益生菌对断奶鼠消化酶活力、肠道运动性及粘膜形态的影响

乳双歧杆菌、副干酪乳杆菌和植物乳杆菌是常见的益生菌，本研究系统评估了3株益生菌对断奶鼠消化代谢的调控作用。将断奶1周后的大鼠和小鼠分成对照组和益生菌处理组分别饲喂5周和4周，在此期间益生菌处理组每天分别灌胃1×109 CFU的乳双歧杆菌、副干酪乳杆菌和植物乳杆菌。试验期末，小鼠用于肠运动性试验，全部大鼠剖检取样进行生化及组织学分析。结果表明，乳双歧杆菌、副干酪乳杆菌和植物乳杆菌都能够显著促进小鼠肠道的运动性。同对照组相比，灌胃乳双歧杆菌、植物乳杆菌能够显著 （P<0.05） 增加大鼠的全期体重增重和肠液中胰蛋白酶活力，其中体重增重分别增加了13.33%和8.52%，胰蛋白酶活力分别提高了28.76%和31.13%。3株益生菌对大鼠的胃蛋白酶和淀粉酶活力、肝脏、脾脏、肾脏和胰腺重量及脏器系数均无显著影响。副干酪乳杆菌、植物乳杆菌均能够显著（P<0.05） 提高大鼠血清中总蛋白和球蛋白的含量，其中总蛋白含量分别增加了6.84%和9.12%，球蛋白含量分别增加了8.80%和6.82%。乳双歧杆菌、副干酪乳杆菌、植物乳杆菌生菌都会显著（P<0.05）升高大鼠血清中总胆固醇和高密度脂蛋白的含量，其中总胆固醇含量分别增加了44.35%、28.23%和17.74%，高密度脂蛋白含量分别增加了22.92%、27.08%和12.50%，对甘油三酯和低密度脂蛋白的含量无显著影响。此外，灌胃乳双歧杆菌、副干酪乳杆菌和植物乳杆菌均能够显著（P<0.05）提高大鼠的空肠和回肠绒毛高度和隐窝深度的比值以及回肠壁厚度，其中空肠绒毛高度和隐窝深度的比值分别增加了30.65%、19.35%和21.94%，回肠绒毛高度和隐窝深度的比值分别增加了30.21%、31.25%和35.94%，回肠壁厚度分别增加了21.14%、22.35%和27.51%。因此，乳双歧杆菌和植物乳杆菌能够通过促进肠道运动性、增加胰蛋白酶活力和改善肠道组织形态来促进宿主的消化吸收功能，进而提高宿主的体重增重同时又不会带来不良影响。

Effect of Probiotics on Digestive Enzymatic Activity,Intestinal Mobility and Mucosal Morphology of Weaned Rodents

Bifidobacterium lactis, Lactobacillus paracasei and Lactobacillus plantarum are common probiotic species. This study systematically evaluated the regulation effect of three probiotics on digestion and absorption metabolism in weaned rodents. The rats and mice were divided into control group and probiotics treatment groups after one week of weaning. The rats and mice were fed with 1×109 CFU of B. lactis, L. paracasei and L. plantarum by gavage for 5 and 4 weeks, respectively. At the end of the experiment, mice were used for intestinal motility test. Results showed that, the B. lactis, L. paracasei and L. plantarum significantly promoted the intestinal motility of mice. Compared with the control group, the body weight gain and trypsin activity in intestinal fluid of rats fed with B. lactis and L. plantarum significantly (P<0.05) increased, among them the body weight gain increased by 13.33% and 8.52%, and the trypsin activity increased by 28.76% and 31.13% respectively, whereas the activities of pepsin and amylase, the weight of liver, spleen, kidney and pancreas, and organ coefficient were not significantly affected. The content of total protein and globulin in rat serum were significantly (P<0.05) improved by L. paracasei and L. plantarum, among them the total protein content increased by 6.84% and 9.12%, and globulin content increased by 8.80% and 6.82%, respectively. The three probiotics could significantly (P<0.05) increase the content of total cholesterol and high-density lipoprotein, but had no significant effect on the content of triglyceride and low-density lipoprotein. And the total cholesterol content increased by 44.35%, 28.23% and 17.74%, and the high-density lipoprotein content increased by 22.92%, 27.08% and 12.50% by B. lactis, L. paracasei and L. plantarum, respectively. In addition, wall thickness of ileum and the ratio of villus height to crypt depth of jejunum and ileum of rats significantly (P<0.05) increased by the three probiotics. Among them, the ratio of jejunal villus height to crypt depth increased by 30.65%, 19.35% and 21.94%, the ratio of ileal villus height to crypt depth increased by 30.21%, 31.25% and 35.94%, and the thickness of ileum wall increased by 21.14%, 22.35% and 27.51% by B. lactis, L. paracasei and L. plantarum, respectively. Therefore, B. lactis and L. plantarum could promote the digestion and absorption function of host by promoting intestinal motility, increase trypsin activity and improve intestinal tissue morphology, so as to improve the body weight gain of the host without adverse effects.