Performance of freshwater angelfish (Pterophyllum scalare) with different crude protein levels in diet

Abstract

The study was performed at Ornamental Fish Laboratory (CAUNESP) to evaluate growth of young freshwater angelfishes for 84 days, with isocaloric (3,338.84 kcal DE.kg^-1) diets varying the crude protein level (CP). Fish, in a total of 400 specimens, were stocked in 30 liters tanks and distributed in four treatments (26%, 28%, 30% and 32%PB), two groups of weight (100-150 mg and 151-200 mg) and five replications. Data were analyzed using ANOVA and polynomial regression (p < 0.05). The most important water parameters were monitored and showed acceptable levels for the species growth. Third order polynomial regression were significant for final weight (FW), weight gain (WG) and food consumed (FC). Fish fed 26%CP showed the worst results. No difference between fish fed 28% and 30%CP was seen. Fish fed 32%CP showed better results. Feed conversion rate (FCR) showed negative linear effect, and specific growth rate (SGR) presented positive linear effect, both showing better results when increasing CP. Protein efficiency ratio (PER) and survival showed no statistical differences. CP levels above 32% may result in better values for FW, WG, FC, FCR and SGR.