Determination of optimum dietary protein level for blue dolphin (Cyrtocara moori, Boulenger 1902)

An experiment was designed to determine the optimum dietary protein level of a freshwater ornamental fish, blue dolphin (Cyrtocara moori, Boulenger 1902). Four isocaloric fish meal based diets ranging from 25% to 50% in protein were fed to triplicate groups of blue dolphin for 8 weeks. Fish (initial weight, 1,50 g) were reared in twelve 80 L aquarium with biological filter and controlled temperature (26.7 °C), in stocking density of ten fish/aquarium. Results showed that dietary protein level significantly influenced final weight, weight gain and specific growth rate of fish. Maximum growth of fish was observed in the 40% protein diet, although this was not significantly different from the 30%, 35% and 45% protein diets (P > 0.05). Specific growth rate and feed efficiency increased from 25% to 40% protein, and thereafter decreased for diet 45% protein. There were statistically significantly differences in feed intake among treatments (P < 0.05). Fish fed with the highest protein diet had lower percentage daily feed consumption values than those of fish fed with the lowest protein diet. Under the experimental conditions applied, juvenile blue dolphin, appear to require 40% dietary protein for optimized growth.Keywords: Blue dolphin, Cyrtocara moori, protein requirements, ornamental fish nutrition, growth.