Ecotoxicological Effects of Microplastics on Bird Embryo Development by Hatching without Eggshell

Microplastics are an emerging global pollutant type that poses a great health threat to animals due to their uptake and translocation in animal tissues and organs. Ecotoxicological effects of microplastics on the development of bird embryos are not known. The bird egg is a complete development and nutrition system, and the entire embryo development occurs in the eggshell. Therefore, a direct record of bird embryo development under the stress of pollutants such as microplastics is highly limited by the opaque eggshell in traditional hatching. In this study, the effects of microplastics on quail embryo development were visually monitored by hatching without an eggshell. The main steps include the cleaning and disinfection of fertilized eggs, the incubation before exposure, the short-term incubation after exposure, and the sample extraction. The results show that compared with the control group, the wet weight and body length of the microplastics-exposed group displayed a statistical difference and the liver proportion of the whole exposed group significantly increased. Additionally, we evaluated external factors that affect the incubation: temperature, humidity, egg rotation angle, and other conditions. This experimental method provides valuable information on the ecotoxicology of microplastics and a novel way to study the adverse effects of pollutants on the development of embryos.