Estimation of nutrient load in the wastes of Nile tilapia reared in cages and fed soybean meal-based diet supplemented with different levels of phytase enzyme

With the rapidly increasing trend of cage fish farming in freshwater, practices to enhance fish farming sustainability are increasing. We estimated how different levels of phytase enzyme (0, 500, 1000, 2000, 4000 FTU kg−1) affects the growth performance and nutrient load of tilapia (5.2 ± 0.1 g) reared in 15 cages for 180 days. The experimental design followed a completely randomized approach, with three replicates. The most significant increase in growth was observed in the groups that were given a diet supplemented with phytase at 4000 FTU kg−1 of feed. These groups reached a slaughter size of 420.2 ± 6.6 g and experienced weight gain approximately three times greater than the control group (final weight: 146.8 ± 4.8 g). The phosphorus and nitrogen load for groups that were given diets with a phytase supplement of 4000 FTU kg−1 of feed were 54% and 32% lower, respectively, compared to the control group and other diets that were supplemented with phytase. Hence, it is advisable to add phytase at a concentration of 4000 FTU kg−1 feed in order to improve the growth performance and increase the availability of nutrients, while also minimizing waste in the cage culture of tilapia.