Abstract The effects of short- and long-term feeding of genetically modified Bt MON810 maize on porcine growth performance and health were investigated in two studies. Bt maize expresses the Cry1Ab toxin from Bacillus thuringiensis which confers insect resistance. Fate of the cry1Ab transgene and Cry1Ab protein were also investigated. Short-term (31 days) feeding of Bt maize to weanling pigs resulted in higher feed intake but overall weight gain and feed conversion efficiency were unaffected. Organ function, as measured by blood biochemistry, organ weight and histology, was unaffected in the Bt group. Minor changes were observed in immune cell population distribution but these were not associated with local or systemic inflammation and there was no Cry1Abspecific immune response. Bt maize consumption had minimal impact on caecal microbial community structure; the only populations affected were Enterococcaceae, Erysipelotrichaceae, Blautia and Bifidobacterium, which were found in low abundance and at low prevalence. The effect of long-term (110 days) feeding of Bt maize to pigs from 12 days post-weaning to slaughter was investigated in a second feeding trial which used a crossover of diets (from isogenic to Bt maize and vice-versa) after 30 days. There were no adverse effects on growth, slaughter parameters, immune response, intestinal histology or microbiology. Organ function was not adversely affected and no histopathology was present. In both short- and long-term studies the transgene was mostly degraded during digestion and neither the transgene nor protein were detected in the blood or organs. Overall, short- or long-term feeding of Bt maize to pigs did not adversely affect any of the growth or health parameters investigated. These findings should provide assurance to pig producers as well as the feed industry of the safety of Bt maize, one of the main ingredients of pig diets. They should also help assure consumers, as a similar lack of adverse effects should be expected in humans, for which pigs are considered an excellent model.
|Publication status||Unpublished - 2011|