Serum Lysozyme Levels in Paddlefish and Walleye

Abstract

The turbidimetric assay of lysozyme activity in serum revealed ranges of 0.0–27.8 units/mL in walleyes Stizostedion vitreum (spawners and nonspawners) and 11.1–238.9 units/mL in paddlefish Polyodon spathula (spawners and juveniles). A unit of lysozyme activity was defined as the amount of the sample causing a decrease in absorbance of 0.001 /min. Lysozyme activity was significantly different (P < 0.05) in the two species. This first demonstration of lysozyme in the sera of paddlefish and walleye is further evidence of the occurrence of this nonspecific immune factor, which has been ubiquitous in fishes investigated to now.