Submitted to: Aquaculture Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 12/5/2012
Publication Date: 2/24/2013
Citation: Liu, K., Barrows, F. 2013. Methods to concentrate proteins from grains for use in aquafeeds. Aquaculture Conference Proceedings. Program Book, page 79.
Technical Abstract: The expansion of aquaculture and static supply of fish meal has created a need for a diversity of high quality protein ingredients. Typical protein levels of unprocessed grains are too low for use in high protein fish feeds. However, innovative processing can result in lower cost, high quality protein from non-marine sources. An ongoing program in the Agricultural Research Service has followed two major strategies to develop improved ingredients: 1) further process/fractionate an existing ingredient for nutritional enhancement, and 2) to develop or modify existing processing methods. Using the two strategies, we have developed several protein ingredients for fish feed, including barley and oat protein concentrates and two products derived from corn distiller's dried grains with solubles (DDGS). DDGS typically has characteristics that limit the inclusion level for some fish feeds, such as high fiber, low digestibility and low protein. In order to add value to this by-product from the ethanol industry, reclaim nutrients into a more useable form and provide ingredients to the aqua feed industry, a novel method to recover co-products from dry-grind processing of grains into fuel ethanol has been developed. The method results in not only a more consistent distiller grains and but also two new co-products with unique composition, including a high protein product (hereto referred to as ARS protein supplement) and a concentrated mineral-rich product (referred to as ARS mineral supplement). Both were found to have high nutrient digestibility in 500 g rainbow trout. To evaluate the ARS protein supplement for palatability and effect on growth, first feeding rainbow trout were fed diets where the primary protein source was the test ingredient. Four tanks of 100 fish per tank were fed the test diets to excess for 6 weeks. The trout grew from 0.2 g/f to 3-4 g/f. At the end of the trial the trout fed the protein supplement had growth rates equivalent to fish meal and greater than trout fed the feed grade soy protein concentrate or soybean meal.