Oral Insulin Stimulates Intestinal Department and Enzyme Maturation in Newborn Pigs

The effects of oral insulin on intestinal tissue growth and brush border enzyme activities in newborn pigs were examined in this study. Newborn unsuckled pigs were bottle-fed for3 days with artificial milk(M),milk supplemented with 60mIUmL-1 of insulin(IH)or hydrolyzed milk(HM). Compared with newborn unsuckled pigs,piglets bottle-fed for 3 days all gained in intestinal weight and length significantly despite a mild loss in body weight during the experimental period. The activities of lactase and alkaline phosphatase(AKP)in the small intestinal mucosa declined markedly in pigs fed with M,but the activity of maltase increased significantly during the experimental period. Dietary protein pre-hydrolysis had no significant effect on intestinal tissue mass or length,but it moderated the decline of intestinal lactase and AKP activities. Dietary supplementation of insulin significantly increased mucosal protein content and brush border activities of lactase,maltase,AKP and aminopeptidase(AP)in the small intestine.The effect. of insulin treatment was particularly obvious at the distal region of the small intestine. These results demonstrate that oral insulin can stimulate intestinal digestive enzyme activities in newborn pigs. The finding supports the hypothesis that milk-borne insulin plays a role in regulating postnatal gut development in the suckling young.     

Morphometric evaluation of changes in the digestive tract of rainbow trout (Oncorhynchus mykiss) due to fish meal replacement with soy protein concentrate

Effects of the complete replacement of fish meal (FM) by soy protein concentrate (SPC) in high-energy diets (23 MJ kg^− 1 gross energy) on intestinal and liver histology were investigated in rainbow trout (Oncorhynchus mykiss). We developed a novel morphometric method to quantify the changes at the macro- and micromorphology level. Fish were acclimatized to the diet for 90 d and were then fed 1.0 g kg BW^− 1 d^− 1 once per day for 14 d before 10 fish per diet were randomly sampled, 6 h after their last meal. Fold height, epithelium length, stroma proportion of the proximal and distal intestines were not affected by the diet. No significant diet effect was detected on the features of the valve in the distal intestine. Fold height was linked to epithelium length in the proximal and distal intestines and this relationship was not modified by FM replacement. Enterocyte height and width were lower in SPC-fed fish in the distal intestine, but in the proximal intestine their morphology was not affected by the diet. There was no diet effect on the number of cells infiltered between the enterocytes in the proximal and distal intestines. The enterocyte nucleus was closer to the apex in the proximal and distal intestines in SPC-fed fish, but the features of the nucleus were not affected by the diet. The mean hepatocyte volume was on an average 36% lower in SPC-fed fish and was positively correlated to the hepatosomatic index for fish fed this diet only. In conclusion, SPC used in the present study did not either cause inflammatory reaction of the gut nor affected the epithelium surface. We suggest that the modifications due to SPC are linked to variations in the metabolic status of the enterocyte.     

Gut health:The results of microbial and mucosal immune interactions in pigs

There are a large number of microorganisms in the porcine intestinal tract. These microorganisms and their metabolites contribute to intestinal mucosal immunity, which is of great importance to the health of the host. The host immune system can regulate the distribution and composition of intestinal microorganisms and regulate the homeostasis of intestinal flora by secreting a variety of immune effector factors, such as mucin, secretory immunoglobulin A (sIgA), regenerating islet-derived III (RegIII)γ, and defensin. Conversely, intestinal microorganisms can also promote the differentiation of immune cells including regulatory T cells (T_reg) and Th17 cells through their specific components or metabolites. Studies have shown that imbalances in the intestinal flora can lead to bacterial translocation and compromised intestinal barrier function, affecting the health of the body. This review focuses on the composition of the pig intestinal flora and the characteristics of intestinal mucosal immunity, discusses the interaction mechanism between the flora and intestinal mucosal immunity, as well as the regulation through fecal microbiota transplantation (FMT), dietary nutritional composition, probiotics and prebiotics of pig intestinal microecology. Finally, this review provides insights into the relationship between intestinal microorganisms and the mucosal immune system.