Potential of replacing fish meal with cottonseed protein concentrate in black sea bass (Centropristis striata) diet

Replacement of fish meal in aquafeed has been recognized asa key to sustainable development of aquaculture industry due to the fast expansion of aquaculture industry in the last 40 years. Various plant ingredients, including cottonseed meal, were tested as fish meal substitute in fish feed, however, complete replacement of fish meal with plant ingredients in carnivorous fish feed remains a problem. Cottonseed protein concentrate (CPC) is a novel cottonseed protein ingredient with high protein content and low free gossypol, however, knowledge about CPC as a fish meal substitute in carnivorous fish feed is scarce. In this study, a 10-week feeding trial was conducted to evaluate the potential of replacing fish meal with CPC in black sea bass (Centropristis striata) diet. A single factor experiment including four fish meal levels was done. A control diet (C) was formulated to contain 35% fish meal. In the other three diets, 40% (R40), 60% (R60) and 80% (R80) of the fish meal in diet C were replaced with CPC, respectively. Each diet treatment was triplicated. Initial body weight of black sea bass was (29.5±0.5) g. During the trial, fish were fed with the test diets twice daily. The results showed that the replacement of fish meal with CPC did not significantly affect feed intake, growth, feed utilization efficiency, body composition and wastes of nitrogen, phosphorus and carbon. However, the ratio of fish meal consumption to fish production (RCP) declined with the decrease of dietary fish meal level. According to a multiple dimension analysis based on growth, feed cost, feed utilization efficiency, environment impact and RCP, the farming benefits of black sea bass fed diet R80 was different from those fed diets R40 and R60. This study reveals that fish meal content in black sea bass diet could be reduced to 7% by CPC inclusion.