This study was conducted to determine the proximate composition, mineral composition and amino acid profile of some selected commercially important fish species in Oba Reservoir, South West Nigeria. Seven fish species; Tilapia guineensis, Tilapia dagetti, Tilapia zilli, Tilapia nilotica, Sarotheroon galilaeus, Oreochromis niloticus and Hepsetus odoe were sampled and analysed for the period of six months using standard laboratory procedures. The results of the water analyses showed that all the parameters analysed were determined and were not significantly deviated from WHO standards, though the additive effects of these parameter should not be underestimated. This results also showed that there were varied level of statistical significant difference among the sampling sites and the parameters. The results of the present study also showed that the percentage of crude protein, fat and ash contents are highest in Oreochromis niloticus and this value was highly significantly differ from S. galilaeus, H. odoe, T. zilli, T. guineensis, T. dagetti and T. niloticus. Moreover, all the mineral element were significantly high in all the sampled fish population with zinc occurred mostly in all the fish species. The amino acid profile also revealed that fish species contain all the essential amino acid needed for growth. The highest amount of essential amino acid was recorded in Hepsetus odoe and T. zilli. There were mixed significant correlations among the fish species in respect of the proximate composition, mineral composition and the amino acid profile. The study clearly indicated that the measured parameters and their corresponding values obtained would be useful in helping consumers in choosing fish based on their nutritional values and will also provide an update to food composition database.
The freshwater fish species provide food, subsistence and supplemental income to a wide range of people, especially those that live around various rivers (Mohammed and Alim, 2012). Fish and fishery products represent a valuable source of nutrients for diversified and healthy diets (Fawole et al., 2007). With a few exceptions of selected species, fish is usually low in saturated fats, carbohydrates and cholesterol. Fishprovides not only high-value protein, but also a wide range of essential micronutrients, including various vitamins (A, B and D), minerals (e.g. calcium, iodine, zinc, iron and selenium) and omega-3 fatty acids (docosahexaenoic acid, DHA and eicosapentaenoic acid, EPA).
Fish are known to be a source of protein rich in essential amino acids (lysine, methionine, cysteine, threonine and tryptophan) (FAO, 2011). It is recognized that essential amino acids play an important role in human nutrition and health promotion (Limin et al., 2006). There is an evidence of beneficial effects of fishconsumption (FAO, 2011) in relation to coronary heart disease (Mozaffarian and Rimm, 2006), stroke, agerelated muscular degeneration and mental health (Peet and Stokes, 2005). There is also convincing evidence of benefits in terms of growth and development, particularly for women during gestation and children during infancy for optimal brain development (Young and Conquer,2005).
It is important to assess the meat quality of freshwater fish species that are less frequently analysed prior to their processing and storage. Such information can help to preserve the quality especially during post harvest processing and storage of fish which otherwise could be affected by the level of moisture, protein and fat contents (Mohamed et al., 2010). Fish has an important role in food security and poverty alleviation in both rural and urban areas of Pakistan but little is known about the nutritional value of the Indus fishes of our selected study area. Better knowledge of their nutritional value, which is expected to be closely associated with fish species, could contribute to the understanding of variability in meat quality of different species of the Indus fish. Moreover, the measurement of some proximate profiles such as protein, lipids and moisture contents are often necessary to ensure that they meet the requirements of food regulations and commercial specifications (Waterman, 2000). Therefore, the present study compared the chemical and amino acid contents of the commercially most preferred ten species, (synodontis robianus, synodontis omias, synodontis clarias, tilapia digeti, tilapia zilli e.t.c). From Oba river in Ikose, Ogbomoso Oriire Local Government area of Ogbomoso In Oyo State, Nigeria. In spite of the commercial value and wide availability of these fish species, there is no available report on their nutritive or caloric values and amino acid composition from the study area.
