Effect of incorporation of Spirulina platensis into fish diets, on growth performance and biochemical composition of Nile Tilapia, Oreochromis niloticus

The aquaculture industry is facing a growing need for a cost-effective, sustainable, and highly nutritious alternative to fish meal (FM) due to the increasing gap between supply and demand. This study investigated the effect of substituting (FM) with probiotics ( Spirulina platensis ) in fish feed on the survival, growth, and biochemical parameters of Oreochromis niloticus. Live tilapia fingerlings were stocked in 100-l glass aquaria. The feeding regimen consisted of four controls: commercial feed (C), formulated feed with FM (FMR 0 ), and formulated feeds with 25% and 50% replacement of FM (FMR 25, and FMR 50 ), respectively. The trial groups included FMR 25 S 5 (25% FM replacement with 5% Spirulina), FMR 50 S 5 (50% FM replacement with 5% Spirulina), FMR 25 S 10 (25% FM replacement with 10% Spirulina), and FMR 50 S 10 (50% FM replacement with 10% Spirulina). The trial period lasted for 24 weeks. Weight gain (WG) was most pronounced in FMR 50 S 10 (p < 0.05). The SGR (specific growth rate) was highest for FMR 50 S 10, FMR 50 S 5, and FMR 50. A similar pattern was exhibited in the FMR 50 S 10 group for length gain (LG). The protein efficiency ratio (PER) values were maximum in FMR 50, FMR 50 S 5, and FMR 50 S 10. FMR 25 S 10, FMR 0, and FMR 25 exhibited the highest feed intake (FI) (p < 0.05). Trial diets supplemented with Spirulina enhanced the activities of SOD, CAT, and MPO. FMR 25 S 10 exhibited the highest GPx activity and appreciable flesh quality. Collectively, S. platensis enhanced growth and feed utilization and modulated biochemical endpoints in feeds.