la piel se dilatan para transportar el calor corporal interno a la superficie de la piel, lo que provoca la pérdida de calor por convección, radiación y conducción (Kpomasse et al. 2021Kpomasse, C.C., Oke, O.E., Houndonougbo, F.M. & Tona, K. 2021. "Broiler production challenges in the tropics: A review". Veterinary Medicine and Science, 7(3): 831-842, ISSN: 2053-1095. https://doi.org/10.1002/vms3.435. ). El hecho de que factores como la vitamina C, PHFE y raza y las interacciones: raza x vitamina C; vitamina C x PHFE y raza x vitamina C x PHFE aumentó el VCE, GR y CH en este estudio sugiere que estos nutrientes son importantes para aumentar la proporción de masa total de eritrocitos con respecto al volumen total de sangre, el número de eritrocitos y la concentración de moléculas de proteína en los glóbulos rojos que transportan oxígeno a los pulmones.

Por lo tanto, considerando estos resultados, los pollos de engorde con anemia pueden ser tratados adicionándole vitamina C y PHFE a sus dietas, separada o combinada. El VCE, los GB y CH mejorado con vitamina C, PHFE, raza x vitamina C x PHFE pudiera ser la actividad antioxidante o propiedades de estos suplementos combinándolos con el factor raza (Yadav et al. 2016Yadav, S.S., Kolluri, G., Gopi, M., Karthik, K., Malik, Y.S. & Dhama, K. 2016. "Exploring alternatives to antibiotics as health-promoting agents in poultry- A review". Journal of Experimental Biology and Agricultural Sciences, 4(3S): 368-383, ISSN: 2320-8694. http://dx.doi.org/10.18006/2016.4(3S).368.383. and Osowe et al. 2021Osowe, C.O., Olowu, O.P.A., Adu, O.A., Oloruntola, O.D. & Chineke, C.A. 2021. "Proximate and mineral composition, phytochemical analysis, and antioxidant activity of fig trees (Ficus spp.) leaf powder". Asian Journal of Biochemistry, Genetics and Molecular Biology, 9(1): 19-29, ISSN: 2582-3698. https://doi.org/10.9734/ajbgmb/2021/v9i130206. ).Además la contribución de PHFE al perfil mineral esencial de los pollos de engorde (Osowe et al. 2021Osowe, C.O., Olowu, O.P.A., Adu, O.A., Oloruntola, O.D. & Chineke, C.A. 2021. "Proximate and mineral composition, phytochemical analysis, and antioxidant activity of fig trees (Ficus spp.) leaf powder". Asian Journal of Biochemistry, Genetics and Molecular Biology, 9(1): 19-29, ISSN: 2582-3698. https://doi.org/10.9734/ajbgmb/2021/v9i130206. ), así como el posible rol complementario del suplemento vitamina C ayudando a la descomposición de aminoácidos y a la absorción de minerales , específicamente el hierro, manteniedolos en un reducido estado ferroso, pudiera ser responsable de un heritrograma mejorado causado por esos suplementos (Yadav et al. 2016Yadav, S.S., Kolluri, G., Gopi, M., Karthik, K., Malik, Y.S. & Dhama, K. 2016. "Exploring alternatives to antibiotics as health-promoting agents in poultry- A review". Journal of Experimental Biology and Agricultural Sciences, 4(3S): 368-383, ISSN: 2320-8694. http://dx.doi.org/10.18006/2016.4(3S).368.383. ). EL conteo de los GR en la raza AB compardo con la raza CO sugiere que las variables genéticas pueden influenciar en el conteo de eritrocitos. Investigaciones anteriores han demostrado que las variables genéticas influyen en los indicadores hematológicos como el VCE, GR,CH, concentración de células de hemoglobina y concentración media de hemoglobina, entre otros (Chineke et al. 2006Chineke, C. A., Ologun, A. G. & Ikeobi, C. O. N. 2006. "Haematological parameters in rabbit breeds and crosses in humid tropics". Pakistan Journal of Biological Sciences, 9(11): 2102-2106, ISSN: 1812-5735. https://doi.org/10.3923/PJBS.2006.2102.2106. and Etim et al. 2014Etim, N. N., Williams, M. E., Akpabio, U. & Offiong, E.A. 2014. "Haematological parameters and factors affecting their values". Agricultural Science, 2(1): 37-47, ISSN: 2690-4799. https://doi.org/10.12735/as.v2i1p37. ). Los valores de VCE, GR y CH en este estudio están todos dentro del rango normal (VCE: 22-35 %, GR: 2.5-3.5 x 106/L, y CH: 7-13 g/dL) reportado por Bounous and Stedman (2000)Bounous, D. & Stedman, N. 2000. Normal avian hematology: chicken and turkey. In: Feldman BF, Zinkl JG, Jain NC, editors. Schalm’s veterinary hematology. New York: Wiley; 2000. p.1147-1154..

