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As a Chinese local chicken breed, Hongshan chickens have 2 kinds of tail feather phenotypes, normal and taillessness. Our previous studies showed that taillessness was a sex-linked dominant trait. Abnormal development of the tail vertebrae could be explained this phenomenon in some chicken breeds. However, the number of caudal vertebrae in rumpless Hongshan chickens was normal, so rumplessness in Hongshan chicken was not related to the development of the caudal vertebrae. Afterwards, we found that rumplessness in Hongshan was due to abnormal development of tail feather rather than abnormal development of caudal vertebrae. In order to understand the genetic foundation of the rumplessness of Hongshan chickens, we compared and reanalyzed 2 sets of data in normal and rumpless Hongshan chickens from our previous studies. By joint analysis of genome-wide selection signature analysis and genome-wide association approach, we found that 1 overlapping gene (EDIL3) and 16 peak genes (ENSGALG00000051843, ENSGALG00000053498, ENSGALG00000054800, KIF27, PTPRD, ENSGALG00000047579, ENSGALG00000041052, ARHGEF28, CAMK4, SERINC5, ENSGALG00000050776, ERCC8, MCC, ADAMTS19, ENSGALG00000053322, CHRNA8) located on the Z chromosome was associated with the rumpless trait. The results of this study furtherly revealed the molecular mechanism of the rumpless trait in Hongshan chickens, and identified the candidate genes associated with this trait. Our results will help to improve the shape of chicken tail feathers and to rise individual economic value in some specific market in China. [ABSTRACT FROM AUTHOR]

Pullorum disease is characterized by white diarrhea resulting from infection by S. Pullorum, but arthritis associated with S. Pullorum infection has become increasingly frequent recently, especially in Chinese native chicken flocks. In this study, we isolated and identified 4 S. Pullorum strains from the Qingjiaoma chicken breeders with arthritis symptoms. The LD 50 of the isolate 20JS04 was 1.33 × 106 CFU, which was considered as a highly virulent strain in chicks. Reproducible arthritis symptoms were observed in the experimentally chickens infected with the isolate 20JS04, and the disease occurrence was 27.78% (5/18). In addition to the characteristics of high virulence and induced-arthritis, our results confirmed that the arthritis-causing isolate 20JS04 had greater negative impact on BW, ADFI, and ADG, compared with the white diarrhea-causing S. Pullorum standard strain CVCC526 (P < 0.05). These results suggest that the pathogenic diversity of S. Pullorum in China deserves more attention and stringent measures should be taken to control salmonellosis. [ABSTRACT FROM AUTHOR]