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

Abstract

RESUMO.-[Morfogênese do sistema respiratório da ema (Rhea americana) em diferentes estágios embrionários e fetais.] A ema (Rhea americana) representa importante espécie silvestre que vem se destacando na pecuaria nacional e internacional. Esta pesquisa objetiva analisar o desenvolvimento embrionário-fetal, em diferentes fases, do sistema respiratório de emas. Vinte e três embriões e fetos foram eutanasiados, fixados e dissecados. Fragmentos do sistema respiratório: cavidade nasal, laringe, traqueia, siringe, brônquios e pulmões, foram coletados e processados para estudos por meio de microscopia de luz e microscopia eletrônica de varredura. A cavidade nasal apresentou, nas primeiras fases de desenvolvimento, epitélio estratificado cúbico. A laringe exibiu epitélio respiratório típico entre 27 e 31 dias. A traqueia aos 15 dias apresentou início de formação da cartilagem hialina. Na siringe a túnica mucosa de fetos de 18 dias e formada por epitélio estratificado ciliado na região bronquial. Os brônquios principais apresentavam epitélio estratificado ciliado com células caliciformes na região siringeal. No pulmão, o estágio parabronquial of the rhea (Rhea americana) respiratory system in different embryonic and foetal stages. Pesquisa Veterinária Brasileira 38 (1):154-166. The rhea (Rhea americana) is an important wild species that has been highlighted in national and international livestock. This research aims to analyse embryo-foetal development in different phases of the respiratory system of rheas. Twenty-three embryos and foetuses were euthanized, fixed and dissected. Fragments of the respiratory system, including the nasal cavity, larynx, trachea, syrinx, bronchi and lungs, were collected and processed for studies using light and scanning electron microscopy. The nasal cavity presented cubic epithelium in the early stages of development. The larynx exhibited typical respiratory epithelium between 27 and 31 days. The trachea showed early formation of hyaline cartilage after 15 days. Syrinx in the mucous membrane of 18-day foetuses consisted of ciliated epithelium in the bronchial region. The main bronchi had ciliated epithelium with goblet cells in the syringeal region. In the lung, the parabronchial stage presented numerous parabronchi between 15 and 21 days. This study allowed the identification of normal events that occur during the development of the rhea respiratory system, an important model that has not previously been described. The information generated here will be useful for the diagnosis of pathologies that affect this organic system, aimed at improving captive production systems.

Developmental events in the lung of the Japanese quail (Coturnix coturnix japonica): Morphological, histochemical and electron‐microscopic studies

“…Moreover, the present study as well as Maina (2005) and Tzou et al (2016) revealed that the bronchial system formed via monopodial branching not by differential cell proliferation. This mode of branching give rise to the primary, secondary, and tertiary bronchi in the avian lung including quail (Reese et al, 2006; Sousa et al, 2018). The primordia of the secondary bronchi in quail embryos appeared as evaginations of the lining epithelium.…”

“…However, Scheuermann et al (1998) detected them on the 8th day in the same bird. Romanoff (1960) observed them on the10 th day of chick incubation while, Sousa et al (2018) noticed them on the 13‐15th day of rhea embryos. Both light and electron microscopic observations of the parabronchi of the studied bird revealed that, the reorganization of the parabronchial epithelium occurred firstly by elongation of the apical portion of the columnar cells forming aposomes.…”

Extraembryonic membrane morphology in greater rheas (Rhea americana americana Linnaeus, 1758)

“…The greater rhea ( Rhea americana americana ) is a ratite belonging to the Rheidae family and Rhea genus (Sousa et al 2018 ). This species is distributed throughout different Brazilian regions, i.e., the midwest, south and northeast (Sick 2001 ), displaying scientific importance due to its captivity adaptability (Costa et al 2018 ) and zootechnical value, due to the high amount of greater rhea by-products, such as meat, eggs, leather, feathers and oil (Romanelli et al 2008 ; Torquato et al 2015 ).…”

Intussusception Associated with Sand Accumulation in a Greater Rhea (Rhea americana)

“…Greater rhea (Rhea americana) are large birds that belong to the group of ratites, order Rheiforme, family Rheidae, and genus Rhea [1]. They hold signifi cant scientifi c importance because of their remarkable adaptability in captivity and zootechnical value for producing meat, leather, and feathers [2].…”