Evaluation of the ability of Pichia guilliermondii to improve growth performance and disease resistance in rainbow trout (Oncorhynchus mykiss)

Abstract

This study examined supplementation of a novel yeast product containing Pichia guilliermondii on juvenile rainbow trout, Oncorhynchus mykiss, growth, and disease resistance. In two separate trials, fish (initial weight 6.2 and 10.6 g, respectively), were fed an extruded diet (41% digestible protein and 18% crude lipid) supplemented with 0.3 or 0.6% P. guilliermondii alone or 0.3% P. guilliermondii with a dietary gut supplement at 0.1%. Prior to the end of each trial, a subsample of fish from each tank was exposed by immersion to Yersinia ruckeri (Trial 1) or injection with Flavobacterium pyschrophilum (Trial 2). At the conclusion of the trials, supplementation of either P. guilliermondii or the gut supplement improved growth and food conversion efficiency in rainbow trout when fed for 16-weeks. No effects of supplementation on mortality were observed. These results suggest potential as functional additives; however, additional investigation regarding the efficacy of whole-cell and disrupted wall components of P. guilliermondii is needed to better assess their potential effects on rainbow trout immune responses.