Effect of macromolecule supplement on nuclear and cytoplasmic maturation, cryosurvival and in vitro embryo development of dromedary camel oocytes

The current evaluation of oocyte vitro maturation (IVM) media has progressed toward more defined conditions in human and livestock. In this study, the replacement of fetal calf serum (FCS) with bovine serum albumin (BSA) and polyvinyl alcohol (PVA) was evaluated during IVM in dromedary camel. Nuclear maturation rates in presence of FCS and PVA were comparable (81.6 ± 1 and 75.5 ± 5%, respectively). BSA, whether used alone or in combination with FCS, significantly reduced nuclear maturation (51.6 ± 3.9 and 54.6 ± 1.1%, respectively), compared to FCS and PVA. BSA also increased the rates of chromosome aberrations compared to FCS and PVA (25.7 ± 7.4, 8.8 ± 2.3 and 6.0 ± 2.0%, respectively). IVM macromolecule differentially affected morphological aspects of cumulus expansion and FCS promoted the highest dissociation of cumulus cells, compared to all the other groups. FCS significantly increased mean lipid intensity of oocytes compared to BSA, FCS-BSA and PVA which could explain the lower cryo-survival of oocytes matured in presence of FCS compared to BSA and PVA (56.1 ± 5.2, 91.0 ± 19.5, and 87.8 ± 6.7%, respectively). Mitochondrial activity was not affected by macromolecules, but oocytes cultured with PVA had the best redox status, compared to other IVM groups. Cleavage was not affected by IVM macromolecule, but FCS promoted significantly higher rate of morula development (51.6 ± 5.2 vs. 33.6 ± 2.9% for PVA) and blastocyst development (36.8 ± 1.4 vs. 20.5 ± 2.0% for BSA). Although adding FCS during IVM supported highest hatching rate of the resulting blastocysts, differential cell number showed no long lasting effect of IVM macromolecules on blastocyst quality. Obtained results suggest the possibility to switch from undefined to more defined IVM systems for efficient in vitro maturation and subsequent vitrification of dromedary camel oocytes. Keywords: camel, oocyte maturation, protein supplement, cryosurvival. •Macromolecule supplement affects in vitro maturation of dromedary camel oocytes.•PVA supported comparable maturation rate of oocytes to FCS.•BSA suppressed nuclear maturation, either alone or in combination with FCS.•PVA supported the lowest oxidative activity of oocytes.•PVA is a defined macromolecule supplement for efficient IVM in dromedary camel.