Biochemical composition of eggs in relation to egg quality in the Japanese eel, Anguilla japonica

Abstract

This paper presents the relationship between egg quality and egg biochemical composition of cultured and wild Japanese eel, Anguilla japonica. Eggs were obtained by artificial induction of maturation. Fertilization and hatching rates were used as characteristics of egg quality. Egg quality characteristics showed large variation; fertilization rate, 0–96; hatching rate, 0–84%. The biochemical composition also showed a large variation. There was no marked relationship between egg quality and fatty acid contents of eggs, except for n-6 highly unsaturated fatty acids (HUFA). Both the fertilization and hatching rates increased proportionally with increases of the α-tocopherol g(α-Toc) content in eggs. A more significant correlation was found between the amount of α-Toc relative to the amount of HUFA and egg quality. The results of this study show that the egg quality of Japanese eel is affected by the α–Toc level, and in particular, the ratio of α-Toc to HUFA in the eggs. Abbreviations: BHT – butylhydroxytoluene; EFA – essential fatty acids; FAME – fatty acid methyl esters; HPLC – high performance liquid chromatography; HUFA – highly unsaturated fatty acids; NADH – nicotinamide adenine dinucleotide; NADPH - nicotinamide adenine dinucleotide phosphate; ROS – reactive oxygen species; α-Toc – α-tocopherol.