Effect of supplementation of lysine and methionine on growth performance, nutrients digestibility and serum biochemical indices for growing sika deer (Cervus Nippon) fed protein deficient diet

This study was conducted to investigate the effect of supplementation of lysine (Lys) and methionine (Met) on growth performance, nutrients digestibility and serum biochemical indices for growing sika deer fed crude protein (CP) deficient diet. Sixteen 5-month-old growing male sika deer were randomly assigned to 4 groups receiving diets (n=4): i) CP-adequate (16.63%) diet; ii) CP-deficient (13.77%) diet with 3 g/kg Lys; iii) CP-deficient with 3 g/kg Lys and 1 g/kg Met; iv) CP-deficient diet with 3 g/kg Lys and 2 g/kg Met. The digestibility of dry matter P<0.01), organic matter (P<0.01), CP (P<0.01), serum albumin (P<0.01), and total protein (P<0.01) concentrations of groups receiving CP-adequate or Met supplementation were improved. The average daily gain (P=0.10), gain to feed ratio (P=0.07), the digestibility of acid (P=0.07) and neutral detergent fibre (P=0.09), and the serum globulin (P=0.08) concentrations had a tendency to increase as the Met or CP level increased. Meanwhile, blood urea nitrogen (P<0.01) and alanine aminotransferase (P<0.01) were decreased for CP-deficient, but no response to Met-added diets; aspartate aminotransferase (P=0.04) depressed for both CP-deficient and Met-added diets. Therefore, amino acids added to CP-deficient diets show high efficiency: they remain among the simplest ways for growth performance, while cutting down environmental waste and economic consumption.