Parthenogenesis in mated Chinese Painted quail (Coturnix chinensis) hens decreases sperm-egg penetration and alters albumen characteristics.

Parthenogenesis, embryonic development without fertilization, resembles very early embryonic mortality in fertilized eggs. Also, parthenogenesis alters egg albumen characteristics in virgin Chinese Painted quail hens genetically selected for parthenogenesis (PV). When these PV hens are mated (PM), hatchability is reduced versus control mated (CM) hens that were not genetically selected for parthenogenesis. However, it is unclear if parthenogenesis, which occurs in PM hens, reduces hatchability due to infertility and altered albumen characteristics. Sperm-egg penetration (SEP) holes are indicative of true fertilization and may be useful in identifying if eggs from PM hens exhibit a decrease in fertility versus CM hens. Therefore, the objectives of this study were to determine if parthenogenesis in PM hens (1) decreases SEP, (2) alters albumen characteristics similar to parthenogenesis in eggs from PV hens, and (3) yields albumen characteristics similar to fertilized eggs containing early mortality. Daily, PV and PM eggs were collected, labeled, and incubated for 10 days, then broken out to determine the incidence of parthenogenesis and albumen characteristics. Also daily, fresh PM and CM quail eggs were macroscopically examined to determine if an egg was infertile with no embryonic development, parthenogenetic, or fertile. Each of these eggs was then microscopically examined for SEP. For both PV and PM incubated eggs, parthenogenesis decreased albumen pH, O2, and protein concentrations yet increased Ca(2+) and CO2 concentrations versus eggs with no development. For incubated PM eggs, albumen pH and O2 were lower, yet CO2 was higher for eggs containing parthenogens or early dead embryos versus infertile eggs. For SEP, fresh eggs classified as infertile or parthenogenetic from PM and CM hens had similar SEP holes but only one sixth as many SEP holes as eggs classified as fertilized. Eggs from CM hens had 3.5 times as many SEP holes as PM eggs. In conclusion, parthenogenesis that occurs in mated quail hens inhibits fertility and alters albumen characteristics similarly to parthenogenesis in unfertilized eggs and early embryonic mortality in fertilized eggs.

Parthenogenetic embryos from unfertilized Chinese painted quail eggs alter albumen pH, gases, and ion concentrations during incubation.

Parthenogenesis is a form of embryonic development that occurs without fertilization. Recently, parthenogenesis has been reported in Chinese painted quail eggs. In Japanese quail, it has been shown that albumen pH of incubated fertile eggs is lower than that of incubated infertile eggs. However, it is unknown if alterations, similar to those in incubated fertile eggs, occur in albumen pH, gases, or ion concentrations from unfertilized eggs exhibiting parthenogenetic development. Therefore, the objective of this study was to determine if any differences in pH, gases, or ion concentrations exist between incubated unfertilized eggs exhibiting parthenogenetic development versus unfertilized eggs with no development over incubation. In this study, eggs were collected daily from Chinese painted quail hens that were separated from males at 4 weeks of age, before sexual maturity. Eggs were stored for 0 to 3 days at 20 °C and incubated at 37.5 °C for 12 days. Eggs were weighed before and after incubation to obtain percentage egg weight loss. After incubation, embryo size and albumen O2, CO2, Ca(2+), Na(+), and Cl(-) concentrations as well as pH were obtained from each incubated egg. Over incubation, albumen from unfertilized eggs exhibiting parthenogenetic development had a lower pH as well as less O2 and Cl(-), yet a higher Ca(2+) and Na(+) concentration as compared with the albumen of unfertilized eggs with no development. Also, eggs exhibiting parthenogenetic development had a higher albumen CO2 concentration as compared with eggs without development. The rate of egg weight loss was much lower in eggs exhibiting parthenogenetic development as compared with eggs without development. Also, as parthenogen size increased, there was a decrease in albumen pH, O2, and Cl(-), yet an increase in CO2 and Ca(2+). In conclusion, it appears that, over incubation, parthenogenetic development from unfertilized eggs alters the composition of albumen as compared with the albumen from unfertilized eggs with no parthenogenetic development.

Selection for the parthenogenetic trait in Chinese Painted Quail (Coturnix chinensis) affects hatchability parameters.

Poultry are capable of laying unfertilized eggs in which embryonic development occurs; this phenomenon is called parthenogenesis. Through genetic selection, the incidence of parthenogenesis in virgin Chinese Painted Quail hens can be increased. However, it is unknown if selection for this trait affects hatchability of fertilized eggs. Therefore, the objective of this study was to determine if genetic selection for parthenogenesis in virgin Chinese Painted Quail affects hatchability of mated hens. At 4 wk of age, females were separated from males and individually caged. Daily, eggs were collected, labeled, and stored from 0 to 3 d at 20°C then incubated at 37.5°C. At d 10 of incubation, eggs from virgin hens were broken out to determine the incidence of parthenogenesis. After the incidence of parthenogenesis in virgin hens was determined, hens were selected for mating. Eggs from the parent stock and generations 1 through 7 that did not hatch were examined for stage of hatching failure and categorized as infertile or possible parthenogens as well as early, middle, and late embryonic mortality. For hatch of set and hatch of fertile eggs, generation 1 hatched the greatest percentage of eggs compared with the other generations. Also, as the generation of selection increased, there was a linear decline in the percentage of eggs hatched for both hatch of set and hatch of fertile eggs. Additionally, generation 2 had the highest percentage of infertile eggs. There was a linear increase as generation of selection increased for both the percentage of eggs exhibiting possible parthenogens and early embryonic mortality. Unlike early embryonic mortality, the parent generation had the greatest percentage of embryos die in both the middle and late stage of incubation. In conclusion, it appears that selecting Chinese Painted Quail for the parthenogenetic trait impairs hatchability when hens are mated.