In the world, swine population has had a sustained growth in recent years, due to the fast development of technology for production, nutrition and genetic improvement, so it constitutes a source of food and economic income for population (FAO 2020FAO. 2020. Cerdos y la nutrición humana. Available: <http://www.fao.org/ag/AGAinfo/themes/es/pigs/HH_nutrition.html>.). However, pig feeding represents around 70% of production cost. Hence, the importance of seeking alternative sources to mitigate costs in pig production (Castro and Martínez 2015Castro, M. & Martínez, M. 2015. "La alimentación porcina con productos no tradicionales: cincuenta años de investigaciones en el Instituto de Ciencia Animal". Cuban Journal of Agricultural Science, 49(2): 189-196, ISSN: 2079-3480.).
In Ecuador, there is a wide range of agricultural and agro-industrial by-products, viable for pig feeding. These include distillery residues (vinasses), tubers and taro foliage. In Pastaza province, for example, vinasses does not receive an adequate treatment. This residue is eliminated in water sources, which generates harmful effects for the environment, such as eutrophication and pollution of rivers (Zuñiga and Gandini 2013Zuñiga, V. & Gandini, M. 2013. "Caracterización ambiental de las vinazas de residuos de caña de azúcar resultantes de la producción de etanol". DYNA, 80(177): 124-131, ISSN: 2346-2183. ). Tubers and taro foliage, when supplied in natural state, cause irritation and a burning sensation in the mouth and throat of animals, which is explained by the high content of calcium oxalate crystals (Hang et al. 2011Hang, D.T., Binh, L.V., Preston, T.R. & Savage, G.P. 2011. "Oxalate content of different taro cultivars grown in central Viet Nam and the effect of simple processing methods on the oxalate concentration of the processed forages". Livestock Research for Rural Development, 23(6), Available: <http://www.lrrd.org/lrrd23/6/hang23122.htm>.).
Nowadays, several researches are carried out with alternative foods, such as silages, which show favorable results in the productive performance and health of animals (Lezcano et al. 2017Lezcano, P., Martínez, M., Vázquez, A. & Pérez, O. 2017. "Main methods of processing and preserving alternative feeds in tropical areas. Cuban experience". Cuban Journal of Agricultural Science, 51(1): 1-10, ISSN: 2079-3480.). Tubers and foliage of taro provide nutrients that favor growth of yeasts and lactic bacteria (Caicedo et al. 2015Caicedo, W., Rodríguez, R., Lezcano, P., Ly, J., Valle, S., Flores, L. & Ferreira, F.N.A. 2015. "Chemical composition and in vitro digestibility of silages of taro (Colocasia esculenta (L.) Schott) tubers for feeding pigs". Cuban Journal of Agricultural Science, 49(1): 59-64, ISSN: 2079-3480), and vinasses help to quickly reduce the pH of raw material until stabilizing it, so a good quality fermented product is achieved for its use in pig feeding (Lezcano et al. 2014Lezcano, P., Berto, D.A., Bicudo, S.J., Curcelli, F., González, P. & Valdivié, M. 2014. "Yuca ensilada como fuente de energía para cerdos en crecimiento". Avances en Investigación Agropecuaria, 18(3): 41-48, ISSN: 0188-7890, Available: <http://hdl.handle.net/11449/137082>.).
Therefore, the objective of this study was to determine the chemical composition of a silage of taro tubers and foliage (Colocasia esculenta L. Schott) and its effect on productive indicators of rearing pigs.
Location. This research was carried out at the Bromatology Laboratory of the Universidad Estatal Amazónica (UEA), Puyo main campus, and at Buena Esperanza pig farm, located in San José parish, Santa Clara canton. The study area has a semi-warm or humid subtropical climate, with rainfall between 4,000 and 5,000 mm per year. It is located at an altitude between 500 to 900 meters above sea level, with relative humidity of 87% and mean minimum and maximum temperature between 18 and 36 ºC (INAMHI 2014INAMHI. Instituto Nacional de Meteorología e Hidrología. 2014. Anuario Meteorológico. Quito, Ecuador, p. 28, Available: <http://www.serviciometeorologico.gob.ec/wp-content/uploads/anuarios/meteorologicos/Am%202011.pdf>. and Uvidia et al. 2014Uvidia, H., Buestán, D., Leonard, I. & Benítez, D. 2014. "La distancia de siembra y el número de estacas en el establecimiento del Pennisetum purpureum". REDVET Revista Electrónica de Veterinaria, 15(7): 1-8, ISSN 1695-7504.).
