Effects of waterborne nickel on the physiological and immunological parameters of the Pacific abalone Haliotis discus hannai during thermal stress

In this study, the 96-h LC(50) at 22 and 26 °C values was 28.591 and 11.761 mg/L, respectively, for NiCl(2) exposure in the abalone. The alteration of physiological and immune–toxicological parameters such as the total hemocyte count (THC), lysozyme, phenoloxidase (PO), and phagocytosis activity was measured in the abalone exposed to nickel (200 and 400 μg/L) under thermal stress for 96 h. In this study, Mg and THC decreased, while Ca, lysozyme, PO, and phagocytosis activity increased in the hemolymph of Pacific abalone exposed to NiCl(2) when compared to a control at both 22 and 26 °C. However, these parameters were not affected by a rise in temperature from 22 to 26 °C in non-exposed groups. Our results showed that NiCl(2) below 400 μg/L was able to stimulate immune responses in abalone. However, complex stressors, thermal changes, or NiCl(2) can modify the immunological response and lead to changes in the physiology of host–pollutant interactions in the abalone.