Effects of temperature,nutritional factors and salinity on the uptake of L-methionine by the Sydney rock oyster Saccostrea commercialis

The effects of physiological and nutritional factors and of temperature on the uptake of L-methionine by Saccostrea commercialis were investigated on cultured rock oysters from Port Stephens, New South Wales, Australia, in 1983. Optimum conditions for L-methionine accumulation were 30°C, 18 h exposure and concentrations of other amino acids less than that of L-methionine. The uptake of L-glycine was inhibited by L-methionine in a reciprocal manner. There was no effect of salinity on the accumulation of L-methionine by acclimated oysters. During the latter investigations the range of osmoconformity was found to be 15 to 45 S. Oysters take 2 d to conform to new media osmolarities after salinity changes of 15. Amino acid supplements in oyster diets should be kept within the same order of magnitude to reduce inhibition of uptake.