Can starvation influence cellular and biochemical parameters in the crab Carcinus aestuarii?

Crustacea experience periods of starvation during moulting or when limited food availability occurs. The effects of starvation on Crustacea physiological responses have been demonstrated, whereas the effects of starvation on Crustacea immune parameters remain to be more fully studied. In the present study the effects of starvation on immune parameters and antioxidant enzyme activities of the crab Carcinus aestuarii were evaluated for the first time. Treated crabs were starved for 7 days, whereas control crabs were fed daily with mussels. Total haemocyte count (THC), haemocyte diameter and volume, haemocyte proliferation, cell-free haemolymph (CFH) glucose and total protein levels, and phenoloxidase (PO) activity in both haemocyte lysate (HL) and CFH were measured in crabs. In addition, superoxide dismutase (SOD) and catalase (CAT) activities were evaluated in both gills and digestive gland from crabs, in order to evaluate whether starvation induced oxidative stress in C. aestuarii. THC increased significantly in starved crabs, with respect to controls, whereas no significant variations were observed in haemocyte diameter, volume and proliferation. In CFH of starved animals glucose concentration significantly increased, whereas total protein concentration significantly reduced. A significantly higher PO activity was recorded in HL from starved crabs, than in control crabs. Conversely, PO activity did not vary significantly in CFH. Starvation did not cause significant alterations in antioxidant enzyme activities in both gills and digestive gland. Results obtained demonstrated that starvation influenced crab immune parameters, but did not induce oxidative stress. Results also indicated that C. aestuarii can modulate its cellular and biochemical parameters in order to cope with starvation.