Estudo comparativo da morfologia espermática entre cachorro-do-mato (Cerdocyon thous, Linnaeus 1766) e o cão doméstico (Canis lupus familiaris)

Abstract

Wild canids are mammals with great diversity and the main obstacle to the success of their reproduction is the still limited knowledge about the behavior and physiology of species such as the bush dog (Cerdocyon thous). Domestic canids (Canis lupus familiaris), on the other hand, have a wide natural distribution among terrestrial mammals and exhibit a high genetic variability. The objective of this research is to conduct a comparative study of normal sperm morphology and its abnormalities between two canids, the bush dog and the domestic dog. Eight semen samples from wild dogs and eighteen from domestic dogs were used, both previously collected in other research and stored in the Animal Reproduction Laboratory of the Federal University of Uberlândia. The sperm dimensions were analyzed through photomicrographs evaluated using the open-source software "Image J" to obtain information regarding the total length, head, midpiece, and tail dimensions of the sperm. Sperm morphology was assessed using the wet-mount preparation method under phase-contrast optical microscopy for morphological evaluation and semen smears stained with Congo Red to evaluate dimensions. The data were presented descriptively in terms of mean and standard deviation, and the comparison between the cells of the two species was made using the Student's t-test. Sperm dimensions were very similar between the bush dog and the domestic dog, with total lengths of 62.22 µm and 55.98 µm, respectively. The normal sperm morphology of both species was also very similar, although a high quantity of sperm abnormalities was observed in the bush dog compared to the domestic dog, with rates of 53.2% and 35.5%, respectively. The results of this study can contribute to enhancing our understanding of the andrological evaluation of wild and domestic canids, potentially aiding in assisted reproduction efforts for these species.