A protocol and cultivation system for gnotobiotic Atlantic cod larvae (Gadus morhua L.) as a tool to study host microbe interactions

Commensal bacteria in the gut of all vertebrates play essential roles in the development and functionality of the host. Studying the host raised in the absence of bacteria, or under gnotobiotic conditions (with a known composition of bacteria) has become an important tool to unravel the complex host–microbe interactions. In this study we describe a protocol to generate bacteria-free Atlantic cod (Gadus morhua L.) larvae, independent on the continued addition of antibiotics. An experimental system allowing for feeding of the larvae was also developed, and used successfully during a gnotobiotic start feeding experiment.