Effects of probiotic BaSC06 on intestinal digestion and absorption function, antioxidant capacity and macrophage polarization and microbiota composition in fattening pigs

Abstract

Background: The previous study in our team found that supplementation of probiotic Bacillus amyloliquefaciens SC06 (BaSC06) as an alternative to antibiotics (Kitasamycin) can effectively reduce the diarrhea rate and promote the growth performance of weaned piglets. We speculate that BaSC06 may become a better substitute for antibiotics for fattening pigs. Hence, the objective of the present study is to evaluate the effects of BaSC06 substitute antibiotics on growth performance, digestive functions, antioxidant capacity, macrophage polarization and intestinal microbiota of fattening pigs. Methods: A total of 117 fattening pigs with similar weight and genetic basis were selected and divided into three groups: Anti group, fed with basal diet supplemented with 40 g/t Kitasamycin; Anti + Ba group, fed with 1 × 108 CFU/kg BaSC06 and 20 g/t Kitasamycin; Ba group, fed with 1 × 108 CFU/kg BaSC06 replaced Kitasamycin. Each treatment had three replications of 13 pigs per pen. Results: It indicated that BaSC06 replacement significantly improved ADFI and ADG in fattening pigs. It also improved intestinal digestion and absorption function with the increased activities of intestinal digestive enzymes and higher expression of glucose transporters SGLT1 and small peptide transporters PEPT1, maintained intestinal integrity significantly. Besides, supplementation with BaSC06 enhanced intestinal and body antioxidant capacity by activating Nrf2/ Keap1 antioxidant signaling pathway. In addition, BaSC06 as a substitute could alleviate intestinal inflammation by inhibiting the production of pro-inflammatory cytokines and chemokine and simultaneously increase the expression of M1 and M2 macrophage marker proteins in the intestinal mucosa. The transcription factor STAT3 regulated M2 polarization, which maintained immune homeostasis and reduced inflammation. What’s more, BaSC06 could improve the composition of the microbiota as well by increasing the proportion of Firmicutes, and reducing the proportion of Bacteroidetes and Proteobacteria. Conclusions: Taken together, our findings indicated that diet supplementation with BaSC06 instead of antibiotics increased the growth performance of piglets by improving the digestion and absorption of nutrients, intestinal microbiota composition and mucosal structure, antioxidative capacity and immune functions (including increasing M1and M2 polarization of macrophage).

Subtherapeutic Kitasamycin Promoted Fat Accumulation in the Longissimus Dorsi Muscle in Growing–Finishing Pigs

“…The disparities in results may be attributed to differences in animal growth stages, the types of antibiotics used, and the composition of fat and protein in their diets. In this study, the decreased ATTD of ether extract may be associated with reduced activity of digestive and absorptive enzymes or compromised intestinal barrier function [14]. However, the precise mechanism underlying the decreased ATTD of ether extract induced by subtherapeutic KM requires further investigation.…”

“…Its inhibitory effects on protein synthesis make it valuable in various therapeutic contexts, including fibrosis prevention after fistulating glaucoma surgery [12]. In both weaned piglets and growing-finishing pigs, KM has been shown to inhibit diarrhea, but has adverse effects on intestinal barrier function [13,14]. However, there are limited studies exploring the impact of different doses of KM on the metabolic health of pigs.…”