A Moncton zoo is changing how it handles donated carcasses after one of its two Siberian tigers died from eating meat tainted with drugs used to euthanize animals.

The endangered Siberian tigers have been one of the main attractions at the Magnetic Hill Zoo, said manager Bruce Dougan.

The female tiger, Pasha, died two weeks ago. An autopsy revealed she had eaten donated meat that contained barbituates used by veterinarians to euthanize sick farm animals.

"I was angered that this happened and very concerned that it doesn't happen again," said Dougan, who considered Pasha his favourite beast at the zoo.

"Did someone not tell us the truth about the animal? That's what I tend to think," he said. "I know my staff always asks if the animal had drugs in it."

Now the zoo has changed the rules on accepting donated meat.

In the past, farmers were simply asked if the animal they were handing over had died of natural causes. Now they will have to sign a statement saying the animal was not put down using drugs, and giving the attending veterinarian's name for verification.

"It's just unfortunate that that happened," farmer Lloyd Jones, a regular donor to the zoo, said of Pasha's death.

Zookeeper Jamie Carson says the new measures are necessary, although tainted meat isn't a widespread problem.

"We have received several hundred to several thousand animals to be used for food with little or no trouble," said Carson.

The zoo hopes the new rules won't reduce the number of carcass donations. It can't afford to buy the quantities of meat it needs to feed the carnivores among its 400-animal population.