Replacement of dietary fishmeal for fenugreek seed meal on the growth, body composition, innate immunological responses and gene expression of hepatic insulin‐like growth factors in African catfish (Clarias gariepinus)

An 8‐week feeding trial was conducted to assess the suitability of fenugreek seed meal (FKSM; Trigonella foenum‐graecum) to replace fishmeal (FM) in diets of African catfish Clarias gariepinus. Five isonitrogenous and iso‐energetic diets were formulated with increasing amounts of FKSM, at the expense of FM, at 0 (Control), 100 (FKSM100), 180 (FKSM180), 260 (FKSM260) or 340 g/kg (FKSM340). Each treatment was triplicated, with 30 fish in each replicate (initial mean ± SD of 9.3 ± 0.5 g). Growth performance, haematology, serum biochemistry, carcass and fillet proximate composition, some innate immunological parameters and hepatic insulin‐like growth factor (IGF) I and II were measured. Growth, feeding efficiencies and hepatic IGF‐I and IGF‐II gene expression were unchanged in the dietary FKSM100 or FKSM180 treatments, compared to the control. In the FKSM180 treatment, blood haemoglobin, haematocrit, red blood cell counts, respiratory burst activity and lysozyme activity of catfish significantly increased. Carcass crude protein, ash and hepatic IGF‐I gene expression were significantly lower in the FKSM260 and FKSM340 treatments. Results show that up to 180 g/kg FKSM can replace FM at 350 g/kg, on a total protein basis in the diets of C. gariepinus.