Morphogenesis of the rhea (Rhea americana) respiratory system in different embryonic and foetal stages
Morfogênese do sistema respiratório da ema (Rhea americana) em diferentes estágios embrionários e fetais
Pesqui. vet. bras; 38 (1), 2018
Publication year: 2018
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.(AU)
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.