ABSTRACT

Fish consumption is gaining more grounds everyday majorly because of the scientific knowledge of their nutritive value and proposed substitute for meat consumption. However fishes of different species do not provide the same nutritional value. This study investigated the proximate: crude protein, crude fat, moisture, crude fiber, metabolizable energy, nitrogen free extract and ash content of four specie of fishes (catfish, croaker, mackerel and tilapia) commonly consumed in Nigeria. The fishes were purchased and oven dried to constant weight. The proximate analysis was done according to the AOAC method of analysis. Results from the study revealed a significant (P<0.05) variation in the all proximate parameters for the different species of fish. The protein content ranged between 46.09% in mackerel to 67.71% in Tilapia. Also, the lipid content varied significantly (P<0.05) with high amounts of lipid observed in Croaker (32.11%) and mackerel (36.4%). Low lipid content was observed in catfish (8.32%) and tilapia (8.68%) when compared to croaker and mackerel. Moisture content ranged from 5.56% in croaker to 7.64% in tilapia, whereas the ash value ranged from 10.30% in croaker to 20.60 percent in catfish. Metabolizable energy for all samples was found to be high. Crude fiber was very meager in all samples and was not detected in mackerel and tilapia. Similarly, nitrogen free extracts was not detected in catfish, mackerel and tilapia fish. The level of protein and lipids in all samples is accountable for the amount of metabolizable energy available for each specie. Also the moisture content of all fishes was reflective of the amount of lipid present. This is because an inverse relationship exists between lipid and moisture. The findings in this study revealed that all investigated fishes contain variable nutritional value i.e. one fish may be high in lipid concentration and low in protein compared to another; amidst this differences, they are all good sources of protein, lipids, minerals and energy.