Endocrine and genetic factors affecting egg laying performance in chickens: a review

ABSTRACT

1. Egg-laying performance reflects the overall reproductive performance of breeding hens. The genetic traits for egg-laying performance have low or medium heritability, and, depending on the period involved, usually ranges from 0.16 to 0.64. Egg-laying in chickens is regulated by a combination of environmental, endocrine and genetic factors.

2. The main endocrine factors that regulate egg-laying are gonadotropin-releasing hormone (GnRH), prolactin (PRL), follicle-stimulating hormone (FSH) and luteinising hormone (LH).

3. In the last three decades, many studies have explored this aspect at a molecular genetic level. Recent studies identified 31 reproductive hormone-based candidate genes that were significantly associated with egg-laying performance. With the development of genome-sequencing technology, 64 new candidate genes and 108 single nucleotide polymorphisms (SNPs) related to egg-laying performance have been found using genome-wide association studies (GWAS), providing novel insights into the molecular genetic mechanisms governing egg production. At the same time, microRNAs that regulate genes responsible for egg-laying in chickens were reviewed.

4. Research on endocrinological and genetic factors affecting egg-laying performance will greatly improve the reproductive performance of chickens and promote the protection, development, and utilisation of poultry. This review summarises studies on the endocrine and genetic factors of egg-laying performance in chickens from 1972 to 2019.

KEYWORDS:

• Chicken
• endocrine hormones
• candidate genes
• novel genes
• microRNAs
• egg laying performance

Disclosure statement

The authors confirm that this article content has no conflicts of interest.

Additional information

Funding

This work was financially supported by the Major Science and Technology Project of Yunnan Science and Technology Plan Project [2016ZA008], the Project of National Science Foundation of China [U1702232, 31572359, 31560618], Academician Nancy Lane Workstation of Yunnan Provincial Department of Science and Technology [2017IC048] and by Training Funds for Yunling Scholars and Leading Technical Personnel of Yunling Industry.