| In this paper, the effects of different dose of tannin in diet and high tannin diet supplemented with PEG on the rumen fermentation parameters,cellulase activity and protease activity, nutrients degradability and apparent digestibility in sheep and cashmere goats were studied. At the same time shielding effect of PEG on anti-nutritional effect of tannin was also investigated, so as to provide theoretical basis for exploitation of tannin-riched shrub resources.Four sheep and four cashmere goats, age of 1.5-2 years old, weight of 40 kg, fitted with permanent ruminal cannula, were used as experimental animals. The study was conducted in consecutive four periods, and divided into four groups, including control group (basal diet, â… ), group â…¡ (basal diet+2% tannin), group â…¢ (basal diet+6% tannin) and group â…£ (basal diet+6% tannin+12%PEG). Each period lasted for 30 days consisted of a 12-day pre-test period and 18-day test period.Ruminal content was collected before morning feeding (0h),2h,4h,6h and 9h after feeding. Then the rumen fernetation parameters (pH, NH3-N concentration, BCP concentration, and VFA concentration), cellulase activity and protease activity were measured. Complete faece collection digestion experiment were conducted to measure nutrients apparent digestibility and nitrogen metabolism rate. Nylon bag technique was used to measure the degradation of nutrients in the rumen.The results showed that:1) Rumen fermentation parameters were affected by tannin supplementation. The bacterial protein synthesis were significantly decreased at 0h,6h and 9h with supplementation of 2% tannin in cashmere goats and sheep, as well as the acetic acid concentration in sheep at 2h (P<0.05). The rumen pH at 2h and ammonia concentration at Oh and 9h of sheep and goats were significantly decreased in group â…¢ as compared with control group (P<0.05). As compared with control group, the concentration of acetic acid, propionic acid and total volatile fatty acids in sheep and goats at 9h were significantly decreased in group â…¢ (P<0.05).2) As compared with control group,6% tannin supplementation significantly decreased the apparent digestibility of OM, CP, NDF and ADF in sheep and goats. At the same time, the nitrogen utilization and nitrogen metabolic rate of sheep and goats were also significantly decrease by adding of 6% tannin in diet (P<0.05).3) The activity of CMCase at 9h, filter paper enzymen at Oh,2h,6h,9h, xylanase at Oh,2h,4h, salicin at 2h,6h and proteolytic enzyme at 4h of sheep and goats were significantly decrease by supplementation of 6% tannin in diet (P<0.05). The rumen effective degradatility of DM, CP and NDF of hay in group III were significantly lower than those of group â… (P<0.05).4) After adding PEG, the rumen fermentation was improved. As compared with group â…¢, the ammonia concentration at 9h of sheep and goats were significantly increased in group IV (P<0.05). In addition, acetic acid, propionic acid, total volatile fatty acid concentrations at 9h in goat of group IV were significantly higher than those of group â…¢ (P<0.05). The activity of carboxymethyl cellulase, xylanase and proteolytic enzyme were higher for group â…£ than those of group â…¢. Rumen NDF effective degradability of sheep and goats were significantly higher in group â…¢ than that of group â…£ (P<0.05). The digestible nitrogen utilization and nitrogen metabolism rate of sheep in group â…£ were also significantly increased as compared with group â…¢ (P<0.05).5) The apparent digestibility of DM, OM, CP and NDF in sheep were significantly higher than those of goats (P<0.05). The effective degradability of DM, CP and NDF in control group, DM effective degradability in group â…¡, NDF effective degradability in group â…¢ of sheep were significantly higher than those of goats (P<0.05). The mean value of concentration of acetic, propionic, TVFA and Ac/Pr in control group were higher for sheep than for goats (P<0.05). The concentration of acetic and Ac/Pr in group â…¡, concentration of acetic in group â…¢ and TVFA concentration in group â…£ were also higher for sheep than for goats (P<0.05). The activity of xylanase in control group was higher for sheep than for goats, whereas the reverse result was observed for activity of protease (P<0.05). |
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