Optimal Dietary Protein Levels in Juvenile Electric Blue Cichlid (Sciaenochromis fryeri)

Abstract

A feeding trial was conducted to determine the dietary protein requirement of juvenile electric blue cichlids (Sciaenochromis fryeri). Groups of fish (0.50±0.01 g) were fed one of four isocaloric diets containing protein levels ranging 35-50% for 12 weeks. According to the broken-line model, the dietary protein requirement was estimated as 38.8%. The feed conversion ratio ranged from 1.73 in the 50%-protein group to 2.16 in the 35% group. There were statistically significantly dif- ferences in feed intake and protein efficiency ratio. In general, the protein efficiency ratio decreased as the dietary protein level increased. For optimum growth, feed conversion, and pro- tein utilization, a diet containing 39-40% protein, 11% crude lipid, and 20.7 MJ gross energy/kg diet is recommended for juvenile S. fryeri.