Sirusa Kritsanapuntu*,Nilnaj Chaitanawisuti
This study presented the first research conducted on the use of tuna by-product from the tuna canning industry for growing hatchery-reared juvenile spotted babylon (Babylonia areolata) to marketable sizes. A feeding trial was conducted to evaluate the effects of five levels of partial to complete replacement of fishmeal by tuna-cooking liquid effluent on growth performance and body composition of snails reared under a flow-through culture system over 150 days. Five experimental diets were formulated to contain 0%, 25%, 50%, 75%, and 100% of tuna-cooking liquid effluent (diets TCLE0, TCLE25, TCLE50, TCLE75, and TCLE100, respectively). Results showed that significant differences (P<0.05) in specific growth rate, feed conversion ratio, and protein efficiency ratio were observed among the snails fed diets containing 0, 25, 50, 75, and 100% replacement of fishmeal by tuna-cooking liquid effluent meal. The best specific growth rate, feeding conversion ratio, and protein efficiency ratio were found in the group of snails fed a diet of TCLE100, while the lowest specific growth rate, feeding conversion ratio and protein efficiency ratios were found in snails fed diets of TCLE0 and TCLE25. No significant differences (P>0.05) in final survival rate was found among snails fed all experimental diets. Survival rates ranged from 94.2%-94.6%. Moreover, the snails fed diets of 100% replacement of fishmeal by tuna-cooking liquid effluent meal (TCLE100) showed the highest protein content, lowest lipid content, and lowest cholesterol content compared with snails fed all the other diets. The whole body composition of snails fed TCLE50 was significantly higher (P<0.05) in saturated fatty acid, monounsaturated fatty acid, polyunsaturated fatty acid, unsaturated fatty acid, eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), arachinodic acid (ARA), n-6 PUFA, and n-3 PUFA contents than the groups of snails fed all the other diets The results of this study indicated that tuna-cooking liquid effluent meal can completely replace fishmeal protein with positive effects on snail growth performance and whole body composition.