Asian Journal of Biotechnology and Genetic Engineering

Methionine is a crucial essential amino acid for fish, serving as the first limiting amino acid in many commercial aquafeeds. It plays a vital role in protein biosynthesis, acts as a methyl group donor in key metabolic pathways, and supports the synthesis of enzymes, hormones, and antioxidants necessary for cellular integrity and optimal growth. This study evaluated the optimal dosage of methionine supplementation in commercial feed to improve growth performance, feed efficiency, protein efficiency ratio, and protein retention in Sangkuriang catfish fingerlings. The experiment was conducted from December 2024 to February 2025 at the Faculty of Fisheries and Marine Sciences, Padjadjaran University, using a completely randomized design with four treatments (0, 4, 6, and 8 g methionine per kg feed) and four replications. Juvenile catfish were fed the experimental diets for 56 days, and parameters measured included absolute weight gain, feed conversion ratio (FCR), protein efficiency ratio (PER), and protein retention. Data were analyzed using ANOVA and Duncan’s Multiple Range Test at a 95% confidence level. The results showed that supplementation with 6 g methionine/kg feed (treatment C) significantly increased absolute weight gain (157.90 ± 15.10 g), resulted in the lowest FCR (1.580 ± 0.093), the highest PER (2.042 ± 0.235), and the highest protein retention (7.504 ± 0.856%) compared to other treatments. These findings indicate that 6 g/kg methionine supplementation is optimal for enhancing growth and nutrient utilization in Sangkuriang catfish (Clarias gariepinus). The results highlight the importance of targeted amino acid supplementation for improving productivity and sustainability in aquaculture systems.