La interacción de vitamina C y PHFE produciendo reducción de VCM y HCM indica la presencia de anemia microcitica, la cual es frecuentemente asociada al déficit de hierro. Además, el aumento de los niveles de VCM y HCM en las razas CO indican anemia macrocitica, la cual se define por el excesivo aumento de los glóbulos rojos e implica que los estos son pocos y transportan menos hemoglobina, significando que la sangre no está tan oxigenada como debería (Aslinia et al. 2006Aslinia, F., Mazza, J. J. & Yale, S. H. 2006. "Megaloblastic anemia and other causes of macrocytosis". Clinical Medicine and Research, 4(3): 236-241, ISSN: 1554-6179. https://doi.org/10.3121/cmr.4.3.236. ). Sin embargo, los niveles observados en este estudio están dentro del rango normal (VCM: 90 - 140 fl; HCM: 33-47 pg/cel) como lo reportado por (Bounous and Stedman 2000Bounous, D. & Stedman, N. 2000. Normal avian hematology: chicken and turkey. In: Feldman BF, Zinkl JG, Jain NC, editors. Schalm’s veterinary hematology. New York: Wiley; 2000. p.1147-1154.); por lo tanto los valores elevados de VCM inducidos por las razas o los valores reducidos de VCM producidos por la suplemrntación de vitamina C no deben ser de interés para la salud (Bounous and Stedman 2000Bounous, D. & Stedman, N. 2000. Normal avian hematology: chicken and turkey. In: Feldman BF, Zinkl JG, Jain NC, editors. Schalm’s veterinary hematology. New York: Wiley; 2000. p.1147-1154.).

El cuerpo está protegido por los leucocitos y sus diferenciales desde dañino o infiltración de organismos externos, así como la producción de anticuerpos y dispersión (Oloruntola et al. 2016aOloruntola, O.D., Ayodele, S.O., Agbede, J.O, Oloruntola, D.A, Ogunsipe, M.H. & Omoniyi, I.S. 2016a. "Effect of Alchornea cordifolia leaf meal and enzyme supplementation on growth, haematological, immunostimulatory and serum biochemical response of rabbits". Asian Journal of Biological and Life Sciences, 5(2): 190-195, ISSN: 2278-5957.). Además, algunos fitógenos tienen propiedase inmunomodulatorias (Dashputre and Naikwade 2010Dashputre, N. L., & Naikwade, N. S. 2010. "Preliminary Immunomodulatory activity of aqueous and ethanolic leaves extract of O. basilicum Linn in mice". International Journal of PharmTechn Research, 2(2): 1342-1349, ISSN: 2455-9563. and Oloruntola et al. 2016 aOloruntola, O.D., Ayodele, S.O., Agbede, J.O, Oloruntola, D.A, Ogunsipe, M.H. & Omoniyi, I.S. 2016a. "Effect of Alchornea cordifolia leaf meal and enzyme supplementation on growth, haematological, immunostimulatory and serum biochemical response of rabbits". Asian Journal of Biological and Life Sciences, 5(2): 190-195, ISSN: 2278-5957.,bOloruntola, O.D., Ayodele S.O., Agbede J.O. & Oloruntola, D.A. 2016b. "Effect of feeding broiler chicken with diets containing Alchornea cordifolia leaf meal and enzyme supplementation". Archivos de Zootecnia, 65(252): 489-498, ISSN: 0004-0592.). Esto explica el incremento del conteo de GB como resultado de la suplementación de PHFE, comparado con el control en este estudio. Las propiedades inmunomodulatorias de los fitogénos pueden estar unidas a las