Serum proteins in the leopard seal, Hydrurga leptonyx, in Prydz Bay, Eastern Antarctica and the coast of NSW, Australia

Blood protein analysis including total serum protein and albumin by chemical methods, fibrinogen estimation and serum protein electrophoresis (SPE) was performed on the leopard seal, Hydrurga leptonyx. The most commonly observed SPE pattern was eight fractions designated albumin, α1a, α1b, α2a, α2b, β1, β2 and γ-globulin. Significantly higher total serum protein and albumin concentrations, as determined by chemical methods, and significantly higher α2-globulin concentrations, determined by SPE, were seen in free-ranging male seals compared to females, whilst significantly higher β-globulin concentrations were seen in female seals. Season of sampling influenced fibrinogen and β2-globulin concentrations, whereas there were no significant differences in any protein concentrations with moult status. Qualitative comparison of SPE traces of leopard seals in Antarctica with “sick” individuals in NSW, Australia revealed obvious differences, as did quantitative comparison of protein concentrations where differences in α1, α2, β1, β2, and γ-globulin concentrations were seen. These findings suggest that SPE is a useful tool for investigating serum proteins in the leopard seal, with applications for the investigation of “sick” individuals and the assessment of variation in homeostasis. This technique could also be used to identify the presence of environmental stressors, subclinical disease and physiological variation within specific seal populations.