The Change Rule And Sex Difference Of Steroid Hormones In Male And Female Hatched Hen Eggs

Around the world,billions of day-old roosters are slaughtered every year for lack of productivity effects in laying hens industry.It not only wastes the resources and the cost of investment,but also violates the rules of animal welfare,if the sex of chicken embryo can be identified non-destructively during incubation periods,which could not only save incubation space and input costs,but also meet the requirements for further food processing of male embryonic eggs to improve the additional value of products.Therefore,non-destructive sex identification of eggs directly affects the production and economic benefits of egg industry.It has become an urgent problem to screen out sex targets in male and female eggs,and the steroid hormones were associated with sex differentiation in eggs.So in this paper,we chose the chicken embryonic eggs as the research model,and the efficient and rapid ELISA method was adopted to study androgens and estrogens levels systematically in multiple parts of male and female embryo eggs during different incubation stages.The main research results were as follows:(1)The change rules and sex differences of steroid hormones in the mix of egg yolk and embryo during incubation periods from 2 to 7 days were explored.The results showed that E3 was the highest among the six maternal hormones.E1,E2,E3 and A4 all showed significant decrease trends,while T and DHT showed overall increase trends.The significant sex differences between male and female eggs were mainly reflected in the following aspects.the E1% remained stable in male embryos,but increased gradually in female embryos.There were significant differences of E1%,E2%,E3% and T in male and female on 7d.In addition,males had higher level of A4 and A4% than females on 5d.(2)The change rules and sex differences of steroid hormones in the mix of egg yolk and embryo during incubation from 8 to 13 days were explored.The results showed that androgen level in eggs was significantly higher than estrogen,especially T hormone.During the incubation periods from 8 to 13 days,E1,E3,T,A4 and DHT all presented a trend of decreasing first and then increasing on the whole.Sex differences of hormoneswere mainly reflected in two aspects.First,sex difference was presented at a certain point in the incubation period,for example,E1 was significant higher in males than females on11 d.Both DHT and A4 concentrations showed sex differences on 9d.Secondly,there were significant sex differences in the change trends of T/DHT and E3/E2.The T/DHT decreased significantly in female embryos,but fluctuated around 8 in male embryos without significant change.E3/E2 was increased significantly in female embryos,but remained fluctuating in male embryos.In the stage of gonadal differentiation,it was not possible to detect the hormonal changes in the whole eggs by using the whole embryonic egg as the sample.(3)The change rules and sex differences of serum hormones during the incubation periods from 8 to16 days in chicken embryo eggs were investigated.The results showed that the androgen and estrogen in serum showed significant increase trends during the incubation periods from 8 to 16 days and the androgen level was significantly higher than estrogen,among which T hormone was the highest and accounted for the largest proportion.E2,E3,T and A4 all showed increasing trends with the incubation time.DHT showed a trend of decrease first and then increase.E1 increased gradually in male embryos and decreased slightly in female embryos.During the incubation periods from 8to 16 days,the androgen in serum of male embryos was significantly higher than that of female embryos,while the estrogen was significantly lower than that of female embryos,resulting in a higher proportion of androgen and a lower proportion of estrogen in male embryos.E1,E2,E3,T,A4 and DHT were significantly correlated with sex.E1/A4,T/E2,E3/E1 and E1/E2 were significantly correlated with sex and age.The sex difference of hormones in the serum of male and female eggs was especially obvious in the later hatching stage,that is,the sex differentiation was more significant in the later stage(4)The change rules and sex differences of hormones in allantoic fluids and amniotic fluids during the incubation periods from 8 to16 days in chicken egg embryos were investigated.The results showed that androgen level in allantoic fluids and amniotic fluids was significantly higher than estrogen,and the T level was the highest while E2 was the lowest.The change trends of six hormones in allantoic fluids and amniotic fluids were similar.T,DHT and A4 all showed decrease trends,while E1,E2 and E3 all show increase trends.There was no significant sex difference in the content of six sex hormones in allantoic fluid,but the growth rate of E1,E2 and E3 in allantoic fluid of male embryo was twice that of female embryo,and the reduction rate of T,A4 and DHT was about 10% higher than that of female embryo.At only 16 d,T% in amniotic fluids was significantly higher in female embryos than in male embryos.It was speculated there might be some regulatory effect between the blood,allantoic fluids and amniotic fluids,which affected the hormones change in these three tissues.(5)The change rules and sex differences of physical characteristics and small molecular substances of embryonated eggs during incubation periods from 8 to 16 days were explored.The results showed that the weight loss and the rate of weight loss of embryonic eggs showed increasing trends during the incubation periods.The volume of allantoic fluids reached its maximum value on 12 d and gradually decreased at the later stage;the pH remained unchanged before 14 d,but decreased to around 7.5 on 16 d,maintaining weak alkalinity;the osmotic pressure decreased significantly due to urate crystallization.The volume of amniotic fluids showed an increasing trend,and the pH value continued to decrease from weak alkalinity to neutrality.The osmotic pressure of amniotic fluids was significantly higher than that of allantoic fluids.There was no significant sex difference in weight loss,volume,pH and osmotic pressure of allantoic fluids and amniotic fluids.In the NMR experiment,the possible substances in allantoic fluids were analyzed,mainly inorganic acids,organic acids,amino acids,amines,sugars,salts and other small molecules,but no significant differences were found between the sexes.