Transcriptome analysis of the livers of ducklings hatched normally and with assistance.
OBJECTIVE
"Hatchability" is an important economic trait in domestic poultry. Studies on poultry hatchability focus mainly on the genetic background, egg quality, and incubation conditions, whereas the molecular mechanisms behind the phenomenon that some ducklings failed to break their eggshells are poorly understood.


METHODS
In this study, the transcriptional differences between the livers of normally hatched and assisted ducklings were systematically analyzed.


RESULTS
The results showed that the clean reads were de novo assembled into 161,804 and 159,083 unigenes (≥200-bp long) by using Trinity, with an average length of 1,206 bp and 882 bp, respectively. The defined criteria of the absolute value of log2 fold-change ≥1 and false discovery rate≤0.05 were differentially expressed and were significant. As a result, 1,629 unigenes were identified, the assisted ducklings showed 510 significantly upregulated and 1,119 significantly down-regulated unigenes. In general, the metabolic rate in the livers of the assisted ducklings was lower than that in the normal ducklings; however, compared to normal ducklings, glucose-6-phosphatase and ATP synthase subunit alpha 1 associated with energy metabolism were significantly upregulated in the assisted group. The genes involved in immune defense such as major histocompatibility complex (MHC) class I antigen alpha chain and MHC class II beta chain 1 were downregulated in the assisted ducklings.


CONCLUSIONS
These data provide abundant sequence resources for studying the functional genome of the livers in ducks and other poultry. In addition, our study provided insight into the molecular mechanism by which the phenomenon of weak embryos is regulated.
Institute of Animal Husbandry and Veterinary Science, Zhejiang Academy of Agricultural Sciences, Hangzhou, Zhejiang 310021, China.|Zhejiang Animal Husbandry Techniques Extension Station, Hangzhou, Zhejiang 310020, China.
Yali
Y
Liu
Zhejiang Animal Husbandry Techniques Extension Station, Hangzhou, Zhejiang 310020, China.
Shishan
S
He
Institute of Animal Husbandry and Veterinary Science, Zhejiang Academy of Agricultural Sciences, Hangzhou, Zhejiang 310021, China.
Tao
T
Zeng
Institute of Animal Husbandry and Veterinary Science, Zhejiang Academy of Agricultural Sciences, Hangzhou, Zhejiang 310021, China.
Xue
X
Du
Institute of Animal Husbandry and Veterinary Science, Zhejiang Academy of Agricultural Sciences, Hangzhou, Zhejiang 310021, China.
Junda
J
Shen
College of Animal Science and Technology, Zhejiang Agricultural and Forestry University, Linan, Zhejiang 311300, China.
Ayong
A
Zhao
Institute of Animal Husbandry and Veterinary Science, Zhejiang Academy of Agricultural Sciences, Hangzhou, Zhejiang 310021, China.
Lizhi
L
Lu
Assisted Ducklings; De novo; Normally Hatched; RNA-seq; Transcriptome