Effects Of Animal And Plant Protein Sources On Feed Intake, Growth And Protein And Lipid Metabolism Of Japanese Flounder, Paralichthys Olivaceus

Five feeding trials were conducted to investigate the effects of protein (fish protein and soy protein) and non-protein compounds such as soybean oligosaccharides (SBOS), non-starch polysaccharide (NSP) and cholesterol in animal and plant protein sources on feed intake, digestibility, absorbing, anabolism, catabolism and excretion of Japanese flounder (Paralichthys olivaceus). The objectives of the present study were to investigate why aquatic animal can not effectively utilize the plant protein sources, and how to increase the dosage of plant protein sources in aquatic feed by pretreatment and nutritional combination. The present studies include the following: (1) Effects of replacing fish meal (FM) with soy protein concentrate (SPC) on feed intake (FI), growth and protein and lipid metabolism of Japanese flounder; (2) Supplemental effects of coated crystalline amino acids (CAA) on growth, body composition and key metabolic enzymes of Japanese flounder; (3) Effects of animal and plant protein sources on FI, growth and protein and lipid metabolism of Japanese flounder; (4) Supplemental effects of SBOS on FI, growth and protein and lipid metabolism of Japanese flounder; (5) Supplemental effects of cholesterol on FI, growth, protein and lipid metabolism of Japanese flounder fed various protein sources-based diets; (6) Preliminary study on hypocholesterolemic effect of soy protein sources. The results were summarized as follows:⑴Using FM and SPC as protein sources, eight isonitrogenous (crude protein 49%) and isocaloric (gross energy 19KJ/g) practical diets were formulated to meet the protein and energy requirements of Japanese flounder. Among these diets, six experimental diets (S0, S25, S50, S75, S87.5 and S100) without amino acid (AA) supplementation were formulated to contain graded levels of SPC, as a substitute for FM, at protein replacement levels of 0, 25, 50, 75, 87.5 and 100%, and the rest diets (S75CAA, S75CAP-AA) were supplemental with a 3.09% essential amino acid (EAA) mixture in the forms of CAA or cellulose acetate phthalate encapsulated amino acids (CAP-AA) based on the Diet S75. Each diet was randomly assigned to triplicate groups of 45 fish (initial weight 2.45±0.01 g) per aquarium. Fish were maintained in flow-through aquaria at water temperature ranged from 18.0 to 26.0...