Interação de aditivos alimentares em dietas ricas em amido à base de sorgo para cordeiras

Abstract

The objective of this study was to evaluate the combined effects of live yeast (Saccharomyces cerevisiae), condensed tannin, and an amylolytic enzyme on feed intake, diet digestibility, nitrogen balance, and blood parameters of ewe lambs fed high-starch sorghum-based diets. Five crossbred ewe lambs (Dorper × Santa Inês), with an average age of 5.6 ± 1.4 months and an initial body weight of 28.8 ± 3.7 kg, were housed in individual metabolic cages for a 75-day experimental period. The experimental diets were formulated with a 20:80 forage-to concentrate ratio, and animals were fed twice daily at 08:00 and 16:00 h. The treatments consisted of: i) diet without additives (control); ii) amylolytic enzyme + tannin (TE); iii) amylolytic enzyme + live yeast (EY); iv) live yeast + tannin (TY); and v) live yeast + tannin + amylolytic enzyme (TYE). During a five-day collection period, nutrient intake and digestibility, as well as protein, enzymatic, and energy-related blood metabolites, were evaluated. Data were analyzed using PROC MIXED of SAS, considering differences significant at P ≤ 0.05 and trends at P ≤ 0.10. The experiment was conducted in a 5 × 5 Latin square design. The inclusion of additives increased plasma glucose, dry matter (DM) intake, and the digestibility of DM and starch. The TE, TY, and TYE treatments showed higher crude protein (CP) intake compared to the EY treatment. The digestibility of DM, CP, and starch was reduced in the TY and TYE treatments, which also showed higher fecal output (as-fed basis) and higher fecal dry matter content. The EY treatment reduced nitrogen balance and increased serum LDL concentrations, whereas the TE treatment resulted in lower fecal nitrogen excretion and lower triglyceride concentrations. A tendency toward increased serum urea and creatinine concentrations was observed in the EY and TE treatments. The TYE treatment promoted higher serum alkaline phosphatase activity. No effects of the additives were observed on water intake, fecal starch content, urinary volume and density, fecal dry matter output, fecal score, or urinary nitrogen excretion. A linear effect was observed in the glycemic curve, with the highest value recorded at 17:00 h (71.03 mg dL⁻¹). It is concluded that different combinations of live yeast, condensed tannin, and amylolytic enzyme in high-concentrate diets for ewe lambs increase DM intake and improve DM and starch digestibility without compromising water balance or the evaluated energy, enzymatic, and protein metabolic parameters.