Nutritional and functional benefits of Gracilaria tenuistipitata in aquafeed: Impacts on growth, hemato-biochemical profile, and economic efficiency in Nile tilapia culture

Macroalgae are a valuable source of protein and bioactive compounds like antioxidants, are gaining attention for their nutritional and functional benefits in aquafeed. The study was undertaken to evaluate the efficacy of red algae, Gracilaria tenuistipitata (GT) as aquafeed in Nile tilapia fish culture. Fish were fed for 56 days with 2.5 % inclusion of G. tenuistipitata in diet demonstrated notable difference in growth attributes, and feed utilization parameters compared to the control and other treatment groups. Fish fed a diet with 2.5 % GT inclusion showed a significant increase in erythrocyte count, hemoglobin concentration, packed cell volume, and red blood cell indices compared to the control group. In contrast, these parameters significantly decreased (p < 0.05) at the 5 % inclusion level. The regression analysis indicated that an optimal inclusion level of GT in the diet, ranging from 2.52 % to 2.74 %, is recommended based on improvements in weight gain, specific growth rate, and hematological parameters. The results obtained on histology showed no significant alteration (p > 0.05) of liver architecture in 2.5 % GT diet supplementation. PCA results revealed that supplementing with 2.5 % GT positively influenced both nutritional and hemato-biochemical parameters. Among the treatment groups, 2.5 % GT supplementation demonstrated positive economic efficiency by reducing production costs, achieving a high net return, and enhanced eco-friendly ecosystem. Finally, incorporating 2.5 % G. tenuistipitata in Nile tilapia diets is the most recommendable in terms of growth, physiological performance, and economic profit index.