Embryonic development of endoderm in chicken (Gallus gallus domesticus)

Abstract

The poultry industry is a sector of agribusiness which represents an important role in the country's agricultural exports. Therefore, the study about embryogenesis of the domestic chicken (Gallus gallus domesticus) has a great economic importance. The aim of this study was to evaluate embryonic development of the endoderm in chicken (Gallus gallus domesticus). Forty fertilized eggs of domestic chickens, starting from the 1st day of gestation and so on until the 19 days of the incubation were collected from the Granja São José (Amparo, SP, Brazil). Embryos and fetus were fixed in 10% formaldehyde solution, identified, weighed, measured, and subjected to light and scanning electron microscopy. The endoderm originates the internal lining epithelium of the digestive, immune, respiratory systems, and the organs can be visualized from the second day (48 h) when the liver is formed. The formation of the digestive system was complete in the 12th day. Respiratory system organs begin at the fourth day as a disorganized tissue and undifferentiated. Their complete differentiation was observed at the 10 days of incubation, however, until the 19 days the syrinx was not observed. The formation of immune system at 10th day was observed with observation of the spleen, thymus, and cloacal bursa. The study of the organogenesis of the chicken based on germ layers is very complex and underexplored, and the study of chicken embryology is very important due the economic importance and growth of the use of this animal model studies such as genetic studies.

Morphogenesis of the rhea (Rhea americana) respiratory system in different embryonic and foetal stages

“…Corroborating this study, Alcântara et al (2013) identified in chicken embryos at 10 days of incubation, a shell with a typical respiratory epithelium, which was characteristic of rhea foetuses in the middle turbinate region at a proportionately later stage. The rostral nasal turbinate structure in 30-day rhea foetuses exhibited characteristics similar to those observed in the domestic chicken Gallus gallus (Kang et al 2013) at one year of age, and this species displayed stratified squamous epithelium.…”

“…According to Daniely et al (2004), stem cells are capable of differentiating into cells and mucussecreting hair during normal morphogenesis of the tracheal epithelium. In this study, the identification of hair cells occurred in the late period, considering the incubation time of rheas relative to that observed in domestic hens, with pseudostratified epithelium with ciliated cells being reported in this species at six days (Alcântara et al 2013). In contrast, Kalnins & Porter (1969) observed in this same species, tracheal epithelium presenting cells with single primary cilium at 15 days of age.…”

“…Chicken embryos have been widely used by several authors for research relating to embryonic events in birds (Walsh & McLelland 1978, Maina 2003a, 2003b, Alcântara et al 2013. However, there is still a data gap in the literature concerning the morphological characteristics of the respiratory system during embryonic and foetal development in other birds, especially large ones, which restricts, in part, the discussion of our results to a comparison with data available for domestic chicken (Gallus gallus domesticus).…”

“…This groove becomes closed along most of the length of the pharynx, forming a tube, the trachea, which remains open to the pharynx in its forward end, constituting the glottis (Bellairs & Osmond 2005). According to Alcântara et al (2013) on the fourth day of embryonic development of chicken embryonic development, the organs of the respiratory system are formed by disorganized and undifferentiated tissue, with complete differentiation observed after 10 days of incubation.…”

“…Some studies have been performed to describe the morphological characteristics of the respiratory organs, mainly using domestic chicken Gallus gallus domesticus as an experimental model (Alcântara et al 2013, Kang et al 2013, Lopez et al 2000, Maina 2003a). In addition to this, other species of birds, like the ostrich Struthio camelus (Abidu-Figueiredo et al 2012, Makanyaa et al 2012, Yildiz et al 2003, the parakeet Melopsittacus undulatus (Smith et al 1987), the quail Coturnix coturnix japonicum (Cevik-Demirkan et al 2007), the Meleagris gallopavo turkey (Khaksar et al 2012) and the pelican Pelicanus conspicillatus (Runciman et al 2005) have served as models for studies in this area.…”