Abstract
OBJECTIVE: This study was conducted to investigate the effects of hydrolyzable versus condensed tannins on growth performance, nitrogen (N) metabolism, rumen fermentation, and blood parameters in Liaoning cashmere goats. METHODS: A control diet and three experimental diets-supplemented with 0.5% chestnut tannin (CT), tannic acid (TA), or quebracho tannin (QT)-were compared. RESULTS: Goats consuming the QT diet had higher average daily gain and average daily feed intake compared to those on the TA diet (p<0.05). Compared to the control group, the QT group exhibited lower fecal N, urine N, and total N output (g/d, p<0.05), as well as higher N retention (g/d) and N utilization (g/kg N intake) relative to the CT and TA groups (p<0.05). The QT group had lowest urine uric acid level, while the CT and TA groups showed lower creatinine levels compared to the control (p<0.05). Tannin supplementation increased rumen ammonia-N (NH3-N) concentration and reduced protozoa counts (p<0.05). Plasma concentrations of total protein, globulin, superoxide dismutase, catalase, and lysozyme were higher in the QT group than in the CT and TA groups (p<0.05). CONCLUSION: These results suggest that condensed tannin provides greater advantages than hydrolyzable tannin on growth, N balance, and antioxidant function at equivalent dietary inclusion levels.