Cumulus cell expansion and first polar body extrusion during in vitro oocyte maturation in relation to morphological and morphometric characteristics of the dromedary camel ovary

Abstract

The morphological and morphometric characteristics of the ovary are fundamental properties for in vitro oocyte maturation. Nuclear maturation, including first polar body (1PB) extrusion, cytoplasmic maturation and cumulus cell (CC) expansion are the criteria for in vitro maturation (IVM) of oocyte. This study was designed to determine the effect of morphological and morphometric features of the ovary on CC expansion and 1PB extrusion during IVM of oocyte in the adult female dromedary camel. The weight, volume and three dimensions of ovaries from slaughtered dromedary camels and oocytes inside zona diameter and zona pellucida thickness were measured. The follicles were classified in regard to the size and oocytes according to their ooplasm appearance and CC compactness. Aspirated cumulus oocyte complexes (COCs) were incubated for 48 hr (with a 6-hr interval) in Hams-F10, and CC expansion and 1PB extrusion were assessed. Significant differences were seen in the shape, weight, volume and three dimensions of the ovaries between ≤4-year-old and >4-year-old dromedary camel (p < .5). Approximately, 95.82% of follicles were 2-4 mm in diameter. The mean (±SD) of inside zona diameter of the oocyte and zona pellucida thickness was 132.22 ± 13.8 and 14.64 ± 2.24 μm, respectively, in >4-year-old dromedary camel. The CC expansion and 1PB extrusion were seen in 86% and 21.88% of COCs, respectively. Age and sexual conditions of dromedary camel influence the morphological and morphometric characteristics of the ovary. Most COCs retrieved from 2-6 mm follicles are cultivable. The most slaughterhouse-derived COCs retrieved from 2-6 mm follicles of non-pregnant dromedary camels are excellent and good and yielding a most favourable diameter to achieve the developmental competence for IVM in an optimal time of 24-30 hr; the optimal time for CC expansion is 24-30 hr in this species. However, the CC expansion is a prerequisite process, but not sufficient for IVM.

Development and pregnancy rates of Camelus dromedarius-cloned embryos derived from in vivo- and in vitro-matured oocytes

“…Our results showed the same. In this study, The present studythe rates of camel oocyte in vitro maturation showed similar or higher capacity when compared with other studies, meaning that our camel IVM system was appropriate [22][23][24], and analysis revealed thea greater efficiency in obtaining enhanced maturation ratesmatured oocytes from of in vivo-matured oocytes compare to in vitro-sources [Table 1]. Indeed, we confirmed the enhanced capacities for cleavage and blastocyst stage formation of in vivo-matured oocytes.…”

“…These results indicated that it is essential to choose an efficient oocyte maturation method to obtain stable results in the production of live births using SCNT. However, the oocyte maturation rate of camels was lower than that of other species after in vitro maturation, and studies were insufficient [22][23][24].…”

Effects of all<i>-trans</i> retinoic acid on the <i>in vitro</i> maturation of camel (<i>Camelus dromedarius</i>) cumulus-oocyte complexes

“…However, the low reproductive performance of camels is considered an important factor affecting camel populations. Employing in vitro embryo production (IVP) technologies is an efficient means of propagating genetically superior camels; however, compared to other livestock species, camel oocyte in vitro maturation (IVM) has been reported to be inefficient [1,2,3,4]. One of the main contributing factors is the limited availability of oocytes because the majority of the slaughtered animals are either old, culled for infertility, or very young and have not attained maturity; in addition, there is no standardized protocol for IVP in camels [3, 5].…”

História, Meio Ambiente, Desenvolvimento Sustentável E Impactos Das Monoculturas No Sul Da Bahia

“…Cumulus oophorus (CCOs) são indispensáveis para as técnicas laboratoriais. A classificação da qualidade dos ovócitos pondera a aparência do citoplasma, que deve apresentar-se homogêneo e escuro, e as células do CCOs, que preferivelmente devem ser múltiplas (HEWITT e ENGLAND, 1997;LUVONI et al, 2005;MESBAH et al, 2016).…”