휴먼명조 EXOGENOUS PROTEASE AND PHYTASE SUPPLEMENTATION IMPROVED GROWTH, FEED UTILIZATION, INNATE IMMUNITY, NUTRIENT DIGESTIBILITY AND
The study investigated the effects of protease and/or phytase supplementation on growth performance, innate immunity, nutrient digestibility and pathogenic resistance in Pacific white shrimp. A positive (PC) and a negative (NC) control diets were formulated to contain fish meal at 200 mg/kg and 100 mg/kg respectively. Another eight diets were made via supplementing protease at 25 and 50 mg/kg or phytase at 100 and 200 mg/kg and supplementation their combinations. Each diet was fed to quadruplicate groups of 30 juvenile shrimp (initial weight 0.3±0.0 g) for 9 weeks. After the feeding trial, 45 shrimp from each dietary treatment were redistributed into three replicate tanks for the Vibrio parahaemolyticus bacterial challenge. A subset of shrimp with similar size (12±0.0 g) (2 tanks/group, N=20 shrimp/tank) were subjected for nitrogen and phosphorus excretion experiment for four days. The result showed that compared to shrimp fed NC diet, shrimp fed protease and phytase supplemented diets had significantly increased (P＜ 0.05) weight gain and specific growth rate. Shrimp survival against V. parahaemolyticus challenge was not significantly (P˃ 0.05) affected by the dietary protease or phytase. The water nitrogen and phosphorus concentration of all groups showed an increasing tendency during excretion experiment, and protease and phytase supplemented groups showed lower (P＜ 0.05) nitrogen and phosphorus excretion compared to the NC group. The results on innate immunity, gene expression, nutrient digestibility, intestinal morphology and intestinal microbiota abundance will be further discussed in detail.