Effect of mSOF and G1.1/G2.2 Media on the Developmental Competence of SCNT‐Derived Bovine Embryos

Abstract

The objective of this study was to compare the effect of two culture media: modified synthetic oviductal fluid (mSOF) and G1.2/G2.2, on the developmental competence of bovine somatic cell-cloned embryos. Cloned embryos were produced by transferring adult skin fibroblasts into enucleated MII oocytes. After activation, the reconstructed embryos were randomly allotted to either mSOF or G1.2/G2.2 for culture (the embryos were transferred from G1.2 to G2.2 on days 3 of culture). The development competence of cloned embryos in these two culture systems was compared in terms of cleavage rate, blastocyst formation rate and apoptosis cell number in day 7 blastocyts. To investigate the in vivo developmental competence of cloned embryos in the two culture systems, a total of 87 and 104 blastocysts derived from mSOF and G1.2/G2.2 medium groups were transferred individually to recipient Angus cows, respectively. No differences were observed in terms of cleavage rate, day 7 blastocyst rate and blastocyst cell number between these two culture systems. However, the day 6 blastocyst formation rate was significantly higher in G1.2/G2.2 than that in mSOF. In addition, blastocysts cultured in mSOF have a higher percentage of apoptotic blastomeres compared to those in G1.2/G2.2 (8.5 ± 1.2 vs 16.8 ± 1.5, p<0.05). Although difference in pregnancy rate was not observed 40 days after embryo transfer, significantly higher pregnancy rate was observed in G1.2/G2.2 group after 90 days of embryo transfer (12.4% vs 37.5%, p<0.05). Moreover, calving rate was significantly improved in G1.2/G2.2 group compared to mSOF group (27.9% vs 6.7%, p<0.05). In conclusion, our results indicate that G1.2/G2.2 can improve developmental competence of bovine SCNT embryos both in vitro and in vivo, which is more suitable for culture of bovine SCNT embryos than mSOF medium.

Ardışık İnsan Embriyo Kültür Medyumu Sığır Embriyolarının in vitro Kültüründe Kullanılabilir mi?

“…Therefore, sequential media may theoretically be more optimal for culture of developing embryos than single culture medium. Commercially available sequential media have been widely for embryo culture in various species and have shown better competence to support development of IVF embryos both in vitro and in vivo than single culture media in some previous studies [1,3,8] . In addition, some studies showed that a medium cultured for long periods of time can rapidly deteriorate, resulting in its inability to support embryo development [1,4,16] .…”

“…In addition, some studies showed that a medium cultured for long periods of time can rapidly deteriorate, resulting in its inability to support embryo development [1,4,16] . Sequential culture media formulated for in vitro development of mammalian embryos overcome this problem [8,16] . Currently, there are different sequential media available for culturing mammalian embryos such as G1/G2 [8,21] , Quinn's Advantage sequential medium and Sydney IVF medium [5,7] .…”

“…Sequential culture media formulated for in vitro development of mammalian embryos overcome this problem [8,16] . Currently, there are different sequential media available for culturing mammalian embryos such as G1/G2 [8,21] , Quinn's Advantage sequential medium and Sydney IVF medium [5,7] . Problems with pregnancies following in vitro culture have primarily been attributed to the presence of serum in the culture system [1,12,14,22] .…”

“…Among these studies, mSOF culture medium containing BSA or FBS is widely used for producing bovine embryos [8,9,17,18] . However, comparisons between studies, even those evaluating the same culture system, remain problematic due to variations in culture parameters including type of overlay, oxygen tension, culture drop volume, serum supplement, combined procedures such as IVF/ICSI and many more [9,[18][19][20] .…”

“…Synthetic oviductal fluid (SOF) is one of the medium commonly used for bovine embryo culture in vitro. Synthetic oviductal fluid has subsequently been modified by the addition amino acids [4,8,9] . Numerous studies have examined the ability of bovine embryos to develop in vitro using a wide variety of culture media.…”