This study identified single nucleotide polymorphisms (SNPs) that affect the body weight of chickens. Analysis of body weight showed that the Cornish breed had the highest body weight, and the Korean native chicken (Gray Brown) had the lowest body weight. TSH is composed of an α-subunit and a β-subunit, and the TSH-β gene encoding the β-subunit has been reported to be associated with obesity. In chickens, it is located on chromosome 26 and is reported to be associated with growth. The calcium-sensing receptor gene (CaSR) plays a role in the regulation of extracellular calcium homeostasis and is responsible for calcium absorption in the urinary tract, which affects the eggshell quality in poultry. It was shown that TSH-β was strongly correlated with weight in Cornish and Korean native (Gray Brown) chickens, particularly in those with the CC trait. However, CaSR showed no association with body weight in poultry; it was associated with calcium and the eggshell. Thus, selection for TSH-β can be used to produce individuals with more favorable traits in terms of body weight.

ABSTRACT
INTRODUCTION
MATERIALS AND METHODS
DISCUSSION
CONFLICTS OF INTEREST
ACKNOWLEDGEMENTS
AUTHOR CONTRIBUTIONS
AUTHOR’S POSITION AND ORCID NO
REFERENCES

• Dongyep Oh(Gyeongsangbuk-Do Livestock Research institute, Yeongju 36052, Korea)
• Jae Jung Ha(Gyeongsangbuk-Do Livestock Research institute, Yeongju 36052, Korea)
• Jun Koo Yi(Gyeongsangbuk-Do Livestock Research institute, Yeongju 36052, Korea)
• Dae Hyun Kim(Gyeongsangbuk-Do Livestock Research institute, Yeongju 36052, Korea)
• Seung Min Oh(Gyeongsangbuk-Do Livestock Research institute, Yeongju 36052, Korea)
• Songmi Kim(Center for Bio-Medical Engineering Core Facility, Dankook University, Cheonan 31116, Korea, Department of Microbiology, Dankook University, Cheonan 31116, Korea)
• Kyudong Han(Center for Bio-Medical Engineering Core Facility, Dankook University, Cheonan 31116, Korea, Department of Microbiology, Dankook University, Cheonan 31116, Korea)
• Yong-Soo Park(Korea National College of Agriculture and Fisheries, Jeonju 54874, Korea) Corresponding author