The effect of multi-strain probiotics as feed additives on performance, immunity, expression of nutrient transporter genes and gut morphometry in broiler chickens

Objective: This study was conducted to investigate the effects of dietary multi-strain probiotic (MSP) (Bacillus coagulans Unique IS2 + Bacillus subtillis UBBS14 + Saccharomyces boulardii Unique 28) on performance, gut morphology and expression of nutrient transporter related genes in broiler chickens. Methods: A total of 256 (4x8x8) day-old CARIBRO Vishal commercial broiler chicks of uniform body weight were randomly distributed into four treatments with 8 replicates each and having eight chicks in each replicate. Four dietary treatments were T-1 (negative control-basal diet), T-2 (positive control-antibiotic bacitracin methylene disalicylate at 20 mg/kg diet), T-3 (MSP at 10(7) colony-forming unit [CFU]/g feed), and T-4 (MSP at 10(8) CFU/g feed). Results: During 3 to 6 weeks and 0 to 6 weeks, the body weight gain increased significantly (p<0.05) in T-3 and T-4 groups. The feed intake significantly (p<0.05) reduced from T-1 to T-3 during 0 to 3 weeks and the feed conversion ratio also significantly (p<0.05) improved in T-3 and T-4 during 0 to 6 weeks. The humoral and cell mediated immune response and the weight of immune organs were also significantly (p<0.05) improved in T-3 and T-4. However, significant (p<0.05) dietary effects were observed on intestinal histo-morphometry of ileum in T-3 followed by T-4 and T-2. At 14 d post hatch, the relative gene expression of glucose transporter (GLUT5), sodium-dependent glucose transporter (SGLT1) and peptide transporter (PepT1) showed a significant (p<0.05) up-regulating pattern in T-2, T-3, and T-4. Whereas, at 21 d post hatch, the gene expression of SGLT1 and PepT1 was significantly (p<0.05) down regulated in MSP supplemented treatments T-3 and T-4. Conclusion: The supplementation of MSP at 10(7) CFU/g diet showed significant effects with improved performance, immune response, gut morphology and expression of nutrient transporter genes. Thus, the MSP could be a suitable alternative to antibiotic growth promoters in chicken diets.