Effects of exogenous cellulase and xylanase enzyme preparations on feed intake, nutrient digestibility, growth, and economics of rearing Mongolian lambs

In a completely randomised design, twenty four 12-months old Mongolian breed male lambs averaging 21.6 ± 0.48 kg of body weight (BW) were used to evaluate the effects of exogenous cellulase and xylanase enzyme preparations on feed intake, digestibility of nutrients, growth and economics of rearing lambs. The lambs were randomly assigned to six treatment groups with four animals per treatment. The treatment combinations comprised: i) two enzyme preparations, i.e. cellulase vs. xylanase (ENZc, ENZx), ii) two ration types, i.e. wheat straw + wheat bran (diet W) vs. barley straw + wheat bran (diet B) and iii) two control diets (diet W and diet B without enzyme preparations, –ENZ). Lambs were fed the cellulase and xylanase treated wheat and barley straws ad libitum whereas the wheat bran was offered at 400 g DM per day. Significant effects were observed for nutrient intake of diet B+ENZc, and for crude protein (CP) and neutral detergent fibre (NDF) digestibility of diet W+ENZc. The average daily gain (ADG) increased in all enzyme treated groups with highest values found in diet B+ENZc, but without significant differences found between the two enzyme preparations. Both enzyme preparations had positive effects on feed conversion ratio (FCR) of both diets, where by the highest values were found for diet B +ENZc. Enzyme preparation had no effect on the total feed cost for both diet types and showed positive effects on other economic parameters, where by cellulase yielded better results than xylanase. These results suggest that cellulase addition is effective for improving digestibility of nutrients, growth performance and net revenue ingrowing lambs.