FOOD INTAKE, GROWTH AND FEED UTILIZATION OF PUFFERFISH (TAKIFUGU FASCIATUS) AFTER DIFFERENT SALINITY PRETREATMENTS

A 4-week trial was conducted to assess the further effects of salinity on growth and feed utilization of pufferfish Takifugu fasciatus (82.35±2.97g). The fish were transferred to freshwater directly after reared in 8‰, 18‰ and 35‰ salinity for more than 2 months. Triplicate groups of each treatment were fed practical diets with 50.5% protein (dry matter) to satiation. The growth, food intake and food conversion ratios of pufferfish were investigated and also compared results between present study and prior salinity experiment. The results indicated that high salinity (35‰) could suppress the growth of pufferfish while compensatory growth was observed when fish were free from salinity stress. Food intakes increased with prior experimental salinity and its range was 1.83%-2.51% and there were significant differences among treatments (P0.05); Specific growth rations exhibited the same tendency as food intake and increasing from 0.83% to 1.28% and there also showed significant difference; however, food coefficient decreased with prior salinity and from 1.67 to 1.47. Comparison between present SGR in freshwater and pre-experiment SGR in corresponding salinity showed significant differences except the fish in low salinity (8‰) of prior trail. The results observed in the pre-and present trials suggest that 1-year old pufferfish growth fast and scarcely suffer disease, therefore, 8‰ salinity could be assumed as suitable environment for this species in the stage.