Sucrose assists selection of high‐quality oocytes in pigs |
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Authors: | Thanh Quang Dang‐Nguyen Hiep Thi Nguyen Tamas Somfai David Wells Nguyen Thi Men Nguyen Viet‐Linh Junko Noguchi Hiroyuki Kaneko Kazuhiro Kikuchi Takashi Nagai |
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Institution: | 1. Institute of Agrobiological Sciences, National Agriculture and Food Research Organization (NARO), Tsukuba, Ibaraki, Japan;2. The United Graduate School of Veterinary Science, Yamaguchi University, Yamaguchi City, Yamaguchi, Japan;3. Institute of Biotechnology, Vietnam, Academy of Science and Technology, Hanoi, Vietnam;4. Institute of Livestock and Grassland Science, NARO, Tsukuba, Ibaraki, Japan;5. AgResearch Ltd., Ruakura Research Centre, Hamilton, New Zealand;6. Department of Research Planning and Coordination, NARO, Tsukuba, Japan |
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Abstract: | We investigated whether high‐quality in vitro matured (IVM) oocytes can be distinguished from poor ones based on the morphological changes after treatment with hyperosmotic medium containing 0.2 mol/L sucrose in pigs. We hypothesize that IVM oocytes maintaining round shape have higher quality than mis‐shapened oocytes following dehydration. Oocyte quality was verified by determining embryonic developmental competence using in vitro fertilization, nuclear transfer and parthenogenetic activation. In all cases, the round oocytes had greater (p < .05) developmental competence than that of mis‐shapened oocytes in terms of blastocyst rate and total cell number in blastocysts obtained after 6 days of in vitro culture. We also confirm that round aged oocytes are higher in quality than mis‐shapened aged oocytes. In an attempt to find out why high‐quality oocytes maintain a round shape whereas poorer oocytes become mis‐shapened following sucrose treatment, we examined the arrangement of actin microfilaments and microtubules. Abnormal organization of these cytoskeletal components was higher (p < .05) in mis‐shapened oocytes compared to round oocytes after 52 hr of IVM. In conclusion, sucrose treatment helps selection of high‐quality oocytes, including aged oocytes, in pigs. Abnormal cytoskeleton arrangements partly explain for low developmental competence of mis‐shapened oocytes. |
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Keywords: | embryonic development competence oocyte quality pig sucrose |
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