Seasonal Variation in the Proximate Composition of Edible Oyster (Crassostrea sp.) along the Coastal Region of Bangladesh

Abstract

Oysters are highly esteemed sea food and considered as a delicacy throughout the world. Yet this resource is not optimally utilized in several parts of the world. Quality aspects of oysters (Crassostrea madrasensis) in the Moheshkhali Channel, Cox’s Bazar were examined in different seasons over a 12 month period spanning March 2018 to February 2019. The aim of this study is to highlight its nutritional importance using biochemical composition analysis and nutritional attributes of oyster meat. Proximate composition, fatty acid and amino acid profiles were determined by following AOAC 1984 & 2000 methodology for biochemical analysis. Oyster meat was rich in macro-minerals and polyunsaturated fatty acids (PUFA) were highest in lipids among whereas, Ecosa-pentaenoic acid, Docosa-hexaenoic acid and Linoleic acid were the prominent fatty acids. The omega-3 is the dominant fatty acid among the different type of fatty acids content in this species. Total amino acid content was 99.33 g/100 g crude protein, of which, essential amino acid lysine was the most abundant. Nutritional quality parameters of oysters were determined at different seasons of the year. Seasonal variations were also observed in the nutrient content, with particular regard to protein 45.27% to 66.92%; Moisture 69.85% to 76.96%, Lipid 6.06% to 9.38% ash 9.32% to 12.61% in oysters. These variations were done due to heavy rainfall, hydrological factor and surface runoff water into the channel. In spite of eco-physiological variability, the nutritional quality of the oysters was generally good, especially just before gamete release when the concentration of nutrients was at its maximum. A low level of fat was detected in the edible meat of oysters. This study is important to comprehend the seasonal variation of proximate composition & heavy metal content of oyster and will be useful for the development of aquaculture technology of the edible oyster. As Oysters form good protein food, a comprehensive knowledge of their biochemical constituents during different seasons of the year would be valuable for large-scale exploitation from natural resources and to promote culture.