Susceptibility of Pacific Herring to Viral Hemorrhagic Septicemia Is Influenced by Diet

Abstract

Groups of specific-pathogen-free Pacific herring Clupea pallasii were highly susceptible to infection by viral hemorrhagic septicemia virus (VHSV); however, the level of mortality was influenced by diet during the 40–71 d before, during, and after the first exposure to the virus. Cumulative mortality was highest among the herring maintained on an experimental soy-based pellet, intermediate among those maintained on a commercially available fish-meal-based pellet, and lowest among those maintained on a second commercially available fish-meal-based pellet containing β-glucans. Additionally, the herring maintained on the experimental soy-based feed demonstrated less growth than those on the commercially available feeds. The results indicate the importance of standardizing diet during empirical determinations of disease susceptibility and provide insights into the risk factors affecting VHS susceptibility in wild populations.

Received August 26, 2011; accepted November 4, 2011

ACKNOWLEDGMENTS

Technical support was provided by R. Wade (Marrowstone Marine Field Station); VHSV isolates were provided by K. Garver and G. Traxler, Fisheries and Oceans Canada, Pacific Biological Station. Herring eggs were provided by Kurt Stick and Adam Lindquist (Washington Department of Fish and Wildlife). Funding was provided by the Exxon Valdez Oil Spill Trustee Council (project 070819) and the Fisheries and Aquatic Ecosystem Resources Program of the USGS. All animal experiments were conducted under a protocol approved by the Institutional Animal Care and Use Committee of the WFRC. Reference to trade names does not imply endorsement by the U.S. Government.