The recent ban on the use of antibiotics as a feed additive has led to the search for alternative sources of antibiotics in the feed industry. Presently, probiotics are considered as a potential substitute for antibiotic as a live biotherapeutic agent to improve animal health and performance. Accordingly, study was focused on evaluating the effect of Saccharomyces boulardii (Sb) and Bacillus subtilis B10 (Bs) on ultrastructure modulation and mucosal immunity development in broiler chickens. A total of three hundred 1-d-old Sanhuang broilers (a Chinese cross breed) were randomized into 3 groups, each group with 5 replications (n = 20). The control group (Ctr) was fed a basal diet containing an antibiotic (virginiamycin, 20 mg/kg). Meanwhile, broilers in experimental groups received Sb and Bs (1 × 10(8) cfu/kg of feed) in addition to the basal diet for 72 d. The results of the experimental groups revealed a significant improvement in live BW and relative weight of bursa of Fabricius and thymus. Also, intestinal villus height, width, and number of goblet cells increased in the Sb and Bs groups. Meanwhile, modulation in the intestinal ultrastructure and increased mRNA expression levels of occluding, cloudin2, and cloudin3 (P < 0.05) were observed in the Sb and Bs groups. Moreover, IgA-positive cells significantly increased in the jejunum of Sb- and Bs-supplemented groups (P < 0.05). Intestinal cytokines interleukin-6, tumor necrosis factor-α, interleukin-10, transforming growth factor-β, and secretory IgA concentrations were (P < 0.05) improved in the probiotic groups; however, Sb induced inflammatory and antiinflammatory cytokines (P < 0.05) in comparison with the Ctr group. The present findings conclusively revealed that Sb and Bs increased IgA-positive cells in the lumen of the intestinal villus and revealed that Sb and Bs could modulate intestinal ultrastructure through increasing occluding, cloudin2, and cloudin3 mRNA expression levels in broiler intestine.

Our and others' previous studies have shown that Schistosoma japonicum (SJ) infection can inhibit allergic reactions. Moreover, we found that adoptive transfer of dendritic cells (DCs) from inhibited mice showed a similar inhibitory effect on allergy, suggesting a critical role of DCs in SJ-infected mediated inhibition of allergy. In this study, we further examined the mechanism by which DCs contribute to inhibition of allergy. Our results showed that DCs from SJ-infected mice (SJDCs) produced significantly higher levels of IL-10 compared to those from naive control mice (NDCs). Adoptive transfer of SJDCs, unlike NDCs, significantly increased CD4+CD25+Foxp3+ T cells and CD4+CD25+IL-10+ T cells regulatory T-cell responses in vivo. This was correlated with significantly reduced production of IL-4 and IL-5 by CD4+ T cells, eotaxin in lung tissues and reduced airway allergic inflammation in the SJDC recipients following allergen sensitization and challenge. These data suggest that helminth infection may induce tolerogenic DCs that can inhibit the development of airway allergic inflammation through enhancing T regulatory cell responses.