Colorado State University Shutters Animal Study After Pressure From National Research Ethics Group

FORT COLLINS, Colo. — The Physicians Committee for Responsible Medicine, a nonprofit national medical ethics group, applauds Colorado State University for its decision to shutter a nutrition study for which the university had approved the killing of 17,766 animals. The study, funded by the U.S. Department of Agriculture and the university, claimed to investigate the effect of legumes on the human gut microbiome. Public records reveal the primary investigator had to date used 1,587 mice.

An initial USDA grant of $498,500 funded the experiments. A subsequent USDA Cooperative Agreement, active through Dec. 31, 2025, shared ongoing costs with the university.

Over the past two months, the Physicians Committee wrote to Dr. Cassandra Moseley, vice president for research at CSU, and to CSU President Amy Parsons to express scientific and ethical concerns about the studies and request an investigation into the need to kill thousands of animals. The nonprofit also reached out directly to the primary investigator.

“Dietary studies investigating the effects of pulse-rich diets on the gut microbiome and noncommunicable disease outcomes are ethically and effectively conducted using human volunteers,” Janine McCarthy, acting director of research policy for the Physicians Committee, wrote in the letter to Parsons.

Additionally, she wrote, although a search for alternatives to animals is required by federal regulation and the university’s Institutional Animal Care and Use Committee (IACUC), the search conducted by the researcher was flawed, resulting in the primary investigator’s failure to consider viable alternatives to animal use. The IACUC failed to challenge the faulty search.

In response to a Physicians Committee public records request, the university wrote in an email to Ms. McCarthy on Aug. 11, 2025, that the primary investigator had shut down the experiment on July 15, 2025, and that he did not have any active protocols to conduct animal experiments.

“We are grateful that CSU reconsidered these experiments and decided to stop them,” said Ms. McCarthy. “We hope other universities across the country will follow suit by ending animal experiments and shifting to research approaches that are more accurate, cost-effective, and most importantly, more relevant to humans. We also call on the USDA to end funding for animal experiments for human nutrition and instead invest in modern, human-specific science.”

Note to reporters: To arrange an interview with Ms. McCarthy, please contact Kim Kilbride at 202-717-8665 or kkilbride [at] pcrm.org (kkilbride[at]pcrm[dot]org).