Peng Ding ^1,2 Xi He ^2* Minxi Li ^1* Sai Jiang ¹ Yanmei Peng ^1*

• ¹ Hunan Academy of Chinese Medicine, Hunan University of Chinese Medicine, Changsha, Anhui Province, China
• ² Hunan Agricultural University, Changsha, Hunan, China

Surface sterilization of the fertile eggs is a common process for the commercial broiler breeding to avoid the pathogenic bacterial infections before incubation. However, it is also possible to remove the beneficial microbes which might contribute to the development of chicken embryos. Thus, we established a model to mimic the surface sterilization in lab which simply used 70% ethanol to rub over the fertile eggs and investigated the effect of eggshell surface sterilization on yolk microbiota and its potential role on chicken (Gallus gallus) embryo development. Four hundred and sixty Ross 308 fertile eggs were randomly divided equally into eggshell surface sterilized group (CS, commercial egg sterilization group) and eggshell surface unsterilized group (CC, commercial egg control group). The shell surface of group CS was sterilized with 70% alcohol before incubation (E0, embryonic stage), while that of group CC was not sterilized before incubation. At each sampling day (E0, E07, E15, E21), Twenty-four fertile eggs from each of two groups were randomly selected to collect the yolk samples and weigh the embryos. The results showed that the surface sterilization of eggshell before incubation improved the development of chicken embryos from E15 to E21 but reduced the diversity of the yolk microbiota. In the whole process of embryogenesis, the relative abundance of Firmicutes, Bacteroidetes, Actinobacteria in egg yolk of group CS were lower than that of group CC before incubation. Indeed, the surface sterilization of fertile eggs significantly reduced the relative abundance of Staphylococcus saprophyticus and other pathogenic bacteria in yolk, which may result in the better development of chicken embryos.