Developing low cost feed grade soybean protein concentrates for aquaculture

Authors: Liu, Keshun; Barrows, Frederic

Submitted to: International Soybean Processing and Utilization Conference
Publication Type: Abstract Only
Publication Acceptance Date: 6/15/2016
Publication Date: 7/26/2016
Citation: Liu, K., Barrows, F. 2016. Developing low cost feed grade soybean protein concentrates for aquaculture. In:Proceeding of Soybean Chemistry and Functionality, at the 7th International Soybean Processing and Utilization Conference. August 8-10, 2016, Harbin, China. Section:3.

Interpretive Summary:

Technical Abstract: One emerging area in the global soy industry, particularly the U.S. soybean industry, has been developing soy-based feeds as an alternative protein source to meet the growing needs of aquaculture in China and elsewhere. Traditionally, fishmeal is a key protein ingredient in fish diets, but its supply has stagnated and its cost has increased. At present, defatted soy meal is a widely used ingredient for fish feed because of its low cost and abundant availability. However, defatted soy meal is far from an ideal fishmeal replacement, because its protein content is significantly less than fishmeal and the presence of soluble and insoluble carbohydrates limits its inclusion levels for some fish. In contrast, soy protein concentrate (SPC) is better suited for fish meal replacement. Yet, currently, only about 30-40% SPC produced worldwide is used for animal feeds (aquafeed and terrestrial animal feed) while the remainder is mostly used for human consumption. The two major constraints that limits use of SPC in animal feed (particularly in aquafeed) are high production costs associated with current processing methods and limited availability. Therefore, at the U.S. Department of Agriculture, Agricultural Research Service, we have focused on developing low cost feed grade SPC for aquafeed to address these constraints. Food grade and feed grade SPC have differing requirements for protein content, levels of anti-nutritional factors, physical and functional properties, color, and flavor. Because of these differences, we have been able to lower the cost of feed grade SPC production at both laboratory and pilot plant scales without sacrificing nutritional quality. Our strategies centered around three important aspects in SPC production: choosing a low cost raw material, using alternative solvents, and employing alternative drying methods. Feeding studies with rainbow trout showed that fish fed with the new feed grade SPC performed as well as those fed food grade SPC.