Effect of Replacing Canola Meal for Fish Meal on the Growth, Digestive Enzyme Activity, and Amino Acids, of Ovate Pompano, Trachinotus ovatus

Ovate Pompano (Trachinotus ovatus) is one of the most highly valued aquaculture species due to its commercial value, rapid growth, high quality flesh, and suitability for cage culture. Ovate Pompano were fed diets containing graded levels of canola meal to replace the fish meal. Six diets containing 45% crude protein and 12% crude lipid were fed to the fish during the 8-week feeding trial. Weight gain of the fish was negatively related to canola meal ratio in the diets. Protein efficiency and feed conversion ratio were inversely related to the canola meal inclusion in the diets. The crude lipid of the fish was positively related to the dietary canola meal, while an inverse trend was found in the crude protein of the fish. Protease activity and amylase activity showed a similar trend to the crude protein, while the lipase activity showed an inverse trend. No significant differences were observed in the moisture, ash, or fillet yield of the fish among dietary treatments. The “delicious amino acid ”i.e. those eliciting Umami flavor (UEAA), e.g. glutamic acid and others, essential amino acid, and total amino acid content of the fish were inversely related to the canola meal ratio in the diets. The results of the experiment indicated that canola meal can replace 18.17 % fish meal without affecting growth. Higher substitution levels of canola meal produced adverse influences on growth, digestive enzyme activity, and amino acid content of Ovate pompano.