Effects of dietary supplementation of tea saponins (Ilex kudingcha C.J. Tseng) on ruminal fermentation, digestibility and plasma antioxidant parameters in goats

Four goats (25 ± 2.5 kg) fitted with the ruminal, duodenal and ileal cannulae were used in a 4 × 4 Latin square design experiment to determine effects of dietary supplementation of tea saponins (TS) extracted from tea leaves (Ilex kudingcha C.J. Tseng) on ruminal fermentation, digestibility and plasma antioxidant parameters in goats. The goats were fed the same basal diet with levels of TS supplementation of 0 (TS0), 400 (TS400), 600 (TS600) or 800 (TS800) mg TS/kg dry matter (DM). Dietary TS levels did not affect apparent disappearance in the forestomach of DM, N, neutral detergent fiber (NDFom) or acid detergent fiber (ADFom), or apparent digestibility in the small intestine of NDFom and ADFom. Ruminal pH, ammonia N and volatile fatty acid concentrations were not affected by TS addition, as was the plasma concentrations of glutathione peroxidase and malondialdehyde. However triacylglycerol level declined linearly (P<0.01) with increasing levels of TS addition, Results indicate that dietary supplementation of TS did not affect nutrient digestibility, patterns of rumen fermentation, and plasma metabolite concentrations.