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.