sustancias alimenticias como los fitoestrógenos, los cuales, cuando son ingeridos, pueden imitar los efectos de la hormona estrógeno. (Cady et al. 2020Cady, N., Peterson, S.T., Freedman, S.N. & Mangalam, A.K. 2020. "Beyond metabolism: The complex interplay between dietary phytoestrogens, gut bacteria, and cells of nervous and immune systems". Frontier in Neurology, 11: 1-15, ISSN: 1664-2295. https://doi.org/10.3389/fneur.2020.00150. ); el estrógeno controla la respuesta immune eliminando la selección negativa de células B autoreactivas de alta afinidad, influenciando la función de la célula B, y provocando la respuesta de Th2 (Taneja 2018Taneja V. 2018. "Sex Hormones Determine Immune Response". Frontiers in Immunology, 9: 1931, ISSN: 1664-3224. https://doi.org/10.3389/fimmu.2018.01931 ).El incremento del conteo de linfocitos observados en este estudio como resultado de las interacciones (raza x vitamina C x PHFE), suplementación de vitamina C, y suplementación de PHFE realzó el potencial del impacto de la vitamina C (Shojadoost et al. 2021Shojadoost, B., Yitbarek, A., Alizadeh, M., Kulkarni, T. T., Astill, J., Boodhoo, N. & Sharif S. 2021. "Centennial Review: Effects of vitamins A, D, E, and C on the chicken immune system". Poultry Science, 100 (4): 1-17, ISSN: 1525-3171. https://doi.org/10.1016/j.psj.2020.12.027. ), PHFE (Dashputre and Naikwade 2010Dashputre, N. L., & Naikwade, N. S. 2010. "Preliminary Immunomodulatory activity of aqueous and ethanolic leaves extract of O. basilicum Linn in mice". International Journal of PharmTechn Research, 2(2): 1342-1349, ISSN: 2455-9563. and Oloruntola et al. 2016 aOloruntola, O.D., Ayodele, S.O., Agbede, J.O, Oloruntola, D.A, Ogunsipe, M.H. & Omoniyi, I.S. 2016a. "Effect of Alchornea cordifolia leaf meal and enzyme supplementation on growth, haematological, immunostimulatory and serum biochemical response of rabbits". Asian Journal of Biological and Life Sciences, 5(2): 190-195, ISSN: 2278-5957.,bOloruntola, O.D., Ayodele S.O., Agbede J.O. & Oloruntola, D.A. 2016b. "Effect of feeding broiler chicken with diets containing Alchornea cordifolia leaf meal and enzyme supplementation". Archivos de Zootecnia, 65(252): 489-498, ISSN: 0004-0592.) y sus interacciones con el factor raza (Zahoor et al. 2018Zahoor, I., Ghayas, A. & Basheer, A. 2018. "Genetics and genomics of susceptibility and immune response to necrotic enteritis in chicken: a review". Molecular Biology Reports, 45(1) 31-37, ISSN: 1573-4978. http://dx.doi.org/10.1007/s11033-017-4138-8. ) en las condiciones inmunológicas de las aves.Además, el alto conteo de linfocitos en la raza AB comparado con la raza CO en este estudio sugiere una diferencia en la respuesta de la capacidades inmunológicas de las aves y el impacto de la estructura genética en la respuesta inmunológica experimental de las aves (Zahoor et al. 2018Zahoor, I., Ghayas, A. & Basheer, A. 2018. "Genetics and genomics of susceptibility and immune response to necrotic enteritis in chicken: a review". Molecular Biology Reports, 45(1) 31-37, ISSN: 1573-4978. http://dx.doi.org/10.1007/s11033-017-4138-8. ).

