title: Ultrastructure of the bullfrog (Lithobates catesbeianus-Shaw, 1802) oviduct in different seasons.
abstract: The bullfrog (Lithobates catesbeianus) is an exotic animal that adapted perfectly to the climatic conditions of Brazil after introduction in the country. These climatic conditions favor the reproduction and fattening of bullfrogs. However, the development of the bullfrog is significantly reduced in colder regions because low temperatures affect the secretion of gonadotropins and change the sensitivity of the germinal epithelium to gonadotropic hormones. Thus, the temperature and photoperiod are abiotic factors that influence the life cycle of this species, especially with regard to reproduction. Samples from different regions of the oviducts (the infundibulum, magnum, and isthmus) of 9 bullfrogs were collected in the different seasons of the year. The samples were fixed and processed for analysis with scanning and transmission electron microscopy. A comparison of the morphology of the oviducts collected during different seasonal periods suggests that the frogs have greater reproductive potential in the spring due to the development of the structures related to the oviduct, presence of developed cilia, and electron-dense granules. However, seasonal changes were noted in the animal throughout the year in preparation for reproduction during the spring and summer.
authors: Faculty of Veterinary Medicine of Rio Preto, Sao Jose do Rio Preto, Sao Paulo, Brazil.
authors: Sthefanie
authors: S
authors: Fernandez
authors: Rosângela Felipe
authors: RF
authors: Rodrigues
authors: Rose Eli Grassi
authors: RE
authors: Rici
authors: Phelipe Oliveira
authors: PO
authors: Favaron
authors: Alan Peres Ferraz
authors: AP
authors: De Melo
mesh_terms: D000818:Animals; D001938:Brazil; D005260:Female; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D010057:Oviducts / Q000648:ultrastructure*; D011892:Rana catesbeiana / Q000033:anatomy & histology*; D012621:Seasons