Investigating mushroom stump waste as a broiler feed supplement

Mushroom stumps for the research were obtained from a commercial mushroom farm in southwest Pennsylvania. Photo: Canva

Just over 90,000 mt of mushroom stump waste is generated yearly from the production of button mushrooms. Stumps waste comprises nearly 30% of total mushroom weight. Could this agricultural by-product reduce waste and lower feed costs for broiler producers?

Pennsylvania is a leader in the production of broiler chickens and button mushrooms, and so it seems fitting that a team of Penn State researchers conducted a study to better understand how supplementing broiler feed with mushroom stump waste affected the health and growth of the chickens.

During harvest, the head of the button mushroom is separated and used for human consumption, while the stump is composted as an agricultural by-product. “Roughly 93,264 metric tonnes of button mushroom stumps are composted yearly,” says research team leader John Boney, Vernon E. Norris Faculty Fellow of Poultry Nutrition in the College of Agricultural Sciences.

Boney adds: “The stump is fibrous and contains therapeutic bioactive compounds with antimicrobial and antioxidant activities. Because of its nutritive and medicinal properties, mushroom stump waste may be a viable feedstuff.”

Feeding mushrooms stumps to broilers

Altogether, 480 broiler chickens which were divided into groups and fed 6 dietary treatments. The control group received no fungi supplementation while the other groups had diets with 1%, 2%, 3%, 4% and 5% mushroom stump waste. Mushroom stumps were dried in a small grain drier and ground to be included in the poultry feed.

The researcher team tested birds in the study for their ability to digest 17 amino acids. The growth and health of the birds was tracked.

What did the researchers discover?

Following a 21-day trial, the Penn State researchers reported that broiler chickens fed up to 3% mushroom stump waste grew at the same rate as birds in the study that didn’t receive fungi supplementation, and their digestion was unaffected. They noted that higher levels f supplementation – at 4% and 5% – resulted in slowed growth and interfered with the birds’ digestion of amino acids, or the organic compounds used to make proteins.

The detailed study results have been published in The Journal of Applied Poultry Research.