title: Use of soybean meal and papain to partially replace animal protein for culturing three marine fish species: Fish growth and water quality.
abstract: The main aim of this study was to investigate the feasibility of using soybean meal added with papain to replace half of the fishmeal used in the moist pellets (49% fishmeal and 45% trash fish) developed by the Hong Kong Agriculture, Fisheries and Conservation Department (AFCD) for culturing marine fish. Gold-lined seabream (Rhabdosargus sarba), brown spotted grouper (Epinephelus bleekeri) and pompano (Trachinotus blochii) were farmed at one of the research stations (Kat-O) of AFCD, for a period of 340 days. Results indicated that diets containing papain resulted in better fish growth (reflected by relative weight gain and feed conversion ratio) than diets without papain. In general, wet weight gain of fish depends on the amount of papain added in diet rather than the diet composition. Soybean used in conjunction with papain also contributed to a more effective growth than fish fed with the moist pellets alone. A laboratory experiment (using tanks) was conducted to study the effects of the diets on concentrations of ammonia, nitrite and nitrate in the tank water. Results showed that concentrations of ammonia and nitrate were significantly lower (p < 0.05) when the fish were fed with papain-supplemented (with or without soybean meal) diets. It is envisaged that by using plant protein incorporated with enzymes could promote better growth of marine fish and lower the adverse impact of trash fish and fishmeal on water quality of the mariculture zones.
authors: Consortium on Health, Environment, Education and Research (CHEER), and Department of Science and Environmental Studies, The Education University of Hong Kong, Tai Po, Hong Kong, China.
authors: W Y
authors: WY
authors: Mo
authors: Consortium on Health, Environment, Education and Research (CHEER), and Department of Science and Environmental Studies, The Education University of Hong Kong, Tai Po, Hong Kong, China.
authors: R S S
authors: RSS
authors: Lau
authors: Agricultural, Fisheries and Conservation Department, Hong Kong, China.
authors: A C K
authors: ACK
authors: Kwok
authors: Consortium on Health, Environment, Education and Research (CHEER), and Department of Science and Environmental Studies, The Education University of Hong Kong, Tai Po, Hong Kong, China; Key Laboratory for Heavy Metal Pollution Control and Reutilization, School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen, China; School of Environment, Jinan University, Guangzhou, China. Electronic address: minghwong@eduhk.hk.
authors: M H
authors: MH
authors: Wong
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D000818:Animals; D017756:Aquaculture / Q000379:methods*; D006723:Hong Kong; D010206:Papain / Q000378:metabolism*; D010473:Perciformes / Q000254:growth & development* / Q000378:metabolism*; D013025:Glycine max / Q000378:metabolism*; D060753:Water Quality
chemical_list: D010206:Papain
keywords: Brown spotted grouper; Gold-lined seabream; Pompano; Trash fish