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Early life adversity significantly impacts organ development and predisposes animals towards greater risk of diseases later in life. In the previous research in pigs, long lasting intestinal barrier dysfunctions have been found to be associated with early weaning stress. However, the underlying mechanism is not fully elucidated. Intestinal epithelial functions are associated with the number and maturation of multicellular components, including enterocytes, goblet cells, Paneth cells, and enteroendocrine cells (EEC). Intestinal epithelial stem cells (IESC) give rise to the whole epithelium within 5 to 7 days. Such rapid turnover rate allows intestinal adaptation to stress conditions. We hypothesized that the early life stress impacted stem cells activities which would contribute to the long-lasting post-stress functional changes in intestinal epithelium. The objective of the present study is to evaluate the epithelium component cells and IESC proliferation and differentiation activities in an early weaning stress model in pigs. Piglets (n = 18) were obtained from commercial litters and were pair-weaned at the age of d 15 (early weaning, EW) and d 26 (late weaning, LW). Piglets were co-housed and raised under the same conditions. At the age of d 35, ileal tissues were isolated and fixed for morphological measurements. Intestinal crypts were isolated and cultured in the Matrigel matrix to form enteroids. The proliferation activities of IESCs were measured by enteroids morphology; differentiation capacity was measured by quantification of epithelial cell markers with and without chemicals-induced enteroids differentiation. Gene expressions and (or) staining of specific markers for IESCs (Olfm4, BMI1), enterocytes (ALP1), goblet cells (Muc2), Paneth cells (LYZ), and EECs (ChgA) in ileal tissue and ileal enteroids were also quantified. Data were analyzed by the student's t-test. Our results showed that EW significantly (P < 0.05) reduced ileal villus width and crypt fission rate, while no changes were found on villus height and crypt depth compared with LW control. The alterations of ileal epithelium components in EW pigs were indicated by significantly fewer number of EECs, greater number of the goblet cells, and reduced ALP1 marker expression. The enteroids formation and budding rates were both significantly suppressed in EW pigs, which indicated a reduced IESC proliferating activity. In the fully developed enteroids, gene expressions of LYZ, ALP1, BMI1, Olfm4, and Hes1 were least in EW, but Muc2 expression was greater compared with control. In the differentiation culture media, the enteroids from EW pigs exhibited significantly enhanced potential for goblet cell differentiation but reduced capacity for enterocyte differentiation compared with LW pigs. Overall, the results indicate that early weaning stress affects the programming and activity of IESCs, which leads to an altered epithelium cell population and intestinal functions. Further understanding of mechanisms regulating IESCs activity will shed light on novel strategies mitigating stress-associated intestinal dysfunctions. [ABSTRACT FROM AUTHOR]

Intestinal nutrient sensing and enteroendocrine functions are critical in controlling feed intake and nutrient transport, yet have been overlooked in agricultural animals. Enteroendocrine cells (EECs) residing on intestinal epithelium monitor luminal chemical environment and orchestrate body neuronal and hormonal responses. After nutrient stimulation, the EECs release hormones, such as glucagon-like peptide 2 (GLP2), which dynamically regulates intestinal nutrient transport and epithelial barrier homeostasis. In pigs, early weaning stress has negatively impacted intestinal development and functions. The objective of the present study is to evaluate effects of early weaning on intestinal nutrient sensing functions, EEC-derived GLP2 production, and epithelial nutrient transport in pigs. Commercial pig littermates (females, n = 9) were split-weaned at the age of d15 (early weaning, EW) and d 26 (late weaning, LW). Piglets were all raised under the same conditions and euthanized at 35 days of age. Intestinal tissues were collected and preserved for later immunohistochemistry staining and gene expression analyses. Immediately post euthanasia, the mucosal layers from jejunum and ileum were mounted on the Ussing chambers to investigate physiological functions. Nutrients transport activities were measured by short circuit current changes (ΔIsc) in response to luminal nutrients (glucose, alanine, lysine, and di-peptide) applications. Nutrient sensing function was measured by GLP2 release rate following glucose stimulation in Ussing chambers. Serum and intestinal tissue concentrations of GLP2 were also measured by ELISA. Data were analyzed by the student's t-test. Our results showed altered electrogenic nutrients and ion transport activities between EW and LW pigs. The ileal basal Isc was significantly less in EW pigs, indicating a reduction in ions transport. The EW pigs significantly downregulated electrogenic lysine transport, while upregulated active transport of dipeptide. The EECs number in ileum was reduced in EW pigs, indicated by less ChgA (EEC cell marker) mRNA and significantly less ChgA positive-stained cells. In addition, EW pigs exhibited a pattern of EECs relocation, in which the ChgA-positive cells enriched towards the lower half of villi. Nutrient sensing activities of the EECs were suppressed in both jejunum and ileum in EW pigs, indicated by a significant reduction in the glucose-stimulated GLP2 release on Ussing chambers. Moreover, in contrast with the significantly greater GLP2 concentration in ileum, the serum GLP2 concentration was significantly less in the EW pigs, which reflected a decreased GLP2 release rate. In summary, our results suggested that early weaning stress altered EECs number and locations on epithelium, reduced EECs nutrient sensing activities and endogenous GLP2 release, and changed nutrient transport activities. Understanding the mechanism by which early weaning stress regulates intestinal nutrient sensing and transport functions will lead to novel feeding strategies that improve intestinal health and animal production. [ABSTRACT FROM AUTHOR]

With restricted usage of growth-promoting antibiotics, identifying alternative feed additives that both improve intestinal barrier function and reduce inflammation is the center to improve chickens' health. This study examined the effects of a microencapsulated feed additive containing citric acid, sorbic acids, thymol, and vanillin on intestinal barrier function and inflammation status. A total of 240 birds were assigned to either a commercial control diet or control diet supplemented with 500 g/MT of the microencapsulated additive product. Birds were raised by feeding a 2-phase diet (starter, d 1 to d 21; and grower, d 15 to d 42). Growth performance was recorded weekly. At d 21 and d 42, total gastrointestinal tract permeability was evaluated by FITC-dextran (FD4) oral gavage. Jejunum-specific barrier functions were evaluated by Ussing chamber. Intestinal gene expression of selected epithelial cell markers, tight junction (TJ) proteins, inflammatory cytokines, and endocannabinoid system (ECS) markers were determined by RT-PCR. Statistical analysis was performed using Student t test. Results showed significant improvement of feed efficiency in the birds supplemented with the blend of organic acids and botanicals. At d 21, both oral and jejunal FD4 permeability were lower in the supplemented group. Jejunal transepithelial resistance was higher in the supplemented birds. At d 21, expression of TJs mRNA (CLDN1 and ZO2) was both upregulated in the jejunum and ileum of supplemented birds, while CLDN2 was downregulated in cecum. Proliferating cell marker SOX9 was higher expressed in jejunum and ceca. Goblet cell marker (MUC2) was upregulated, while Paneth cell marker (LYZ) was downregulated in the ileum. Proinflammatory cytokine expressions of IL1B, TNFA , and IFNG were downregulated in jejunum, while anti-inflammatory IL10 expression was higher in jejunum, ileum, cecum, and cecal tonsil. The ECS markers expressions were upregulated in most intestinal regions. Together, these results demonstrated that the blend of organic acids and botanical supplementation reduced inflammation, improved the TJs expression and intestinal barrier function, and thus improved chicken feed efficiency. The activated ECS may play a role in reducing intestinal tissue inflammation. [ABSTRACT FROM AUTHOR]