Mr Erlandsson reacted after learning that a Danish producer part-owned by Swedish meat producer Scan makes pig feed that contains pig blood, among other ingredients, according to Sweden's The Local.

"It is ethically objectionable to eat one's own species," he said.

Following the mad cow disease crisis in the 1990s, meat and bone meal were banned as feed for pigs, cows and chickens. Cannibalism was cited as a reason for the spread of mad cow disease, officially known as bovine spongiform encephalopathy (BSE).

However, across Europe, pigs can now be fed entirely legally with feed containing pig blood and fat, Sveriges Radio's news bulletin Ekot reported on Tuesday.

In Sweden, Scan and other large meat producers have agreed not to use blood or animal fat in animal feed for pigs, among others. However, Scan is part-owner of Danish company Daka, which produces pig feed based on pig blood and fat.

Scan's communications director Margaretha Thorngren thinks that it is unethical if to give pigs animal feed derived from their own species and now wants to see a change.

Leo Virta, head of marketing at Daka, told Ekot that the blood and fat processing is so refined at the plant that it is something completely different than the pigs for meat and bone meal.

"Strictly speaking, one can say that there has been an industrial version of a natural raw material that becomes natural again," he said.