La enzima transaminasa, la aspartato aminotransferasa (AST) catalizan la transformación de aspartato y alfa-cetoclutarato en oxalacetato y glutamate.Excepto para los huesos, AST se puede detectar en todos los tejidos, con el mayor contenido en los músculos esqueléticos y el hígado. La concentración de dicha enzima aumenta después de procesos dañinos, daños tisulares, necrosis , neoplasmas, o infecciones del hígado y los músculos (Washington and Van Hoosier, 2012Washington, I. M. & Van Hoosier, G. 2012. Clinical Biochemistry and Hematology. In: The Laboratory rabbit, guinea pig, hamster, and other rodents. Edited by Mark A. Suckow, Karla A. Stevens and Ronald P. Wilson. Academic Press, USA. pp 1247-1268. https://doi.org/10.1016/C2009-0-30495-X. ). Por lo tanto, la reducción de concentración de suero de la AST sérica por la interacción (vitamina C x PHFE) y la concentración de vitamina C en este estudio muestra la propiedades antioxidantes y el papel protector de la vitamina C y los efectos de la interacción de vitamina C con el suplemento fitogénico (PHFE) contra el hígado o los daños musculares. La vitamina C protege a las proteínas de la alquilación mediente los productos de la peroxidación electrófilica lipídica, estress oxidativo inducido por daños celulares de las especies reactivas del oxígeno y vitamina E dependiente de la neutralización los radicales hidroperóxidos de lípidos (Traber and Stevens, 2011Traber, M. G. & Stevens, J. F. 2011. "Vitamins C and E: beneficial effects from a mechanistic perspective". Free Radical Biology and Medicine, 51(5): 1000-1013, ISSN: 1873-4596. https://doi.org/10.1016/j.freeradbiomed.2011.05.017. ). Además, la vitamina C ayuda a las funciones endothelial de óxido nítrico sintetiza (eNOS) a través del reciclaje del cofactor de eNOS de tetrahidrobiocterina, la cual es importante para la elasticidad arterial y el manejo de la presión sanguínea (Miranda et al. 2009Miranda, C. L., Reed, R. L., Kuiper, H.C., Alber, S. & Stevens, J. F. 2009. "Ascorbic acid promotes detoxification and elimination of 4-hydroxy-2(E)-nonenal in human monocytic THP-1 cells". Chemical Research in Toxicology, 22(5): 863-874, ISSN: 1520-5010. https://doi.org/10.1021/tx900042u. , Chavez et al. 2010Chavez, J., Chung, W.G., Miranda, C.L., Singhal, M., Stevens, J.F. & Maier, C.S. 2010. "Site-specific protein adducts of 4-hydroxy-2(E)-nonenal in human THP-1 monocytic cells: protein carbonylation is diminished by ascorbic acid". Chemical Research in Toxicology, 23(1): 37-47, ISSN: 1520-5010. https://doi.org/10.1021/tx9002462. and Traber and Stevens 2011Traber, M. G. & Stevens, J. F. 2011. "Vitamins C and E: beneficial effects from a mechanistic perspective". Free Radical Biology and Medicine, 51(5): 1000-1013, ISSN: 1873-4596. https://doi.org/10.1016/j.freeradbiomed.2011.05.017. ).

