STUDIES ON MUSCLE OF AQUATIC ANIMALS-XXXIII

SEASONAL VARIATION OF NITROGENOUS EXTRACTIVES IN SQUID MUSCLE

Abstract

In order to demonstrate the seasonal variation of nitrogenous extractives in squid muscle, free amino acids, trimethylamine oxide and betaine determined in the mantle muscle of squids at several stages of the life cycle.
In Ommastrephes sloani pacificus, as shown in Table 2 and Fig. 1, amounts of free amino acids decreased in summer or autumn when the squid grew up in size, and increased during winter and spring, and amounts of trimethylammonium compounds increased with the growth. In Sepia esculenta, as shown in Table 4 and Fig. 2, amounts of free amino acids decreased with the growth, and trimethylamine oxide increased rapidly during autumn and winter when the squid grew up.
On the basis of these results, it was assumed that a retaining mechanism of trimethylamine oxide may effectively operate during a season when amounts of free amino acids rapidly decreased and squids grow up in size, for some purposes such as osmoregulation in squid muscle.