Effect of Lysine Supplementation and Feeding Frequency on the Nutrient Digestibility of African Catfish Clarias Gariepinus

The African catfish Clarias gariepinus is a key aquaculture species in sub-Saharan Africa, valued for its rapid growth and feed efficiency. This study evaluated the effect of lysine supplementation and feeding frequency on the apparent nutrient digestibility of African catfish, aiming to evaluate the effect of lysine supplementation, feeding frequency, and their combined effect on the nutrient digestibility of African catfish. A 56-day feeding trial was conducted using 360 juvenile fish in a 3×2 factorial design: three lysine inclusion levels [T (0%, 2%, 4%)] and two feeding frequencies [I (2 and 4 times)] daily, replicated thrice. The Diets were labelled as D1(T0I2- Control 1), D2(T0I4- Control2), D3(T2I2), D4(T2I4), D5(T4I2), D6(T4I4). Fish were fed 35% crude protein diets, and digestibility was assessed using Acid-Insoluble Ash (AIA) as an internal marker. Apparent digestibility coefficients (ADCs) for protein, lipid, carbohydrate, ash, and fiber were calculated. Data were analyzed using two-way ANOVA. Results showed that diet D5 has the highest protein (88.31%) and carbohydrate (58.95%) digestibility. Lipid digestibility was high (>91%) in all treatments with feeding frequency having significant effect on its digestibility. Fiber digestibility was significantly affected by both lysine and feeding rate, with the lowest (44.04%) in D6. Statistical analysis confirmed significant effects (p