Effects of faba beans ( <i>Vicia faba</i> <scp>L</scp> .) on the growth, amino and fatty acids compositions, flesh quality and oxidative stability of <scp>African</scp> catfish, <i>Clarias gariepinus</i>

The African catfish, Clarias gariepinus, is a commercially vital fish that is cultured worldwide, but it often exhibits low-quality flesh despite high production, which limits its market value. Consequently, there is increasing interest in identifying alternative feed ingredients that can improve flesh quality without severely compromising growth performance. Previous studies have shown that the inclusion of raw faba beans (Vicia faba L.) in the diet can improve muscle quality in species like tilapia and grass carp by increasing muscle crisped, yet information on their effects in C. gariepinus remains limited. This study aimed to assess the impacts of 0% (Diet I, control group), 40% (Diet II), 50% (Diet III), 60% (Diet IV) and 70% (Diet V) dietary faba beans inclusion on growth performance, physiological parameters and muscle quality of C. gariepinus during 90 days of cultivation. Compared to the control group, C. gariepinus fed faba beans-containing diets exhibited lower body weight, body weight gain rate (WGR) and specific growth rate (SGR), accompanied by a significant decline in glucose-6-phosphate dehydrogenase activity (p < 0.05). Histological analysis revealed that C. gariepinus receiving faba bean-supplemented diets exhibited a higher density of muscle fibres, broader gaps between fibres and reduced fibre diameter compared with the control group. Fish fed 50% and 60% faba bean diets exhibited significantly greater muscle hardness (p < 0.05) at 60 and 90 days. In addition, the total protein content in muscle was significantly lower in the 50% faba bean group, whereas the total lipid content and n-6/n-3 ratio were higher (p < 0.05). In conclusion, whereas high faba bean inclusion levels reduced growth performance and altered physiological parameters, moderate levels (50%-60%) improved muscle texture and enhanced certain amino acid and fatty acid profiles. These results indicate that faba beans can enhance muscle quality in C. gariepinus; however, inclusion levels must be carefully managed because of their adverse effects on growth.