Digestibilidade dos nutrientes de alimentos volumosos determinada pela técnica dos sacos móveis em eqüinos

Abstract

RESUMO -Objetivou-se estimar a digestibilidade de nutrientes de forrageiras em eqüinos utilizando-se a técnica de sacos de náilon móveis. Foram avaliados alfafa (Medicago sativa), amendoim forrageiro (Arachis pintoi), desmódio (Desmodium ovalifolium), estilosantes (Stylosanthes guianensis), guandu (Cajanus cajan), macrotiloma (Macrotyloma axillare) e capimcoastcross (Cynodon dactylon cv. coastcross). O delineamento foi em blocos inteiramente casualizados com sete alimentos e cinco blocos (animais). Foram utilizados cinco eqüinos mestiços com 17 a 27 anos de idade e peso vivo médio de 350 kg.O ensaio teve duração de 12 dias: três para a adaptação às baias, cinco para inserção gástrica dos sacos através de sonda nasogástrica e quatro de coleta dos sacos nas fezes. No período pré-experimental de 30 dias, os animais foram mantidos em piquetes com dieta composta de 80% de feno de coastcross e 20% de concentrado. Na confecção dos sacos, utilizou-se náilon com porosidade de 45 μ e dimensão de 7,5 × 2 cm. Em cada saco, foram inseridos 510 mg de matéria seca de amostra do alimento.Os coeficientes de digestibilidade dos nutrientes das forragens foram calculados considerando o resíduo obtido no saco. A digestibilidade dos nutrientes do amendoim, estilosantes e macrotiloma foram superiores à da demais forrageiras, com destaque para a digestibilidade da proteína bruta, cujos valores foram de 91,4; 94,9 e 97,0%, respectivamente. O amendoim e macrotiloma apresentaram digestibilidade da fibra em detergente neutro de 72,3 e 65,2% e da fibra em detergente ácido de 70,9 e 59,4%, respectivamente. O amendoim forrageiro, macrotiloma e estilosantes apresentam digestibilidade dos nutrientes satisfatória e têm potencial para o uso em dietas para eqüinos.Palavras-chave: cavalos, digestão, fibra, forragem Nutrient digestibility of forage feed determined using mobile bag technique in horsesABSTRACT -This work was carried out to evaluate the nutrient digestibility of forages using mobile bags technique in horses. The forages were lucerne (Medicago sativa), peanut (Arachis pintoi), desmodio (Desmodium ovalifolium), stylo (Stylosanthes guianensis), pigeon pea (Cajanus cajan), lime-yellow pea (Macrotyloma axillare) and coastcross (Cynodon dactylon cv. coastcross). A randomized block design was used with seven treatments (feeds) and five blocks (horses). Five crossbreed horses were used with age ranging from 17 to 27 years and average weight of 350 kg. The assay lasted 12 days, being three days for adaptation to barns, five days for nasogastric insertion of bags and four days for bags collection in feces.The diet of horses was composed of 80% of coastcross hay and 20% of commercial concentrate. During the pre-experimental period of 30 days, the horses were maintained in paddocks feeding the diet. Nylon cloth had 45μ pore size, and bags presented dimensions of 7,5 × 2 cm with 510 mg of DM of forage sample/bag. The nutrient digestibility of forages were calculated through residues inside the bags. The nutrient digestibility of peanut, stylo and l...

Roughage digestion evaluation in horses with total feces collection and mobile nylon bags

“…The transit time of 23.6 h observed for nylon bags was similar to the described by Silva et al (2009), of 23.3h. Oliveira et al (2003), evaluating the kinetics of passage in horses fed diets with different levels of forage, observed transit time of 27 hours of the solid fase of the digesta in horses fed only forage.…”

“…The mean retention time of the bags was of 52.2 h, higher than the value observed by Silva et al (2009), of 48.6 h, also with bags in horse's digestion studies. The difference on mean retention time values may be related to the difference in the size of the bags.…”

“…The difference on mean retention time values may be related to the difference in the size of the bags. The bags in this study were bigger, with 6.5 × 3.0 cm, and the bags used by Silva et al (2009) measured 7.5 × 2 cm, and this could result in a slower time of passage through the large intestine. Oliveira et al (2007) observed a mean retention time of 47.86 h of digesta in the digestive tract of horses fed mixed diets, and these values are close to the observed in this study.…”

“…Santos et al (2008), evaluating the digestibility of coastcross hay by total feces collection, observed values of digestibility of NDF and gross energy of 47.9% and 45.5% respectively, and these values were similar to the observed in this assay with the mobile nylon bags technique, of 42.5% and 44.9%,. Similarly, Silva et al The digestibility coefficients of forage peanut are below the values mentioned by Silva et al (2009), of 83.7% of dry matter digestibility, 72.2% of NDF digestibility and 70.9% of ADF digestibility, and this variation can be explained by differences in the composition of the feed.…”

“…After the confection of the bags, they were identified, oven-dried (55-60 ºC, 24h) and weighed. In each bag, a sample of 633 mg of each feed, grounded at 1 mm was inserted in a relation of 17 mg DM/cm 2 (Silva et al, 2009). Then, bags were sealed with heat with an automatic sealer (Araújo et al, 1996).…”