Bacteriological Analysis of Nile Tilapia Fish (Oreochoromis niloticus)

Abstract

Fish is a major food in great demand throughout the world. Fish protein is better and safer than meat
(animal protein) because it contains lower cholesterol. A research was conducted to analyze the
bacterial habitat and content of Tilapia fish. Total seven fishes were taken. The samples were examined
in microbiology laboratory by serial dilution method. Sections of the skin, gills and intestine of fishes
were aseptically removed by means of a sterile scalpel and pair of sterile scissors. A serial dilution was
prepared and from last dilution 0.1ml was plated on nutrient agar plates. Total eighteen different
species of bacteria were isolated and identified. Gram negative include Pseudomonas sp. and Enterobacter
sp., while gram positive species include Staphylococcus aureus and Streptococcus sp. Some of these
pathogens have tendancy to transmit to man (who eat fish meat or deal with fish and fish products).
Streptococcus infection was detected in high prevalence among cultured fresh water fishes, especially
during summer seasons. The most common signs of Streptococcosis in fish were septicemia, skin
ulcers, hemorrhages of the eye, in some cases changed cloudy and destructed (pop –eye) and hemorrhages
on the skin especially in the base of fins and tail. Hence it is considered that a variety of bacterial
species can be associated with fresh Tilapia fish related pathogen to humans.