Interaction of feeding frequency and feeding rate on growth, nutrient utilization, and plasma metabolites of juvenile genetically improved farmed Nile tilapia, Oreochromis niloticus

We evaluated the possible interaction between feeding frequency (FF) and feeding rate (FR) on growth, nutrient utilization, body composition, and plasma metabolites of juvenile Nile tilapia, Oreochromis niloticus (6.57 g). We tested three FFs: two, four, and six times a day, and two FRs: apparent satiation (AS) or restricted regime (RR), following a completely randomized design in a factorial arrangement, in quadruplicate. The daily weight gain and specific growth rate were 56 and 19% higher in fish fed to AS than in fish fed under the RR, respectively. However, feed efficiency was 14% higher in fish fed in the RR. Fish fed to AS presented the highest body lipid (8.92%), whereas the fish fed in the RR showed the lowest (6.64%). Glucose and triglycerides were also higher in fish fed to AS. The protein retention ratio was highest in the RR (49.17% vs. 42.51%, respectively). Fish fed to AS showed 34% more body protein but 62% more body fat than the fish fed in the RR. There was no difference in feed efficiency or weight gain regarding FF, regardless of the FR. Therefore, feeding Nile tilapia juveniles twice a day is enough to achieve optimum growth.