Preparation of the silage of tubers and taro foliage. Waste taro tubers and foliage came from San José parish, in Santa Clara canton. Once collected at Buena Esperanza pig farm, they were washed and drained for one hour, and then cut into a hammer mill, with a 2 cm sieve. Subsequently, homogeneous mixing was carried out for 5 minutes, at room temperature, on plastic and on a concrete floor under roof, with the ingredients that silage was composed of (table 1). Raw materials were placed as follows: 1) chopped tubers, 2) chopped foliage, 3) wheat powder, 4) sugar cane molasses, 5) vitaminized pecutrin, 6) calcium carbonate and 7) sugar cane vinasse. A part of this mixture was placed in five microsilos, with a capacity for 1 kg, and the rest was packed in black hermetic bags, of 50 kg. Food was kept indoors, protected from sunlight, for seven days before use.
1Each kg contains: calcium 17 to 20%, phosphorus 18%, NaCl 0.5 to 1%, magnesium 3.0%, biotin 50 mg, zinc 8,000 mg, manganese 1,500 mg, iron 500 mg, copper 2,000 mg, iodine 160 mg, cobalt 30 mg, selenium 70 mg, vitamin A 300,000 IU, vitamin D3 50,000 IU, vitamin E 100 IU, calcium-phosphorus ratio 1.3: 1, zinc-copper ratio 4: 1
Chemical analysis of the silage. Nutrient determination was conducted in the UEA bromatology laboratory. Verification of temperature and pH was carried out in five microsilos, on day seven of fermentation, according to procedures of Cherney and Cherney (2003)Cherney, J.H. & Cherney, D.J.R. 2003. Assessing silage quality. In: Silage Science and Technology. Buxton, D.R., Muck, R.E. & Harrison, J.H (eds). American Society of Agronomy, Inc., Crop Science Society of America, Inc., Soil Science Society of America, Inc., Madison, Wisconsin, USA, p. 141-198, ISBN: 9780891182344. and Caicedo (2013)Caicedo, W. 2013. Potencial nutritivo del ensilado de tubérculos de papa china (Colocasia esculenta (L.) Schott) para la alimentación de cerdos. MSc. Thesis. Universidad de Granma, Bayamo, Granma, Cuba, p. 60. Dry matter (DM), crude fiber (CF), ash, crude protein (CP), ether extract (EE) and nitrogen-free extract (NFE) were determined according to AOAC (2005)AOAC (Official Method of Analysis: Association of Official Analytical Chemists). 2005. 18th Ed. Ed. Association of Official Analytical Chemists, Inc. Gaithersburg MD, USA, ISBN: 978-0-935584-87-5.. Organic matter (OM) was the result of subtracting ash percent from 100. Gross energy (GE) was determined by calorimetry, with an adiabatic pump (Parr brand, model 1241). Analyzes were conducted by triplicate for each nutrient.
Animal management and facilities. Pigs were managed according to Animal Welfare regulations of the Republic of Ecuador (AGROCALIDAD 2017AGROCALIDAD (Agencia Ecuatoriana de Aseguramiento de la Calidad del Agro). 2017. Manual de aplicabilidad de buenas prácticas porcícolas. Quito, Ecuador, p. 127, Available: <http://www.agrocalidad.gob.ec/wp-content/uploads/pdf/Guia-BPA-publicaciones/2017/enero/manual-buenas-practicas-porcicolas-24-01-2017.pdf >.) and the experimental protocol, according to Sakomura and Rostagno (2007)Sakomura, N. & Rostagno, H. 2007. Métodos de pesquisa em nutrição de monogástricos. Jaboticabal: Funep, p. 283, ISBN: 978-85-87632-97-5.. For this study, 16 commercial crossbreed (Landrace x Belgian White) castrated male animals, of 45 days old and with an initial mean weight of 12 ± 2 kg were used. Each pig constituted an experimental unit. Animals were placed in individual cages, 1.0 mx 1.40 m (1.40 m2), equipped with a hanging cone feeder and a nipple drinker, located in a warehouse with 1-meter-high walls, concrete floor with rice husk of 20 cm and curtains to regulate the temperature. Water was available at will. Average ambient temperature in the facility was 24 ° C.