La creatinina es un residuo del nitrogéno que no se basa en las proteínas, y sus mediciones pueden ser usadas para evaluar la función renal (Salazar 2014Salazar, J.H. 2014. "Overview of Urea and Creatinine". Laboratory Medicine, 45(1): e19-e20, ISSN: 0007-5027. https://doi.org/10.1309/LM920SBNZPJRJGUT. ). La reducción de la concentración de la creatinina sérica por la suplementación de vitamina C y PHFE registrada en este estudio permite además los beneficios para la salud de la suplementación de la vitamina C y PHFE en preservar las funciones fisiológicas y anátomicas del riñón, lo cual se debe a la propiedades antioxidantes de la vitamina C (Traber and Stevens 2011Traber, M. G. & Stevens, J. F. 2011. "Vitamins C and E: beneficial effects from a mechanistic perspective". Free Radical Biology and Medicine, 51(5): 1000-1013, ISSN: 1873-4596. https://doi.org/10.1016/j.freeradbiomed.2011.05.017. ) y el PHFE (Osowe et al. 2021Osowe, C.O., Olowu, O.P.A., Adu, O.A., Oloruntola, O.D. & Chineke, C.A. 2021. "Proximate and mineral composition, phytochemical analysis, and antioxidant activity of fig trees (Ficus spp.) leaf powder". Asian Journal of Biochemistry, Genetics and Molecular Biology, 9(1): 19-29, ISSN: 2582-3698. https://doi.org/10.9734/ajbgmb/2021/v9i130206. ).

El colesterol sérico se produce en el hígado y es derivado a partir de la dieta. Un nivel alto de colesterol es signo de enfermedades del corazón. Niveles reducidos de colesterol sérico pueden ser causados por dietas bajas en grasas, disminución de ingestión de colesterol, o mala absorción intestinal (Adegbeye et al. 2020 Adegbeye, M.J., Oloruntola, O.D., Asaniyan, E.K., Agunbiade, B., Oisagah, E.A. & Ayodele, S.O 2020. "Pawpaw, black cumin, and mustard seed meal dietary supplementation in broiler chickens: Effect on performance, gut microflora, and gut morphology". Journal of Agricultural Science and Technology, 22(5): 1235-1246, ISSN: 2345-3737. ). En este estudio, las capacidades hipocolesterolemicas de los fitogénos son mostradas por los reducidos niveles de colesterol en sangre de los pollos de engorde después de haber sido alimentados con dietas suplementadas con PHFE. El efecto hipocolesterolémico puede ser debido a los fitosteroles en el PHFE limitando la absorción de colesterol en el intestino debido a la similitud estructural del colesterol y el firosterol(Adegbeye et al. 2020 Adegbeye, M.J., Oloruntola, O.D., Asaniyan, E.K., Agunbiade, B., Oisagah, E.A. & Ayodele, S.O 2020. "Pawpaw, black cumin, and mustard seed meal dietary supplementation in broiler chickens: Effect on performance, gut microflora, and gut morphology". Journal of Agricultural Science and Technology, 22(5): 1235-1246, ISSN: 2345-3737. and Ayodele et al. 2021Ayodele S.O., Oloruntola O.D., Ayeyeye S.A., Jimoh O.A., Falowo A.B. & Omoniyi I.S. 2021. "Supplementation value of Mucuna seed powder on performance, antioxidant enzymes, meat cholesterol and peroxidation, and serum metabolites of broiler chickens". Malaysian Journal of Animal Science, 24(1): 11-22, ISSN: 2550-2123. ). Además, uno de los fitoquímicos en el PHFE, saponinas, es conocido como modulador de los lípidos en sangre (Osowe et al. 2021Osowe, C.O., Olowu, O.P.A., Adu, O.A., Oloruntola, O.D. & Chineke, C.A. 2021. "Proximate and mineral composition, phytochemical analysis, and antioxidant activity of fig trees (Ficus spp.) leaf powder". Asian Journal of Biochemistry, Genetics and Molecular Biology, 9(1): 19-29, ISSN: 2582-3698. https://doi.org/10.9734/ajbgmb/2021/v9i130206. ).

