Influence of water extract viscosity and exogenous enzymes on nutritive value of rye hybrids in broiler diets

Broiler chickens were fed diets based on four hybrids of rye varying in viscosity of grain water extract (WEV). These diets were prepared with or without arabinoxylan degrading enzymes to study the effect of grain viscosity and xylanase and arabinosidase supplementation on growth rate and feed efficiency, metabolisable energy (AME(n)), apparent retention of protein (APR) and digestibility of arabinoxylans in young broiler chickens. A wheat-based diet was used as:a control. Elimination of the detrimental effect of soluble arabinoxylans (SAX) by the addition of both enzymes significantly improved the feed intake, weight gain and feed to gain ratio, on average by 30, 57, and 21%, respectively, as compared with the results of birds fed the corresponding unsupplemented diets. These improvements were achieved as a result of improvement in AME(n), APR, and digestibility of soluble and total arabinoxylans by 5, 8, 45 and 34%, respectively. In general, the poorer the nutritive value of the tested rye, the greater the benefit following enzyme supplementation. The results of this study showed that it is possible to improve the nutritive value of rye for broiler chickens by selection and breeding of rye varieties with a lower WEV and SAX content together with the appropriate choice of feed enzymes that can hydrolyse and thus lower the viscosity of gut digesta and increase retention of nutrients.