Food management. Treatments consisted of two diets: a control T0 (corn and protein concentrate) and T30 (inclusion of 30% of silage in the diet). Diets were formulated according to NRC (2012)NRC (National Research Council). 2012. Nutrient Requirements of Swine. 11th Ed. Ed. National Academies Press, Washington D.C., USA, p. 400, ISBN: 978-0-309-22423-9 procedures for rearing pigs (table 2). Intake was adjusted according to live weight of pigs (Rostagno et al. 2011Rostagno, H.S., Teixeira, L.F., Donzele, L.J., Gomes, P.C., Oliveira, Rita., Lopes, D.C., Ferreira, A.S., Toledo, S.L. & Euclides, R.F. 2011. Tablas Brasileñas para Aves y Cerdos. Composición de Alimentos y Requerimientos Nutricionales. 3rd Ed. Ed. Departamento de Zootecnia Universidad Federal de Viçosa, Viçosa, Brasil, p. 167.). Food was provided twice a day in equal parts (8:00 a.m. and 3:00 p.m.).
1Ingredients: soybean paste, rice co-products, wheat, corn DDGS , wheat co-products, palm oil, bakery co-products, sugar cane molasses, calcium carbonate, sodium chloride, L-lysine 78%, dicalcium phosphate, propionic acid at 50%, sodium aluminosilicate, DL-methionine 99% and L-threonine 98%.
Nutrient contribution: protein 35%, fat 4%, fiber 5%, ash 7%, humidity 13%, lysine 0.92% and methionine 0.27%.
2Vitamin and mineral premix (vit A 2’300,000 IU, vit D3 466,667 IU, vit E - 5,000 IU, vit K3 667 mg, vit B1 333 mg; vit B2 1,000 mg, vit B6 400 mg, vit B12 4,000 μg, folic acid 67 mg, niacin 6,660 mg, pantothenic acid 4,000 mg, biotin 17 mg, choline 43 g, iron 26,667 mg, copper 41,667 mg, cobalt 183 mg, manganese 16,667 mg, zinc 26,667 mg, selenium 67 mg, iodine 267 mg, antioxidant 27 g, vehicle qsf 1,000 g).
3Calculated according to NRC (2012)NRC (National Research Council). 2012. Nutrient Requirements of Swine. 11th Ed. Ed. National Academies Press, Washington D.C., USA, p. 400, ISBN: 978-0-309-22423-9 and/or determined
Evaluation of productive indicators. After selecting animals for the experiment, they were dewormed with granulated Fenbendazole, at a rate of 10 g 100 kg LW-1. Pigs were individually weighed, every 7 days, with a 200 kg capacity Cardinal brand scale. Daily food intake (DFI), daily weight gain (DWG), food conversion (FC) and final weight (FW) were verified, according to Flores et al. (2015)Flores, L., Elías, A., Proaño, F., Granizo, G., Medina, Y., López, S., Herrera, F. & Caicedo, W. 2015. "Effects of a microbial preparation, a probiotic and commercial antibiotic on the productive performance and pig’s health in post-weaning period". Cuban Journal of Agricultural Science, 49(3): 357-365, ISSN: 2079-3480..
Experimental design. To examine the chemical composition data of silage (DM, OM, CP, CF, EE, ash, NFE and GE), descriptive statistics was used and, mean, standard deviation and coefficient of variation were determined. Results of productive indicators (DFI, DWG, FC and FW) were processed by the analysis of variance (Steel et al. 1997Steel, R.G.D., Torrie, J.H. & Dickey, M. 1997. Principles and Procedures of Statistics. A Biometrical Approach. 3rd Ed. Ed. MacGraw-Hill Book Company Inc. New York, USA, p. 666, ISBN: 978-0-07-061028-6.), according to a completely randomized design. Means were compared using Fisher (1954)Fisher, R.A. 1954. Statistical Methods for Research Workers. 12th Ed. Oliver and Boyd (eds.), Edinburgh, England, ISBN: 0-05-002170-2. test (P<0.05). All analyzes were performed with Infostat statistical program (Di Rienzo et al. 2017Di Rienzo, J.A., Casanoves, F., Balzarini, M.G., González, L., Tablada, M. & Robledo, C.W. 2012. InfoStat. version 2012, [Windows], Universidad Nacional de Córdoba, Argentina: Grupo InfoStat. Available: http://www.infostat.com.ar.).
