Effects of genetically modified T2A-1 rice on faecal microflora of rats during 90 day supplementation

J Sci Food Agric. 2011 Aug 30;91(11):2066-72. doi: 10.1002/jsfa.4421. Epub 2011 Apr 26.


Background: Many animal studies have been performed on products with the Bacillus thuringiensis insecticidal toxin-encoding gene (Bt products), but less have focused on its effects on intestinal microflora owing to difficulties in culturing. This 90 day study was designed to assess unintended effects of genetically modified T2A-1 rice (GMR) on selected intestinal bacteria (Lactobacillus group, Bifidobacterium genus, Escherichia coli subgroup, Enterococcus genus and Clostridium perfringens) of rats by the real-time polymerase chain reaction (PCR) method.

Results: During the whole experiment, no statistically significant differences in the numbers of specific bacteria and total bacteria were found between the GMR group and its parental group. At all stages of the experiment the two main probiotics (Lactobacillus group and Bifidobacterium genus) in faeces accounted for 11-23% of the total bacteria, whereas the conditional pathogens (E. coli subgroup, Enterococcus genus and C. perfringens) made up less than 1% of the total bacteria. B/E (log(10) copies of Bifidobacterium genome g(-1) faeces/log(10) copies of E. coli genome g(-1) faeces) ratios from 1.19 to 1.34 were obtained. Furthermore, significant correlations (P < 0.01) between the real-time PCR method and the plate count method were found, with r values ranging from 0.60 to 0.75.

Conclusion: No adverse effects on the numbers of specific bacteria in rat faeces were observed as a result of GMR feeding. The real-time PCR method is recommended in further studies on the composition and dynamics of the intestinal bacteria community for better safety assessment of GM materials.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Colony Count, Microbial
  • Cryptochromes / genetics
  • Escherichia coli / classification
  • Escherichia coli / isolation & purification
  • Feces / microbiology*
  • Female
  • Food Safety
  • Food, Genetically Modified / adverse effects*
  • Gram-Positive Bacteria / classification
  • Gram-Positive Bacteria / isolation & purification
  • Male
  • Molecular Typing
  • Oryza / adverse effects*
  • Oryza / genetics*
  • Plants, Genetically Modified
  • Random Allocation
  • Rats
  • Rats, Sprague-Dawley
  • Real-Time Polymerase Chain Reaction
  • Reproducibility of Results
  • Seeds / adverse effects*
  • Seeds / genetics*
  • Specific Pathogen-Free Organisms


  • Cryptochromes