| Wenchang Chicken,a endemic chicken in Hainan Province,is characterized by a small head,small feet,small neck,short neck,and short feet with a round and plump outer phenotype.Commercial Wenchang chickens currently marketed commercially are all hens,so during the production of Wenchang chickens,so in the production process of Wenchang chickens,the chicks should be identified on the day of hatching.At present,the everted anal identification technique used in the company’s breeding grounds is observation of the genital prominences to do sex determination which is inefficient and costly,and because continuous work makes the accuracy difficult to ensure(95%-98%accuracy at present).In addition,the meconium of chicks becomes contaminated with each other during eversion anal manipulation,with the problem of cross infection between chicks.In this study,we proposed to use the existing breeding population of Yexiangyoupin Wenchang fowls to establish autosexed by early and late feathered lines.First we separated the early and late feather groups from the existing Wenchang Chicken breeder flocks with the help of the chicken early and late feather molecular identification technology already available in our laboratory;The paternal(early feather)line was established based on the early feather mass,and mainly target traits such as 95 day weight(market weight)were selected.Due to the small number of late feathering groups in the existing Wenchang chicken breeding flock,Therefore,the late-feathered population was expanded by mating late-feathered roosters with late-feathered hens,and then the heterozygous late-feathered roosters were eliminated by testing,and the late-feathered pure roosters were selected to form the base group of the hen(late-feathered)strain with the late-feathered hens.The accuracy rate of early and late feathering self hermaphrodites was finally validated using early feathering roosters versus late feathering hens mated.The main results are as follows:(1)The purebred population of Wenchang chickens used for production had more than 8500 hens and 507 roosters,and all roosters were individually ankle-ringed,and2000 hens were selected to be ankle-ringed,and blood samples were taken according to the ankle-ring numbers and brought back to the laboratory for molecular identification of early and late feathers.The results showed that 1,637 hens out of 2,000 hens were early-feathered and 279 hens were late-feathered;389 roosters out of 507 were early-feathered and 77 were late-feathered.According to the body weight,650early-feathered hens and 65 early-feathered roosters were selected as the base flock of the early-feathered line;279 late-feathered hens and 76 late-feathered roosters were selected to expand the base flock of the late-feathered line.(2)After two generations of selection of the parent(early-feathered)strain,the early-feathered ratio increased to 99.43 %;the fertilization rate increased from 90.22 %to 93.86 %,and the hatching rate increased from 82.37 % to 84.97 %.In addition,the newborn weight,6-week-old weight and 95-day weight(market weight)of early-feathered chickens also showed a progressive increase from 27.3 g,607.2 g(rooster),533.4 g(hen)and 1763.9 g(rooster)and 1501.9 g(hen)in the first generation to 28.9 g,635.4 g(rooster),567.2 g(hen)and 1788.1 g(rooster)and 1531.1 g(hen),respectively.The statistical test revealed significant differences(P < 0.05)in body weight between the three stages.According to the results of the body measurements,the body slope length,chest depth and chest width increased,but the keel length did not change significantly,indicating that the body shape of Wenchang chickens was more rounded,and the tibia length was shortened and the tibia circumference became thicker,which indicated that the initial selection for traits such as market weight of Wenchang chickens produced obvious effects,and the selected Wenchang chicken sires were closer to the market demand for large,round and short legs,The selected Wenchang chicken sires were closer to the market demand for characteristics such as large,round body and short legs.(3)During the maternal(late feather)line breeding process,the late feather population did not show a high rate of only 15.0% in the whole Wenchang Chicken population,and the late feather building group was not in sufficient number,so the late feather line was firstly expanded for one generation to obtain a sufficient number of late feather populations.Seventy six late feathering roosters were trained to collect and 71 roosters were used to mate with 279 late feathering hens after culling five roosters with poor semen quality at an approximate rooster: hen ratio of 1:4.A total of 3 batches of breeder eggs were collected and taken for lineage hatching,and the progeny early feathers were all eliminated,eventually resulting in 2711 feathers for late feathering chicks.After eliminating the weak chicks,1296 late-feathered roosters and 1415late-feathered hens were selected and retained.Based on the number of early and late feathering individuals in each family recorded at the time of brood emergence,the proportion of early and late feathering in their emerged progeny was counted in the half sib family,and the offspring of the half sib family with late feathering: early feathering was selected as 3:1 roosters,and a total of 203 roosters were selected to enter the next testing cross.(4)A total of 203 roosters used in late feathering test crosses were mated 1 : 5 to early feathering hens at rooster to hen ratio,and 1 batch of eggs was collected and subjected to lineage hatching,with the number of early and late feathering offspring recorded at the time of brood emergence.Mated roosters whose progeny appeared to be early feathering chicks were eliminated,and a total of 98 of the offspring chicks were all late feathering mated roosters,which were further screened based on the late post feathering generation,using late post feathering generation≥5 as the standard(probability of being homozygous for the late feathering roosters selected at this time≥95%),A total of 65 homozygous late feathering roosters were selected for use as those in the late feathering foundation colony;late feathering hens were selected 650 by market weight to form the base group for the hen(late feathering)strain.(5)At the same time of testing,we selected 40 early feathering roosters and 200 late feathering hens to preliminarily verify the effect of self hermaphroditism,gameted according to rooster to hen ratio 1:5,collected 1 batch of breeder eggs and performed lineage hatching,and first identified the chick sex according to early and late feathering,early feathering for rooster and late feathering for hen broods after emergence.Two hundred rooster and one hundred hen broods were randomly selected for necropsy.Sex was judged based on the gonads,and it was found that there was no discrimination error in early feathering hen rudiments,with a self hermaphrodite accuracy of 100%;Five maternal rudiments appeared in late feathering rooster and hen with 97.50% self accuracy;The average accuracy of the rooster brood was 98.75%,and the accuracy reached the production requirement.In summary,the early-feathered sire line of the early-feathered rooster and hen line of the early-feathered hen line has completed the selection and breeding work;the late-feathered hen line has also established a good base group,and the self-differentiation of rooster and hen has been verified to be effective.In addition,the reproductive performance and growth shape of the early-feathered line have been improved,and the body weight,fertilization rate,hatching rate and body size are better than before the selection;the establishment of the foundation group of the late-feathered line is also more successful,and the late-feathered line can normally carry out the next selection work in the future,and after the establishment of the late-feathered hen line,the early-feathered and late-feathered self-separating rooster and hen matching line can be put into production.In summary,the early and late feathering derived from the sex rooster and hen companion line paternal(early feathering)strain of Wenchang Chicken in Yexiangyoupin company completed 2 generations of breeding,and its market weight was significantly increased and body size was more consistent with the market demand;A matrilineal(late feather)strain foundation group was also established;Through verification,the accuracy of self-identification of fast and slow feathers is 98.75%.In addition,the reproductive performance of early feather lines is improved somewhat compared to that before breeding;In the future,the late feather line can be further bred and improved as the breeding goal is set. |
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