Re-Evaluation of the Effect of Daily and Within-Day Mixed Feeding Schedules of Varying Dietary Protein Content on the Growth Performance of Nile Tilapia Fry Using Constant Ingredient Composition

Abstract

Feed is the main cost to aquaculture production, management practices, and feeding strategies are aimed at optimizing feed intake and efficiency. Knowledge about feeding protocols and behavior habits may be of an interest for optimization of aquaculture production, reducing aquaculture waste output and to achieve sustainability. This study investigated trends based on daily feeding schedules. Two growth trials were conducted to investigate the effect of day to day mixed feeding schedules on the growth performance of Nile tilapia. Three experimental isocaloric diets of low (A; 20%), regular feeding (RF; 30%) and high (B; 40%) protein levels were prepared. In the first trial, fish were continuously fed a normal protein diet (RF-30%), alternate feeding of a 1-day diet A; followed by a 1-day diet B (1A/1B) and alternate feeding of 2-day diet A; followed by a 2-day diet B (2A/2B) and a 3-day diet A followed by a 3-day diet B (3A/3B) were tested. In the second trial, three times a day feeding schedules were continuously examined by feeding tilapia with diet (RF), alternate feeding of diet A in the morning followed by diet B in the afternoon (A am/B pm) and alternate feeding of diet B in the morning followed by diet A in the afternoon (B am/A pm). In the first trial, the best specific growth rate (SGR) was observed for fry maintained on the RF diet followed by (2A/2B). In the second trial, the mixed feeding schedule (A am/B pm) showed the best SGR and feed conversion ratio (FCR) followed by a RF diet. The overall ranking of daily mixed feeding schedules was the highest for RF diet with the mixed feeding schedule of (3A/3B). In addition, day to day mixed feeding schedules showed that fish utilize high protein diet more efficiently during an afternoon phase rather than a morning phase. The results from this study show that, the daily feeding schedule achieved better growth performance, nutrients retention and feed utilization of Nile tilapia rather than alternate feeding schedules between days for Nile tilapia.