Effect of different levels of fermented water hyacinth leaf meal on feed utilization and performance of juvenile Nile tilapia

This study was conducted to evaluate the effects of different inclusion levels of water hyacinth leaf meal fermented with Aspergillus niger on feed utilization efficiency and growth performance of Nile tilapia (Oreochromis Niloticus L.). Fermented water hyacinth leaf (FWHL) at 0, 10, 20 and 30% inclusion levels were incorporated into four isonitrogenous (35% CP), and isoenergetic (18 KJ g-1 g) test diets. The fishes were stocked in 80 liters aquarium units, in a closed, recirculating indoor system. The diets were fed to triplicate groups of fish fingerlings (1.6 g average body weight) twice a day, at 6% of body weight/day, for three months. The study demonstrated that Nile tilapia fed FWHL at levels 30% had a significant negative impact (P<0.05) on weight gain, specific growth rate, feed utilization efficiency, and whole body composition. But, there were no significant changes between diets supplemented with 10% and 20% FWHL when compared with the control group. Therefore, supplementation of fermented water hyacinth leaf meal to diets of Nile tilapia is recommended up to 20% because it is cheaper than fish meal and corn.