| The Homeobox C8(Hoxc8)gene is a member of the Homeobox family of homeoboxes,it is a class of evolutionarily highly conserved transcription factors.The expression regulation of Hoxc8 gene was related to the formation of bone in embryonic development and the formation of crested traits in chickens.The crested traits is an unique appearance of Wumeng crested chickens,it can identify themselves include their live birds and carcasses,there were little research on the relationship between the regulation of Hoxc8 gene expression and the crested traits of Wumeng crested chickens and the correlation between the characteristics of crested and the production performance of Wumeng crested chickens.To promote the protection,development and utilization of the genetic resources of Wumeng crested chickens,this experiment exploreed the molecular genetics mechanism of the crested traits of Wumeng crested chickens from the perspective of epigenetics and transcriptional regulation.At the same time,the relationship between the characteristics of the crested traits and the growth,meat quality and reproduction of Wumeng crested chickens was studied.To explore the effects of Hoxc8 gene transcriptional regulation on the crested and production traits of Wumeng crested chickens.The main results are as follows:1.The classification and growth performance of Wumeng crested chickens’ crested traits were determined: the area of Wumeng crested chickens’ crested was related to the crown feather area,the area of Wumeng crested chickens’ crested can be directly used to evaluate the size of its crested traits;At 0 weeks of age,the weight of Wumeng crested chickens were higher than that of medium-crested,small-crested Wumeng crested chickens(P>0.05).And significantly higher than large-crested Wumeng crested chickens(P<0.05);with the 0~4 weeks of age,non-crested Wumeng crested chicken were heavier than large-crested,medium-crested and small-crested Wumeng crested chickens.With the 8~24 weeks of age,the weight gain of large-crested,medium-crested,small-crested Wumeng crested chickens increased more than that of non-crested Wumeng crested chickens.Moreover,at 8 and 20 weeks of age,the weight gain of medium-crested Wumeng crested chickens were significantly higher than that of non-crested Wumeng crested chickens(P<0.05);At 16 weeks of age,the weight gain of large-crested Wumeng crested chickens were significantly higher than that of non-crested Wumeng crested chickens(P<0.05).At 20~24 weeks of age,the large-crested Wumeng crested chickens were significantly higher than that of non-crested Wumeng crested chickens(P<0.01).It can be seen that in terms of weight gain,large-crested,medium-crested,small-crested Wumeng crested chickens showed slower in the early stage and faster in the later period,and the non-crested Wumeng crested chickens were just the opposite,the 8 weeks old was a significant interval.In terms of body size,although there are differences between the body size indicators at each age: large-crested Wumeng crested chickens 8 weeks old chest width,chest depth,16 weeks old chest width,pelvis width,sacral circumference,20 weeks old chest depth,keel length,pelvic width,24 weeks old chest depth,chest width,sputum The length was significantly higher than that of non-crested Wumeng crested chickens(P<0.05);Medium-crested Wumeng crested chickens 8 weeks old chest depth,chest angle and keel length,12 weeks old body length,chest width,16 weeks old chest width,keel length,sacral circumference,pelvic width,20 weeks old body length The circumference of the chest was deep and the chest angle was significantly higher than that of the non-crested Wumeng crested chickens(P<0.05).The overall result showed that the body size index of the larger crested Wumeng crested chickens were better than that of the non-crested Wumeng crested chickens.2.In terms of reproductive performance: the production weight of medium-crested Wumeng crested chickens was significantly higher than that of small-crested Wumeng crested chickens(P<0.05),which was significantly higher than that of non-crested Wumeng crested chickens(P<0.01).The egg weight of medium-crested Wumeng crested chickens was higher than that of non-crested Wumeng crested chickens(P<0.05).The egg production of small-crested Wumeng crested chickens was best,which the number of eggs produced at the age of 150-180 days was the highest,and it was 2.4 times that of the number of eggs produced non-crested chickens.It can be seen that small-crested Wumeng crested chickens had obvioused advantages in egg performance selection.3.Slaughter performance and meat quality measurement index: there was no significant difference between the different types of crested Wumeng crested chickens(P>0.05).4.Organizational differential expression: the expression of Hoxc8 gene was highest in the crested of Wumeng crested chickens(P<0.01).The expression level of Hoxc8 gene was significantly decreased in large-crested,medium-crested,small-crested,and non-crested Wumeng crested chickens(P<0.01),which expression level was the large-crested in Wumeng crested chickens,and the lowest in non-crested chickens(P<0.01);In the scalp tissue,the expression level of Hoxc8 gene in non-crested Wumeng crested chickens was higher than that of large-crested,medium-crested,small-crested Wumeng crested chickens(P<0.01).There were gender differences in the expression of Hoxc8 gene in large-crested,medium-crested,small-crested,and non-crested Wumeng crested chickens.The results showed that the presence or absence and large or small of crested traits of Wumeng crested chickens were related to the regulation of Hoxc8 gene expression.5.The methylation rate of CpG island in the promoter region of Hoxc8 gene in large-crested,small-crested,and non-crested Wumeng crested chickens were studied.The result showed that the methylation rate of CpG island in the promoter region of Hoxc8 gene of large-crested Wumeng crested chickens were significantly lower than that in small-crested,and non-crested Wumeng crested chickens(P<0.05);The overall rule of CpG island methylation rate in the promoter region of Hoxc8 gene in large-crested,small-crested,and non-crested Wumeng crested chickens were: non-crested > small-crested > large-crested.6.The association between the methylation rate of the CpG island in the promoter region of Hoxc8 gene in large-crested,small-crested,and non-crested Wumeng crested chickens and the correlation between the expression of Hoxc8 gene and the production traits of large-crested,small-crested,and non-crested Wumeng crested chickens were analyzed,The result showed that the Hoxc8 gene of large-crested Wumeng crested chickens had the highest expression in the crested tissue,the lowest methylation rate,and the fastest weight gain after 16 weeks of age.While the Hoxc8 gene of non-crested Wumeng crested chickens had the lowest expression in the crested tissue,the hightest methylation rate,the after 16 weeks,its growth performance were poor. |
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