PLASMA METABOLITES OF LAKE TROUT (SALVELINUS-NAMAYCUSH) IN RELATION TO DIET AND STORAGE-CONDITIONS

1. The effects of storage temperature (2, -20 and -80-degrees-C) and duration (3, 9 and 27 days) on plasma metabolites concentrations of lake trout fed three dietary protein levels (20, 40 and 60%) and a single lipid level (20%) for 28 days were investigated. 2. Significantly high plasma urea and glucose concentrations were associated with low (20%) and high (60%) dietary protein intake in fish; while, high plasma creatinine concentration seems to characterize insufficient dietary protein and energy consumption. 3. Deproteinization of plasma with 5.0% sulfosalicylic acid did not confer better storage stability for any of the plasma metabolites except ammonia which was significantly high in non-deproteinized samples when stored at 2-degrees-C over 3, 9 and 27 day periods. 4. These studies suggest that non-deproteinized fish plasma can be stored at -20-degrees-C without affecting the baseline concentrations of ammonia, creatinine and glucose for up to 9 days and, urea and total protein for up to 27 days.