Biochemical composition of the ovary and partial characterisation of yolk protein vitellin in Metapenaeus monoceros (Fabricius, 1798)

Abstract

Yolk protein vitellin in ‘speckled shrimp’ Metapenaeus monoceros was partially characterised employing polyacrylamide gel electrophoresis (PAGE). There was an increase in the level of expression of vitellin in the ovary, with the advancement of maturation. The vitellin fraction was not expressed in immature and spent ovaries. Molecular weight of vitellin was 326 kDa. Confirmation of the vitellin band by selective staining showed that the yolk protein was a lipoglyco- carotenoprotein possessing a calcium moiety. A protein fraction with molecular weight 270 kDa, which was a lipoprotein, was expressed in ovaries of all maturity stages as well as in testis. The major biochemical constituents of mature yolk of M. monoceros on dry weight basis were protein (59.36±1.18%), lipid (31.23±2.98%) and carbohydrates (2.97±0.81%). Carotenoids accounted for 0.70±0.81% wet weight of yolk.