Fermented spent coffee ground in African catfish (Clarias gariepinus) diets: Effects on growth performance, digestive enzyme, protein digestibility, amino acid profile, and immune-related gene

Abstract

The application of fermented spent coffee ground (FCG) as animal feed has been documented by multiple prior studies, while others have explored its potential as aquafeed. The current research investigated the influence of FCG as a protein substitution at various levels (0 %, 10 %, 20 %, 40 %, and 80 %) on the growth, health, digestive enzymes, protein digestibility, amino acid profile, and gene expression of African catfish (Clarias gariepinus). Five dietary formulations were designed, and FCG was incorporated at different levels: 0 % FCG/control (T1); 10 % FCG (T2); 20 % FCG (T3); 40 % FCG (T4); 80 % FCG (T5). The fish were divided into 15 tanks (350 L) for a feeding trial that lasted for 70 days (n = 70 fish/per tank). The results showed that the T2 group exhibited the most significant enhancement (p < 0.05) under growth conditions relative to other treatments. The apparent protein digestibility (APD) values exhibited variability (p < 0.05), with T2 showing the highest APD, while a decreasing trend was observed from T3 to T5. Among the treatments, fish receiving 10 % FCG displayed the most pronounced activity of the digestive enzymes, protease, lipase, and amylase. In addition, the muscle, liver, and intestinal amino acid composition showed the highest (p < 0.05) in the T2-supplemented group demonstrated the highest total essential amino acids (EAA) and non-essential amino acids (NEAA). Besides, fish fed with the T2 diet exhibited significant (p < 0.05) and highest TGF-β1, NF-kβ, hsp90a and lyzg gene expression compared to other treatments in the fish intestine. To conclude, incorporating FCG as a fishmeal substitute in aquafeed notably improved the growth and health of C. gariepinus in this study. A 10 % inclusion of FCG proved effective for aquafeed, especially for African catfish and other freshwater species.