Evaluation of Dietary Anti-nutritional Factors and Amino Acids Supplementation on Growth, Feed Efficiency Ratio, and Apparent Digestibility of Japanese Flounder (Paralichthys olivaceus) at Equal Feed Intake

Abstract

A 30-day feeding trial was conducted to evaluate the anti-nutritional factors in fish meal-based diets, and limiting amino acids in soybean meal-based diets on growth, feed efficiency ratio (FER), and nutrient apparent digestibility (AD) of Japanese flounder (Paralichthys olivaceus) at equal feed intake. Four isonitrogenous and isoenergetic diets were formulated: Diet 1 contained fish meal as the main dietary protein source; Diet 2 was based on Diet 1 and supplemented with anti-nutritional factors; Diet 3 contained both fish meal and soybean meal as main protein source; Diet 4 was based on Diet 3 and supplemented with crystalline amino acids. All diets were assigned to triplicate groups of 5 fish per aquarium. Results from Diet 1 showed that force-feeding was a possible method to rear Japanese flounder with high FER and 100% survival rate. In the first three periods (4 days/period), weight gain (WG) and FER of fish fed Diets 2, 3 & 4 were significantly lower (P<0.05) than in fish fed Diet 1. After 30 days of the feeding trial, WG and FER of fish fed Diets 3 & 4 were significantly lower than in fish fed Diet 1 (P<0.05). No significant difference in WG and FER was observed either between fish fed Diets 1 & 2, or between fish fed Diets 3 & 4. The AD of dry matter and crude lipid of fish fed Diets 3 & 4 were significantly lower than those of fish fed Diet 1 (P<0.05). Results indicated that supplementation of anti-nutritional factors in a fish meal-based diet, or supplementation of crystalline amino acids in a soybean meal-based diet did not significantly affect growth performance of Japanese flounder by force feeding.