Molecular Characterization and Haemolysis of Bacteria Associated with Tilapia zilli from Ijaka-Oke Location on Yewa River

Abstract

Fishes are a source of animal protein, rich in minerals, amino acids, and essential fatty acids. Fishes can be confronted with microbial contamination in their natural habitat and their transformation products can be a source of microbial infections and food poisoning. In the natural habitat, microorganisms are usually found on the entire outer surface (skin and gills) and in the intestines of fishes. Genetic diversity study of the bacteria isolates was done using RAPD technique. Bacteria were isolated from the gills, gut and skin of Tilapia zilli from Ijaka-Oke location on Yewa River. Morphometric characteristics of the 20 Tilapia zilli sampled was done. DNA were extracted from 20 bacteria isolates using CTAB method, PCR amplification of the 20 isolated DNA was carried out using five RAPD primers. Haemolysis of the 20 bacteria was also carried out using 7% of sheep blood in Nutrient Agar and it was used to culture a pure colony of the isolates and incubated at 37°C for 18 hours. The mean total length of the fishes was 30.00±9.00 (cm), weight 220±4.3 (g), head length 7.4±2.00 (cm) and standard length 21.30±4.50 (cm). The water quality parameters were also recorded with the water temperature at 22.90C, the pH of the water was 6.1 and Dissolved Oxygen 6.89 mg/l. Fifty – two (52) polymorphic markers were generated from the 5 RAPD markers. There were also 15 monomorphic markers from the primers. A total number of 67 markers were generated. The haemolysis showed that none of the bacteria displayed complete haemolysis.