Impacts of Feeding Three Commercial Trout Starter Diets to Rainbow Trout on Bacterial Coldwater Disease-Induced Mortality

Affiliation

¹South Dakota Department of Game, Fish, and Parks, Cleghorn Springs State Fish Hatchery, 4725 Jackson Blvd. Rapid City, South Dakota 57703 USA

²South Dakota Department of Game, Fish, and Parks, McNenny State Fish Hatchery, 19619 Trout Loop, Spearfish, South Dakota 57783 USA

Citation

Barnes, M.E., et al. Impacts of Feeding Three Commercial Trout Starter Diets to Rainbow Trout on Bacterial Coldwater Disease-Induced Mortality. (2017) J Marine Biol Aquacult 3(2): 1- 5.

Abstract

Bacterial Coldwater Disease, an infection caused by Flavobacterium psychrophilum, causes substantial mortality during the initial feeding of salmonids in hatcheries around the world. This study evaluated the potential impacts of three commercial starter diets on Bacterial Coldwater Disease-induced mortality during rainbow trout (Oncorhynchus mykiss) rearing. Two Bio Oregon (Longview, Washington, USA) diets, Bio-Vita and BioPro2, and Skretting (Toele, Utah, USA) Starter Crumble were fed for 71 days. Mortality due to F. psychrophilum began to sharply increase 14 days after the start of the trial. Mean mortality in the tanks receiving Skretting Starter Crumble was 69.8%, which was significantly higher than the 55.4% mean mortality observed in the tanks of trout fed Bio-Vita. Mean mortality in the BioPro2-fed tanks was 58.0%, and was not significantly different than that observed in the tanks receiving the other two diets. Rainbow trout lengths and weights at the end of the study were not significantly different among the dietary treatments. To minimize mortality due to Bacterial Coldwater Disease, rainbow trout should receive Bio-Vita beginning at initial feeding. However, as indicated in this study, diet alone is not enough to fully manage Bacterial Coldwater Disease, necessitating the use of additional therapeutic actions.