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MEPS prepress abstract   -  DOI: https://doi.org/10.3354/meps13375

Stress-on-stress responses of a marine mussel (Perna canaliculus): food limitation reduces the ability to cope with heat stress in juveniles

N. J. Delorme*, L. Biessy, P. M. South, L. N. Zamora, N. L. C. Ragg, D. J. Burritt

*Corresponding author:

ABSTRACT: The marine environment is ever-changing, with daily and seasonal variations in factors such as food availability and seawater temperature. This study assessed the effects of food limitation (i.e. fasting) on heat-stress responses in juveniles (~1.3 mm in shell length) of the green-lipped mussel, Perna canaliculus. Fasting for up to 24 h did not have a significant effect on oxidative damage (protein carbonyls and lipid hydroperoxide accumulation) or the activity of antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase) after exposure to heat stress. However, fasting for 54 h and subsequent heat stress resulted in increased oxidative damage and decreased activity of antioxidant enzymes in juvenile mussels. On the other hand, gene expression of 70 kDa heat shock protein (hsp70) was only significantly affected by heat shock, rather than nutritional status. Tissue carbohydrate and protein levels were significantly depleted by 54 h of fasting; as these proximate components represent key energy substrates for bivalves, it is suggested that energy limitation contributes to compromised antioxidant activity and predisposition to oxidative damage.