Characterization And Cultivation Progress Of A New Strain For Meat In Runzhou Crested White Duck

China is a major producer and consumer of duck meat.In recent years,with the improvement of people’s material living standards,the consumption market of duck meat has gradually presented the characteristics of diversification.People’s demand for high quality local duck products is gradually increasing.As a unique local breed,Runzhou crested white duck is popular among consumers because of its excellent ornamental and economic value.In order to clarify the effect of crested characters on individual crested ducks,the differences and correlations between the number of crested heads and serum biochemical indexes of Runzhou crested white ducks were analyzed.In addition,although the team’s previous studies have clarified the phenotypic characteristics of duck crested traits,the formation mechanism of crested tissue cell level has not been reported so far.Therefore,this study also investigates the cellular basis of the development of the crested tissue of Runzhou crested white ducks at the Single-cell level through single-cell RNA sequencing(scRNA-seq).To provide theoretical basis for the interaction between different cell types and crested tissue.Runzhou crested white ducks are smaller in size,and their feed conversion rate and meat yield are lower.In order to solve this problem,Cherry Valley ducks with faster growth rate and larger body size and higher meat yield were selected as the male parent and Runzhou crested white ducks as the female parent for crossbreeding,aiming at breeding large size crested white ducks for meat that retained the crested character.In this experiment,the weight,growth performance,slaughter performance,meat quality and egg quality of the hybrid progeny were determined,which provided a reference for the subsequent development and utilization of Runzhou crested white ducks.The results are as follows:1.This experiment studied the effect of the number of crested white ducks on Runzhou crested white ducks.A total of 322 duck eggs were collected for incubation.A total of 286 eggs were fertilized and 251 successfully hatched.All Runzhou crested white ducks were weighed and counted after 100 days,and their crested volume was measured.The results showed that the number of crested heads was positively correlated with body weight and volume(P<0.05).The results showed that the contents of Ca,Mg,Fe,Cu,Zn and Se in serum of multi-crested group were significantly higher than those of single-crested group(P<0.05);The levels of triglyceride,immunoglobulin A,immunoglobulin G,immunoglobulin M and immunoglobulin D were also significantly higher than those in the single crested group(P<0.01).Glycosylated low density lipoprotein(P<0.01)showed the opposite.The results showed that the contents of propionic acid and acetic acid in serum of ducks in two groups were significantly different(P<0.05),butyric acid content(P<0.01)was higher in the multi-crested group.Therefore,the increase of the number of crested was consistent with the changes of various serum biochemical indexes.The number of crested heads may be involved in the regulation of various mechanisms of Runzhou crested white ducks and may have immunomodulatory effects.2.This chapter takes the crested tissue of Runzhou crested white ducks as the object of study,isolating and preparation of single-cell suspension of the phoenix-head tissue for scRNA-seq,quality control of the sequencing results,13,279 cells are obtained after filtration.It was identified as 8 different cell types,namely nerve cells,fat cells,epithelial cells,endothelial cells,hair follicle cells,muscle cells,tumor cells,immune cells.CCL3 and POMP genes were specially expressed in immune cells of crested head tissue.FBP1,TOP2A,HES5,KCNK1 were specifically expressed in nerve cells of crest cushions.3.In this chapter,a new strain of Runzhou crested white ducks for meat was cultivated according to the character and production performance of crested duck.In this experiment,Runzhou crested white ducks and Cherry Valley duck were hybridized in order to breed a new strain--large crested white duck.Firstly,the body weight and body size of the larger-size crested white ducks with the sixth generation were measured respectively.The results of difference analysis showed that the larger-size crested white ducks were significantly higher than those of Runzhou crested white ducks(P<0.05),most of the body size indexes were between Cherry Valley duck and Runzhou crested white ducks.On this basis,the growth performance of Runzhou crested white ducks and large crested white ducks were measured respectively.The results showed that the weight gain of large crested white ducks after 2 weeks of age was higher than that of Runzhou crested white ducks under the same feeding environment.The breeding performance test results showed that the breeding age of 5%female.Runzhou crested white ducks was shortened by 3 days.The fertilization rate of eggs increased from 89.71%to 90.99%,and the hatching rate increased from 88.82%to 90.29%.The results of egg quality test showed that the ratio of egg weight to yolk of large crested white duck was improved after breeding.Egg shell strength,egg yolk color and Haugh unit were significantly higher than those of Runzhou crested white ducks(P<0.05),protein height was significantly lower than that of Runzhou crested white ducks(P<0.05).The slaughtering performance results showed that the slaughtering performance indexes of large crested white ducks were significantly higher than those of Runzhou crested white ducks,and the abdominal fat percentage was significantly lower than that of Runzhou crested white ducks(P<0.05).The results of meat quality measurement showed that the content of shear force,protein and collagen in breast muscle of large type crested white ducks were higher than those of Runzhou crested white ducks(P<0.05);Meat color brightness value L*,yellowness value b*,water loss rate and fat content were lower than those of Runzhou crested white ducks(P<0.05).The results of conventional meat quality of leg muscle showed that the redness value a*,shear force,protein and collagen contents of leg muscle of large crested white ducks were significantly higher than those of Runzhou crested white ducks(P<0.05);Brightness value L*,yellowness value b*and water loss rate were significantly lower than those of Runzhou crested white ducks(P<0.05).The above results indicated that the breeding of the new strain for meat type of crested white duck was successful,which provided theoretical reference for further development and utilization of Runzhou crested white ducks in the future.