Produção de proteína microbiana em cordeiros Santa Inês alimentados com resíduo de cervejaria desidratado

Abstract

The objective of this work was to estimate the microbial protein synthesis through urinary excretion of purine derivatives in Santa Ines sheep fed with dehydrated brewery residue (RCD) in the proportions of 0, 20, 40, 60 and 80% of inclusion in the concentrated portion of the feed. The experiment was conducted in the Animal Digestibility sector of the Departament of Animal Science of the Federal University of Ceara, using 35 lambs of the Santa Ines breed, with mean body weight of approximately 16.00, ± 1.69kg, approximately 70 days of age, evaluated in a completely randomized design with five experimental rations and seven replications. Urine specimens were obtained from the lambs using the spot collection technique. The duration of the experiment was determined by the time required for the mean body weight of the animals of one treatment to reach 28 kg, at which time all experimental animals were slaughtered. A linear decreasing effect (P<0,05) was observed for total creatinine excretions, expressed as mg/kg PC/dia and mg/kg PC0,75. The daily excretion of purine derivatives, expressed in mmol/day, had a linear decreasing effect (P<0,05) for the allantoin and total purine variables. However, for the uric acid variable, there was no interference of inclusion levels of dehydrated brewery residue (P>0,05). The variable xanthine + hypoxhantine showed quadratic effect (P<0,05), with lower value for the excretion of the purine derivative with the inclusion of the byproduct in the diet. The daily absorption of microbial purines, expressed in mmol/day, showed a linear decreasing effect (P<0,05) as RCD was added to the diet. The same behavior was observed for the synthesis of microbial compounds in the rumen, expressed in g/day. The percentage of daily excretion for the variables allantoin and daily purine absorption presented a linear decreasing effect (P<0,05), whereas for the uric acid variable no significant effect was obtained (P>0,05). The xanthine + hypoxanthine variable, expressed in %, showed a increasing linear effect with by-product addition. The efficiency of microbial proteins synthesis, expressed in g/kg, for the variables of microbial N and microbial PB consumed (DOMC), by digestible organic matter apparently fermented in the rumen (DOMAFR) and by total digested nutrients consumed (TDNC) were not influenced (P>0,05) by the inclusion of dehydrated brewery residue in concentrated feed. The inclusion of dehydrated brewery residue in the concentrated portion of Santa Ines lamb rations does not influence the microbial protein synthesis..