Xilanase e probiótico em dietas para frangos de corte

Abstract

Broiler diets are generally composed of ingredients of plant origin, which may have high amounts of non-starch polysaccharides, which are considered antinutritional factors in broiler nutrition. Thus, the use of enzymes and probiotics can ensure greater availability of nutrients of plant origin minimizing the effects of NSP. Two experiments were carried out to study xylanase and probiotic supplementation in diets for broilers. Experiment I was carried at IFAM/Parintins, in an experimental shed, conducted in a completely randomized design with four treatments, with six replications of seven birds each. For the composition of the treatments, Colostrum Mix commercial products were used for the probiotic source and Smyzime Xylanase for the enzymatic source, and the enzyme was valued at 150 kcal/kg of feed. The treatments consisted of: reference diet; reference diet with probiotic addition; basal diet with xylanase addition and basal diet with xylanase addition and probiotic. The reference diet met all the nutritional requirements of the chickens, while the basal diet was formulated with 150 kcal/kg less metabolizable energy. Performance, carcass characteristics and intestinal viscosity were evaluated. Experiment II was performed in metal cages at UFAM/Manaus, conducted in a design and with treatments similar to that described above, and all diets were supplemented with wheat bran and birds challenged orally with commercial Eimeria vaccine administered 10x above recommendation. Performance, carcass, intestinal viscosity and pH and ileal microbiota were evaluated. In experiment I, the treatments influenced weight gain and feed intake, in which the isolated or combined supplementation of the additives did not differ, but led to greater gains in relation to the diet without supplementation from 1 to 35 days of age. Intestinal viscosity was significantly lower in treatment with xylanase alone (1.01 cP). In experiment II, from 10 to 35 days of age, isolated xylanase and probiotic bedding provided greater weight gain. The reference treatment presented higher viscosity in duodenum (1.42 cP) and ileum (1.21 cP), and higher duodenal pH value (6.54), with the probiotic diet resulting in lower pH value in the cecum (6 , 11). The ileal microbiota was influenced by the treatments, in which broilers fed the diet containing probiotic alone presented higher frequency of the genera Lactobacillus (94.20%). Xylanase and probiotic supplementation provided improvements in animal performance, intestinal viscosity and modulated the ileal microbiota. Combined feed additives in feed provided similar improvements to the isolated feed, so they had no associative effects.