Effects of monochromatic green light environment on the physical and chemical properties of eggshell during incubation

Abstract: Incubation is the last step of the whole breeding for the better performance of poultry production. Among them, the hatching rate and healthy chick rate can be always considered research hotspots in the field. Particularly, lighting has been one of the most important environmental conditions during poultry hatching in recent years. Cold light sources can be used to regulate the hatching, including fluorescent lamps and LED. The light environment can be tailored for the eggs breeding during the hatching process. Alternatively, the LED light source can be used to explore the significant influence of different monochromatic spectra on chicken embryo development and growth after hatching. Eggshell is an important medium of gas exchange between chicken embryos and the outside world during chicken embryo development. The eggshell can be antibacterial to effectively resist external physical damage. Meanwhile, the structure and morphology of eggshells are also important factors affecting the development of chicken embryos. As reported in previous research, the performance of hatching depends largely on the physical and chemical properties of the eggshell. More importantly, the monochromatic green light irradiation can shorten the hatching time of breeding eggs, leading to a higher hatching rate and the anti-stress ability of chicks. In this study, the fertilized eggs were treated with the monochrome green light by LED lamps from the two sides of the egg tray during the whole incubation process. Specifically, the illumination period was L:D= 18:6, and the illumination intensity was 120-220 lx. The influencing factors were monitored during incubation with the monochrome green light regulation, such as eggshell color, eggshell structure, pigment content, and element content. An optimal mechanism for the chick hatching was established under the monochrome green lighting. The results indicated that the incubation environment of monochromatic green light promoted the adaptive response of the eggshell. Also, the surface brightness L *of the eggshell decreased significantly (P < 0.01), and the decomposition of biliverd in the eggshell was inhibited (P<0.01). In addition, the monochrome green light was beneficial to the absorption and utilization of Ca element in the eggshell. There was also a significant increase in the weathering and the pore area of the eggshell surface during hatching (P<0.000 1). Consequently, the enhanced permeability and heat dissipation of eggshell were achieved to improve the hatchability for less mortality during the hatching process. This finding can also provide the promising prospect for the better hatchability and utilization of monochrome green light in the incubation industry, as well as promoting the coordinated development of the poultry industry and energy conservation to enhance sustainable agriculture.