Evaluation of the effects of grading and starvation on the lysosomal membrane stability in pacific oysters, Crassostrea gigas (Thunberg) by using neutral red retention assay

In this study the neutral red retention (NRR) assay was used to evaluate the effects of simulated rotational grading, starvation, and their combination on lysosomal membrane stability in Pacific oysters. NRR results showed that both duration of simulated grading and duration of subsequent recovery after grading in 15 °C water had a significant effect on lysosomal stability. In general, the oysters that underwent longer durations of grading had lower NRR times at most time points. The NRR times in the oysters graded for shorter periods returned to the control level more quickly than those graded for longer periods during the post-grading recovery in 15 °C water.After 42 days starvation, the condition index and NRR times in starved oysters were significantly lower than those in fed animals and the control animals. The NRR times in the oysters that were fed during this period also decreased significantly in comparison with day 0 controls although the animals' CI increased slightly. Significant differences in responses to 3 min simulated grading were found between the oysters that were starved and fed for 42 days.