Effect of barley processing and enzyme supplementation on broiler performance, gut morphometry, and the occurrence of ascites syndrome in broiler chickens.

Abstract

An experiment was conducted to evaluate the nutritive value of processed barley grains and their influence upon growth performance, gut function, and the occurrence of ascites syndrome in broiler chickens. Day-old broilers (n=504) were randomly assigned to six treatments (3 levels of grain processing × 2 levels of enzyme supplementation). Results showed that chicks fed with germinated barley significantly gained more weight compared to unprocessed barley in all feeding stages (P = 0.0001). Chicks received roasted barley showed a slowdown in their growth so that their weight gain was significantly lower than the control and germinated barley groups in the finishing period and the entire experiment (P = 0.0001). Enzyme supplementation of barley-based diets improved weight gain so that a significant improvement was observed in the growing (P = 0.0002) and throughout the trial (P = 0.0098) over the unsupplemented diets. Chickens fed with germinated barley had a higher length of jejunal villi whereas they had a lower crypt depth compared to untreated or roasted barley groups. As a result, the ratio of villus length to crypt depth as well as villus absorptive surface were significantly higher in birds received germinated barley than those fed with unprocessed or roasted barley. Barley processing resulted in a lower viscosity of digesta in the jejunum so that both processing methods showed a significantly lower viscosity compared to unprocessed barley. Birds received unprocessed barley showed a significantly lower concentration of total cholesterol (P = 0.0370) and LDL-cholesterol (P < 0.01) than those received processed barley. Plasma uric acid (P = 0.0350) and total protein (P = 0.0050) concentrations were significantly greater in birds fed with germinated barley as opposed to other experimental treatments. The mortality from ascites was lower in broilers fed with germinated barley compared to untreated barley, particularly in the absence of NSP-degrading enzyme supplement. In conclusion, germinated barley could significantly improve the performance, gut morphometry, and ascites indices of broiler chickens when compared to untreated barley.