Evaluation of the biochemical responses of catfish (Clarias gariepinus Burchell, 1822) after replacing fish oil with plant-based oils in their diets

Abstract

This study evaluated biochemical responses of Clarias gariepinus after replacing fish oil with plantbased oils in their diets. The sources of oils were coconut, olive, crude palm, sunflower and sesame seed. These oils were incorporated at 7% level to produce five isonitrogenous (41.03% protein) diets.The sixth diet contained fish oil and served as control experiment. Feeding trial was conducted in floating hapa  (1m3) system for 12 weeks. At harvest, blood samples were taken and examined for serum protein, albumin, globulin, electrolytes and tissue lipid peroxidation. Results showed that kidney function parameters (protein, albumin and globulin) increased significantly (p < 0.05) in palm oil treated group while the highest (p < 0.05) serum ions were observed in olive oil treated fish. The amount of malondialdehyde (MDA) formed in fish tissues also increased (p < 0.05) in palm oil group by 41%, 14%, 39% and 14 % in the liver, kidney, gill and heart respectively. However, no  significant difference (p > 0.05) was observed in MDA formation in fish fed olive oil and control diets. Inferences from this study conclusively support the direct use of palm and olive oils as total replacement for fish oil in diets of Clarias gariepinus.

Key Words: Clarias gariepinus, fish oil, plant oils, substitution, fish health, fish diet.