Species and individual variation in lysozyme activity in fish of interest in aquaculture

Abstract

Kidney lysozyme activity was tested in fish of 12 different species, as part of a project directed towards the improvement of disease resistance by breeding or by gene transfer. Within species, there was typically a 5- to 10-fold variation in activity. Highest activities were found in the rainbow trout ( Salmo gairdneri), the average being approx. 500 times that in the species with least lysozyme. A more detailed investigation of the intra-species variation in rainbow trout indicated the existence of a genetic influence on the lysozyme levels.