Meeting Abstract

P3.104  Tuesday, Jan. 6  Nutritional constraints on the innate immune system of the Rusty Crayfish Orconectes rusticus WAGNER, N.D.*; FROST, P.C.; RAFFERY, S.P.; Environmental and Life Science Graduate Program Trent University Peterborough, Ontario; Trent University Peterborough, Ontario; Trent University Peterborough, Ontario nicolegoulding@trentu.ca

We examined the effects of poor food quality on immune function of the rusty crayfish, Orconectes rusticus. After two weeks of acclimatization to a laboratory environment, crayfish were fed artificial diets having different nitrogen (N) and phosphorus (P) levels for 16 days. After this period, we measured respiratory rates and nutrient excretion to verify physiological effects of food quality on Orconectes. One the final day of the experiment, hemolymph from each crayfish was assayed for both phenoloxidase activity and superoxide production in both unstimulated and LPS-stimulated samples. All animals were saved for measurements of dry weight and elemental (C, N, and P) body content. N- and P-content of the diet altered respiration rates and excretion of crayfish suggesting changes to metabolic rate and nutrient status of these animals. High N diets increased baseline superoxide production on a per cell basis and slightly increased phenoloxidase, however phenoloxidase appears to be more sensitive to P limitation than to N limitation. Despite low baseline superoxide production, nutrient-limited animals showed a high level of stimulation from LPS. We also collected crayfish from streams across eastern/southern Ontario and measured their immunocompetence as described above. These measurements showed considerable between-stream differences in crayfish immunocompetence but generally higher immunocompetence than laboratory held animals. We show that crayfish immune function is sensitive to the elemental content of their diet with both N and P being important in different aspects of immunocompetence.