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

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. A total of 256 (4×8×8) 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 T1 (negative control-basal diet), T2 (positive control-antibiotic bacitracin methylene disalicylate at 20 mg/kg diet), T3 (MSP at 107 colony-forming unit [CFU]/g feed), and T4 (MSP at 108 CFU/g feed). During 3 to 6 weeks and 0 to 6 weeks, the body weight gain increased significantly (p<0.05) in T3 and T4 groups. The feed intake significantly (p<0.05) reduced from T1 to T3 during 0 to 3 weeks and the feed conversion ratio also significantly (p<0.05) improved in T3 and T4 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 T3 and T4. However, significant (p<0.05) dietary effects were observed on intestinal histo-morphometry of ileum in T3 followed by T4 and T2. 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 T2, T3, and T4. Whereas, at 21 d post hatch, the gene expression of SGLT1 and PepT1 was significantly (p<0.05) downregulated in MSP supplemented treatments T3 and T4. The supplementation of MSP at 107 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.