日粮中添加酵母β-葡聚糖对早期断奶犊牛体内大肠杆菌数量的影响

Effects of Yeast β-glucan on the Count of Escherichia coli in Pre-ruminant Calves

本试验分别通过体外和体内试验比较了酵母β-葡聚糖与杆菌肽锌对大肠杆菌数量的影响。结果显示:体外试验中,当培养基基础pH为6和7时,单独添加酵母β-葡聚糖培养3 h后大肠杆菌数仍显著低于对照组(P<0.05),当基础pH为8时,培养6 h后培养基中大肠杆菌数仍显著少于对照组(P<0.05);体内试验中,口服大肠杆菌(O141‥K99)攻毒后,添加酵母β-葡聚糖与杆菌肽锌组ADG比对照组分别提高了30.38%和30.81%(P<0.05),各处理组F/G均显著优于对照组(P<0.05),同时,各处理组犊牛粪便指数显著低于对照组(P<0.05),各处理组犊牛攻毒后12 h和24 h时直肠中大肠杆菌数量显著降低(P<0.05)。试验结果表明,在日粮中添加75 mg/kg酵母β-葡聚糖能缓解由大肠杆菌K99攻毒所导致的生长性能下降,并能在一定程度上替代或减少抗生素的使用。

The object of this experiment was to study the effect of yeast β-glucan and bacitra-cin zinc on the count of Escherichia coli in vitro and in vivo. The results showed that the number of Escherichia coli after 3 h was significant lower in the group which supplemented with yeastβ-glucan when the pH of medium were 6 and 7（P＆lt;0.05）. When the pH of medium were 8, the number of Escherichia coli was significant lower in the group which supplemented with yeast β-glucan than the control group after 6 h（P＆lt;0.05）. Compared with the control group, ADG of the calves in two treatments that supplemented with yeast β-glucan and bacitracin zinc were increased by 30.4 and 30.8% after the Escherichia coli challenged（P＆lt;0.05）. F/G in two treatments was lower than that in the control group. The count of Escherichia coli in the rectum was decreased（P＆lt;0.05） after the challenge in 12 h and 24 h. It could be concluded that yeast β-glucan at the dosage of 75 mg/kg could erase the decrease of growth performance of pre-ruminant calves which challenged with Esche-richia coli K99, thus using β-glucan in calves feed may decreased the usage of antibiotics.