Sex-biased regulation of respiratory burst, phagocytic activity and plasma immune factors in lined seahorse (Hippocampus erectus) after subchronic benzo[a]pyrene exposure

Abstract Both wild and aquacultured seahorses are currently under great threat from marine pollution, notably from the potent contaminant and carcinogen benzo[ a ]pyrene (BaP). However, very little data are available regarding the immunomodulating effects of BaP in seahorses. Therefore, in this study, we exposed lined seahorses ( Hippocampus erectus ) for 7 d to BaP at three dosages (0.5, 5, and 50 μg/L) to evaluate sexual dimorphism in immune response. We measured eight immune parameters in the blood, including respiratory burst (RB), phagocytic activity (PA), monocytes/leucocytes, immunoglobulin M, complement 3, complement, interferon-a, and interleukin-2. Male seahorses had significantly higher parameters than females, except in terms of monocytes/leucocytes ( P H. erectus as a sentinel species for crude contamination, whereas PA and RB are valuable bioindicators of marine contaminants such as BaP.