Morphological aspects of the placenta and fetal annexes of Paca (Agouti paca, L.,1766)

Author(s)

Waleska Marques da Silva

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina Veterinária e Zootecnia (FMVZ/SBD)
• Defense date: 2001-08-07

Examining board members

Márcia Rita Fernandes Machado; Marcos Lania de Araujo; Maria Angélica Miglino

• Advisor: Márcia Rita Fernandes Machado

Abstract

On this research we peform the macroscopic analysis of the umbilical cord and placenta structure, the macroscopic analysis of umbilical cord and placenta valcularization, and analysis with light microscopy of umbilical cords constituents of paca, aiming to increase the knowledge about the reproductive morphology in this species. To achieve that we used nine female pacas, which came from the Wild Animal Sector of the Zootechnology Departament at the Faculty of Agrarian and Veterenary Sciences of Jaboticabal - UNESP -, in early, entermediary and late phases of pregnancy. The animals had their pregnanty uterine horn taken out on surgery. After opening the uterus, we identified the fetal membranes and measured the umbilical cord and the cephalococcyga distance. Than we identified the umbilical cords vessels with were injected with latex (Neoprene®) dyed by specific pigment; after the injections, the vessels were dissected for visualization of the disposition of arteries and veins in the placenta. Three animals were carried out to microscopic analysis of the umbilical cord that , after the collect, was sectioned in proximal, intermediary and distal portions wich were set and than went to an usual histological processing with furthering colorations with hematoxilin-eosin and Masson tricome method. In these animals we noticed a discoid globular placenta, and the fetal membranes were constituted by chorion-alantois and amnion. The averages of the umbilical cords length and the crown-rump distance were 7,31 cm and 14,5 cm respectively. Macroscopically, we noticed the presence of two umbilical cord arteries, one umbilical cord vein, the allantois and onfalomesenteric vessels; microscopically, we noticed that the umbilical cord arteries and veins were muscly, the alantoic duct was formed by a cubic double layer epthelium and this sctructures, together with the onfalomezenteric vessels, were surrounded by the Wharton´s gelatin. The presence of vasa vasorum was also observed. The dissection of the injected umbilical cord vessels pointed that veins were basically placed that the placenta periphery and arteries presented a central position. (AU)