Utilization of fermented skipjack tuna viscera as a dietary protein source replacing fish meal or soybean meal for juvenile abalone Haliotis discus hannai

This study was carried out to evaluate the utilization of fermented skipjack tuna viscera (FSTV) in the diet for juvenile abalone Haliotis discus hannai. Lactobacillus bulgaricus was used for fermentation of skipjack tuna viscera. Eight isonitrogenous (about 30% crude protein) diets were formulated to include different levels (0%, 10%, 20% and 30%) of FSTV as a replacer of either dietary fish meal or soybean meal. Three replicate groups of abalone were fed the experimental diets containing different levels of FSTV for 7 weeks. The inclusion of FSTV up to 30% in fish meal-based diet had no significant effect on survival, body weight, shell growth, and proximate composition of abalone (P>0.05). Weight gain of abalone fed the diet substituting 10% FSTV for soybean meal was not significantly different to that of abalone fed the control diet, however this value decreased in abalone fed the 20% and 30% FSTV (P<0.05).The contents of crude protein and lipid of soft body in abalone fed soybean meal-based diets were significantly affected by dietary FSTV level (P<0.05). The results of this study indicate that FSTV can be used as a partial substitute protein source for fish meal or soybean meal in the formulated diet for juvenile abalone.