Plant protein-based diets can replace a fish meal-based diet for sustainable growth and body composition of zebrafish (Danio rerio).

This 3 × 2 factorial study involving three diets at two stocking densities tested the effect of replacing fish meal (FM) with either soybean meal (SBM) or rapeseed meal (RSM) in diets on growth and body composition of zebrafish (Danio rerio). Fish were fed three times daily for eight weeks. Morphometric and water quality parameters were also determined. The survival rate of the fish ranged from 95.2 - 97.8%. The water quality remained within the acceptable limits for tropical aquaculture. The stocking density did not show any significant difference (p>0.05) for the length and weight of the fish. The length, weight and condition factors were significantly higher (p<0.05) in the fish fed FM based diet. The fish length and weight related well (R2) across the diets but this was more significant for RSM than those fed the other two diets. The weight gain (WG), feed conversion ratio (FCR) and protein intake (PI) were significantly higher (p<0.05) in the fish fed the FM based diet than the other diets. No significant differences observed (p>0.05) in the specific growth rate (SGR), food intake (FI) and protein efficiency ratio (PER) among the fish fed the three diets. The crude protein CP, nitrogen-free extract (NFE) and ash contents of these fish did not differ significantly (p>0.05). However, the ether extract (EE) of the fish fed SBM diet was significantly lower (p<0.05 than the other two diets. It appears that both SBM and RSM as sustainable source to partially FM in the diets of zebrafish and similar fish species.View Full Text