Nutritional value of rice brans supplemented with phytase determined by different methodologies on birds / Valor nutricional de farelos de arroz suplementados com fitase, determinado por diferentes metodologias com aves

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

Most rations for birds is formulated on the basis of corn and soybean meal, feedstuffs of high cost. But, the use of non-conventional feeds will be able to make them more economical, since they do not affect negatively the performance of those animals. Five metabolism trials were conducted in the Poultry Production Sector of the Animal Science Department of the Universidade Federal de Lavras. The aim was to evaluate the efficiency of the enzyme phytase on the values of energy and the digestibility of nutrients dry matter, crude protein, ether extract, starch and neutral detergent fiber, observed in the ileal digesta, in the excretes of cecectomized roosters and intact chickens, fed with rations based on corn and soybean meal, the whole rice and defatted rice bran by utilizing different methodologies. The trials to evaluate the experimental rations were conducted in a completely randomized design in a 3 x 2 factorial arrangement to evaluate three types of diets (based on corn and soybean meal, of whole and defatted rice bran) with and without addition of phytase. The values of digestibility of the feeds utilized in the ration were calculated by using the replacement methodology of the feeds in the reference ration, their being analyzed in a 2 x 2 factorial arrangement to evaluate 2 feeds (whole and defatted rice bran) with and without addition of the enzyme. The trial where the Sibbald methodology (direct) was utilized to evaluate the pure feedstuffs served for comparisons with the values found in the Sibbald trial (indirect) in which the replacement methodology of the feeds proposed by Matterson et al (1965) was utilized. Six replicates were utilized and the number of birds per experimental unit was according to the trial accomplished. In the surveys of the data of the rations, the parameters which presented, in the analysis of variance, F values significant (P<0.05), the SNK test for comparison of he means was applied. In the analyses of the data of the feeds obtained by the replacement methodology, the F test (P<0.05) was applied for comparisions of the means. Use of the enzyme phytase in the rations formulated with corn and soybean meal, corn and soybean meal containing 30% of whole rice bran, corn and soybean meal containing 30% of defatted rice bran with 0.30% of available phosphorus, improved the digestibility of the nutrients evaluated, in all the methodologies utilized. Increased values of digestibility of nutrients were observed in the rations formulated on the basis of corn and soybean meal. The ileal digestible energy of whole and defatted rice bran, obtained by means of the substitution calculations of the feed in the reference ration, was of 2.587 kcal/kg and of 1.906 kcal/kg of dry matter, respectively. The corrected apparent metabolizable energy of whole and deffated rice bran, obtained by means of the substitution calculations, was of 2.536 kcal/kg and of 1.948 kcal/kg of dry matter, respectively. The corrected true metabolizable energy of the whole and deffated rice bran, obtained with forced feeding by utilizing cecectomized roosters, by means of substitution calculations, was of 3.867 kcal/kg and 2.726 kcal/kg of dry matter, respectively. Whereas, the corrected true metabolizable energies of the feeds ground corn, soybean meal, whole rice bran and defatted rice bran were of 3.636 kcal/kg, 2.955 kcal/kg, 3.619 kcal/kg and 2.599 kcal/kg of dry matter, respectively.

ASSUNTO(S)

arroz rice enzima fytase digestibilidade ave digestibility zootecnia enzyme fitase poultry

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