Microanatomical Study of Embryonic Gonadal Development in Japanese Quail (Coturnix japonica).

Sittipon Intarapat,Orawan Satayalai

doi:10.1155/2014/168614

Sittipon Intarapat, Orawan Satayalai

Open Access

https://doi.org/10.1155/2014/168614

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Abstract

Gonadal development of quail embryos was examined histologically using histological and histochemical methods. In the present study, quail embryos were studied at various stages of incubation period based on phases of gonadogenesis. Germ cell migration was observed on day 3-4 but gonadal differentiation and gonadal function were observed on day 6–8 and day 11–14, respectively. During germ cell migration, quail primordial germ cells (qPGCs) were successfully detected in both left and right genital ridges as well as the dorsal mesentery by lectin histochemistry. Unexpectedly, qPGCs-like cells were found next to the neural tube by Mallory-AZAN stain. During gonadal differentiation, embryonic sex can be distinguished histologically since day 8 of incubation. Embryonic testis exhibited a thin cortex, whereas embryonic ovary exhibited a thick cortex. Testicular cord formation was found in the medulla of embryonic testes while the lacunae and fat-laden cells were found in the medulla of embryonic ovary during gonadal function. This is the first report on a comparison of phases of gonadogenesis and histochemical study of quail embryonic gonads in both sexes.

Highlights

Avian embryos have become a favorable model in developmental biology and stem cell biology [1, 2]
According to phases of gonadogenesis described by Clinton and Haines, 2001, in the present study, gonadogenesis of quail embryos was studied in three phases such as genital ridge formation, gonadal differentiation, and gonadal function
This study revealed the details of major phases of gonadogenesis in quail embryos in both sexes based on histological and histochemical observations

Summary

Introduction

Avian embryos have become a favorable model in developmental biology and stem cell biology [1, 2]. Quail embryos have several advantages as an animal model: the embryos take about 16 days to develop inside their eggs until hatching [7, 8] while chicken embryos take about 22 days [9], the eggs are available all year round [10, 11], and the embryonic development is well studied [7, 8, 12]. Quail embryos and their reproductive organs are recommended for studying reproductive and development toxicology [8, 13,14,15,16]

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