The Probiotic Bacillus subtilis MB40 Improves Immunity in a Porcine Model of Listeriosis

Abstract

Probiotics for humans and direct-fed microbials for livestock are increasingly popular dietary ingredients for supporting immunity. The aim of this study was to determine the effects of dietary supplementation of Bacillus subtilis MB40 (MB40) on immunity in piglets challenged with the foodborne pathogen Listeria monocytogenes (LM). Three-week-old piglets (n = 32) were randomly assigned to four groups: (1) basal diet, (2) basal diet with LM challenge, (3) MB40-supplemented diet, and (4) MB40-supplemented diet with LM challenge. Experimental diets were provided throughout a 14-day (d) period. On d8, piglets in groups 2 and 4 were intraperitoneally inoculated with LM at 108 CFU/mL per piglet. Blood samples were collected at d1, d8, and d15 for biochemical and immune response profiling. Animals were euthanized and necropsied at d15 for liver and spleen bacterial counts and intestinal morphological analysis. At d15, LM challenge was associated with increased spleen weight (p = 0.017), greater circulating populations of neutrophils (p = 0.001) and monocytes (p = 0.008), and reduced ileal villus height to crypt depth ratio (p = 0.009), compared to non-challenged controls. MB40 supplementation reduced LM bacterial counts in the liver and spleen by 67% (p < 0.001) and 49% (p < 0.001), respectively, following the LM challenge, compared to the basal diet. MB40 supplementation was also associated with decreased circulating concentrations of monocytes (p = 0.007). Altogether, these data suggest that MB40 supplementation is a safe and well-tolerated approach to enhance immunity during systemic Listeria infection.

Lactobacillus acidophilus protects against Corynebacterium pseudotuberculosis infection by regulating the autophagy of macrophages and maintaining gut microbiota homeostasis in C57BL/6 mice

“…The intestinal microbiota is involved in the body’s metabolic function, immune system improvement, anti-infection effects, development, and behavior ( 27 , 28 ). Previous studies have shown that probiotics can effectively enhance the body’s anti-infective effect against pathogens ( 29 , 30 ). In this study, we found that preemptive oral administration of L. acidophilus effectively prevented C. p infection, which was reflected in reducing organ pathology, tissue damage, and bacterial load in the liver and kidneys.…”

Spore-Based Probiotic Bacillus subtilis: Current Applications in Humans and Future Perspectives

“…The multifaceted effects of probiotic B. subtilis have been extensively studied in animal models. Recent research has evaluated the effects of different strains of B. subtilis on health maintenance and disease resistance in pigs [30,31], dogs [32][33][34][35], and chickens [36][37][38][39] in terms of the probiotic potential to enhance health in pets and health/productivity in farm animals. However, this review primarily focuses on recent research utilizing various strains of B. subtilis in human populations.…”