EAST ST. LOUIS, Ill.

Seven southwestern Illinois men who were among more than two dozen suspects swept up last summer in the country's largest dogfighting crackdown have been ordered to spend at least a year in federal prison.

The seven, sentenced Tuesday on felony conspiracy counts, also were sentenced to three years of post-prison supervision and must reimburse what the Humane Society of Missouri's Debbie Hill said Wednesday was its roughly $1 million tab for caring for the seized pit bulls and their puppies born since the raids.

The prison terms were the latest meted out following the arrest of 26 suspects and seizure of more than 500 dogs last July in a series of raids in Illinois, Iowa, Mississippi, Missouri, Nebraska, Oklahoma and Texas. It was the largest coordinated multistate dogfighting raid in U.S. history.

Missouri's Humane Society has said some 160 of the dogs were euthanized because of injuries, illness or behavior that made them unacceptable for adoption.

Hill heralded Tuesday's sentences in the crackdown she called "unprecedented in so many ways," insisting "that they actually will spend significant time in jail is extremely important in sending the message that this kind of conduct is not allowed in a civilized society and will not be tolerated."

"I guarantee you that the (continuing) perpetrators of this are watching and keeping tabs of the sentences, and they'll have to weigh the risks of what they want to continue to do," said Hill, who said some $300,000 of the agency's million-dollar tab for caring for the seized animals remains unreimbursed. Much of the rest has been covered by the U.S. government, she said.

Courtney Cox, the U.S. attorney for southern Illinois, did not immediately return calls seeking comment.

Federal prosecutors say the Illinois men's conspiracy spanned from late 2008 through at least April 18 of last year in St. Clair and Madison counties, where one suspect, Joseph Addison, used alligator clips attached to an extension cord to electrocute one of his losing pit bulls.

Addison, 41, of East St. Louis, got a two-year sentence the stiffest of the seven handed down.

Court documents allege the suspects played varying roles, from sponsoring or refereeing the fights to breeding or kenneling the dogs.

Last December, four Missouri men who also pleaded guilty to conspiring to violate federal animal fighting laws got federal prison sentences. In many of those cases, their attorneys described them as family men caught up in a rural American culture where dogfighting was acceptable claims that didn't fly with the judge, who imposed the prison terms after pressing that "culture is not a mitigating factor."

Pre-sentencing documents prepared for that court showed the men had the dogs electrocuted or shot for poor performance or serious injuries from the fighting ring, or left them to freeze to death while chained to a stake in the ground without shelter.