Screening Of Fast And Slow Feather Genes And Comparison Of Production Performance Among Different Slow Feather Types In Daheng High Quality Broilers

In the modern large-scale poultry breeding,the male and female identification technology is a common technology for the male and female identification of poultry newborn chicks.Through the establishment of a fast and slow feathering self-mating line,it is possible to achieve the self-mating of newborn chicks.The pure slow feathering rooster is selected as the paternal parent by genotyping,and the production performance of its offspring with different slow feathering types(inverted type,equal length type,non-growing type)is compared to select the slow feathering hen that is more suitable for cooperation as the paternal parent,providing a reference for the establishment of the fast and slow feathering self-mating line.By measuring the expression of feather growth-related genes SPEF2,PRLR and d PRLR/d SPEF2 in the hair follicle tissues of 1 day of age,1 week of age,2 week and3 week of age fast and slow-feathered(inverted,isometric,non-growing)roosters,the marker genes that control the growth of feather type were selected;At the same time,the molecular identification of the ancestral slow feathering rooster was carried out by PCR genotyping,and the heterozygous gene individuals were further eliminated by Taq Ⅰ enzyme digestion method.The homozygous gene individuals were used as the male parent to breed the parents,and the production performance of different types of slow feathering(inverted long type,equal long type,not long type)was compared.Then,the slow feathering hens were hybridized with the pure line faster the roosters to study the feather type separation of their offspring and the accuracy of self identification.The research results are as follows:(1)The expression of SPEF2 gene was the highest in the inverted slow feathering at the age of 1 day,which was significantly higher than the other three feathering types,but there was no significant difference between the expression of SPEF2 gene in the fast feathering type and that in the isometric slow feathering type and non emerging slow feathering type;At different growth ages,the expression of PRLR gene in fast feathering was significantly lower than that in three slow feathering;The d PRLR/d SPEF2 fusion gene was only expressed in the three slow feathering species.(2)There was no significant difference in the body weight of the parents of the three feather types(inverted type,isometric type and non growing type)at the age of 0-10 weeks,but there was a growth peak at the age of 7 weeks for the non growing type,and the growth and weight gain were stable.The slaughter performance of 70 day old rooster was higher than that of hen,but there was no significant difference among three feather types(3)The results showed that the absolute weight gain per week of different slow feather types(inverted type,isometric type,and non growing type)cocks was not significantly different(P>0.05)except at 1,3,5,7,and 10 weeks of age,while the absolute weight gain per week of 2,4,6,and 8 weeks of age of non growing type was significantly higher than that of inverted type and isometric type(P<0.05),while the absolute weight gain of 9 weeks of age of inverted type and isometric type was significantly higher than that of non growing type(P<0.05).There was no significant difference in the absolute weight gain among the three feather types at the age of 1week(P>0.05).The absolute weight gain of the inverted type at the age of 4,6,7 and8 per week was significantly higher than that of the non elongated type and the isometric type(P<0.05),and the absolute weight gain of the inverted type at the age of 9 and 10 per week was significantly higher than that of the inverted type and the isometric type(P<0.05).(4)By comparing the relative performance of 66 week egg laying: 66 week egg laying rate,seed egg fertilization rate,fertilized egg hatching rate and healthy chick rate,the inverted type and the non growing type were higher than the isometric type,but the difference was not significant(P>0.05);The shell breaking rate of 66 week egg laying of isometric type was significantly lower than that of non elongated type and inverted elongated type(P<0.05).(5)The results of egg quality showed that there was no significant difference in egg quality among the three feather types(inverted,equal and non growing)(P>0.05).(6)By crossing three types of slow feathered roosters(inverted long type,inverted long type,and non long type)with fast feathered pure line hens,the number of slow feathered males and females and fast feathered males and females in non long type offspring was the highest,and significantly higher than that in inverted long type and inverted long type offspring(P<0.05);The proportion of feather type separation in hybrid offspring is highest in the non elongated type,and significantly higher than that in the inverted and isometric types(P<0.05).In conclusion,the PRLR gene and d PRLR/d SPEF2 fusion gene can be used as marker genes for fast and slow feather identification.In the process of establishing male and female mating lines with fast and slow feathers,molecular breeding techniques should be appropriately combined;At the same time,when selecting the first male parent slow feathered rooster,targeted selection can be made for both immature and inverted individuals,while avoiding the use of equal length individuals as much as possible.