effect of protease and alpha-galactosidase supplementation on the nutritive value of peas for growing and finishing pigs

Two experiments were conducted to investigate the effects of the addition of α-galactosidase and neutral protease to pea (Pisum sativum) based diets fed to growing-finishing pigs. The design was a 2 × 2 factorial plus a control diet based on barley, wheat and soyabean meal. In experiment 1, the effects of enzyme supplementation on total tract apparent digestibility coefficients of organic matter (OM), nitrogen (N), energy, ash and neutral detergent fibre (NDF) were determined when peas were included at 400 g/kg of the ration. In experiment 2, performance was measured with individually fed pigs (12/diet) offered the following diets ad libitum: (1) control (barley, wheat, soyabean meal, tallow and molasses), (2) 400 g peas per kg of ration, (3) 400 g peas per kg of ration plus α-galactosidase, (4) 400 g peas per kg of ration plus neutral protease, and (5) 400 g peas per kg of ration plus both α-galactosidase and protease. All diets were formulated, using standard values for ingredients, to have similar concentrations of digestible energy (13.7 MJ/kg) and lysine (11 g/kg). In experiment 1, the addition of α-galactosidase, protease or both had no effect on nutrient digestibility or digestible energy content of the diets. In experiment 2, the addition of α-galactosidase reduced (P < 0.05) feed intake and growth rate during the grower stage (39 kg to 60 kg). Gains (kg/day) of 0.934, 0.862, 0.860, 0.887 and 0.843 (s.e. 0.030; P < 0.05) and food conversion ratios (FCR) of 2.43, 2.62, 2.55, 2.50 and 2.55 (s.e. 0.048; P < 0.05) were recorded for Treatments 1 to 5, respectively, from 39 kg to finish. In conclusion, the addition of α-galactosidase had no effect on the nutritive value of diets containing peas while the addition of neutral protease alone improved FCR in the growing pig.