Abstract:
Aquaculture plays a critical role in global food security, and optimizing nutrition is essential for enhancing fish health and growth performanceThis study evaluates the effects of liquid phytase (Ronozyme® HiPhos; 20,000 FYT) on growth, feed efficiency, phosphorus retention, economic return, and immune response in Nile tilapia (Oreochromis niloticus) through laboratory and field trials.
Methodology: In the laboratory trial, triplicate groups of mixed-sex Nile tilapia (initial weight 18.55 g) were fed for 3 months on either a phosphorus-rich diet (10 kg mt^-1) or a phosphorus-free extruded diet supplemented with Ronozyme® HiPhos at varying levels (0, 1000, 1500, 2000, and 3000 FYT kg^-1). Performance metrics, as well as flesh and bone phosphorus concentrations, significantly increased with dietary HiPhos levels up to 2000 FYT kg^-1. Immune parameters, including lysozyme activity, respiratory burst, ACH50, phagocytic cells, superoxide dismutase, and phenoloxidase, were significantly enhanced, while liver enzyme activity decreased. In the field trial, adult all-male Nile tilapia (70 g) were stocked in 2-m³ hapas and fed for 80 days on a commercial extruded diet supplemented with either 10 kg monocalcium phosphate (MCP) mt^-1 (control), 2000 FYT HiPhos kg^-1, or 1000 FYT HiPhos kg^-1 plus 5 kg MCP mt^-1.
Results: Our findings indicated that the 2000 FYT HiPhos diet was more profitable than the control diet.
Conclusion: This research demonstrates that supplementing 2000 FYT HiPhos per tonne of extruded feed can effectively replace 10 kg of MCP without compromising the growth performance, body composition, or physiological functions of farmed Nile tilapia.