344. Effects of Using Tannin and Yeast in Rations on Performance, Some Blood and Rumen Parameters and Carcass Characteristics of Beef Cattle.

Abstract This study aimed to investigate the metabolic responses of supplementing the diet with condensed tannins and live yeast on fattening performance and some rumen and blood parameters in beef cattle.In the study, 32 male beef cattle of cross breeds with an average live weight of 521.68 ± 17.84 kg at 15-mo-old were used. The animals were divided into 4 groups: Control (no supplementation), Yeast (saccaromyces cerevisiae 12X1010 CFU/g; 50 g/head/d), Tannin (Schinopsis spp. 30 g/head/day), and Tannin+ Yeast. The study lasted 6 months (1-mo adaptation, 5-mo trial). During the study period, no statistically significant difference was observed between the groups in terms of average daily gain and dry matter intake (P > 0.05). Feed conversion ratios varied between 8.53 and 12.36. Although statistical analyses showed no significant difference between the groups in carcass weight and dressing percentage (P > 0.05), the highest carcass weight was determined in the Yeast+ Tannin group as 421.52 ± 21.46 kg (P > 0.05). The highest dressing percentage was measured in the Yeast group at 59.00 ± 0.73%, but the difference between the groups was not statistically significant (P = 0.32). When the effects on biochemical parameters were examined, no significant changes were observed in albumin (ALB), triglyceride (TG), and cholesterol (CHOL) levels (P > 0.05), while significant differences were detected in urea, blood urea nitrogen (BUN), calcium, and phosphorus levels (P < 0.05). Although the differences between groups in terms of rumen fluid parameters such as propionic acid (PA), butyric acid (BA), valeric acid (VA), isobutyric acid (IBA), branched-chain fatty acids (BSFA), ammonia, and pH changes were not statistically significant (P > 0.05), modulatory effects were observed in acetic acid (AA), isovaleric acid (IVA), total short-chain fatty acids (TSCFA), and short-chain fatty acids (SCFA) levels (P < 0.05). In conclusion, the research findings indicate that the effects of adding tannins and yeast to the ration on fattening performance were limited. However, changes in certain blood and rumen parameters indicate a potential physiological impact of these additives. Especially SCFA concentration elevations in rumen and blood glucose and urea levels elevations may have potential for performance improvements. It can be concluded that the age of the cattle, the fattening period, and the doses of the additives used are determining factors in limiting the effects.