Benefits of resistant starch (RS) consumption on host physiology encompass microbial activity-derived attenuation of intestinal inflammation. However, little is known about anti-inflammatory properties of RS of type 4. This study compared the effects of transglycosylated starch (TGS) consumption on the jejunal barrier function and expression of genes related to inflammation, barrier function and the mucosal defence in jejunum, ileum, caecum and colon of pigs. Moreover, interactions of TGS-induced alterations in bacterial metabolites and composition with host mucosal responses were assessed using sparse partial least squares regression and relevance network analysis. Intestinal samples were collected after pigs (n 8/diet; 4 months of age) were fed the experimental diets for 10 d. Consumption of TGS did not modify jejunal barrier function and gene expression. By contrast, TGS down-regulated the caecal expression of zonula occludens-1 and mucin 2 and of genes within the toll-like receptor 4 and NF-κB pro-inflammatory signalling cascade. Relevance networks revealed a microbiome signature on ileal, caecal and colonic mucosal signalling as TGS-derived changes in bacterial genera and fermentation acids, such as propionic acid, correlated with the differently expressed genes in ileum, caecum and colon of pigs. In conclusion, the present findings suggest certain anti-inflammatory capabilities of TGS by down-regulating the expression of pro-inflammatory pathways in the caecal mucosa, which seems to be mediated, at least in part, by TGS-induced changes in microbial action in the large intestine.

Probiotic administration can be a nutritional strategy to improve the immune response and growth performance of fish. The current study aimed to evaluate the effects of a probiotic blend (Bacillus sp., Pediococcus sp., Enterococcus sp., Lactobacillus sp.) as a dietary supplement on growth performance, feed utilization, innate immune and oxidative stress responses and intestinal morphology in juvenile Nile tilapia (Oreochromis niloticus). The probiotic was incorporated into a basal diet at three concentrations: 0 g/kg (A0: control), 3 g/kg (A1: 1.0×106 colony forming unit (CFU)/g) and 6 g/kg (A2: 2.3×106 CFU/g diet). After 8 weeks of probiotic feeding, weight and specific growth rate where significantly higher in fish-fed A1 diet than in fish-fed A0. Alternative complement in plasma was significantly enhanced in fish-fed A2 when compared with A0. The hepatic antioxidant indicators were not affected by probiotic supplementation. Villi height and goblet cell counts increased significantly in the intestine of fish-fed A1 and A2 diets compared with A0. The dietary probiotic supplementation was maintained until 20 weeks of feeding. Then the selected immune parameters, digestive enzymes and apparent digestibility of diets were studied. No effect of probiotic feeding was observed after that longer period supplementation. The dietary supplementation of mixed species probiotic may constitute a valuable nutritional approach towards a sustainable tilapia aquaculture. The improvement of the immune responses and intestinal morphology play an important role in increasing growth performance, nutrient absorption and disease resistance in fish, important outcomes in such a competitive and developing aquaculture sector.