The aquaculture industry in Zambia is expanding rapidly, necessitating the development of cost-effective and nutritionally optimized feed. One major challenge is the lack of established nutrient requirements for indigenous species, particularly for essential amino acids such as methionine. Methionine is critical for growth and metabolic processes, but is often limiting in plant-based feed formulations.
This study aims to estimate and compare the methionine requirements of two key strains of Oreochromis andersonii—the domesticated Kafue strain and the genetically improved GIP strain at the juvenile stage. Conducted within a recirculating aquaculture system (RAS), the experiment used a 2×6 factorial design with six graded levels of dietary methionine (0.51%, 0.60%, 0.80%, 0.90%, 1.10%, and 1.30%) across both strains. Fish were fed formulated diets and monitored over a 12-week period, with growth performance, feed intake, and survival rates recorded.
Baseline and end-point analyses were conducted to evaluate nutrient retention and amino acid utilization. Sampling included whole-body composition, liver and visceral indices, and proximate analyses of both diets and carcasses. This data enabled calculation of optimal methionine levels specific to each strain.
The outcomes of this study contribute to improved feed efficiency and reduced reliance on costly imported supplements, supporting the development of sustainable aqua feeds tailored to indigenous species.
This research will provide crucial input for Zambia’s aquaculture feed strategy, aligning with national goals to boost fish production and nutrition security using locally adapted species and feed resources.