Growth Response, Survival and Phenotypic Sex Ratio of Oreochromis niloticus Fry Fed Diets Containing Different Inclusion Levels of Eriosema psoraloides Leaf Meal
Nwangwu, D. C.
Bake, G. G.
Sadiku, S. O. E.
Mann, A.
Abstract
This study evaluated the potential of Eriosema psoraloides leaf meal (EPLM) as a natural sex-modulating feed additive in Nile tilapia (Oreochromis niloticus) fry to address aquaculture challenges associated with mixed-sex populations, such as uncontrolled reproduction and stunted growth. A four-week feeding trial was conducted at the National Institute for Freshwater Fisheries Research, Nigeria, using 540 fry randomly assigned to six dietary treatments (D1–D6) with graded EPLM inclusion levels (0–10%) in a completely randomized design. Phenotypic sex was determined using modified acetocarmine squash method, while growth performance was assessed via mean weight gain (MWG), specific growth rate (SGR), and survival rate (SR). Although a visible trend toward male-biased sex ratios was observed peaking at 66.7% male in group D6,Chi-Square analysis revealed no statistically significant association between diet and sex differentiation, χ² (10) = 9.516, p = .484. Growth performance was highest at 4% and 10% EPLM inclusion levels, with mean final weights of approximately 0.32±0.01g and 0.33±0.02g, respectively. Survival rate declined progressively with increasing EPLM inclusion, with the lowest rate (87.77±0.56%) recorded in D6, suggesting a potential toxicity threshold. Overall, EPLM demonstrated potential to promote male-biased sex differentiation and enhancing growth under the experimental conditions, presenting a natural alternative to synthetic sex reversal agents. However, due to the lack of statistical significance in sex ratio shifts, further research is needed to validate its masculinizing potential. Dosage optimization remains critical to ensure fish welfare and sustainable production outcomes.
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