Experimental intra-ovum infection of coho salmon (Oncorhynchus kisutch) eggs with Renibacterium salmoninarum using a microinjection technique

Abstract

Renibacterium salmoninarum , the causative agent of bacterial kidney disease in salmonids, is transmitted from parent to progeny via the egg. Natural intra-ovum infection rates are low, making it necessary to use large sample sizes when attempting any conclusions on the efficacy of treatments to eliminate these infections. A microinjection technique was developed for inducing intra-ovum infections at high prevalence. The technique, using relatively inexpensive equipment, resulted in good egg survival rates (73% to the eyed stage), and ensured high intra-ovum infection rates: 91 and 82% at the eyed and alevin stages, respectively.