Effects of salinity stress on growth, antioxidant enzyme activity, and nutritional quality of the Jinjiang oyster <i>Crassostrea ariakensis</i>

Salinity stress is a common abiotic stress that significantly affects the physiological and biochemical indices of marine bivalves. The Jinjiang oyster Crassostrea ariakensis, a euryhaline bivalve, holds considerable importance in aquaculture. To explore the effects of salinity stress on C. ariakensis, the oysters were cultured at different salinities: 17.5‰ (low salinity, LS), 28.5‰ (natural salinity, NS), and 39.5‰ (high salinity, HS) for a duration of two weeks. Changes in growth, antioxidant enzyme, and nutritional quality were assessed. The survival rate and meat yield of LS and HS group were decreased. The superoxide dismutase (SOD) and catalase (CAT) activities showed different trends in LS and HS groups compared to the NS group. However, Total antioxidant capacity was inhibited in both LS and HS groups. Low/high salinity stress has complex effects on the nutritional quality of C. ariakensis. The crude protein, essential amino acids, the ratio of polyunsaturated fatty acids (PUFA)/saturated fatty acids in the LS group and the moisture, total amino acids, the ratio of n-6/n-3 PUFA in the HS group all decreased. Therefore, salinity stress not only poses a risk to the survival of C. ariakensis, but also changes the quality of oysters.