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From Spent Brewery Grains to Sustainable Fish Food

Dec 2, 2021 | News

Aquaculture production is growing worldwide, and there is an emerging need to develop new protein sources for nutritionally balanced, cost-effective, and sustainable ​fish feeds. As part of the Consortium’s 2020-2022 research portfolio, the Mariculture section at the S.C. Department of Natural Resources (SCDNR) is collaborating with three Charleston-area craft breweries—Low Tide Brewing, Holy City Brewing, and Tradesman Brewing Company​—to evaluate the potential of using dried spent grains from the beer-brewing process as an ingredient in fish feeds.

Researchers collected monthly samples from each brewery for one year to examine the nutritional composition of the spent grain material. They studied whether there were differences throughout the year or between the three breweries. The initial data reveal little difference either between breweries or over the course of time, an encouraging finding to be able to scale-up and use spent grains on a consistent basis.

The researchers are in the midst of conducting a digestibility trial to determine if juvenile red drum (Sciaenops ocellatus) can digest and use the nutrients in the spent grains. Next, they will run a graded-tolerance feeding trial, using increasing quantities (0-35% of the diet) of spent grain in the feed formulation and evaluating growth of juvenile red drum.

(Editor’s note: Special thanks to Aaron Watson with SCDNR for providing this update to the FY2020-2022 project.)