Improvement of goose embryonic and muscular developments by wider angle egg turning during incubation and the regulatory mechanisms

Egg turning during incubation plays important roles in achieving high hatching performance and gosling quality. The objective of this study was to improve embryonic and muscular developments so to achieve better gosling quality by wider egg turning angles during incubation, and to unravel the associated regulatory molecular mechanisms. In each of three con-secutive incubations, 1,728 goose eggs were divided into 3 groups that were set in the same type of commercial incubators with turning angles adjusted differently to 50 degrees, 60 degrees, and 70 degrees, respectively. On average of the 3 tests, incubation with wider 70 degrees turning angle reduced the post-18-day embryo mortality, promoted embryonic growth and development, improved the hatchability and gosling quality. On embryonic day of 29, gene mRNA expression levels of the hypothalamic growth hormone-releasing hormone (GHRH), pituitary growth hormone (GH), and liver insulin-like growth factor 1 (IGF-1) were higher in the 70 degrees turning group than in the 50 degrees or 60 degrees groups. Wider angle turning also increased mRNA expression levels of the muscle development reg-ulatory genes such as MYF5, MyoD, Myogenin (MyoG), and MRF4. Changes in expression of the above genes, together with the upregulation of the Pax3 and Pax7 genes in leg muscles, well explained the enhancement of the muscular growth and development when eggs were incubated by wider turning angles. These results also extended our understanding of the impacts and mechanisms of egg turning during incuba-tion on hatching performance and gosling quality.

Automated summary

The study demonstrates that using a wider 70-degree egg turning angle can reduce post-18-day embryo mortality, promote embryonic growth and development, improve hatchability, and enhance gosling quality. Additionally, wider turning angles also increase the mRNA expression levels of genes related to muscle growth and development.