Transcriptome analysis of follicles reveals the importance of autophagy and hormones in regulating broodiness of Zhedong white goose.

Jing Yu,Yaping Lou,Ayong Zhao

doi:10.1038/srep36877

Abstract

Broodiness, a maternal behavior and instinct for natural breeding in poultry, inhibits egg production and affects the poultry industry. Phenotypic and physiological factors influencing broodiness in poultry have been extensively studied, but the molecular regulation mechanism of broodiness remains unclear. Effective research strategies focusing on broodiness are hindered by limited understanding of goose developmental biology. Here we established the transcriptomes of goose follicles at egg-laying and broody stages by Illumina HiSeq platform and compared the sequenced transcriptomes of three types of follicles (small white, large white and small yellow). It was found that there were 92 up-regulated and 84 down-regulated transcription factors and 101 up-regulated and 51 down-regulated hormone-related genes. Many of these genes code for proteins involved in hormone response, follicular development, autophagy, and oxidation. Moreover, the contents of progesterone and estradiol in follicles were altered, and the autophagy levels of follicles were enhanced during the broody stage. These results suggest that hormone- and autophagy-signaling pathways are critical for controlling broodiness in the goose. We demonstrated that transcriptome analysis of egg-laying and broody Zhedong white goose follicles provided novel insights into broodiness in birds.

Highlights

Broodiness, a maternal behavior and instinct for natural breeding in poultry, inhibits egg production and affects the poultry industry
We found that the autophagy of large white follicles (LWF) and small yellow follicles (SYF) appeared stronger in the broody stage than in the egg-laying stage, which is considered the main reason for broodiness in geese[7]
It is believed that the altered levels of reproductive endocrine hormones, including gonadotrophin (GnRH), prolactin (PRL), luteinizing hormone (LH), progesterone (P4), and estradiol (E2), are the major factors inducing the occurrence of broodiness[7,8,9,10,11,12]

Summary

Introduction

Broodiness, a maternal behavior and instinct for natural breeding in poultry, inhibits egg production and affects the poultry industry. The contents of progesterone and estradiol in follicles were altered, and the autophagy levels of follicles were enhanced during the broody stage These results suggest that hormone- and autophagy-signaling pathways are critical for controlling broodiness in the goose. The Zhedong white goose, characterized by strict seasonality, a high tendency to broodiness and incubation, and a low rate of egg laying, is one of the classical seasonal reproductive animals in China[1]. They have 3 or 4 laying cycles (Laying-Broodiness-Recovery) per year, and their laying periods are from October to April of the following year in Zhejiang province, China. Sample BSWF1 BSWF2 BSWF4 BLWF1 BLWF3 BLWF4 BSYF1 BSYF3 BSYF4 LSWF11 LSWF12 LSWF13 LLWF11 LLWF12 LLWF13 LSYF11 LSYF12 LSYF13

Methods

Results

Conclusion