Off-flavor Mitigation in Atlantic Salmon Grown in RAS via the Use of a Novel Single Cell Protein Based Feed

Recently several large commercial aquaculture farms have started their operations asrecirculated aquaculture systems (RAS). As these enterprises are closely watched by the seafoodcommunity they face numerous challenges off-flavors are consistently ranked among top issuesfacing the RAS industry.Off-flavors are caused mainly by geosmin (GSM) and 2-methylisoborneol (MIB) whichaccumulate in edible tissues and confer highly undesirable muddy/musty taste. Currently fishare purged to remove GSM/MIB - implying significant increases in OpEx doubled with weightand quality loss.Past trials repeatedly showed that feeds containing our single-cell flour (KBM) reduced the GSMand MIB fillet contents in three species. Moreover these effects were seen while all fish sharedthe same water and the fillet and water GSM/MIB levels were poorly correlated. Therefore wehypothesize that GSM/MIB are primarily produced by the fish gut microbiome and absorbedthough enterocytes.We intend to use such feeds in a finishing diet approach. The proposed trial would see market- size Atlantic salmon fed a control or a KBM-containing feed for 8 weeks. At the 4- and 8-weektimepoint fish will be sampled for fillet for measurement of GSM and MIB. The fish fish tankand biofilter will be sampled for microbiome evaluation.The results will provide critical information on the mitigation methods of off-flavors in RASand our path to commercialization with major feed manufacturers. Clear benefits includeimmediate reduction of the purge and its related costs and biomass losses. This is in directalignment with NIFA SBIR's topic area 8.7 priority #4.