Histological description of Cerdocyon thous (Linnaeus, 1766) respiratory system

Abstract

ABSTRACT: The massive agricultural expansion converted the Cerdocyon thous, a South American native predator, in vulnerable specie. Basic data, such as histological description, are important to raise awareness on animal species, helping on preservation strategies. Considering the difficult in obtain samples, as the euthanasia of wild animals for this purpose is not allowed, data on histology are very scarce or inexistent. The objective of this paper was to provide a detailed histological description of the trachea and bronchial tree of the crab-eating fox Cerdocyon thous (Linnaeus, 1766). The specimens (one adult male and one adult female) used were provided by the Federal University of Pelotas (Pelotas, RS, Brazil) Rehabilitation Center of Wild Fauna (NURFS). Tissue samples were fixed in 10% formalin and included in paraffin. After slicing, samples were stained with HE (hematoxylin and eosin), PAS (periodic acid-Schiff) and resorcin fuchsin. Trachea had an average diameter of 7.87mm, and approximately 57% of the mucosa ciliated pseudo-stratified columnar epithelium was composed of goblet cells, mostly in the dorsal region. Bronchia and bronchioles had a mucosal fold with higher number of goblet cells. Using all these techniques there is no great remarkable differences from C. thous trachea and lung, when compared with the previous described structures for carnivores and most mammals, except for the goblet cells “regionalization”. Described results are important to understand the animal physiological and behavioral habits, allowing the development of preservation and protection strategies.