| Poultry breeding plays an important role in the production of animal husbandry in China.In the actual breeding process,the sex of chicken determines many economic traits and productivity.Therefore,the sex control of chicken embryo may become an important technical way to improve the efficiency of chicken production.However,at present,the sex differentiation stage of chicken embryo is uncertain,and the factors and mechanisms affecting sex differentiation are also unclear.Therefore,this study first determined the sex differentiation period of chicken embryo,then regulated the incubation temperature,and then explored the effect of incubation temperature on the gonad development and sex differentiation of chicken embryo,in order to provide a theoretical basis for production practice.The content of this study includes two parts: firstly,210 fertilized eggs of 1-day-old yellow feather broiler were taken as the research object.The egg shape index method,embryo line observation method,gonad organ morphology observation method,gonad histology observation method and molecular biology identification method were used to determine the sex differentiation stage in the process of chicken embryo development.The experiment was repeated three times.The results showed that there was no significant difference in egg shape index between male and female fertilized eggs(P > 0.05);The embryo line observation showed that the sex differentiation stage of chicken embryo might be the third day of incubation;By observing the morphology of gonadal organs,it was preliminarily determined that the sex differentiation stage of chicken embryo was the 8th day of incubation period.The sex differentiation stage of chick embryo can be preliminarily determined as the 7th day of hatching period by histological observation of gonads.Further molecular biological identification showed that the chicken sex differentiation stage might be the 4th day of incubation period.To sum up,the sex differentiation stage of chicken is about the 3-8 day of embryo incubation period through several methods.Secondly,in order to further explore the effect of incubation temperature on gonad development and sex differentiation of chicken embryo.360 fertilized eggs of yellow feather broilers on the first day of incubation period were randomly divided into 3 groups:low temperature group(36.8 ℃,60 RH),normal temperature group(37.8 ℃,60 RH)and high temperature group(38.8 ℃,60 RH).During the whole incubation period,the temperature was controlled for 6 hours every day,120 pieces in each group.Samples were collected on the 8th day of incubation period and the first day after incubation for observation,and the test was repeated for 3 times.The results showed that there was no significant difference in the number of females and males between the high temperature group and the low temperature group(P > 0.05),but the number of males in the high temperature group was significantly higher than that in the low temperature group(P <0.05);It was found that the number of males in the high temperature group was significantly higher than that in the normal temperature group and the low temperature group(P < 0.05),but there was no significant difference in the number of females and males between the normal temperature group and the low temperature group(P > 0.05);The histological observation of gonads showed that the number of males in the high temperature group was significantly higher than that in the normal temperature group and the low temperature group(P > 0.05);Through molecular biological identification,it was found that the number of females and males in the normal temperature group was not significantly different from that in the high temperature group and the low temperature group(P > 0.05),while the number of males in the high temperature group was significantly higher than that in the low temperature group(P < 0.05);The number of males in the high temperature group was significantly higher than that in the normal temperature group and the low temperature group(P < 0.05),but there was no significant difference between the normal temperature group and the low temperature group(P >0.05).In conclusion,the sex differentiation stage of chicken embryo was determined as the 3-8 day of incubation period;The effects of incubation temperature on gonad development and sex differentiation of chicken embryo were studied.With the increase of incubation temperature,the number of males increased and the number of females decreased;As the incubation temperature decreased,the number of males decreased and the number of females increased. |
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