A new scientific review finds that hemp-derived feeds and cannabinoids may influence gut bacteria, fermentation and intestinal health in livestock, with some studies reporting increases in beneficial bacteria, reductions in E. coli and lower methane production.
The review, published in Advances in Animal and Veterinary Sciences, was conducted by researchers affiliated with Bingol University and Ankara University in Türkiye. Researchers examined how dietary hemp compounds interact with the gut microbiota and endocannabinoid system in ruminants and poultry.
Researchers searched Google Scholar, PubMed, Scopus and Web of Science for studies published from January 2008 through April 2026. Of 412 records initially identified, 16 studies were ultimately included in the narrative review, comprising nine ruminant or in vitro rumen studies and seven poultry or in vitro gut studies.
The review found particularly notable results in poultry. Hemp seed products and micronized hemp fiber were associated with an approximately 0.50 log10 CFU increase in Lactobacillus or other lactic acid bacteria and an approximately 0.80 log10 CFU reduction in E. coli or coliform bacteria. CBD may also support intestinal barrier function and immune responses, particularly during infections involving Clostridium perfringens.
One study involving micronized hemp fiber found that total volatile fatty acids in broiler cecal fermentation increased by 28%, from 29.2 to 37.5 mmol/mL. Acetic acid increased 20%, propionic acid rose 23% and butyric acid increased 43%. The researchers said hemp fiber may exert a prebiotic-like effect by encouraging fermentation that supports beneficial bacteria while potentially making conditions less favorable for pathogens.
Results in ruminants were more mixed. Overall ruminal microbial diversity generally changed little, but hemp supplementation was associated in some studies with shifts in community composition, fermentation patterns and methane-producing archaea.
In one in vitro study, Cannabis sativa residue powder reduced methane production by roughly 35%, while decreasing Methanobacteriales and increasing propionate. Researchers said the broader evidence suggests hemp products could alter microbial pathways involved in methane production, although a direct causal mechanism has not yet been established.
The review also notes that hemp itself provides nutritional value beyond cannabinoids. Hemp seeds typically contain 20% to 25% highly digestible protein, while hemp seed meal can contain 30% to 50% protein. Hemp products also contain substantial amounts of polyunsaturated fatty acids and have an omega-6 to omega-3 ratio of approximately 3 to 3.5-to-1.
However, researchers stressed that the evidence remains preliminary. Most studies involved relatively small numbers of animals and short study periods, hemp preparations were poorly standardized, and researchers used substantially different methods to analyze microbiota. Of the reviewed studies, only one performed detailed terpene profiling, while several provided little or no chemical characterization of the hemp products used.
Researchers concluded that hemp-derived compounds should not yet be routinely used specifically to manipulate livestock microbiota, saying the current evidence is better viewed as hypothesis-generating.
“The hemp–microbiota interplay represents an emerging candidate mechanism, but current livestock evidence remains insufficient for routine application,” researchers said.
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