Compositional and Animal Feeding Assessments of a Novel Herbicide-Tolerant Maize Variety

ZDAX5 is a variety of herbicide-tolerant maize that contains the modified P450-N-Z1 gene isolated from Cynodon dactylon (L.) Pers. and the cp4 epsps gene isolated from the Agrobacterium tumefaciens strain CP4 and exhibits high tolerances to flazasulfuron and glyphosate under field conditions. Once ZDAX5 corn is available on the market, the evolution of herbicide-resistant weeds will be delayed by applying glyphosate and flazasulfuron to corn fields. Prior to commercialization, it is critical to assess the safety of ZDAX5 maize. Compositional analysis and feed consumption studies in rodents are an important consideration in the safety assessment of genetically modified crops. The nutritional components of ZDAX5 were analyzed and compared with those of its non-transgenic counterpart. The data showed that all the analyzed components in the herbicide-tolerant maize plants were substantially equivalent to those of its non-transgenic counterpart. Furthermore, most of the measured values from ZDAX5 were within the range of values reported for other commercial maize varieties. The sub-chronic feeding trial was carried out with grains from GM, and non-GM maize were independently added into rodent diets at concentrations of 12.5%, 25% and 50%. As a control, another set of rats was fed with a marketed diet. At the end of the 90-day feeding study, no negative effects associated with the consumption of GM maize were found. These results indicate that the herbicide-tolerant maize ZDAX5 is as nutritious and safe as non-transgenic maize.