亮氨酸对哺乳期湖羊羔羊小肠发育的影响

Effects of Leucine on Small intestine Development of Hu Lambs in Suckling Period

本试验旨在研究亮氨酸对哺乳期湖羊羔羊小肠组织形态、屏障功能及菌群组成的影响。选取30只体重[(3.60±0.37)kg]相近的5日龄湖羊羔羊,随机分成对照组(Con组,未添加亮氨酸)和亮氨酸组(Leu组,添加0.66 g/d亮氨酸),每组5个重复,每个重复3只羔羊。试验期25 d。结果显示:1)与Con组相比,Leu组的空肠绒毛高度有增加的趋势(P=0.073),空肠隐窝深度显著降低(P<0.05),空肠绒毛高度/隐窝深度显著增加(P<0.05);回肠绒毛高度显著增加(P<0.05)。2)与Con组相比,Leu组的空肠上皮超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和谷胱甘肽过氧化物(GSH-Px)的基因相对表达量均显著升高(P<0.05)。3)与Con组相比,Leu组的空肠上皮咬合蛋白(Occludin)和闭锁小带蛋白-1(ZO-1)的基因和蛋白相对表达量均显著或极显著升高(P<0.05或P<0.01)。4)与Con组相比,Leu组的空肠布雷德菌属(Bulleidia)的相对丰度有增加的趋势(P=0.076),而空肠颤螺旋菌属(Oscillospira)和链球菌属(Streptococcus)的相对丰度显著降低(P<0.05)。5)相关性分析结果显示,空肠Bulleidia的相对丰度与空肠ZO-1的基因相对表达量呈极显著正相关(P<0.01),空肠Streptococcus的相对丰度与空肠隐窝深度呈极显著正相关(P<0.01)。由此可见,添加亮氨酸可增强湖羊羔羊空肠抗氧化能力,调控肠道上皮紧密连接蛋白的表达,改变空肠菌群结构,从而促进哺乳期羔羊小肠发育。

This experiment was conducted to investigate the effects of leucine on the morphology,barrier function and microflora composition in small intestine of Hu lambs in suckling period.Thirty 5-day-old Hu lambs with similar body weight[(3.60±0.37)kg]were randomly assigned to the control group(Con group,without leucine supplementation)and leucine group(Leu group,supplemented with 0.66 g/d leucine),each group contained 5 replicates and 3 lambs in each replicate.The experiment lasted for 25 days.The results showed as follows:1)compared with the Con group,the jejunal villus length of the Leu group tended to increase(P=0.073),the jejunal crypt depth was significantly decreased(P<0.05),and the jejunal villus length/crypt depth was significantly increased(P<0.05);the ileal villus length was significantly increased(P<0.05).2)Compared with the Con group,the gene relative expression levels of superoxide dismutase(SOD),catalase(CAT)and glutathione peroxidase(GSH-Px)in jejunum of the Leu group were significantly increased(P<0.05).3)Compared with the Con group,The gene and protein relative expression levels of Occludin and zonula occluden-1(ZO-1)in jejunum of the Leu group were significantly increased(P<0.05).4)Compared with the Con group,the relative abundance of Bulleidia in jejunum of the Leu group tended to increase(P=0.076),while the relative abundances of Oscillospira and Streptococcus in jejunum were significantly decreased(P<0.05).5)The correlation analysis results showed that the relative abundance of Bulleidia in jejunum was positively correlated with the gene relative expression level of ZO-1 in jejunum(P<0.01),and relative abundance of Streptococcus in jejunum was positively correlated with the jejunal crypt depth(P<0.01).In conclusion,the leucine supplementation can enhance the jejunal antioxidant capacity of Hu lambs,regulate the expression of intestinal epithelial tight junction protein,and change the jejunal microflora structure,so as to promote the small intestine development of lambs in suckling period.