Long-term safety assessment of insect-resistant genetically modified maize: A one-year feeding study

Genetically modified (GM) maize carrying two insect resistance genes, mCry1Ab and mCry2Ab has benefits for crop production. To adequately evaluate its safety, a one-year feeding study was conducted in wistar rats (n = 120, half male and half female). All the rats were randomized into three groups, GM maize group (GM group, 70% GM maize), a non-GM parental maize control group (NG group, 70% zhengdan 958 maize), and AIN-93 standard diet control group (AIN group). Body weight and food intake were recorded. And blood biochemistry tests were performed at months 3 and 6 and at the end of the trial, respectively, and urine and histopathology were performed at the end of the trial, and metabolites in the terminal serum were also analyzed using untargeted metabolomics. The results showed some differences between the GM group and the NG group or the AIN control group in the results of food consumption and utilization, hematology and urinalysis, blood biochemical parameters, and organ coefficients, but no adverse effects were observed in the histological examinations. Metabolomics analysis showed significant gender differences in metabolites, but no between-group differences were found for the same sex. In conclusion, no chronic toxicity or other unintended adverse effects were found in rats after long-term consumption of GM maize at a high level up to 70%.