Evaluation of the use of commercial-type and synthetic diets to test a nucleotide-rich yeast-derived product as a growth promotor for first feeding rainbow trout fry raised at 10oC or 16oC

A nucleotide-rich yeast-derived product (Maxi-GenTM; CBS Bio Platforms, Inc.; Calgary AB, Canada), was fed to rainbow trout fry housed at 10oC or 16oC to determine its effect on weight gain and feed intake. Rainbow trout fry housed in 40 16-L tanks (25 fish / tank) were fed commercial-type or synthetic diets with or without the nucleotide-rich yeast product added (0 or 0.5% inclusion) until they reached 60 days of age (5 tanks / 4 diets / 2 temperatures). Fish housed at 16oC consumed significantly more feed and gained significantly more weight than fish housed at 10oC. Trout fed the commercial-type diet gained significantly more weight than those fed the synthetic diet without the nucleotide-rich yeast product added. There was no significant difference in weight gain or feed intake among fish fed either commercial-type diet and the fish fed the synthetic diets with the nucleotide-rich yeast product added, although fish fed the commercial-type diets had significantly better feed conversion efficiencies than those fed the synthetic diets. The nucleotide-rich yeast product could be used in low fish meal, low fish oil first feeding diets, as the aquaculture industry decreases fish meal and oil use in aquafeeds in response to their increasing cost and decreasing availability.