Metabolite Profiling And Target Analysis Of Antinutritional Factors (ANF) In Selected Aquafeed Ingredients

In search of alternative aquafeed components due to a limited access to marine resources, new diets will heavily rely on plant raw materials and potentially, also biotechnologically derived products.1 In order to describe and predict the nutritional value of aquafeeds on the one hand, and possible adverse and toxic effects of antinutritional factors (ANF) on the other hand,2 it is imperative to gain detailed chemical information of raw materials used in fish diets with regard to primary (carbohydrates, proteins, lipids) and so-called plant secondary metabolites.3,4 The latter often exert certain biological activities when applied to other organisms, including farmed fish. The present project is aimed at the untargeted metabolic profiling for the identification and quantification of single compounds of nutritional value (amino acids, fatty acids, carbohydrates, sugar alcohols, organic acids) and specifically potential ANFs from different chemical structure groups within one analytical run (e.g. sinapic acids and phenols in general, flavonoids, sterols, alkaloids). The primary analytical tool-of-choice is gas chromatography/ mass spectrometry analysis (GC/MS) of volatile or derivatized samples, which will be followed up by target analysis of compound groups with focus on the identification of ANFs, which might impact on the digestibility of novel aquafeeds and influence growth performance and health of farmed fish, including total phenols, total flavonoids, glucosinolates, alkaloids and structures related to the heterogenous group of so-called phytoestrogens. In preliminary studies, extracts of plant raw materials and processed products of soybeans, corn, peas, beans, and rapeseed were subjected to metabolic profiling by GC/MS. As an example, metabolic screening of conventional and gene modified rapeseed (Brassica napus) revealed differences in the amino acid and carbohydrate profiles. Furthermore, the sinapic acid content of transgene rapeseed was reduced by 25 %. Expected results from our on-going metabolic profiling studies of selected plant sources frequently used in aquafeeds will be presented in-depth. REFERENCES 1. Gatlin D.M., Barrows F.T., Brown P., Dabrowski K., Gaylord T.G., Hardy R.W., Herman E., Hu G., Krogdahl Å. et al. 2007. Expanding the utilization of sustainable plant products in aquafeeds: a review. Aquacult. Res. 38: 551-579. 2. Francis G., Makkar H.P.S., and Becker K. 2001 Antinutritional factors present in plant-derived alternate fish feed ingredients and their effects in fish. Aquacult. 199: 197-227. 3. Schauer N., Zamir D., and Fernie A.R. 2005. Metabolic profiling of levaes and fruit of wild species tomato: A survey of the Solanum lycopersicum complex. J. Exp. Bot. 56: 297-307. 4. Rohloff J., and Bones A.M. 2005. Volatile profiling of Arabidopsis thaliana – Putative olfactory compounds in plant communication. Phytochemistry 66: 1941-1955.