Evaluation of a practical tilapia feed using a saturation kinetic model

1. 1. Two practical Tilapia feeds were fed in ten graded levels to three replicate groups of Oreochromis niloticus fingerlings (mean weight 3 g). Ten fish per group were tested for 5 weeks in 10 gallon (371) aquaria. 2. 2. The dietary nutrient response of the two practical tilapia feeds fit the saturation kinetics model. O. niloticus weight gain and net nutrient (crude protein gross energy, crude fat) deposition were described as a function of the dietary nutrient intake graphically and numerically. 3. 3. Comparison of the abilities of the two diets and their nutrients to promote O. niloticus weight gain or net nutrient deposition were based on parameters calculated from the saturation kinetics model as follows: (1) R_max (maximum response such as weight gain or net nutrient deposition) of O. niloticus fingerlings as a result of feeding a specific diet or nutrient, (2) K_0.5 (dietary nutrient intake level that produced half maximum response by the fish), and (3) Ir = 0 (the dietary or nutrient intake at maintenance level no gain no loss). 4. 4. Application of the model may provide a useful comparison of diets and their nutrients. Additionally, it may provide information concerning maximum efficiency, overall efficiency, and rates of utilization.