Evaluation of the Optimal Protein Required in Granulated Microdiets for Rockfish (Sebastes schlegeli) Larvae

Abstract

Protein is an essential nutrient that supports fish growth, and the inadequacy in formulating their diets with an optimum protein level can deteriorate their growth performance. The protein requirement in granulated microdiets was estimated for rockfish (Sebastes schlegeli) larvae. Five granulated microdiets (CP42, CP46, CP50, CP54, and CP58) containing 42% to 58% crude protein levels with a 4% increment at a constant gross energy level (18.4 kJ/g diets) were prepared. The formulated microdiets were also compared with imported microdiets, Inve (IV) and love larva (LL) from Belgium and Japan, respectively, and a locally marketed feed (crumble). At the cessation of the study, the survival of larval fish was not different ( P > 0.05 ), but the weight gain (%) of fish fed the CP54, IV, and LL diets was significantly ( P < 0.0001 ) higher than that of larval fish fed the CP58, CP50, CP46, and CP42 diets. The crumble diet achieved the poorest weight gain of larval fish. Furthermore, the total length of rockfish larvae fed the IV and LL diets was significantly ( P < 0.0001 ) longer than that of the fish fed all other diets. The chemical composition of the fish’s whole body, except for ash content, was not influenced by the experimental diets. The experimental diets affected essential amino acid profiles, such as histidine, leucine, and threonine, and nonessential amino acid profiles, such as alanine, glutamic acid, and proline of the whole body of larval fish. Conclusively, based on the broken line analysis of weight gain of larval rockfish, protein requirement in granulated microdiets was estimated to be 54.0%.

Effects of Bacillus halophilus on growth, intestinal flora and metabolism of Larimichthys crocea

“…Many fish have a high demand for proline. In order to attain the highest growth, enough proline must be obtained from the diet, so it is often classified as a conditionally essential amino acid or functional amino acid for fish [ 85 ]. L-Glutamic-gamma-semialdehyde was positively associated with Bacteroides , as Bacteroides increase.…”

Effects of Dietary Protein and Lipid Levels in Practical Formulation on Growth, Feed Utilization, Body Composition, and Serum Biochemical Parameters of Growing Rockfish Sebastes schlegeli

“…7 Vitamin premix (mg/kg or IU/kg diet): vitamin A 7,500.00 IU, vitamin D 1,500.00 IU, vitamin E 60.00 mg, vitamin K3 18.00 mg, vitamin B1 12.00 mg; vitamin B2 12.00 mg, vitamin B12 0.10 mg, pantothenate acid 48.00 mg, niacin 90.00 mg, folic acid 3.70 mg, D-biotin 0.20 mg, pyridoxine 60.00 mg, and vitamin C 310.00 mg. 8 Mineral premix (mg/kg diet): Zn 35.00 mg, Mn 21.00 mg, Cu 8.30 mg, Fe 23.00 mg, Co 1.20 mg, I 1.00 mg, and Se 0.30 mg. 9 Ethoxyquin; Weifang Jiayijia Bio-tech Co., Ltd., Weifang, China. 10 Henan Jin Yuan Biological Technology Co., Ltd., Zhengzhou, China. 11 Shandong Longxing Biological Engineering Co., Ltd., Jinan, China.…”

“…Because of its economic and ecological importance, efforts have been made to improve the productivity of rockfish, including seed production, nutrition regulation, vaccine development, and so on. The recent research on nutritional regulation mainly focuses on dietary macronutrients requirements, especially protein (54.0%, [ 10 ]) and lipid (17.3%, [ 11 ]). In addition, an early study reported that the optimum protein and lipid levels for growth and feed utilization of rockfish fry were 50% and 15%, 45% and 19%, pointing to the obvious protein-sparing effect of lipid [ 12 ].…”