Nutritional value of toasted pigeon pea, Cajanus cajan seed and its utilization in the diet of Clarias gariepinus (Burchell, 1822) fingerlings

The nutritional value of toasted pigeon pea Cajanus cajan seed in the diet of African catfish Clarias gariepinus (Burchell, 1822) was investigated in this study by progressively increasing its inclusion level (100, 200, 300 and 400 g kg−1) in isonitrogenous (35% crude protein) and isoenergetic (17.7 kJ g−1) diets. Toasting of the C. cajan seed significantly reduced the anti-nutrients and increased most essential amino acid, protein, and fibre in the seeds. The growth of C. gariepinus (1.36 ± 0.05 g) fingerlings fed in triplicate 1 × 1 × 1m3 hapa pond system (n = 40 in triplicates) was significantly improved by the different inclusion levels of toasted C. cajan in the diets after 56 days. Comparing the performance of the fish fed 400 g kg−1 of toasted C. cajan with that fed raw seed (400 g kg−1) reveal the efficacy of this processing method in improving the utilization of the feedstuff. Mortality was significantly higher (32%) in fish fed the diet containing raw inclusion compared to that fed the control diet or inclusion of toasted C. cajan ( < 5%). Cost analysis revealed that it was economically cheaper to raise the African catfish using toasted C. cajan at 400 g kg−1. It was therefore concluded that toasting improves the nutritional quality of C. cajan, resulting in better performance at higher inclusion levels, hence, can possibly reduce the cost of catfish production.