Substitution of fish meal with sunflower seed meal in diets for Nile tilapia (Oreochromis niloticus L.) reared in earthen ponds

摘要

This study investigated sunflower seed meal (SSM) as dietary protein replacement of fish meal (FM) for Nile tilapia (Oreochromis niloticus) juveniles (initial mean weight of 19.8 ± 6.3 g) reared in earthen ponds for 210 days. SSM replaced 25%, 50%, 75%, and 100% (i.e., D_(25), D_(50), D_(75), and D_(100), respectively) of FM in an isonitrogenous and isocaloric diet. The optimum FM replacement level of D_(25) as predicted by the equation y = 177.5 + 26.5x - 7.9x~2 yielded an optimum weight of about 184 g within 100 days. Thus D_(25) was the most effective SSM level for Nile tilapia growth in earthen ponds. Fish growth declined as SSM exceeded D_(25). The length-weight relationship (r >= 90%) depicted an isometric fish growth. Nutrient utilization parameters were similar in all the diets except for D_(100). The protein content offish carcass was highest in the control and D_(25), while fiber level was highest in D10o-Amino acids imbalance and high fiber content could have reduced the fish growth atD_(50), D_(75), and D_(100).