Influence of hydrolyzable versus condensed tannins supplementation in Liaoning cashmere goats: growth performance, nitrogen metabolism, rumen fermentation, and blood metabolites.

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 fed the QT diet had higher average daily gain (ADG) and average daily feed intake (ADFI) than those fed the TA diet (p<0.05). Compared to the control, the QT group exhibited lower fecal N, urine N, and total N output (g/d, p<0.05), along with higher N retention (g/d) and N utilization (g/kg N intake) than the CT and TA groups (p<0.05). The QT group had the lowest urine uric acid level, while the CT and TA groups showed lower creatinine levels than 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 (SOD), catalase (CAT), 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 exerts more beneficial effects than hydrolyzable tannin on growth, N balance, and antioxidant function at equivalent dietary inclusion levels.