Chemical composition of silage of taro tubers and foliage. On the seventh day of production, silage showed an adequate performance of pH and temperature, as well as an appreciable content of DM, CP, NFE, GE and low levels of CF, ash and EE (table 3).
Values of pH, temperature and DM of silage are within the established range for the production of good quality silages. The pH is a very important indicator for silage production, and must be kept at values between 3.8 and 4.5 to achieve good stability and food preservation for a long time (López et al. 2013López, T., Prado-Barragán, A., Nevárez-Moorillón, G.V., Contreras, J.C., Rodríguez, R. & Aguilar, C.N. 2013. "Incremento de la capacidad antioxidante de extractos de pulpa de café por fermentación láctica en medio sólido". CyTA-Journal of Food, 11(4): 359-365, ISSN: 1947-6337, DOI: https://doi.org/10.1080/19476337.2013.773563., Borreani et al. 2017Borreani, G., Tabacco, E., Schmidt, R., Holmes, B. & Muck, R. 2017. "Silage review: Factors affecting dry matter and quality losses in silages". Journal of Dairy Science, 101(5): 3952-3979, ISSN: 0022-0302, DOI: https://doi.org/10.3168/jds.2017-13837. and Caicedo et al. 2019Caicedo, W., Moya, C., Tapuy, A., Caicedo, M. & Pérez, M. 2019. "Composición química y digestibilidad aparente de tubérculos de taro procesados por fermentación en estado sólido (FES) en cerdos de crecimiento". Revista de Investigaciones Veterinarias del Perú, 30(2): 580-589, ISSN: 1682-3419, DOI: https://doi.org/10.15381/rivep.v30i2.16078.). Low pH inhibits the development of ensiled raw material decomposing microorganisms (Caicedo et al. 2016Caicedo, W., Rodríguez, R., Lezcano, P., Ly, J., Valle, S., Flores, L. & Ferreira, F. 2016. "Physicochemical and biological indicators in silages of taro (Colocasia esculenta (L.) Schott) tubers for animal feeding". Cuban Journal of Agricultural Science, 50(1): 121-129, ISSN: 2079-3480. and Wang et al. 2017Wang, S., Yuan, X., Dong, Z., Li, J. & Shao, T. 2017. "Isolating and evaluating lactic acid bacteria strains for effectiveness on silage quality at low temperatures on the Tibetan plateau". Animal Science Journal, 88(11): 1722-1729, ISSN: 1740-0929, DOI: https://doi.org/10.1111/asj.12852.).
Optimal temperature for silage preservation depends on the microorganisms that develop during the process. In general, optimal range for growth of lactic bacteria and yeasts is between 20 and 30 °C (Castillo and Barrera 2013Castillo, C.Y. & Barrera, R.O. 2013. "Fermentación en estado sólido FES de subproductos agroindustriales como alternativa para obtener alimento animal". Memorias 1er Congreso Internacional AGROMERCA. Ciudad Juárez, Chihuahua. México, p. 85. and Granados-Marín et al. 2014Granados-Marín, C., Ching-Jones, R. & Rojas-Bourrillón, A. 2014. "Ensilaje de pasto estrella africana (Cynodon nlemfuensis) con la adición de melaza, suero de leche e inóculos microbiales". UNED Research Journal, 6(1): 47-56, ISSN: 1659-4266, DOI: https://doi.org/10.22458/urj.v6i1.316.). However, temperatures below 10 °C or above 37 °C affect the fermentation process, leading to poor quality silages with low aerobic stability (Bernardes et al. 2018Bernardes, T.F., Daniel, J.L.P., Adesogan, A.T., McAllister, T.A., Drouin, P., Nussio, L.A., Huhtanen, P., Tremblay, G.F., Bélanger, G. & Cai, Y. 2018. "Silage review: Unique challenges of silages made in hot and cold regions". Journal of Dairy Science, 101(5): 4001-4019, ISSN: 0022-0302, DOI: https://doi.org/10.3168/jds.2017-13703. and Zhou et al. 2019Zhou, Y., Drouin, P. & Lafrenière, C. 2019. "Effects on microbial diversity of fermentation temperature (10 °C and 20 °C), long-term storage (5 °C), and subsequent warming on corn silage". Asian-Australasian Journal of Animal Science, 32(10): 1528-153, ISSN: 1976-5517, DOI: https://doi.org/10.5713/ajas.18.0792.).
