Chemical Composition of the Oyster, Ostrea gigas T_HUMBERG

Abstract

The present analysis was planned to see mainly the difference in the chemical composition among different organs and also between the sexes of the oyster during the time of reproduc-tion.
Concerning the seasonal variation in the chemical composition of the whole body, the present results agreed in a general way with those of S_EIINE et al. (1929), O_KAZAKI & K_OBAYASHI (1929) and M_ASUMOTO et al. (1934).
The average amounts of glycogen were as follows ; in the mantle edges 33•58%, hepato-pancreas 19•12%, gills 14•73% and adductor muscle 7•89%. In May when the oyster was not yet ripen, the glycogen content in the gonads was very high, amounting to 34•00%. Thusglycogen was mainly stored during the fattening period in the mantle edges and the gonads. While in August, when the oyster was matured, the amounts of glycogen in the gonads de-creased down to 1•20-6•68%. From these facts there seems to be little doubt that much of the glycogen stored were utilized in the formation of reproductive elements.
The percentages of protein varied inversely with those of glycogen, showing lowest in the mantle edges and highest in the adductor muscle. The percentage of fat was high in the hepatopancreas and matured eggs, and low in the adductor muscle. The fat content of the hepatopancreas decreased as the maturation of gonads proceeded.
Speaking the percentage composition, the eggs contained more fat and glycogen and less inorganic matters and protein than the sperm. Sexual difference in the chemical composition was also found in the mantle edges, gills and adductor muscle.