Dietary supplementation of Bacillus subtilis or antibiotics modified intestinal microbiome of weaned pigs under enterotoxigenic Escherichia coli infection

Abstract

Our previous research reported that supplementation of Bacillus subtilis DSM 25841 promoted growth and disease resistance of weaned pigs under enterotoxigenic Escherichia coli (ETEC) challenge and its efficacy is comparable to carbadox. This follow-up study aimed to characterize the effects of ETEC infection, supplementing B. subtilis DSM 25841 or carbadox on intestinal microbiota of pigs. Forty-eight weaned pigs (6.17 ± 0.36 kg BW) were randomly allotted to one of four treatments: negative control (NC), positive control (PC), antibiotics (AGP, 50 mg/kg of carbadox), and direct fed microbials (DFM, 2.56 × 109 CFU/kg of B. subtilis). The experiment lasted 28 days with 7 days before and 21 days after first E. coli inoculation (day 0). Pigs in the PC, AGP, and DFM groups were orally inoculated with F18 ETEC for 3 consecutive days with 1010 CFU per dose per day. Fecal samples were collected on day −7, and day 7 and day 21 post inoculation, digesta samples were collected from jejunum, ileum, and distal colon on day 21 post inoculation to perform 16S rRNA sequencing. Sampling days and locations influenced (p < 0.05) Chao1 index and beta-diversity. Age increased (p < 0.05) the relative abundance of Firmicutes but decreased (p < 0.05) the relative abundance of Bacteroidetes in feces. ETEC infection increased (p < 0.05) the relative abundance of Proteobacteria in feces on day 7 post inoculation. AGP reduced (p < 0.05) relative abundance of Firmicutes and Lactobacillaceae in feces compared with PC and DFM. AGP reduced (p < 0.05) relative abundance of Bifidobacteriaceae in jejunum and ileum, while DFM reduced (p < 0.05) relative abundance of Actinomycetaceae in jejunum and Lachnospiraceae in ileum, compared with PC. Pigs fed with DFM had greater (p < 0.05) relative abundance of Ruminococcaceae, Veillonellaceae, Bifidobacteriaceae in jejunum, Lactobacillaceae in ileum and colon, and Bifidobacteriaceae in colon than pigs in AGP. Current results indicate that carbadox or B. subtilis had stronger influences on microbial diversity and composition in ileum than other intestinal segments and feces. Supplementation of B. subtilis could increase or maintain the relative abundance of beneficial bacteria in ileum compared with carbadox.

Assessment of the influence on Hypsizygus marmoreus stem waste as a sustainable alternative to corn in Holdobagy geese dietary

“…Bacillus has a variety of probiotic functions, similar to Bacillus amyloliquefaciens and Bacillus subtilis, which are widely used as probiotics in animal husbandry (Jiang et al, 2022;. Bacillus can induce Oscillospira to become a dominant genus (Keerqin et al, 2021) and can be used to treat diarrhea in pigs (Jinno et al, 2022). In this experiment, Bacillus was positively associated with growth performance, serum protein content, and antioxidant level, and negatively associated with serum fat and TC, as consistent with previous studies.…”

Protective Effects of Bacillus subtilis HH2 against Oral Enterotoxigenic Escherichia coli in Beagles

“…However, the lack of clustering in the stool samples from both groups suggests that the impacts of ETEC or B. subtilis HH2 on fecal microbial community composition may be limited, or that commercial dog food could also have influenced the fecal microbial community composition. Similar to studies on weaned pigs, alpha and beta diversity analyses also suggest that dietary supplementation of B. subtilis has a limited impact on the fecal microbiota in fecal samples [ 18 ]. The composition and structure of gut microbes in animals vary during different developmental stages, highlighting the lack of rigor in comparing fecal microbiota at different time points in this study.…”

“…An overabundance of Proteobacteria has been linked to dysbiosis in individuals who have metabolic or inflammatory conditions [ 63 ]. Moreover, previous studies have shown that the ETEC challenge increased the abundance of Proteobacteria and Firmicutes, and reduced the abundance of Bacteroides [ 18 , 64 ]. Similarly, in the dogc group, we observed a significant increase in the relative abundance of Firmicutes and a decrease in the relative abundance of Bacteroides in the stool at 24 h after the oral administration of ETEC.…”

“…exhibit inhibitory effects on ETEC both in vivo and in vitro. Specifically, B. subtilis has been found to hinder the growth and colonization of ETEC within the gut through multiple mechanisms, such as producing antimicrobial compounds [ 17 ], modulating the gut microbiota [ 18 ], and strengthening the gut barrier function [ 19 , 20 ]. In vitro studies have shown that B. subtilis reduces ETEC adhesion to the intestinal cell line while inhibiting ETEC-induced phosphorylation of extracellular signal-regulated kinases 1 and 2 [ 20 , 21 ].…”

Prebiotic galactooligosaccharide improves piglet growth performance and intestinal health associated with alterations of the hindgut microbiota during the peri-weaning period

“…Beta diversity measured post-weaning revealed a significant shift in the community ( P < 0.05), which may be attributed to the increased intake of GOS. In a study observing the effects of Bacillus subtilus or antibiotics on the piglet microbiome, they found that sampling site was the biggest influencer of shifts in beta diversity, but probiotic and antibiotic supplementation also shifted microbial communities [ 46 ]. This is comparable to the results we observed, where NG+ pigs differentiated from NG– pigs.…”