The selected fish represented typical habitats, food niches and market prices. We also examined if variation in weights of selected fish could affect their muscle composition. This study will stimulate research on similar lines as the knowledge of chemical and amino acid compositions of different fish species is essential before selecting suitable methods of fish preservation, processing, product development and fish feed formulation. We anticipate that such information would facilitate the fish grading by using nutrient and amino acid compositions that will help to determine the market price of fish for health conscious consumers and the livelihood of fishing community of this study area and beyond. Small indigenous species of fish are valuable and easily available source of food rich in protein, vitamin and minerals, not commonly available in other foods in Oba River, Ikose, Ogbomoso Oriire Local Government , Ogbomoso in Oyo State.
Many SIS are eaten whole contributing calcium, phosphorous and vitamins to the human diet. Hossain et al. (1994) mentioned that among the fishing conuntmities, small fish occupy an ilnportant position as a popular food item. In a cotmhy with a population suffering from malnutrition and protein deficiency, constunption of these fish species may have positive effects in improving the health of the nation. Small fish provide food and nutrition, subsistence and supplemental income to the great majority of people: in this country, particularly the poor and disadvantaged. The need for thorough and long-term investigation on the nutritional value of small indigenous fish is urgently needed.
Considering the importance of the small indigenous fish, this study was undertaken to assess the nutritional value of some small fishes available in Ogbomoso North Local government Area of Ogbomoso in Oyo State Fish is a favorite foodstuff for the majority of societies. Fish meal contains most important nutritional components and serve as a source of energy for human beings (Ojewola and Annah, 2006; Sutharshiny and Sivashanthini, 2011). Fish is also a vitamin and mineral rich food for young as well as old age people (Edem, 2009; Moghaddam et al., 2007).
Majority of the nutritionists recommend that human beings should eat fish every day (Blanchet et al., 2000; Nestel, 2000; Balk et al., 2004). An increasing amount of evidences suggest that, fish meat and oil contains high amount of polyunsaturated fatty acid that are valuable in decreasing the serum cholesterol to prevent a number of coronary heart diseases (Nordoy et al., 2001; Turkmen et al., 2005). Regular consumption of fish can promote the defense mechanism for protection against invasion of human pathogens because fish food has antimicrobial peptide (Ravichandran et al., 2010). Ingesting fish can reduce the risk of heart diseases and lower the risk of developing dementia, including Alzheimer’s diseases (Grant, 1997).
Breastfed babies of mothers who eat fish have better eyesight perhaps due to the omega-3-fatty acid transmitted in breast milk. Fish oil may be useful in treating dys-lipidemia in diabetes (Friedberg et al., 1998). Eating fish during pregnancy may help to reduce the risk of delivery of a premature baby (Olsen and Secher, 2002). Fishmeal is popular in a large segment of the Sri Lankan population who actively select foods for health maintenance and disease prevention since Sri Lanka is an island and surrounded by Indian Ocean (Anonymous, 2008). Fish is an important source of food for mankind all over the world from the times immemorial. Fish is a very important source of animal protein in the diets of man. The importance of fish as source of high quality, balanced and easily digestible protein, vitamins and polyunsaturated fatty acids is well understood now. Fish having energy depots in the form of lipids will rely on this. The amount of protein in fish muscle is usually somewhere between 15 and 20% but values lower than 15% or as high as 28% are occasionally met muscle is always low, usually below 1% and seasonal fluctuations in fat content are noticeable mainly in the liver where the bulk of the fat is stored. Lipids occur in the fish muscles, adipose and liver. The fishes offered as a dietary supplement to the farming pigs has considerably increased their weight and meat yield (Ojewola and Annah, 2006). The consumption of fish and fish products is recommended as a means of preventing cardiovascular and other diseases and has greatly increased over recent decades in many European countries (Cahu et al., 2004). Besides this fishes are good source which possess immense antimicrobial peptide in defending against dreadful human pathogens (Ravichandran et al., 2010).
