日粮添加复合饲用益生菌对肉牛生长性能及肠道微生物的影响

目的] 为研究添加饲用益生菌对肉牛生长性能、血液生理生化指标及肠道微生物区系的影响。方法] 在青海地区选取西门塔尔牛与荷斯坦牛的杂交1代18头，按每组平均体重相近的原则随机分为2组，每组9头，试验组饮食添加地衣芽孢杆菌、枯草芽孢杆菌和酿酒酵母的复合饲用益生菌。结果] 试验结果表明：试验组显著地提高了胸围日增长量（P=0.029）；试验组皮质醇浓度显著（P<0.05）高于对照组，高密度胆固醇脂蛋白、低密度胆固醇脂蛋白与总胆固醇浓度显著（P<0.05）低于对照组；进一步分析肠道微生物发现，两组之间Alpha多样性没有显著差异（P>0.05），Beta多样性差异显著（P<0.05）；Tenericutes、Alistipes和Ruminococcaceae的相对丰度在试验组显著高于对照组（P<0.05），而Alloprevotella相对丰度显著低于对照组（P<0.05）；检测到的芽孢杆菌种没有显著的差异，有趣的是，试验组降低了肠道中的大肠杆菌丰度。结论] 综上，饲喂复合饲用益生菌能够有效降低血清胆固醇的合成、抑制有害微生物的繁殖。该研究为益生菌干预肉牛健康养殖提供了理论依据。

Effects of probiotics supplementation in feed on cattle growth and gut microbiota

Objective] To explore the effect of adding compound probiotics on the growth performance, blood physiological and biochemical indexes and gut microbiota composition of beef cattle. Methods] Eighteen crossbred 1 generation of Simmental and Holstein cattle were selected in Qinghai area, and randomly divided into two groups according to the principle of similar average weight of each group (n=9). The Y1 group was fed with compound probiotics containing Bacillus licheniformis, Bacillus subtilis and Saccharomyces cerevisiae.Results] The daily increase in chest circumference was significantly increased in Y1 group (P>0.05); the concentration of cortisol was significantly higher in the Y1 group (P<0.05), and the concentration of high density liptein cholesterol, low density liptein cholesterol and total cholesterol was significantly lower in the Y1 group (P<0.05). Analysis the gut microbiota by 16S rRNA gene sequencing, there was not significant difference in Alpha diversity between two group (P>0.05), Beta diversity significantly differences of two group (P<0.05). The relative abundance of Tenericutes, Alisipes and Ruminococcaceae were significantly higher than that of the Y2 group (P<0.05), but the relative abundance of Alloprevotella was significantly lower than that of the Y2 group (P<0.05). There was not significant difference in the detected Bacillus sp.. Interestingly, the Y1 group reduced the abundance of E. coli in the gut. Conclusion] Feeding compound probiotics can effectively reduce the synthesis of serum cholesterol and inhibit the reproduction of harmful microbial, which provides a theoretical basis for the healthy breeding of beef cattle.