Introduction
The incorporation of native vegetable protein sources in the formulation of bird’s diets constitutes a necessity for the sustainable development of the poultry industry. Among these sources, Moringa oleifera highlights for its nutritional quality and low content of anti-nutritional factors (Martin et al. 2013).
Savón (2002) reported that, when the recommended fiber levels are exceeded, deleterious effects on nutrients digestibility can occur, due to the limited digestive capacity of birds. Almeida et al. (2016) evaluated the effect of percentages of tree forage meal on digestive indicators of colostomized broilers. However, there is no information available about the effect of the intake of this source on the blood indicators of this species. These indicators are related to the nutritional balance of the rations and show deficiency states or imbalance in the feeding (Campbell 2004).
The objective of this study was to evaluate the effect of moringa forage meal intake on blood indicators of colostomized broilers.
Moringa cv Supergenius plants were sown in June at the Estación Experimental de Pastos y Forrajes “Miguel Sistach Naya”, belonging to the Instituto de Ciencia Animal. To obtain the forage meal, the thickest stems of the plants were removed and dried in the shade to avoid the volatilization of vitamins. Subsequently, they were reduced to a particle size of 3mm in a hammer mill and were stored in 50 kg nylon bags in a cool place until their use. To determine the chemical composition, a sampling of different parts of the bag was made, with the purpose of forming a 100 g sample, which was analyzed in duplicate.
The experimental stage was performed with 24 male broilers (hybrid EB34), from 35 to 65 d of age, with 1.95 kg live weight as average. For the adaptation to the experimental diet, the birds intake the food at will until 47 d. Subsequently, they were colostomized, according to the procedures described by Belay et al. (1993) and were allocated in individual cages for metabolism, with dimensions of 40x40x40 cm. At 55 d, a total of 170 g/animal/d of food were supplied in individual feeders. During the experimental period, they had water ad libitum using automatic nipple drinkers.
The experimental diets for the finishing phase were formulated according to the requirements for this category (NRC 1994).
The dry matter (DM), ash (A), calcium (Ca), phosphorus (Pt) and crude protein (CP) were determined by the techniques described by the AOAC (2012). The neutral detergent fiber (NDF) and acid detergent fiber (ADF), according to van Soest et al. (1991). Table 1 shows the values of these elements.
Table 1.
Chemical composition of moringa forage meal and experimental diets
The birds were slaughtered at 65 d, after 2 h of intake the food. Blood samples from the jugular vein were taken, according to Sánchez (1990) methodology. To determine the hematocrit, the blood was preserved with 2 mg of disodium salt from the ethylenediaminetetraacetic acid (EDTA Na) as anticoagulant. The hematocrit was determined by microcentrifugation at 10,000 r.p.m. for 5 min. The blood sediment was read using a Hawkley microhematocrit reader.
The serum were obtained from blood without anticoagulant, after 3 h of incubation, at 37°C and stored at -20°C until the analysis. The total proteins were calculated by Biuret's colorimetric method at 545 nm. Albumin was quantified by the green bromocresol method in spectrophotometer, at 630 nm (Doumas and Biggs 1976). Total cholesterol was determined by a commercial enzyme kit, Radioisotopes.
A completely randomized design was used, with three treatments and eight repetitions. For the statistical analysis, the computerized statistical program of INFOSTAT (Di Rienzo et al. 2012) was used. The comparison between means was made through the Duncan (1955) test, if necessary.
The hematocrit or agglomerated cell volume is the fraction that red blood cells occupy in the blood volume. It is an indicator that diagnoses anemia. In this study, there were no differences between treatments (table 2). The values remained in the physiological range for the species (30.6 to 37.0 %), according to Haile and Chanie (2014). Total proteins and albumin showed a similar performance. Serum levels coincide with the physiological reference ranges for the species (30.1-50.0 and 11.0-27.4 g/dL, respectively) (Campbell 2004).
Table 2.
Blood indicators in colostomized broilers, which intake moringa forage meal
| Indicators | Moringa forage meal,% | ±SE and Sign | ||
|---|---|---|---|---|
| 0 | 10 | 20 | ||
| Hematocrit,% | 32.95 | 32.8 | 31.70 | 0.6400 P=0.3323 |
| Total proteins, g/dL | 34.9 | 35.5 | 36.4 | 0.2236 P=0.3635 |
| Albumin, g/ dL | 17.7 | 17.9 | 16.7 | 0.0024 P=0.3117 |
Fuentes (2016) evaluated 10% inclusion of moringa foliage meal in the broilers diet and also did not found variation in these indicators. However, Melesse et al. (2013) found that the intake of high levels from the same source increased total proteins in the serum of hens. This response is attributed to the fact that in these birds the metabolism of proteins is more intense.
The achieved results show the nutritional status of birds. In addition, they show that there was no interaction of anti-nutritional factors or deficiency of microelements essential for the synthesis of blood components. Therefore, they reaffirm the nutritional characteristics of the plant, reported by Falowo et al. (2018).
The albumin is synthesized exclusively in the liver, and represents the highest protein fraction of plasma. Therefore, low concentrations of this element are not only associated with nutritional deficiencies, but also with liver and kidney diseases, bad absorption and bad disease states (Moreira 2010). Macroscopically, in this experiment, there were no liver lesions or changes in absolute weight (g) and in relation to live weight (g/kg), indicators that complement the hepatic health of birds, according to Almeida (2015).
Figure 1 shows that the intake of the fibrous source decreased serum cholesterol levels (P <0.05) with respect to the control diet. Among the mechanisms that can explain the hypocholesterolemic action of fiber, is the reduction of bile acid secretion and increased excretion through feces (Elleuch et al. 2011). The presence of lignin and some soluble components (pectins, gums and mucilages) sequestered and eliminated bile salts with feces and consequently, the resorption in the intestinal lumen was reduced. Circulating cholesterol was mobilized to replace the synthesis of bile acids, decreasing the serum concentration. This response corroborates the Botero and Morales (2018) reports.
a,b: columns with different letters differ for P<0.05 (Duncan 1955) SE= ±0.0200 / P=0.0300
Figure 1.
Total cholesterol (mmol/L colostomized broilers which intake moringa forage meal.
The fiber is a heterogeneous fraction, whose components are resistant to the enzymatic activity of the broilers digestive tract (Savón 2015). This property makes it possible to increase intestinal peristalsis and consequently reduce the recycling of cholesterol through the lower ileum. Martínez et al. (2010), when including Morus alba foliage meal in the broilers diet, they found a similar physiological effect to the one previous described.
Bustamante et al. (2015) characterized the same fibrous source and reported that the fibrous content is susceptible to the hydrolysis processes in the digestive tract of these species. This aspect can contribute to the hypocholesteroleminic activity through the fermentation products of soluble fiber that originate in the caecum, mainly propionic acid. This causes the inhibition of the enzyme hydroxymethylglutaryl coenzyme-A reductase and reduces the metabolism of endogenous cholesterol (Anderson et al. 1990).
It is concluded that the moringa forage meal intake did not change the blood indicators of protein profile in the diet of colostomized broilers. However, fiber intake decreased the total cholesterol levels, results that favor beneficial effects on bird health.