La hemo-concentración, la alta producción de globulina, lipaemia y la hemotolisis son las causas más comunes del elevado total de proteínas séricas. Sim embargo, el incremento del total de proteínas séricas y albumina observado, debido a la suplementación de vitamina C no debe ser patológico porque, el nivel de proteínas séricas total (53.30-69.42 g/L) y el nivel de albumina (23.03-34.05 g/L) registrado en este estudio están dentro del rango normal para proteínas totales (52-69 g/L) y albumina (21 - 34.5 g/L) informado por Mitruka and Rawnsley (1977)Mitruka, B. M. & Rawnsley, H. M 1977. Clinical biochemical and hematological reference values in normal experimental animals. Masson Publishing USA, Inc. pp. 134-139. and Oloruntola et al. (2016a)Oloruntola, O.D., Ayodele, S.O., Agbede, J.O, Oloruntola, D.A, Ogunsipe, M.H. & Omoniyi, I.S. 2016a. "Effect of Alchornea cordifolia leaf meal and enzyme supplementation on growth, haematological, immunostimulatory and serum biochemical response of rabbits". Asian Journal of Biological and Life Sciences, 5(2): 190-195, ISSN: 2278-5957. para pollos. La suplementación de vitamina C aumenta los niveles de proteína en la sangrem(Karakilcik et al. 2004Karakilcik, A. Z., Zerinm. K., Arslanm, B., Nazligul, L. & Vural, F. 2004. "Effects of vitamin C and E on liver enzymes and biochemical parameters of rabbits exposed to aflatoxin B1". Veterinary and Human Toxicology, 46(4): 190-192, ISSN: 0145-6296. and Nayila 2020Nayila, I. 2020. "Effect of Vitamin C supplementation on serum ascorbic acid level and liver function profile in healthy individuals". Asian Journal of Medicine and Health, 18(9): 28-39, ISSN: 2456-8414. https://doi.org/10.9734/ajmah/2020/v18i930235. ). La globulinas son una diversa colección de un gran grupo de proteínas séricas que no incluye la albumina (Odunitan-Wayas et al. 2018Odunitan-Wayas, P., Kolanisi, U., & Chimonyo M. 2018. "Haematological and serum biochemical responses of Ovambo chickens fed Provitamin A Biofortified maize". Brazilian Journal of Poultry Science, 20(3): 425-433, ISSN: 1806-9061 http://dx.doi.org/10.1590/1806-9061-2016-0444. ). Además de las variables antes mencionadas que pueden causar incremento en las proteínas totales, incremento en alfa, beta, y ganma globulina que pueden causar incremento en la glubulina sérica. En consecuencia, el incremeto de la concentración de globulina observado en este estudio debido a la suplementación de PHFE sugiere que los fitógenos incrementan la estimulación de producción de globulina en el suero. Esto concuerda con Ghazalah and Ali (2008)Ghazalah, A. A. & Ali, A.M. 2008. "Rosemary leaves as a dietary supplement for growth in broiler chickens". International Journal of Poultry Science, 7: 234-239, ISSN: 1994-7992 ., quienes registraron incremento en la proteína sérica y la concentración de globulina en pollos de engorde alimentados con 5g/kg de hojas de romero suplemntados en la dieta. Los fitógenos puedes estimular las paredes intestinales, incrementando la secresión de enzimas digestivas así como mejorar la absorción de más nutrients, teniendo como resultado, un mejor perfil de proteínas (Abudabos et al. 2016Abudabos, A.M., Alyemni, A.H., Dafallah, Y.M. & Khan, R.U. 2016. "The effect of phytogenic feed additives to substitute in-feed antibiotics on growth traits and blood biochemical parameters in broiler chicks challenged with Salmonella typhimurium". Environmental Science and Pollution Research, 23: 24151-24157, ISSN: 1614-7499. https://doi.org/10.1007/s11356-016-7665-2. ).

Conclusiones

En conclusión, para lograr una ganancia de peso corporal óptima en pollos de engorde, se recomienda la selección de raza (CO) y la suplementación con 200 mg/kg de vitamina C, especialmente en un ambiente tropical típico. Sin embargo, para una mejor inmunidad e hipocolesterolemia en las aves, está indicada la suplementación dietética con PHFE al 1 %. Como suplemento nutricional, el 1 % de PHFE podría combinarse con 200 mg/kg de vitamina C para mejorar el consumo de alimento, el conteo de glóbulos rojos, el volumen de células concentradas y la concentración de hemoglobina; para prevenir daños en el hígado y los tejidos y proteger las células renales del daño en pollos de engorde.