ABSTRACT Visualization and clear understanding of the ovarian structures are important in determining the stage of oestrus, helping to diagnose several pathologies and supporting advances in reproductive technologies. In this research, computerized microtomography (microCT) was used to explore and characterize the ovarian structure of seven mammalian species. Ovaries of rats, female dog, queens, cows, mares, sows and a female donkey were used. After microCT scanning, the same samples were prepared for histologic evaluation, used here as a validation criterion. It was possible to distinguish regions of the cortex and medulla, visualize the morphology and distribution of blood vessels, clearly observe corpus luteum and antral follicles, and visualize oocytes inside some antral follicles. This is the first report using microCT to explore and compare ovarian structures in several domestic mammals. MicroCT revealed great potential for the evaluation of ovarian structures. This research open prospects for the use of computerized tomography (CT) as a non-invasive approach to studying ovarian structures in live animals, which may be especially attractive for scientific study of development of ovarian structures and/or ovarian pathologies in small animals’ models.

This study describes the morphological, morphometric and ultrastructural characteristics of the Amazonian manatee Trichechus inunguis (Natterer, 1883) spermatozoon. The spermatozoa were obtained from a urine sample of an adult T. inunguis kept in captivity. The spermatozoa were analyzed by light and transmission electron microscopy. The head of Amazonian manatee spermatozoa had a flat oval shape and a well distinguishable midpiece. The mean dimensions of the spermatozoa were: head length, 7.49 ± 0.24 µm; head width, 3.53 ± 0.19 µm; head thickness, 1.61 ± 0.13 µm; midpiece length, 11.36 ± 0.34 µm; flagellum length, 40.91 ± 1.94 µm; total tail length, 52.16 ± 1.06 µm; total spermatozoon length, 60.08 ± 1.40 µm. The Amazonian manatee spermatozoa were similar in shape to other sirenian spermatozoa; however, presenting a different size. This study describes, for the first time, the morphometric and ultrastructural characteristics of the Amazonian manatee spermatozoa, and also demonstrates the possible use of spermatozoa retrieved from urine samples for biological studies.