Effects of Graded Levels of Rosary Pea (Abrus precatorius) Leaf Meal on Growth Performance and Nutrient Utilisation of Red-Belly Tilapia (Coptodon zillii) Fingerlings

Abstract

This study evaluated the effects of dietary inclusion of Abrus precatorius leaf meal on growth performance, nutrient utilisation, and physiological responses of Coptodon zillii fingerlings over a 70-day feeding trial. Five iso-nitrogenous diets (35% crude protein) were formulated with graded inclusion levels of 0.0, 0.5, 1.0, 1.5, and 2.0 g/100 g (T1–T5). A total of 225 fingerlings (2.33 ± 0.00 g) were randomly distributed into 15 tanks (15 fish per tank) with three replicates per treatment. Results showed significant differences (p < 0.05) in growth performance, with fish fed 1.0 g/100 g (T3) recording the highest weight gain, final weight, and specific growth rate. Performance declined at higher inclusion levels. Polynomial regression analysis identified 0.8 g/100 g as the optimal dietary inclusion level.. Haematological, biochemical, and carcass parameters improved at moderate inclusion levels, indicating enhanced metabolic activity, immune response, and nutrient utilisation. In conclusion, A. precatorius leaf meal can be safely included at 0.8–1.0 g/100 g to improve growth and physiological performance without adverse effects.