Regarding DM content, Tomich et al. (2003)Tomich, T.R., Gonçalves, L.C., Maurício, R.M., Pereira, L.G. & Rodrigues, J.A. 2003. "Composição bromatológica e cinética de fermentação ruminal de híbridos de sorgo com capim-sudão". Arquivo Brasileiro de Medicina Veterinária e Zootecnia, 55(6): 747-755, ISSN: 1678-4162, DOI: https://doi.org/10.1590/S0102-09352003000600012. and Nkosi et al. (2016)Nkosi, B.D., Meeske, R., Langa, T., Motiang, M.D., Modiba, S., Mutavhatsindi, T.F., Malebana, I.M. & Groenewald, I.B. 2016. "Effects of bacterial inoculation on the fermentation characteristics and aerobic stability of ensiled whole plant soybeans (Glycine max (L) Merr)". South African Journal of Animal Science, 46(2): 129-138, ISSN: 2221-4062, DOI: https://doi.org/10.4314/sajas.v46i2.3. reported that a good quality silage must contain a DM percentage superior to 30%, in order to limit the development of putrefactive microorganisms in the feed. In this study, DM content is within that range. When low DM raw materials are ensiled, with values lower than 20%, it is necessary to include drying material to guarantee a good conservation of the product (Borrás-Sandoval et al. 2017Borrás-Sandoval, L., Valiño, E. & Elias, A. 2017. "Evaluación del efecto de la inclusión de materiales fibrosos en la fermentación en estado sólido de residuos poscosecha de papa (Solanum tuberosum) inoculado con preparado microbial". REDVET Revista Electrónica de Veterinaria, 18(8): 1-16, ISSN 1695-7504.).
CP concentration of silage was improved with respect to the tuber in natural state (8.48%) (Caicedo 2015Caicedo, W. 2015. Valoración nutritiva del ensilado de tubérculos de papa china (Colocasia esculenta (L.) Schott) y su uso en la alimentación de cerdos en crecimiento ceba. PhD Thesis. Universidad de Granma, Bayamo, Granma, Cuba, p. 100). This may be due to the inclusion of foliage (Buntha et al. 2008Buntha, P., Borin, K., Preston, T.R. & Ogle, B. 2008. "Digestibility and nitrogen balance studies in pigs fed diets with ensiled taro (Colocasia esculenta) leaves as replacement for fish mea"l. Livestock Research for Rural Development, 20(Supplement), ISSN: 0121-3784, Available: <http://www.lrrd.org/lrrd20/supplement/bunt2.htm>.), as well as the presence of microbial protein, developed during the fermentation process (Gutiérrez and Gómez 2008Gutiérrez, L. & Gómez, A. 2008. "Determinación de proteína total de Candida utilis y Sacharomyces cerevisiae en bagazo de caña". Revista Lasallista de Investigación, 5(1): 61-64, ISSN: 1794-444., Ritala et al. 2017Ritala, A., Häkkinen, S.T., Toivari, M. & Wiebe, M.G. 2017. "Single Cell Protein-State-of-the-Art, Industrial Landscape and Patents 2001-2016". Frontiers in Microbiology, 8: 2009, ISSN: 1664-302X, DOI: https://doi.org/10.3389/fmicb.2017.02009. and Caicedo et al. 2019Caicedo, W., Moya, C., Tapuy, A., Caicedo, M. & Pérez, M. 2019. "Composición química y digestibilidad aparente de tubérculos de taro procesados por fermentación en estado sólido (FES) en cerdos de crecimiento". Revista de Investigaciones Veterinarias del Perú, 30(2): 580-589, ISSN: 1682-3419, DOI: https://doi.org/10.15381/rivep.v30i2.16078.).
