Norwegian Veterinary Science College feeding trials on rats, mice, pig and salmon have found that GM feed produces significant changes. Rats and fish fed Bt corn grew fatter than the control groups fed non-GM corn. Salmon fed on GM corn were slightly larger and ate slightly more. Their intestines had a different microstructure, they were less able to digest proteins, and there were changes to their immune system and blood.

Prof Ashild Krogdahl of the Norwegian School of Veterinary Science, one of the research team, commented on another worrying finding: “A frequent claim has been that new genes introduced in GM food are harmless since all genes are broken up in the intestines. But our findings show that genes can be transferred through the intestinal wall into the blood; they have been found in blood, muscle tissue and liver in sufficiently large segments to be identified.”