EFFECTS OF HYDROLYSABLE TANNINS ON THE GROWTH PERFORMANCE, TOTAL HAEMOCYTE COUNTS AND LYSOZYME ACTIVITY OF PACIFIC WHITE LEG SHRIMP Litopenaeus vannamei

ABSTRACT: The present study was conducted to evaluate the efficacy of the dietary inclusion of commercial hydrolysable tannins (HT) on the growth performance and haemato-immunological parameters of Pacific white shrimp (Litopenaeus vannamei). Four isonitrogenous and isolipidic practical diets were formulated to contain 0; 0,1; 0,2 and 0,3% of HT obtained from the sweet chestnut (Castanea sativa). The 0,3% HT was designed to be included in a diet with a low level of fish meal (FM) (7,5%), while others included 10% FM. A total of 240 post larvae shrimp with an average initial body weight of 4.24 ± 0,03 g were randomly stocked in four groups, with four replicates per treatment and 15 shrimp per aquaria tank. Results showed that there were no significant differences in terms of final biomass, final mean weight, survival, weight gain (WG), feed conversion ratio (FCR) and thermal growth coefficient (TGC). However, biologically, a better performance was observed when the diets had higher inclusion levels of HT. Shrimp fed diets with 0,2 and 0,3% HT had a significantly higher total haemocytes count, and those fed the diet with 0,2% HT also had a significantly higher lysozyme activity, compared to shrimp from the control group. These results indicated that 0,2 and 0,3% HT could remarkably improve the growth performance and the haemato-immunological parameters of Pacific white shrimp, and have potential functional properties when included in commercial diets for shrimp.