However, the most important feature of this food is an advantageous fatty acid profile, resulting from the high content of essential polyunsaturated fatty acids such as eicosa pentaenoic acid (C20:5 n-3) and docosahexaenoic (C22:6 n-3) (Kris-Etherton et al., 2003). In recent years, investigations aimed at identifying the benefits of fish consumption have also indicated that there are risks connected with toxic contaminants such as meth mercury and persistent organic pollutants (Mahaffey, 2004; Domingo et al., 2007a, b; Stern, 2007; Wu et al., 2008; Szlinder-Richert et al., 2008a, b; Szlinder-Richert et al., 2009). In a recent investigation concerning canned fish and other fish products, we showed that these products are characterized by high nutritional quality and that considering the present scenario of the fish consumption in Poland, they do not pose a threat for Polish consumers due to the contaminant levels (Usydus et al., 2008, 2009).
Biochemical composition of flesh is a good indicator for the fish quality (Hernandez et al., 2001), physiological condition of fish and habitat of fish (Aberoumad and Pourshafi, 2010; Shamsan and Ansari, 2010; Ravichandran et al., 2011). Fish of various species don’t provide the same nutrient profile to their consumer (Takama et al., 1999) and the nutritive value of a fish varies with season (Varljen et al., 2003). Moisture, dry matter, protein, lipids, vitamins and minerals are the most important components that act as sources of nutritive value of fish meat (Steffens, 2006).
Quantifying proximate composition is important in ensuring the requirements of food regulations and commercial specifications (Waterman, 2000). Moisture content of flesh is a good indicator of its relative content of energy, protein and lipid (Aberoumad and Pourshafi, 2010). Fish meat contains significantly low lipids and higher water than beef or chicken and is favoured over other white or red meals (Nestel, 2000). The total lipid and ash content of fish vary with the increasing weight or length of the fish; it may also vary with the season and varied habitats (Hassan, 1996). Among the proximate composition, protein in fish is the excellent source, because of the amino acid composition and degree of digestibility (Louka et al., 2004).
Several studies on proximate composition of fish have been made from different parts of the world, so far. De silva and Rangoda (1979) mentioned the information on some chemical characteristics of fresh and salt dried product of Tilapia mossambica from Colombo Lake, Sri Lanka. Nutritional analysis of some fresh water fish were determined by Wimalasena and Jayasuriya (1996) from Narammala, Ibbagamuva and Nikaveratiya in Sri Lanka. Proximate composition of different fresh water fishes specifically Magur (Clarias batrachus), Shingi (Heteropneustes fossilis), Koi (Anabas testudineus), Foli (Notopterus notopterus), Royna (Nandas nandas), Taki (Channa punctatus) and Tangra (Mystus vittatus) in Bangladesh was estimated by Kamal et al. (2007).
For a non piscine organism, bivalve Saccostrea cucullata proximate composition was estimated by Sajjadi et al. (2009). Farhoudi et al. (2011) studied the proximate composition of Cyprinus carpio in Caspian Sea during larval development. Sounndarapandian and Dey (2008) estimated the proximate composition for matured eggs of crab Portunus sanguinolentus (Herbst) in Indian coastal waters. They reported that the protein, lipid and carbohydrate content in matured eggs of Portunus sanguinolentus were found to be 59.70, 21 and 7.58%, respectively. Tawfik (2009) studied the proximate composition and fatty acid profile in most commonly available fish species in Saudi market.
In Sri Lanka, Scomberoides lysan, S. tol and S. commersonianus are the importantly marketed food source among the Scomberoides fish. These are frequently caught by fishermen and often bought by people because of the good quality and unique meat texture. These are normally utilized fresh, preserved, dried or salted. Pregnant mothers and lactating mothers often intake these fishes in Sri Lanka. These are marketed all over the country and transported from one landing centre to another with the assistance of cooler. Knowledge of nutritional value of theses fishes are little known. Hence, it is essential to know the proximate composition of the fish to report their nutrient composition from the public health point of view.
1.2 Aims and Objective
This study aimed to investigate the Nutritional qualities and to vividly assess the nutritional fitness of some selected fish species from Oba Reservoir, Ogbomoso, Nigeria. The objective are: -
- To evaluate the physico-chemical features of the river water
- To investigate the proximate composition of the selected fish species
- To determine the elemental and amino acid profiles of the sampled fish species from the reservoir of some selected fish species inhabiting Oba River in Ikose, Ogbomoso Oriire Local Government of Ogbomoso in Oyo State, Nigeria.