Freshwater fish is one of the most important foods and is valued for its nutritional qualities. Fish protein is a good source of high quality protein containing essential amino acids in the amount and proportion required for good nutrition. It also provides a good source of vitamins and minerals. Today in Nigeria, one out of every two live on less than one dollar ($1) a day (World Bank, 2004).
Fish are the major source of protein rich in essential amino acids (lysine, methionine, cysteine, threonine and tryptophan) (FAO, 2011). It is recognised that essential amino acids play an important role in human nutrition and health promotion (Limin et al., 2006).
Freshwater fish is an excellent and cheaper resource of animal protein with high biological value for a large section of the inhabitants. Proteins play numerous vital roles in the bodies of living organisms. They enter into the formation of body tissues such as muscles, skin, hair, cartilage, and ligaments. Proteins in the form of enzymes, hormones, antibodies and globulins catalyse, regulate, and protect the body through physiological activity. Proteins in the form of haemoglobin, myoglobin and various lipoproteins are responsible for the transport of oxygen and other vital substances within the body.
More than one third of the sub-Sahara African population is under-nourished (FAO, 2011). The report estimated that fish provides 22% of protein intake and exceeds 50% in the poorest countries where animal is expensive and scarce. Eyo (2001) pointed that in the coastal countries of West Africa the proportion of dietary protein from fish is extremely high (47% in Senegal, 67% in Gambia and 63% in Sierra Leone and Ghana). The importance of fish in the diets of infants, young children and pregnant women cannot be over-emphasized. The crude protein content of fish can be of immense nutritional value to pregnant women for proper development of the foetus and prevention of abortion. It will also enhance the proper mental and immunity development against disease among growing children (NAFDAC, 2003). In low-income countries, staple foods such as rice, wheat, maize, and cassava make up the bulk of the food consumed by people and they supply majority of energy. However, some essential nutrients (essential amino acids and micronutrients) are not found in these staples. These important nutrients can be supplied by fish because they contain very light connective tissue (Eyo, 2001).
Fish provide food, subsistence and supplemental income to a wide range of people, especially those that live around various rivers. Fish and fishery products represent a valuable source of nutrients for diversified and healthy diets (Fawole et al., 2007).
Fish is a key ingredient on the global menu, vital factor in the global environmental balance, and an important basis for livelihood worldwide (UNICEF, 2006). Fish has no cultural or religious restrictions which makes it more advantageous than pork, beef and mutton (NIFFR, 1999) Fish is an indispensable source of micronutrients, such as iron, iodine, zinc, vitamin A and B (Haruna, 2003). Present knowledge of the chemical proximate composition of fish species from Nigerian waters is scanty. The measurement of some nitrogen free extract and crude fibre is often necessary to ensure that they meet the dietary requirements and commercial specification (Onyia et al., 2010).