Assessment of serum protein fractions in rainbow trout by means of automated electrophoretic and densitometric system

Background: Although rainbow trout (Oncorhynchus mykiss, Walbaum) are one of the most-studied fish, electrophoretic techniques and classification of serum protein fractions have not been standardized, such that clinically useful values are lacking.Objective: The aim of the present study was to evaluate preliminarily the serum protein fractions of rainbow trout using automated cellulose acetate electrophoresis and densitometry.Methods: Serum samples from 25 rainbow trout (Oncorhynchus mykiss, Walbaum) were electrophoresed on cellulose acetate plates and quantified using densitometry.Results: A maximum of 6 fractions were identified and numbered, in order of decreasing mobility, as I, II, III, IV, V, and VI. In 3 of 25 (12%) samples, 6 fractions were identified; in 18 (72%) samples, 5 fractions were identified; and in 4 (16%) samples, 4 fractions were identified. Fractions I, V, and VI were always clearly identifiable, whereas fractions II and IV were frequently fused and indistinguishable from fraction III. The pattern with 5 fractions was the most probable type (χ2, P<.01). The mean (±SEM) protein concentrations of the 6 fractions were I, 0.8±0.1 g/dL; II, 0.3±0.0 g/dL; III, 1.6±0.1 g/dL; IV, 0.3±0.1 g/dL; V, 0.6±0.0 g/dL; and VI, 0.2±0.0 g/dL. Based on comparison of serum and plasma electrophoretic patterns from 8 fish, fibrinogen was found in fraction V.Conclusion: Automated cellulose acetate electrophoresis and densitometry appear to be a practical method for estimation of serum protein fractions in rainbow trout.[...]