Effects of glucanase inclusion in a de-hulled barley diet on the growth performance and nutrient digestion of broiler chickens

Abstract

A trial was conducted to evaluate the substitution of process de-hulled barley (or pearled barley) for maize in a traditional maize-soy diet and the inclusion of β-glucanase on the growth performance and nutrient digestibility of broiler chickens. The experiment was a randomized design with a 3×2 factorial arrangement with three levels of de-hulled barley substitution and two levels of enzyme inclusion in the diet. De-hulled barley replaced 0, 400 or 800 g maize/kg with versus without β-glucanase inclusion in iso-nitrogenous and iso-caloric experimental diets. Results showed that increasing amounts of barley substitution increased feed intake in the broiler chickens, hence significantly increased the live-weight gain both in the grower and finisher period ( P<0.05). The barley inclusion, however, did not significantly influence the feed conversion of the broilers. Inclusion of β-glucanase did not show improvement in the growth performance of the broilers ( P>0.05). Barley substitution in the broiler diet did not significantly influence the digesta viscosity in the duodenum ( P>0.05), however, a significant increase in the relative weight of the jejunum and caecum was evident in growing broilers and in the ileum weight in the finisher. Barley substitution also depressed dry matter and crude fat digestibility ( P<0.05) in the starting and finishing periods. Enzyme inclusion significantly decreased the relative weight of the GI tracts except for the caecum in the grower and the crop, gizzard and jejunum in finisher broilers. Enzyme inclusion significantly improved fat digestion in grower diet ( P<0.05). Enzyme inclusion also significantly increased the total VFA concentration in the finisher ( P<0.05). It appears that de-hulled barley substitute for maize increased feed intake, hence increased live-weight gains for the broiler chickens and decreased dry matter and fat digestibility in the grower. Inclusion of β-glucanase decreased the relative weight of the GI tract, increased fat digestion in growers and total VFA content in the caecum of finishing broiler chickens.