Assessment of serum protein fractions in rainbow trout using automated electrophoresis and densitometry.

Abstract

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 (chi(2), 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.