PROXIMATE ANALYSIS OF CLAM (BIVALVIA SPECIES)

ABSTRACT


The proximate analysis of clam (bivalvia species) were studied. Freshly caught samples were purchased from Okwagbe waterside while cultured clams were harvested from the Department of Fisheries experimental tanks after culture for eight weeks. Data obtained in triplicates was subjected to analysis of variance.
The proximate composition of cultured Bivalvia specieswas significantly different (p<0.05) from the wild. The highest essential amino acid was leucine (cultured clams) and the lowest threonine (wild clams) while the highest non-essential amino acid was glutamic acid in the cultured clams and the lowest was proline in the clams from the wild. Amino acid in cultured clams significantly differed (p<0.05) from those in the wild. Higher concentrations were found for calcium, potassium and magnesium in soft tissues and sodium in shell for wild samples except zinc in both soft tissues and shell and sodium in soft tissue for cultured samples.
There was significant difference (p<0.05) in the concentration of minerals in both the soft tissue and shell of cultured and wild clams. The higher proximate and amino acid composition in cultured clams and higher metal concentrations in the wild reinforce the fact that clams are rich sources of animal proteins and trace metals. 

CHAPTER 1


Nigeria is among the protein and minerals deficient nations in the world. A sufficient amount of dietary protein, required for survival, growth and development, reproduction and maintenance of good health, is in short supply in the country. To salvage this situation, shellfish can serve as an alternative source of proteins and minerals for man. Shellfishes are aquatic invertebrates with shells. They can be divided into two groups namely; molluscs and crustaceans. Examples of molluscs are cephalopods (squid, octopus, and cuttlefish); gastropods (snails and slugs) and bivalves (clams, oysters, mussels, scallops). Molluscs are delicious and rich in protein. Their nutritive value can be assessed by estimating the levels of proteins, carbohydrates and fats in their body tissues. Bivalve molluscs like mussels, clams and oysters constitute highly nutritive seafood with an increasing demand and source of income in international markets (Fuentes et al., 2009; Karnjanapratum et al., 2013; Orban et al., 2002, 2006; Pogoda et al., 2013). Shellfish meat, particularly clam meat have been recommended in several dietary regimes for their high protein content, low calorific values, low fat/cholesterol profile and lower proportions of saturated fat, the presence of good lipids, significant amounts of omega-3-fatty acids, dietary essential amino acids, vitamin B12 and some important minerals such as iron, zinc and copper has been reported (Krzynowek et al., 1989 and Dong, 2001). 

Bivalvia speciesis a fresh water clam inhabiting the lower reaches of some large West African rivers (Udoidiong and Akpan, 1991). Despite its popularity as a cheap source of animal protein in Nigeria, studies on proximate composition, amino acid and trace metal concentration are limited. There is paucity of the knowledge especially of the nutritional values of E. radiata, so consumption of these nutrient rich molluscs is restricted to communities to communities situated along coastal States. Hence, there is need to determine nutrient compositions of clams with the view of creating awareness on the nutritional benefits of consuming them. Therefore the objective of this study was to evaluate the proximate composition, amino acid and the trace metals of clams from different sources.