Bifidobacterium animalis Promotes the Growth of Weaning Piglets by Improving Intestinal Development, Enhancing Antioxidant Capacity, and Modulating Gut Microbiota.

Probiotics are widely used to promote performance and improve gut health in weaning piglets. Therefore, the objective of this study was to investigate the effects of dietary supplementation with Bifidobacterium animalis subsp. lactis (B. animalis) JYBR-190 on the growth performance, intestine health, and gut microbiota of weaning piglets. The results showed that the dietary addition of B. animalis significantly improved growth performance and decreased diarrhea incidence. B. animalis increased villus height in the duodenum and elevated goblet cell numbers and amylase activity in the jejunum. Additionally, B. animalis supplementation markedly increased total antioxidant capacity in jejunal mucosa but declined the malondialdehyde content. B. animalis treatment did not affect the mRNA expressions associated with the intestinal barrier and inflammatory cytokine in various intestinal segments. Microbiota analysis indicated that a diet supplemented with B. animalis significantly increased the relative abundances of health-promoting bacteria in the lumen, such as Streptococcus, Erysipelotrichaceae, Coprococcus, and Oscillibacter. There was a trend for B. animalis fed piglets to have a higher relative abundance of B. animalis in ileal digesta. Moreover, B. animalis-treated pigs decreased the abundance of Helicobacter and Escherichia-Shigella in ileal mucosa-associated microbiota. In summary, this study showed that B. animalis supplementation stimulated growth performance, improved gut development, enriched beneficial bacteria abundances, and declined intestinal pathogens populations, while B. animalis had limited effects on the intestinal barrier and immune function. IMPORTANCE In the modern swine industry, weaning is a critical period in the pig's life cycle. Sudden dietary, social, and environmental changes can easily lead to gut microbiota dysbiosis, diarrhea, and a decrease in growth performance. To stabilize intestinal microbiota and promote animal growth, antibiotics were widely applied in swine diets during the past few decades. However, the side effects of antibiotics posed a great threat to public health and food safety. Therefore, it is urgent to find and develop antibiotic alternatives. The growing evidence suggested that probiotics can be preferable alternatives to antibiotics because they can modulate microbiota composition and resist pathogens colonization. In this study, our results indicated that dietary supplementation with Bifidobacterium animalis promoted growth in weaning piglets by improving gut development, increasing beneficial bacteria abundances, and declining pathogens populations.