The Developmental Feature And Change Of Beak/Web Color Traits In Nonghua White Duck

The color traits of poultry are important varietal characteristic,including feather color,skin color,beak color,shin color and web color.Color traits are important in the classification and identification of animal species.The feather color,beak color,shin color and web color of duck are not only the varietal characteristics of duck,but also the important packaging traits.At present,the developmental changes of beak and web color and the processes and mechanisms of pigmentation are still not clear.Therefore,in this study,image acquisition,HPLC,histological method and transcriptome analysis were used to analyze the distribution process of pigment deposition in beak and web of meat duck,and to screen the gene regions affecting the distribution of pigment in beak and web.The main results showed that:(1)A method was established for the classification of beak and web colors of ducks,and the developmental changes of beak and web colors were analyzed.The0-week-old beak was divided into 4 categories(black,dark yellow,black pink,yellow)and 0-week-old web into 4 categories(black,green,dark yellow,yellow).At the age of 4 and 8 weeks,the pink black beak disappeared,the gray beak appeared,at the age of 4 weeks,the black web disappeared,at the age of 8 weeks,the green web further disappeared.(2)According to 0 weeks beak and web color classification,comparison between different color types of beak,web color differences in body weight,slaughter and meat quality traits,found that in addition to the 0 weeks,yellow beak or yellow web every weight is significantly higher than black beak or black web every test(P < 0.01),and yellow beak meat duck slaughtering performance than dark yellow beak,powder,black beaks and black beak meat duck(P < 0.05).(3)The histological sections of beak and web and silver ammonia staining results showed that during beak development,eumelanin is gradually transferred from dermis to epidermis,and the proportion of black beak gradually decreased.Eumelanin is gradually decreased during the development of the web.The deposition of melanin is the main reason affecting the changes of beak and web color of nonghua white duck.(4)102 differentially expressed genes(DEGs)were identified in the black-beak and yellow-beak comparison groups and 84 DEGs were identified in the black-web and yellow-beak comparison groups.GO Terms,KEGG pathway and WGCNA analysis showed that DEGs were enriched in melanin biosynthetic and played a key role in melanin production pathway,and the energy metabolism process was related to melanoma cells.Melanin gene expression,protein-protein interaction network and co-expression network showed that EDNRB2 was the main gene controlling the black beak and black web of ducks,which could be further verified in procedure of breeding.