Subchronic feeding study of grain from herbicide-tolerant maize DP-Ø9814Ø-6 in Sprague-Dawley rats

Food Chem Toxicol. 2009 Sep;47(9):2269-80. doi: 10.1016/j.fct.2009.06.014. Epub 2009 Jun 12.


This 13-week feeding study conducted in Sprague-Dawley rats evaluated the potential health effects from long-term consumption of a rodent diet formulated with grain from genetically modified (GM), herbicide-tolerant maize DP-Ø9814Ø-6 (98140; trade name Optimum GAT (Optimum GAT is a registered trademark of Pioneer Hi-Bred)). Metabolic inactivation of the herbicidal active ingredient glyphosate was conferred by genomic integration and expression of a gene-shuffled acetylase coding sequence, gat4621, from Bacillus licheniformis; tolerance to acetolactate synthase (ALS) inhibiting herbicides was conferred by overexpression of a modified allele (zm-hra) of the endogenous maize ALS enzyme that is resilient to inactivation. Milled maize grain from untreated (98140) and herbicide-treated (98140+Gly/SU) plants, the conventional non-transgenic, near-isogenic control (091), and three commercial non-transgenic reference hybrids (33J56, 33P66, and 33R77) was substituted at concentrations of 35-38% w/w into a common rodent chow formula (PMI) Nutrition International, LLC Certified Rodent LabDiet 5002) and fed to rats (12/sex/group) for at least 91 consecutive days. Compared with rats fed diets containing grain from the conventional near-isogenic control maize, no adverse effects were observed in rats fed diets containing grain from 98140 or 98140+Gly/SU maize with respect to standard nutritional performance metrics and OECD 408-compliant toxicological response variables [OECD, 1998. Section 4 (Part 408), Health Effects: Repeated Dose 90-Day Oral Toxicity Study in Rodents, Guideline for the Testing of Chemicals. Organisation of Economic Co-operation and Development, Paris, France]. These results support the comparative safety and nutritional value of maize grain from genetically modified Optimum GAT and conventional, non-transgenic hybrid field corn.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animal Feed / toxicity*
  • Animal Nutritional Physiological Phenomena
  • Animals
  • Behavior, Animal / drug effects
  • Blood Chemical Analysis
  • Body Weight / drug effects
  • Drug Tolerance / genetics*
  • Eating / drug effects
  • Eye / drug effects
  • Female
  • Hematologic Tests
  • Male
  • Muscle Strength / drug effects
  • Nervous System / drug effects
  • Plants, Genetically Modified / chemistry
  • Plants, Genetically Modified / genetics
  • Plants, Genetically Modified / toxicity*
  • Rats
  • Rats, Sprague-Dawley
  • Toxicity Tests*
  • Zea mays* / genetics
  • Zea mays* / metabolism
  • Zea mays* / toxicity