Dietary Lactiplantibacillus plantarum modulated immune responses and intestinal barrier-related gene expression of weaned pigs

This study was conducted to evaluate the effects of probiotic Lactiplantibacillus plantarum (L. plantarum) on growth performance, blood profiles, serum immune responses, serum biochemical parameters, intestinal morphology, and ileal gene expression of weaned pigs. A total of 90 weaned pigs (initial body weight: 7.91 ± 0.83 kg) were assigned to two dietary treatments (5 pigs/pen; 9 replicates/treatment). The two dietary treatments consisted of a commercial corn and soybean meal-based nursery diet (CON) and the same diet supplemented with 0.02% of dietary probiotic L. plantarum (PLA). Pigs fed PLA tended to have higher average daily gain (ADG; p = 0.066), while G:F was higher (p < 0.05) during days 1 to 7. The PLA group tended to have lower (p = 0.078) diarrhea frequency during days 1 to 14. Pigs fed PLA tended to have lower (p = 0.071) HCT levels on day 7 and higher (p < 0.05) HCT levels on day 28. Serum IL-10 concentrations tended to be higher (p = 0.054) in the PLA group. Dietary PLA decreased crypt depth (p < 0.05) and increased villus height to crypt depth ratio (VH:CD; p < 0.05) in the duodenum. Also, the ileal VH:CD ratio tended to be greater (p = 0.093) with PLA supplementation. Goblet cell counts tended to be greater in the duodenum (p = 0.086) and were greater in the jejunum (p < 0.05) in pigs fed PLA. On day 28, dietary PLA upregulated (p < 0.05) the mRNA expression of CLDN3 and OCLN genes, while downregulating (p < 0.05) TNFA, TGFB, IFNA, IL1A, IL1B, IL6, and IL8 in the ileal mucosa. The present study suggested that dietary supplementation with L. plantarum may support intestinal health of weaned pigs, as indicated by improved intestinal morphology and altered expression of tight junction-related genes. In addition, probiotic L. plantarum may have modulated systemic immune response and intestinal expression of inflammatory cytokine genes.