Acta Veterinaria et Zootechnica Sinica ›› 2020, Vol. 51 ›› Issue (2): 288-298.doi: 10.11843/j.issn.0366-6964.2020.02.010

• ANIMAL BIOTECHNOLOGY AND REPRODUCTION • Previous Articles     Next Articles

Effect of Vitrification on Developmental Competence of Immature Oocytes and COC Transcriptome of Yaks

YANG Yuanxiao, ZI Xiangdong*   

  1. College of Life Science and Technology, Southwest Minzu University, Chengdu 610041, China
  • Received:2019-07-24 Online:2020-02-23 Published:2020-02-22

Abstract: The objective of this study was to investigate the effect of vitrification/thawing on developmental competence of immature oocytes and cumulus-oocyte-complexes (COCs) transcriptome of yaks (Bos grunniens), in order to provide theoretical foundation to improve vitrification techniques of yak COCs. Vitrified/thawed yak immature COCs were divided into two groups. Group A:COCs were in vitro matured (IVM) and in vitro fertilized (IVF) with cattle sperms, then in vitro cultured (IVC) in G-1 for 72 h followed by IVC in G-2 for 96 h; Group B:after IVF, zygotes were IVC in G-1 for 120 h followed by IVC in G-2 for 48 h. Fresh immature yak COCs were used as the control (Group C):after IVF, zygotes were IVC in G-1 for 72 h followed by IVC in G-2 for 96 h. Yak fresh immature COCs (n=3) and vitrified/thawed immature COCs (n=3) were used for amplification, library preparation and RNA-seq analysis. The results showed that cleavage rate and blastocyst rate in Group B were significantly higher than those in Group A (P<0.05), but cleavage rate and blastocyst rate in both Group A and B were significantly lower than those in Group C (P<0.05). When|log2(fold change)|≥ 2 and Q-value <0.05 were set as thresholds for identifying deferentially expressed genes (DEGs), a total of 851 DEGs were detected, of which, 846 were up-regulated and 5 were down-regulated in virtrified/thawed COCs compared to fresh COCs. GO analysis showed DEGs were classified into 3 categories:biological processes, cellular components and molecular functions. KEGG annotation showed that there were 258 pathways, of which, 16 were significantly enriched (P<0.05). In conclusion, the results showed that IVC in G-1 for 120 h after IVF could increase subsequent developmental competence of vitrified yak oocytes. Vitrification affected transcriptome of yak COCs, which reduced developmental potential of yak vitrified oocytes. The result provided a theoretical basis for improving vitrification techniques of yak COCs.

Key words: yak, oocyte, in vitro fertilization, vitrification, RNA-seq

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