The silage demonstrated low concentrations of EE, CF and ash. These results are similar to those reported by Himeda et al. (2012)Himeda, M., Njintang, Y.N., Gaiani, C., Nguimbou, R.M., Scher, J., Facho, B. & Mbofung, C.M.F. 2012. "Physicochemical, rheological and thermal properties of taro (Colocassia esculenta) starch harvested at different maturity stages". International Journal of Biosciences, 2(3): 14-27, ISSN: 2222-5234. and Caicedo (2015)Caicedo, W., Rodríguez, R., Lezcano, P., Ly, J., Valle, S., Flores, L. & Ferreira, F.N.A. 2015. "Chemical composition and in vitro digestibility of silages of taro (Colocasia esculenta (L.) Schott) tubers for feeding pigs". Cuban Journal of Agricultural Science, 49(1): 59-64, ISSN: 2079-3480 for taro varieties in their natural state. It should be noted that EE and CF values of silage are within the range allowed for their use in pigs during rearing stage (Bertechini 2013Bertechini, A.G. 2013. Nutrição de monogástricos. 2da Edição Revisada. Ed. UFLA, Lavras, Minas Gerais, Brasil, p. 373, ISBN: 978-85-8127-016-6. and Aragadvay et al. 2016Aragadvay, R., Núñez, O., Velástegui, G., Villacís, L. & Guerrero, J. 2016. "Uso de harina de Colocasia esculenta L. en la alimentación de cerdos y su efecto sobre parámetros productivos". Journal of the Selva Andina Animal Science, 3(2): 98-104, ISSN: 2311-2581. ).
Silage had a high content of NFE and GE, which is explained by the concentration of carbohydrates in the tuber (Caicedo 2015Caicedo, W. 2015. Valoración nutritiva del ensilado de tubérculos de papa china (Colocasia esculenta (L.) Schott) y su uso en la alimentación de cerdos en crecimiento ceba. PhD Thesis. Universidad de Granma, Bayamo, Granma, Cuba, p. 100). For this reason, this food is recommended as an excellent energy source for humans and animals (Ogunlakin et al. 2012Ogunlakin, G.O., Oke, M.O., Babarinde, G.O. & Olatunbosun, D.G. 2012. "Effect of drying methods on proximate composition and physic-chemical properties of cocoyam flour". American Journal of Food Technology, 7(4): 245-250, ISSN: 1557-458X, DOI: https://doi.org/10.3923/ajft.2012.245.250. and Caicedo 2015Caicedo, W. 2015. Valoración nutritiva del ensilado de tubérculos de papa china (Colocasia esculenta (L.) Schott) y su uso en la alimentación de cerdos en crecimiento ceba. PhD Thesis. Universidad de Granma, Bayamo, Granma, Cuba, p. 100).
Productive indicators of rearing pigs, fed silage of taro tubers and foliage. During the study, there were no diarrhea or animal deaths. There was also no effect (P> 0.05) among treatments for the studied indicators: DFI, DWG, FC and FW (table 4). These results coincide with previous research, developed in pigs that were fed taro tuber silage (Caicedo et al. 2019Caicedo, W., Moya, C., Tapuy, A., Caicedo, M. & Pérez, M. 2019. "Composición química y digestibilidad aparente de tubérculos de taro procesados por fermentación en estado sólido (FES) en cerdos de crecimiento". Revista de Investigaciones Veterinarias del Perú, 30(2): 580-589, ISSN: 1682-3419, DOI: https://doi.org/10.15381/rivep.v30i2.16078.). The optimal productive performance of animals fed the alternative diet is related to fermentation process.
DFI: daily food intake, DWG: daily weight gain, FC: food conversion, FW: final weight, SE: standard error
This technique leads to improvements of antioxidant phenolic compounds of raw material, product of microorganisms that develop in this medium through the metabolic route, due to extracellular enzymatic action (Gunawan et al. 2015Gunawan, S., Widjaja, T., Zullaikah, S., Ernawati, L., Istianah, N., Aparamarta, H.W. & Prasetyoko, D. 2015. "Effect of fermenting cassava with Lactobacillus plantarum, Saccharomyces cereviseae, and Rhizopus oryzae on the chemical composition of their flour". International Food Research Journal, 22(3): 1280-1287, ISSN: 2231-7546., Dey et al. 2016Dey, T.B., Chakraborty, S., Jain, K.K., Sharma, A. & Kuhad, R.C. 2016. "Antioxidant phenolics and their microbial production by submerged and solid state fermentation process: A review". Trends in Food Science & Technology, 53: 60-74, ISSN: 0924-2244, DOI: https://doi.org/10.1016/j.tifs.2016.04.007. and Aruna et al. 