短期灌喂民猪源贝莱斯芽孢杆菌M2对SD大鼠生长、免疫及肠道菌群的影响

试验探究了短期灌喂民猪源贝莱斯芽孢杆菌M2对SD大鼠生长、血液生化与免疫、肠道菌群等相关指标的影响，拟为贝莱斯芽孢杆菌在畜禽中的应用提供参考依据。选取21日龄、体重相近、SPF级健康SD雌性大鼠共24只，将其随机分成2组，每组6个重复，每个重复2只。预饲期3 d。试验期，对照组灌喂生理盐水0.2 mL/d，试验组灌喂猪源贝莱斯芽孢杆菌M2菌液0.2 mL/d；每天灌喂1次，连续灌喂7 d。35和45日龄，每个重复随机选取1只大鼠处死采样。结果表明，短期灌喂贝莱斯芽孢杆菌M2有增加末重和日增重、降低日采食量和料重比的趋势（P>0.05）。短期灌喂贝莱斯芽孢杆菌M2显著降低了35日龄大鼠血浆中甘油三酯浓度和IgA、TNF-α的水平（P<0.05），以及45日龄大鼠血浆中IL-6的浓度（P<0.05），并显著提高35日龄大鼠血浆中IgM的浓度（P<0.05）；对35日龄大鼠肠道菌群无显著影响（P>0.05），可显著降低45日龄大鼠放线菌门和变形菌门的比例（P<0.05）。综上所述，短期灌喂贝莱斯芽孢杆菌M2可以调控SD大鼠的脂代谢、免疫力和肠道多种菌群的丰度。

Effects of Short-term Administration of Bacillus velezensis M2 Isolated from Min Pigs on the Growth,Immunity and Intestinal Microflora of SD Rats

The effects of short-term feeding with Bacillus velezensis M2 isolated from Min pigs on the growth performance,blood biochemistry,immunity,and intestinal flora of SD rats were investigated for providing a reference for the application of Bacillus velezensis in livestock and poultry.A total of 24 healthy SD female rats of 21-day-old,similar weight and SPF grade,were randomly divided into two groups(six repeats per group,and two rats per repeat).Pre-feeding period lasted three days.During the trial period,the rats in control group were fed orally 0.2 mL normal saline per day for 7 days,while those in the experimental group were fed orally 0.2 mL bacterial solution per day for 7 days.At the age of 35-and 45-day-old,one rat in each repeat was randomly selected to be executed and sampled.The results showed that feeding with Bacillus velezensis M2 increased the final weight and daily gain,and decreased daily feed intake and feed-gain ratio(P>0.05).Short-term feeding with Bacillus velezensis M2 significantly reduced plasma triglyceride concentration,plasma IgA and TNF-αlevel of 35-day-old rats,and plasma IL-6 level of 45-day-old rats(P<0.05),and significantly increased plasma IgM level of 35-day-old rats(P<0.05).Short-term feeding with Bacillus velezensis M2 had no significant effect on intestinal flora of 35-day-old rats(P>0.05),but significantly reduced the proportion of Actinomycetes and Proteobacteria in 45-day-old rats(P<0.05).These results indicated that short-term feeding with the Bacillus velezensis M2 regulated the lipid metabolism,immunity and intestinal flora abundance in SD rats.