Abstract: The purpose of this study was to investigate the effects of condensed tannin derived from Caragana korshinskii in diets on ruminal fermentation parameters in sheep. A total of 15 healthy Dorper and Mongolian crossbred wether weighing around 40 kg were selected and randomly divided into 3 groups according to their body weight. The control group （n=5） contained no tannins in the diet; the test groupⅠ（n=5） and Ⅱ （n=5） received the diet containing 2% and 4% of tannin, respectively. The ruminal fluid of each group was collected before morning feeding （0 h） and 3 h, 6 h and 9 h after morning feeding, respectively, and the rumen internal environment indicators of the experimental wether, including pH value, ammonia nitrogen （NH₃-N） concentration and bacterial protein （BCP） level, were measured and statistically compared. The results showed that feeding the diets containing 2% （test groupⅠ） and 4% （test groupⅡ） of tannin had no significant （P>0.05） effect on ruminal pH value; the wether had significantly （P<0.05) lower ruminal NH₃-N concentration 3 h and 6 h after receiving the diets containing 2% （test groupⅠ） or 4% （test groupⅡ） of tannin; the ruminal BCP level of the wether was significantly （P<0.05） elevated 6 h and 9 h after receiving the diets containing 2% （test groupⅠ） or 4% （test groupⅡ） of tannin. The combined data suggested that while dietary supplementation of 2% or 4% of tannin derived from Caragana korshinskii had no impact on ruminal pH value in wether, it was able to reduce the ruminal NH₃-N concentration and ruminal BCP level.

Key words: Caragana korshinskii, tannin, sheep, fermentation parameters