Effects of Wheat Flour Substitution by Sorrel (Hibiscus sabdariffa) Meal on Growth Performance, Feed Efficiency and Survival of Nile Tilapia (Oreochromis niloticus) Fry

Abstract

The present study evaluated the effects of substituting wheat flour with sorrel meal in the diet of Oreochromis niloticus fry. A total of 180 fry, with an average weight of 0.09 g, were reared in nine 50 L tanks. Three diets with identical protein content (30%) but different incorporation levels of sorrel (Hibiscus sabdariffa) cake meal—0% (R1, control), 50% (R2), and 100% (R3) were formulated. Each diet was tested on three groups of 20 fish, fed for 45 days. The results showed that fish fed diet R3 (100% sorrel meal) achieved the highest growth parameters. Fry receiving diets R2 and R3 exhibited the lowest Feed conversion rate (FCR) compared to the control. Survival rates at the end of the experiment were 55% for the control, 73% for R2, and 58% for R3. Flesh protein content was significantly higher in fish fed diet R3 and lowest in those fed the control diet. In contrast, fat content was highest in fish fed diet R1, while those receiving diets R2 and R3 had the lowest values. Regarding ash content, the highest values relative to initial fish composition were recorded in fish fed diet R3. These findings indicate that sorrel meal had no adverse effects on the survival of O. niloticus fry. In conclusion, wheat flour can be effectively replaced with sorrel meal in the diet of O. niloticus fry without compromising growth performance. This suggests that sorrel meal is a viable plant-based protein source for fish feed formulation, potentially lowering production costs and improving farm profitability.