The dietary protein requirements of Cichlasoma synspilum Hubbs, 1935 (Pisces: Cichlidae) fry

A 12 week feeding trial was conducted in a closed recirculating system with Cichlasoma synspilum (Hubbs) fry (280 mg) in order to determine their protein requirements. Six diets containing increasing protein levels (30, 35, 40, 45, 50 and 55%) were formulated using brown fish meal as the protein source. The fish were fed by hand daily at a rate of 6% body weight: at 2-week intervals, the fish were bulkweighed and the feeding rate was adjusted accordingly After 90 days, a direct relationship was observed between dietary protein content and fmal body weight, weight gain, and specific growth rate (P < 0,05), with the best results for diets containing 50,45,40 and 55% of protein: feed intake, food conversion ratio, protein efficiency ratio, carcass nitrogen deposition and apparent N utilization were also statistically higher (P < 0,05) for fish fed diets with 50, 45, 40 and 55% of protein content. The lower performance was obtained in those fish fed diets with 30 and 35% protein content. Applying the broken-line response method with SGR data, the protein requirement of C. sytispilum fry was established as 40.81%.