Mushrooms are easy to grow, and they are relatively inexpensive. They thrive in substrates such as horse manure, and thus, they must have a mechanism or two for fighting off pathogenic bacteria. As it happens, the antibacterial properties of mushrooms have already been established, with over 150 species being currently recognized as potential sources of strong antibiotics. Given the vast number of unexplored species, most of which are toxic, it is expected even more varieties will be identified as potential antibiotic sources

So why hasn't the animal nutrition industry explored this ingredient, especially as we are focusing on removing antibiotics not only as growth-promoting agents, but also as therapeutic agents? In fact, in 2004 I reviewed a study about feeding a mushroom extract or dried up mushrooms versus avilamycin. Results were not so promising for the extract, but the high inclusion rate of dried up mushrooms proved beneficial, at least in terms of gut health. The researchers concluded that it was the shitake’s inherent high concentration in antimicrobial compounds that was responsible for the positive effects. This effort was not followed up by other researchers. 

More recently, a great review of the antibacterial properties of mushrooms as a means of safeguarding human food safety has been published in the journal titled “Comprehensive Reviews in Food Science and Food Safety.” This review, titled “Antimicrobials from Mushrooms for Assuring Food Safety,” describes the many species of mushrooms with antimicrobial properties and their potential role. Perhaps we should also have a look at it for potential application into animal nutrition.