In a 6-to-3 ruling, the Mississippi Supreme Court has denied People for the Ethical Treatment of Animals access to documents concerning seven years of Iams pet-food research at Mississippi State University.

PETA, an animal-rights group, had requested information on the number and type of animals used in experiments, on whether surgery had been performed, and on the conditions the animals were held in. The suit raised contentious issues in the university-research world, where the line between protected corporate data and information available publicly is often fuzzy.

According to the Associated Press, the court overturned a lower court’s 2006 ruling that said the information PETA sought did not qualify as trade secrets and should be released. In the Supreme Court decision, released Thursday, Justice Michael Randolph wrote that the advocacy group had “failed to rebut the evidence presented by MSU and Iams,” which insisted that the data solicited contained trade secrets. Data containing trade secrets does not have to released under Mississippi’s public records laws.

In a dissenting opinion, Justice Oliver Diaz Jr. wrote that PETA could not dispute Iams’ claim that the data contained protected trade secrets without first seeing the documents.

“The court missed the mark,” said Heather Carlson, a spokeswoman for PETA, in an e-mail interview. “What is proprietary about the types and numbers of animals tortured in a laboratory?”

The advocacy group does not intend to challenge the ruling, but Ms. Carlson pointed out that Iams could still authorize Mississippi State to release the information. The suit was part of an ongoing PETA campaign against Iams, during which the group solicited research information from 14 other colleges. —Ingrid Norton