Gonadotrophin-induced abnormalities in sheep oocytes after superovulation

Moor, R. M.; Osborn, J. C.; Crosby, I. M.

doi:10.1530/jrf.0.0740167

Cited by 140 publications

(83 citation statements)

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“…Although some evidence has been observed of an alteration in oocyte activation and in patterns of oocyte protein synthesis, or follicular steroidogenesis capacity [24] and ovulation time [39], the reason why FSH alone produces better quality embryos than eCG is not fully understood. Armstrong [2] has suggested that acceleration of follicle development during superovulatory treatment can occur before complete growth to allow completion of maturational process of cytoplasmic oocyte and granulosa cells.…”

Section: Discussionmentioning

confidence: 99%

“…Driancourt and Fry [12] have shown that eCG could determine variations in the morphological features of the preovulatory follicles, altering the size and number of granulosa cells which play an essential role in the transport of regulatory signals and metabolic substrates to full oocyte maturation. This could result in alterations and deficiencies of patterns of protein synthesis during meiotic progression compromising the subsequent potential capacity of oocytes derived from treated sheep to embryo development [24].…”

Section: Discussionmentioning

confidence: 99%

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Sheep embryos derived from FSH/eCG treatment have a lower in vitro viability after vitrification than those derived from FSH treatment

et al. 2001

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-In the non breeding period, the effect of two superovulatory treatments (eCG/FSH in single dose or FSH alone in four decreasing doses) on the production of embryo quality following in vitro viability after vitrification procedures was investigated using forty-four adult Sarda breed ewes. In sheep treated with eCG/FSH, the mean number of corpora lutea was significantly (P < 0.05) higher (11.8 ± 4.0 vs. 8.05 ± 3.8), although the recovery rate was significantly (P < 0.01) lower (74.6 vs. 59.9) than with FSH alone. After vitrification (ethylene glycol and glycerol) was repeated three times, the rates of re-expansion at first and second warming were significantly (P < 0.01) higher in embryos derived from FSH alone than in those with both gonadotrophins (94.9 and 41.9 vs. 72.8 and 18.6) and after the last vitrification the hatched blastocyst rates were 22.5 and 7.6. After differential stain, blastocysts derived from FSH alone showed a mean number of cells significantly higher than blastocysts from eCG/FSH (184.2 vs. 157.7). It was concluded that superovulatory treatment with eCG/FSH may increase the ovarian responses compared with FSH alone, but these embryos showed a reduction in viability rates after repeated vitrification. superovulation / embryo quality / ovine / vitrification / viabilityRésumé -Les embryons ovins obtenus après un traitement de superovulation associant FSH et eCG ont une viabilité in vitro plus faible après vitrification que les embryons obtenus avec un traitement séquentiel de FSH. Pendant la saison non reproductive, on a évalué, chez 44 brebis adultes de race Sarde, l'effet de deux traitements de superovulation (le premier avec les eCG/FSH en une seule administration, le deuxième avec la FSH administrée en quatre doses décroissantes) sur la qualité des embryons produits et sur la viabilité in vitro après vitrification. Dans le groupe traité avec les eCG/FSH, le nombre moyen d'ovulations était plus élevé (11,8 ± 4,0 vs. 8,05 ± 3,8, P < 0,05) tandis que le taux de récupération était plus faible (74,6 vs. 59,9, P < 0,01) par rapport au groupe traité avec la FSH seule. Les embryons ont suivi 3 vitrifications successives (éthylène glycol et glycérol). Reprod. Nutr. Dev. 41 (2001) [239][240][241][242][243][244][245][246] 239

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Sheep embryos derived from FSH/eCG treatment have a lower in vitro viability after vitrification than those derived from FSH treatment

et al. 2001

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“…Watanabe et al [19] observed a biphasic increase of E2 secretion in superovulated ewes when pFSH and eCG were given on Day -2 and Day -1, respectively before sponge removal. The higher estrogen levels from persistent large follicles have been considered to enhance ova transport through the oviducts and become detrimental to fertilization and the development of embryos [7,24,25]. It has been reported that an administration of exogeneous estrogen shortly after ovulation induced premature luteal regression in cows [26] and in rhesus monkeys [27].…”

Section: Discussionmentioning

confidence: 99%

“…ultiple injections of follicle-stimulating hormone (FSH) or a single injection of equine lation, but its relatively high level of estradiol-17β (E2) remaining in the unovulatory follicles and in the blood has imparied oocyte maturation, time of ovulation and the yield of fertilized ova [6,7].…”

mentioning

confidence: 99%

Incidence of Premature Luteal Regression in Ewes Superovulated with a Single Injection of Follicle-Stimulating Hormone Combined with Equine Chorionic Gonadotropin.

Fukui

Okada

Ishida

1998

Journal of Reproduction and Development

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Abstract. The incidence of premature corpora lutea (CL) regression was investigated in three different breeds (Merino x polled Dorset: MD, Suffolk: S, and South-Down: SD), parous and nonparous ewes (a total of 46 ewes) treated for superovulation during and out of the breeding season. Superovulation was induced with a single injection of 20 mg porcine follicle-stimulating hormone (pFSH) 2 days and 500 IU equine chorionic gonadotropin (eCG) 1 day, respectively before the removal of synthetic progestogen (40 mg FGA) vaginal sponges inserted for 12 days. All ewes were inseminated into the uterus with fresh-diluted or frozen-thawed semen by laparoscope, and a number of newly formed and regressed CL were recorded. Breed difference significantly (P<0.005) affected the incidence of premature regressed CL; S (6.3%, n=16) ewes were less in the proportion of the incidence of regressed CL than MD (37.5%, n=16: P<0.05) and SD (71.4%, N=14, P<0.01) ewes. The use of non-parous ewes and treatment during autumn tended to result in higher rates of incidence of premature CL regression than the use of parous ewes and treatment during spring. These results indicate that the incidene of premature CL regression in superovulated ewes was influenced by not only season and parity but also by breed of ewes used for superovulation treatment.

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“…Pregnant mare serum gonadotrophin (PMSG) [6], pituitary extracts of different origin [28,69,96] and human menopausal gonadotrophin [92] are commonly used for superovulation in sheep. The biological properties of the gonadotrophins used for superovulation have been described in detail elsewhere [13]; for review see [45] [67] or later, during early embryonic development as a result of unbalanced hormonal profiles [3,51] [66], association of these two gonadotrophins [91], single versus multiple injections [30,64], or inclusion of GnRH or growth hormone in the treatments [36,111].…”

Section: Superovulationmentioning

confidence: 99%