Effect of supplementation of mannan oligosaccharide and probiotic on growth performance, relative weights of viscera, and population of selected intestinal bacteria in cyclic heat-stressed broilers

Abstract

SUMMARY A study was conducted to elucidate the effects of supplementation of mannan oligosaccharide (MOS), a prebiotic, and probiotic mixture (PM) on growth performance, relative weights (RW) of viscera, and population of selected intestinal bacteria to broilers reared under cyclic heat stress (HS). Two hundred fifty 1-d-old broiler chicks were randomly divided into 5 treatment groups with 5 replicates. From d 22 onward, the broilers were reared either in a thermoneutral zone (TN) or exposed to HS until d 42. Birds were fed either a corn-based basal diet (TN and HS groups) or the same diet supplemented with 0.5% MOS, 0.1% PM, or their combination as synbiotic. Birds were killed on d 42 to collect viscera and jejunal and cecal digesta. Digesta was used to enumerate Clostridium perfringens, total coliforms, and Escherichia coli. The HS decreased mean BW gain, feed consumption, and FE of broilers compared with the TN broilers. The TN group had higher RW of spleen, bursa of Fabricius, and ceca compared with the HS group. The supplementation of PM and SYN improved mean BW gain and FE compared with the HS group. Increase in RW of spleen, bursa, intestine, and ceca was observed in the supplemented groups compared with the HS group. Based on these findings, we concluded that HS has significant negative effects on mean RW of viscera and growth performance of broilers. Moreover, feeding a diet supplemented with either MOS or PM alone or as combination can partially or completely ameliorate these effects.