Performance and immunological responses of rainbow trout ( O ncorhynchus mykiss ) fed bioprocessed plant‐based proteins

Abstract

Marine-derived fish meal (FM) is a traditional component of commercial aquaculture feeds for many farmed fish species. Modern bioprocessing technologies have been developed to produce high-protein plant-based ingredients for aquafeeds to further reduce FM and other conventional animal protein sources. A 90-day feeding trial using juvenile rainbow trout (Oncorhynchus mykiss) (27.9 ± 1.4 g; mean ± SE) was completed to evaluate growth, feed efficiency, general health and immunological responses to diets containing experimental plant-based protein sources and reduced FM. Trout were fed one of four dietary treatments: experimental bioprocessed soy protein concentrate (BSPC), commercially available enzymatically hydrolysed soy protein concentrate (CSPC), experimental bioprocessed barley protein concentrate (BBPC) and a FM control (FMC). At trial termination, there were no significant differences in relative growth (RG) or specific growth rate (SGR) between fish fed either FMC or BSPC (p > .05). Fish fed either CSPC or BBPC resulted in significantly lower RG and SGR than the FMC (p < .05). Significant respiratory burst analysis differences were observed among treatments at day 90 (p < .01), for fish fed either FMC or CSPC diets. This assessment of bioprocessed plant-based protein ingredients facilitates the characterization and incorporation of bioprocessed soy and barley protein as the industry continues to evaluate FM replacements in rainbow trout feeds.