Haemoglobin polymorphism in wild and cultured African catfish (<i>Clarias gariepinus</i> Burchell, 1822)

Abstract

Haemoglobin polymorphism, haemoglobin concentration, blood group and genotypes of wild and cultured Clarias gariepinus were investigated. Blood samples of Clarias gariepinus collected from Lake Alau (wild) and Dalori fish farm (cultured) were subjected to cellulose acetate electrophoresis to reveal the activities of hemoglobin (Hb). The result shows that both wild and cultured C. gariepinus had AA, BB and CC genotypes in the males and females. However, BD genotype was observed only in the female wild C. gariepinus. The percentage AA and BB genotypes of wild male C. gariepinus was 6.6% each. Wild females had AA, BB, CC and BD genotype with frequencies of 26.6, 33.3, 20 and 6.6% respectively. Cultured male C. gariepinus had AA, BB and CC with frequencies of 13.3, 26.6 and 6.6%, respectively, while the female C. gariepinus had AA, BB and CC with frequencies of 20, 13.3 and 20% respectively. Wild C. gariepinus had the highest (10.36 g/dl) haemoglobin  concentration value while the cultured strain had 8.86 g/dl. The blood groups of wild male C. gariepinus were O^- (10% of the population) and AB⁺ (10% of the population). The wild females had O^- , O ⁺ , A⁺ , B⁺ and AB⁺  with 40,   10, 10, 10 and 10% of the population respectively, Cultured male had O⁺ , A⁺ and AB⁺ (10, 20 and 20% of the fish observed) respectively. The blood group observed in the cultured female C. gariepinus were O^- (30%), A⁺ (10%) and B⁺(10%). The BD genotype observed in a wild strain of C. gariepinus indicates incomplete (partial) dominance and rare allele. This could be an indication of natural hybridization.

Keywords: Haemoglobin concentration, polymorphism, genotype, blood group, wild and cultured, Clarias