Ligilactobacillus salivarius and Limosilactobacillus reuteri improve growth and intestinal health in broilers via modulating gut microbiota and immune response.

The present study evaluated the effects of Ligilactobacillus salivarius RBL50, Limosilactobacillus reuteri SW23, and their mixture on growth, gut health, gut microbes, immune response, and serum lipids in broiler chickens. A total of 180 one-day-old broiler chicks were divided into five groups for six weeks: control, antibiotic (BMD), L. salivarius RBL50, L. reuteri SW23, and a combination of L. salivarius RBL50 + L. reuteri SW23. The results showed that probiotics and antibiotic groups had significantly higher average body weight (ABW) and average daily gain (ADG) compared to the control. Probiotics and antibiotics also reduced feed conversion ratio (FCR) and feed intake (ADFI), with the L. salivarius RBL50 + L. reuteri SW23 group showing the best performance. Histomorphological analysis revealed increased villus height (VH) and villus height/crypt depth ratio in the jejunum of probiotic and antibiotic groups, with RBL50 showing the highest values. Broilers treated with probiotic bacteria has higher expression of claudin-1, ZO-1, reduced total viable and coliform counts, and increased Lactobacillus counts in the cecum. Response to intradermal injection of Phyto-haemagglutinin-P (PHAP) was significantly higher in the L. salivarius RBL50 and L. salivarius RBL50 + L. reuteri SW23 groups, but no differences were observed in humoral immune response. Supplementation of L. salivarius RBL 50 and L. reuteri SW23 also increased expression of anti-inflammatory cytokine interleukin-10 (IL-10) in the jejunum and spleen. In conclusion, L. salivarius RBL50 and L. reuteri SW23 can improve growth, gut health, and immune response, making them effective and safe alternatives to antibiotic growth promoters.