EFFECTS OF ADDING CHITOSAN QUATERNARY AMMONIUM SALT IN DIETS ON THE GROWTH PERFORMANCE AND NONSPECIFIC IMMUNITY OF LITOPENAEUS VANNAMEI

The current study investigated growth performance, nonspecific immunity of white shrimp (Litopenaeusvannamei) by supplementation of chitosan quaternary ammonium salt in diets with graded levels of 0.0% (control group), 0.05%, 0.10%, 0.15% and 0.20% chitosan quaternary ammonium salt. Each diet was randomly fed to four cages of white shrimp with initial average weight (3.820.34) g in 20 cages (2.5 m1.5 m1 m) for 8 weeks. The result showed that the chitosan quaternary ammonium salt addition significantly improved growth performance with the best effect of weight gain and SGR in 0.15% group. The activity of lysozyme, alkaline phosphatase and phenol oxidase were significantly increased in the 0.1%, 0.15% and 0.20% trial groups (P0.05). Chitosan quaternary ammonium salt effectively improved the ability of shrimp to resist the vibrio parahaemolytics's infection (P0.05) with the best performance in 0.15% trial group that is 33.24%. These data indicate that chitosan quaternary ammonium salt can significantly improve the growth performance and the ability resisting infection, and the optimum amount under current experimental condition is 0.15%.