Effect of mannan-oligosaccharides (MOS) supplementation on performance, immunity and HSP70 gene expression in broiler chicken during hot-dry summer

Abstract

An experiment was conducted on broiler chicks (n=120), reared in cages on a standard diet up to 14th day of age and thereafter up to 42nd day (14-42d) on test diets with or without MOS. The 14th day old chicks were randomly distributed into three dietary treatment groups viz., T1 (control diet), T2 (control diet with MOS @ 0.3%) and T3 (control diet with MOS @ 0.5%). Each dietary treatment comprised of four replicates of eight birds each. Experiment was carried out during hot-dry summer. It was found that production indices improved (P>0.001) significantly during all phases. Cellular and humoral immunity at 28th day of age improved significantly (P>0.05) due to MOS supplementation. The percentage of hemoglobin, protein, AST and ALT increased significantly (P>0.001) in MOS supplemented group at 28th as well as 42nd day of age. While H:L ratio, serum corticosterone and cholesterol levels decreased significantly (P>0.001) in MOS supplemented groups. Supplementation of MOS at the both levels caused significant (P>0.001) down regulation of HSP70 expression in jejunum tissues during 28th and 42nd day. Based on this study it was concluded that supplementation of 0.3% MOS in broiler diets significantly improved their performance and welfare during heat stressed conditions.