A recent study in the Journal of Organic Systems conducted on the long-term health effects of consumption of genetically modified grains examined 168 pigs over a 22.7 week period. These animals were fed with three types of GMO corn, two of which were engineered to produce Bt, and the third which was engineered to tolerate glyphosate (RoundUp Ready). They also had the addition of RoundUp Ready soy in their feed, the predominant GM soy strain in the market.
While the study notes that over this timespan (the lifespan of a pig destined for the slaughterhouse) that “there were no differences between pigs fed the GM and non-GM diets for feed intake, weight gain, mortality, and routine blood biochemistry measurements,” there were significant differences noted post-mortem in the gastrointestinal tracts and female reproductive organs.
The uteri of the female pigs fed GM crops grew of 25% heavier, and on average, the GM-fed pigs were 2.5x likely to have severe stomach inflammation. In particular, male pigs were four times as likely as their control group counterparts to develop severe stomach inflammation.