Levedura de cana-de-açucar (Saccharomyles cerevisiae) na alimentação de frangos de corte

Abstract

Two experiments were conducted in Federal Rural University of Pernambuco, the first aimed to evaluate the following parameters: animal performance, intestinal morphology and litter quality of broilers fed diets containing sugar cane yeast (Saccharomyces cerevisiae) dried by "spray-dry" method as prebiotic agent. 350 Cobb 500 male broiler chicks were used, divided into 25 plots (five treatments and five replicates) with 14 birds per plot in a randomized design, from 1 to 42 days old, reared on reused litter, with five treatments: diet without yeast and without antimicrobial growth promoter (AGP), diet without yeast and with 0.04% of AGP (based on zinc bacitracin), diet containing 0.5% yeast and without AGP, diet containing 1.0% yeast without AGP and diet with 1.5% yeast and without AGP. The variables evaluated were: feed intake, body weight, weight gain, feed conversion, villous height, litter depth, ammonia production and poultry litter pH. The intestinal morphology parameters were evaluated at 7 days old and the litter quality parameters were evaluated at 21 and 42 days old. There were no treatment effects observed on animal performance over the periods from 01 to 07 days, from 01 to 21 days and from 01 to 35 days. There were no treatment effects observed on parameters of growth performance in periods of one to seven days, from one to 21 days and up to 35 days. In the period of one to 42 days old, only body weight and weight gain were higher in birds fed diet with 1.5% yeast and without AGP, differing from the diet without yeast and without APC. The height of the villi in theduodenum and jejunum was not affected. The crypt depth was higher in birds that did not receive AGP and yeast and lower for those birds that consumed AGP and yeast and only yeast. The litter quality did not provide data that may represent improvements in the comfort of the animals. On the other hand, the second experimental study had the aim to evaluate the animal performance and carcass yield of broilers fed with diets containing different levels of inclusion of sugar cane yeast (Saccharomyces cerevisiae) by dry rolling. 350 Cobb 500 male broiler chicks were used, divided into 25 plots, with 14 birds per plot, from 1 to 42 days old reared on reused litter. Five treatments were used with 0%, 5%, 10%, 15% and 20% of sugar cane yeast inclusion with five replications in an entirely randomized design. Variables analyzed were: feed intake, body weight, weight gain and feed conversion for the periods from one to seven days, from one to 21 days, from one to 35 days and from one to 42 days old. At 42 days ofxv age, two birds per pen were sacrificed for carcass evaluation on the variables of carcass weight and weight of the cuts: breast, thighs and drumsticks, wings and back. The addition of yeast is not recommended in the diets of broiler chickens in the newly hatched, one to seven days of age, because it had a negative impact on the performance of chicks, showing a decreasing linear behavior for body weight and weight gain variables, as well as an increased linear behavior for feed conversion. Over the period from one to 21 days and from one to 35 days, the diet with 20% yeast showed inferior results than those of diet without yeast while the others did not differ. The level of 20% of yeast inclusion did not affect the animal performance and carcass performance of broiler chickens when the entire rearing period (from one to 42 days old) was considered. The yeast did not affect carcass yield of broilers slaughtered at 42 days old.