Reproductive biology, morphology, and morphometry of ovaries and oviducts of Trachemys scripta elegans in Brazilian Cerrado

Abstract

Gradela A., Pires I.C., Matos M.H.T., Corrêa F.M., Faria M.D., Silva J.S., Torres L.R.C. & Milanelo L. 2020. Reproductive biology, morphology, and morphometry of ovaries and oviducts of Trachemys scripta elegans in Brazilian Cerrado. Pesquisa Veterinária Brasileira 40 (2):141-154. Although Trachemys scripta elegans is an exotic species popular as a pet in Brazil, studies on reproductive biology and capacity are non-existent in the Brazilian Cerrado. This study analyzed ovarian and oviduct characteristics and the egg production capacity of T. scripta elegans grown in this biome. The findings will associate with the size of the specimens and the sexual maturity, aiming at comparisons with native and exotic populations, as well as interspecific and contributing to the understanding of its impact on the invaded ecosystems and the establishment of eradication programs. Thus, 39 females had evaluated the body biometry and the morphology and morphometry of the ovaries and oviducts. G2 (N=20): with Class I (>5-10mm) follicles, with Class I and Class II (>10-fold) follicles, 25mm) and G3 (N=9) with Class I, Class II and Class III (>25mm) follicles. Analysis of variance, Scott-Knott's test, and Pearson's correlation analysis showed that there was no significant difference between the groups in body biometry; in the mean gonadosomatic index and gonadal morphometry, only the width of the oviducts in the right antimer and the mass and width in the left antimer were higher in G3, the only one that presented eggs. There was positive and harmonic development between body mass, carapace, and plastron, and gonadal growth occurred concomitantly with body growth, indicating a higher reproductive potential and a positive relationship between the size of the litter and the female litter. The gonadosomatic index proved to be an excellent reproductive indicator, and the ovarian evaluation was a better indicator of sexual maturity than the maximum carapace length. Ovaries were irregular structures, without delimitation between the cortical and medullary regions and filled with vitelogenic follicles of different diameters, atresic follicles, and corpora lutea, which reflected the ovarian complexity of the species and the presence of follicular hierarchy. In the scarce stroma, two germinative beds were observed per ovary and the presence of gaps very close to the follicles and associated with the blood vessels. Analysis of gonadal tissue revealed three types of oocytes according to cytoplasmic characteristics: homogeneous, vesicular or vesicular in the cortex with apparent granules. Oviducts were functional and separated, joining only in the final portion to form the cloaca and subdivided into infundibulum, tuba, isthmus, uterus, and vagina. The structure of the uterine tube was composed of serosa, muscular and mucous, which was full of glands. The presence of eggs in the oviducts indicated PVB-6299 MF

MORFOLOGIA OVARIANA E DOS OVIDUTOS DE Trachemys scripta elegans (WIED, 1839, TESTUDINES) CRIADAS NO CERRADO BRASILEIRO

“…(Nota-se em A-ovário com pouca definição entre as regiões cortical e medular e presença de folículos prévitelogênicos (P) e vitelogênicos (V) próximo às lacunas (L); B-leito germinativo com presença de ovogônias (og) e oócitos I (oc) próximos a vasos sanguíneos (V); C-folículo primordial; Dfolículo primário; E-folículo secundário; F-folículo terciário com ovócito no estágio inicial (Ho); G-folículo terciário com ovócito no segundo estágio (Vc) e H-folículo terciário com ovócito no terceiro estágio (Vp) de desenvolvimento). (Adaptado de Gradela et al 2020).…”

“…Nota-se o ovário (Ov) ricamente vascularizado (V) e repleto de folículos vitelogênicos (F) de diferentes diâmetros e as porções do ovidutos: o infundíbulo (In); a tuba uterina (T); o ístmo (Is), o útero (U) e a vagina (Va). (Adaptado deGradela et al 2020).…”