Protective Effects of Bacillus amyloliquefaciens 40 Against Clostridium perfringens Infection in Mice

Abstract

This study aimed to investigate the protective effects of Bacillus amyloliquefaciens (BA40) against Clostridium perfringens (C. perfringens) infection in mice. Bacillus subtilis PB6 was utilized as a positive control to compare the protective effects of BA40. In general, a total of 24 5-week-old male C57BL/6 mice were randomly divided into four groups, with six mice each. The BA40 and PB6 groups were orally dosed with resuspension bacteria (1 × 109 CFU/ml) once a day, from day 1 to 13, respectively. In the control and infected groups, the mice were orally pre-treated with phosphate-buffered saline (PBS) (200 μl/day). The mice in the infected groups, PB6 + infected group and BA40 + infected group, were orally challenged with C. perfringens type A (1 × 109 CFU/ml) on day 11, whereas the control group was orally dosed with PBS (200 μl/day). The results showed that the BA40 group ameliorated intestinal structure damage caused by the C. perfringens infection. Furthermore, the inflammatory responses detected in the infected groups which include the concentrations of IL-1β, TNF-α, IL-6, and immunoglobulin G (IgG) in the serum and secretory immunoglobulin (SigA) in the colon, and nitric oxide (NO) production and inducible nitric oxide synthase (iNOS) activity in the jejunum, were also alleviated (P < 0.05) by BA40 treatment. Similarly, cytokines were also detected by quantitative PCR (qPCR) in the messenger RNA (mRNA) levels, and the results were consistent with the enzyme-linked immunosorbent assay (ELISA) kits. Additionally, in the infected group, the mRNA expression of Bax and p53 was increasing and the Bcl-2 expression was decreasing, which was reversed by BA40 and PB6 treatment (P < 0.05). Moreover, the intestinal microbiota imbalance induced by the C. perfringens infection was restored by the BA40 pre-treatment, especially by improving the relative abundance of Verrucomicrobiota (P < 0.05) and decreasing the relative abundance of Bacteroidetes (P < 0.05) in the phyla level, and the infected group increased the relative abundance of some pathogens, such as Bacteroides and Staphylococcus (P < 0.05) in the genus level. The gut microbiota alterations in the BA40 group also influenced the metabolic pathways, and the results were also compared. The purine metabolism, 2-oxocarboxylic acid metabolism, and starch and sucrose metabolism were significantly changed (P < 0.05). In conclusion, our results demonstrated that BA40 can effectively protect mice from C. perfringens infection.

Effect of Porcine Clostridium perfringens on Intestinal Barrier, Immunity, and Quantitative Analysis of Intestinal Bacterial Communities in Mice

“…Using the broiler model which was infected by C. perfringens , the pro-apoptosis related genes also showed a significant increase ( P < 0.05) and a dramatic decrease ( P < 0.05) in anti-apoptosis related genes ( 56 ). Our previous study presented the same results, C57B/L mice infected with C. perfringens ATCC 13124 showed a significant decrease in jejunal Bcl-2 gene expression and a significant increase in Bax, p53, Caspase-3 and Caspase-9 gene expression ( 21 ). In the present study, we found that the High group can induce a stronger apoptosis signal compared with other groups.…”

“…It is known that the physical barrier is the first line of defense against pathogens invading into the intestine, and gut health level is related to villus atrophy and crypt hyperplasia degree ( 33 ). Our previous study indicated that C. perfringens infection can trigger serious villous atrophy and intestinal morphology disruption ( 21 ). This study also demonstrated that High dose C. perfringens inoculation impaired the development of the small intestinal morphology, weakened the villus morphology, decreased the ratio of villus height/crypt depth, and triggered an irreparable effect on the crypt depth in the small intestine.…”

“…Serum parameters, including inflammatory cytokines IL-1β, IL-6, TNF-α and immunoglobulin IgA, IgG, and fecal sIgA, were determined using ELISA kits (Jiangsu Enzyme-Labeled Biological Technology, Jiangsu, China). The protocols were carried out according to the manufacturer's instructions and followed by previous studies ( 21 ). Standard 50 μl was added to standard well, then 40 μl sample dilution was added to the to testing sample well, then 10 μl testing sample was added (sample final dilution is 5-fold).…”

“…Gene-specific primers ( Table 1 ) were used for this process. Finally, the β -actin was used as the housekeeping gene, and relative mRNA gene expression were detected by using the 2 −Δ ΔCt method as previously described ( 21 ).…”

The Positive Effects of Exogenous Pancreatin on Growth Performance, Nutrient Digestion and Absorption, and Intestinal Microbiota in Piglets

“…Data regarding microbiota community were analyzed using the free online Majorbio Cloud Platform. Metagenomes were predicted from the copy number-normalized 16S rRNA data according to a previous report ( Jiang et al, 2021 ). Differences were considered statistically significant at p < 0.05.…”