Safety assessment of genetically modified milk containing human beta-defensin-3 on rats by a 90-day feeding study.

In recent years, transgenic technology has been widely applied in many fields. There is concern about the safety of genetically modified (GM) products with the increased prevalence of GM products. In order to prevent mastitis in dairy cows, our group produced transgenic cattle expressing human beta-defensin-3 (HBD3) in their mammary glands, which confers resistance to the bacteria that cause mastitis. The milk derived from these transgenic cattle thus contained HBD3. The objective of the present study was to analyze the nutritional composition of HBD3 milk and conduct a 90-day feeding study on rats. Rats were divided into 5 groups which consumed either an AIN93G diet (growth purified diet for rodents recommended by the American Institute of Nutrition) with the addition of 10% or 30% HBD3 milk, an AIN93G diet with the addition of 10% or 30% conventional milk, or an AIN93G diet alone. The results showed that there was no difference in the nutritional composition of HBD3 and conventional milk. Furthermore, body weight, food consumption, blood biochemistry, relative organ weight, and histopathology were normal in those rats that consumed diets containing HBD3. No adverse effects were observed between groups that could be attributed to varying diets or gender.