Effect of xylanase and protease on the performance of growing-finishing pigs fed corn-based diets

Two experiments were conducted to determine if the performance of growing-finishing pigs fed corn-based diets is improved by enzyme supplementation. In experiment one, 72 crossbred pigs (32 castrates and 40 gilts) were fed one of the two corn-canola meal based diets, identical in composition except that one diet contained 0.12% of an enzyme cocktail (750 beta-glucanase units and 650 xylanase units per gram). In experiment two, 64 crossbred pigs (32 castrates and 32 gilts) were assigned to one of the four corn-soybean meal based diets including an unsupplemented control diet, a diet supplemented with xylanase (200 g/tonne containing 1250 units/g of xylanase and 385 units/g of beta-glucanase), a diet supplemented with protease (200 g/tonne containing 400 units/g ofprotease, 150 units/g of soybean meal hydrolytic activity, 360 units/g of xylanase and 165 units/g of beta-glucanase) or a diet supplemented with the two enzymes in combination (125 g/tonne xylanase and 75 g/tonne protease). The addition of the enzymes did not alter (P > 0.05) the digestibility of dry matter, crude protein or energy. There was no effect (P > 0.05) on weight gain, feed intake or carcass traits. However, during the growing period only, feeding xylanase significantly (P < 0.05) improved feed conversion. It is concluded that there is little justification for the routine inclusion of these enzymes in corn-based diets fed to swine.