The effects of direct-fed microbial supplementation, as an alternative to antibiotics, on growth performance, intestinal immune status and epithelial barrier protein expression in broiler chickens

• Published in: The Journal of immunology (1950) 2017-05, Vol.198 (1_Supplement), p.226-226.2
• Main Authors: Oh, Sungtaek, Gadde, Ujvala Deepthi, Lee, Youngsub, Davis, Ellen, Zimmerman, Noah, Rehberger, Tom, Lillehoj, Hyun S.
• Format: Article
• Language: English
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.198.Supp.226.2

This study was conducted to investigate the effects of Bacillus subtilis supplementation in broiler chicken diets on growth performance, feed efficiency, intestinal cytokine and tight junction (TJ) protein mRNA expression. Day-old broiler chicks (n = 140) were to one of five dietary treatments: basal diet (CON), basal diet supplemented with antibiotic (BMD) or probiotics, namely B. subtilis strain 1781 (PB1), a combination of B. subtilis strain 1104+strain 747 (PB2) or B. subtilis strain 1781+strain 747 (PB3). At 14 days of age, ileal samples were collected and used for intestinal cytokine, TJ protein and mucin gene expression analysis using qRT-PCR. The chickens fed with antibiotic (BMD) and B. subtilis strain 1781 alone (PB1) had significantly higher body weights compared to controls of the same age. Dietary supplementation with antibiotic (BMD) or probiotics (PB1, PB2, PB3) significantly improved the feed efficiency as evidenced by decreased FCR compared to controls. No differences were observed in the expression of IL1β, IL17F, IFNγ and MUC2 gene among the different treatment groups. However, elevated expression of IL6 (BMD, PB1, PB2), IL8 (PB2) and TNFSF15 (PB1, PB2, PB3) compared to controls was observed in the ileum. IL2 and IL10 expression was upregulated in chicks in the PB2 and PB3 groups, and IL4 was elevated in the PB1 group. IL13 was elevated in all probiotic-fed groups. Probiotic supplementation was also shown to significantly increase the expression of TJ proteins JAM2, ZO1 (PB2, PB3) and occludin (PB1, PB2). Taken together, B. subtilis supplementation altered intestinal immune activity and influenced gut barrier integrity through increased expression of TJ proteins.