其他摘要：ABSTRACT This experiment was conducted to examine effect of Gracilaria verrucosa extract in diet with different dosages to enhance immune response and resistance against white spot syndrome virus (WSSV) in the Pacific white shrimp. The experiment consisted of six treatments in three replicates respectively, namely K- (without extract), K + (without extract + infected WSSV), A (2 g/kg of feed + infected WSSV), B (3 g/kg of feed + infected WSSV), C (4 g/kg of feed + infected WSSV), and D (5 g/kg of feed + infected WSSV). White shrimp with initial body weight of 6.07±0.10 g were reared in the (60×30×30) cm with density of 10 shrimps/aquarium. G. verrucosa was extracted with ethyl acetate. Pacific white shrimp had been fed medicated feed three times daily 3% at satiation for 14 days. At 15th days, white shrimp were challenged with WSSV at 0.1 mL/shrimp intramuscularly. The results showed that the immune response shrimp (total hemocyte count, phagocytic activity, respiratory burst, and phenoloxidase activity) fed medicated feed increased significantly compared to positive and negative controls. The best relative percent survival post-challenge test was at 4 g/kg dose of G. verrucosa , i.e 41.07±3.09%. Confirmation of WSSV using PCR showed that shrimps (A, B, C, D, and K+) were positively infected by WSSV. It was concluded that 4 g/kg dose of G. verrucosa gave the best result to enhance immune response and resistance to WSSV infection.
