SPENT HOPS, YEAST AND TRUB FROM CRAFT BREWERIES FOR PROMOTION OF ANIMAL GROWTH AND METHANE REDUCTION IN RUMINANTS

The growing craft brewing industry produces significant amounts of spent yeast, trub (grain proteins) and spent hops that are presently treated as waste. Their disposal can be a headache for the brewer and municipal waste treatment authorities. We have created a combination of these materials called THYM (Trub Hops Yeast Mix) and are developing it into an agricultural feed supplement for cattle. Based on our earlier work with spent craft yeast and anti-microbial hop acids, we expect THYM to improve livestock growth and reduce their production of methane. THYM should improve the digestive response and growth of cattle by altering the metabolism of their gut (rumen) microbes in a manner similar to conventional antibiotics. Commercialization of THYM as a feed supplement faces three major hurdles: a high moisture content-which make it difficult to transport and manipulate, an untested growth potential as a supplement, and a limited understanding of how it affects the cow's digestive response/very important rumen microbes. To address these problems, we will 1) evaluate several industrial methods for drying THYM suitable for a midsize craft brewery, 2) run a 2-month growth and metabolism study in Angus steers and 3) further investigate the natural products in THYM and their effects in the rumen. This ground work will help turn craft brewery byproducts into a commercial feed supplement that improves growth, reduces antibiotic use and lowers greenhouse gas emissions.