2017Aruna, T.E., Aworh, O.C., Raji, A.O. & Olagunju, A.I. 2017. "Protein enrichment of yam peels by fermentation with Saccharomyces cerevisiae (BY4743)". Annals of Agricultural Science, 62(1): 33-37, ISSN: 0570-1783, DOI: https://doi.org/10.1016/j.aoas.2017.01.002.). Antioxidant peptides produced by microorganisms are successfully used in the food industry to formulate functional foods (He et al. 2012He, R., Ju, X., Yuan, J., Wang, L., Girgih, A.T. & Aluko, R.E. 2012. "Antioxidant activities of rapeseed peptides produced by solid state fermentation". Food Research International, 49(1): 432-438, ISSN: 0963-9969, DOI: https://doi.org/10.1016/j.foodres.2012.08.023.). In fact, bioactive components can modulate the immune system in the animal (Ricci et al. 2010Ricci, I., Artacho, R. & Olalla, M. 2010. "Milk protein peptides with angiotens in I- converting enzyme inhibitory (ACEI) activity". Critical Reviews in Food Science and Nutrition, 50(5): 390-402, ISSN: 1549-7852, DOI: https://doi.org/10.1080/10408390802304198.). Anyasi et al. (2018)Anyasi, T.A., Jideani, A.I.O. & Mchau, G.R.A. 2018. "Phenolics and essential mineral profile of organic acid pretreated unripe banana flour". Food Research International, 104: 100-109, ISSN: 0963-9969, DOI: https://doi.org/10.1016/j.foodres.2017.09.063. and Mahloko et al. (2019)Mahloko, L.M., Silungwe, H., Mashau, M.E. & Kgatla, T.E. 2019. "Bioactive compounds, antioxidant activity and physical characteristics of wheat-prickly pear and banana biscuits". Heliyon, 5(10): e02479, ISSN: 2405-8440, DOI: https://doi.org/10.1016/j.heliyon.2019.e02479. point out that health benefits, derived from compounds of an antioxidant nature, occur in symbiosis with the intestinal microbiota, which metabolizes and releases them for their use. In addition, the beneficial microbiota developed in the silage could act as a probiotic, limiting the growth of pathogenic microorganisms and guaranteeing intestinal health of animals, in addition to participating in protein and vitamin synthesis and improving food digestibility (Yang et al. 2015Yang, F., Hou, C., Zeng, X. & Qiao, S. 2015. "The Use of Lactic Acid Bacteria as a Probiotic in Swine Diets". Pathogens, 4(1): 34-45, ISSN: 2076-0817, DOI: https://doi.org/10.3390/pathogens4010034., Chandrasekara and Kumar 2016Chandrasekara, A. & Kumar, T.J. 2016. "Roots and Tuber Crops as Functional Foods: A Review on Phytochemical Constituents and Their Potential Health Benefits". International Journal of Food Science, ID3631647: 1-15, ISSN: 2314-5765, DOI: https://doi.org/10.1155/2016/3631647. and Liao and Nyachoti 2017Liao, S.F. & Nyachoti, M. 2017. "Using probiotics to improve swine gut health and nutrient utilization". Animal Nutrition, 3(4): 331-343, ISSN: 2405-6545, DOI: https://doi.org/10.1016/j.aninu.2017.06.007.).
In roots and tubers, the mixture of small granules and low content of highly soluble dietary fiber promotes its use as an excellent source of carbohydrates for special extruded products, such as weaning diets (Vargas and Hernández 2013Vargas, P. & Hernández, D. 2013. "Harinas y almidones de yuca, ñame, camote y ñampí: propiedades funcionales y posibles aplicaciones en la industria alimentaria". Tecnología en Marcha, 26(1): 37-45, ISSN: 2215-3241.). These, due to their significant contribution to intestinal integrity, allow an adequate nutrient absorption, without affecting weight gain (Pérez-Balladares et al. 2019Pérez-Balladares, D., Castañeda-Terán, M., Granda-Albuja, M.G., Tejera, E., Iturralde, G., Granda-Albuja, S., Jaramillo-Vivanco, T., Giampieri, F., Battino, M. & Alvarez-Suarez, J. 2019. "Chemical Composition and Antioxidant Activity of the Main Fruits, Tubers and Legumes Traditionally Consumed in the Andean Regions of Ecuador as a Source of Health-Promoting Compounds". Plant Foods for Human Nutrition, 74(3): 350-357, ISSN: 1573-9104, DOI: https://doi.org/10.1007/s11130-019-00744-8. and Rinaldo 2020Rinaldo, D. 2020. "Carbohydrate and bioactive compounds composition of starchy tropical fruits and tubers, in relation to pre and postharvest conditions: A review". Journal of Food Science, 85(2): 249-259, ISSN: 1750-3841, DOI: https://doi.org/10.1111/1750-3841.15002.).