Factors influencing oocyte and embryo quality in cattle

Lonergan, Patrick; Rizos, Dimitrios; Ward, F.; Boland, M.P.

doi:10.1051/rnd:2001142

Cited by 80 publications

(44 citation statements)

References 81 publications

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“…To date, morphological parameters, such as shape, homogeneity of cytoplasm, presence of polar body, and compactness of cumulus cells have routinely been utilized as markers of oocyte competence, and in the final analysis select for and generate embryos of increased developmental potential (Armstrong 2001, Lonergan et al 2001, 2003a, Coticchio et al 2004, Krisher 2004. However, it is well known that morphological criteria alone are insufficient to distinguish competent oocytes that have the ability to bring about a full-term pregnancy (Lonergan et al 2003a, Coticchio et al 2004, Krisher 2004.…”

Section: Introductionmentioning

confidence: 99%

Functional genomics studies of oocyte competence: evidence that reduced transcript abundance for follistatin is associated with poor developmental competence of bovine oocytes

Patel¹,

Bettegowda²,

Ireland³

et al. 2007

Reproduction

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109

113

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Poor oocyte competence contributes to infertility in humans and livestock species. The molecular characteristics of such oocytes are generally unknown. Objectives of the present studies were to identify differences in RNA transcript abundance in oocytes and early embryos associated with reduced oocyte competence and development to the blastocyst stage. Microarray experiments were conducted using RNA isolated from germinal vesicle stage oocytes collected from adult versus prepubertal animals (model of poor oocyte competence). A total of 193 genes displaying greater mRNA abundance in adult oocytes and 223 genes displaying greater mRNA abundance in prepubertal oocytes were detected. Subsequent gene ontology analysis of microarray data revealed significant overrepresentation of transcripts encoding for genes in hormone secretion classification within adult oocytes and such genes were selected for further analysis. Real-time PCR experiments revealed greater abundance of mRNA for bA and bB subunits of inhibin/activin and follistatin, but not the a subunit in germinal vesicle stage oocytes collected from adult versus prepubertal animals. Cumulus cell follistatin and bB subunit mRNA abundance were similar in samples collected from prepubertal versus adult animals. A positive association between time of first cleavage (oocyte competence) and follistatin mRNA abundance was noted. Follistatin, bB, and a subunit mRNAs were temporally regulated during early bovine embryogenesis and peaked at the 16-cell stage. Collectively, results demonstrate a positive association of follistatin mRNA abundance with oocyte competence in two distinct models and dynamic regulation of follistatin, bB, and a subunit mRNAs in early embryos after initiation of transcription from the embryonic genome. Reproduction (2007) 133 95-106

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Section: Introductionmentioning

confidence: 99%

Functional genomics studies of oocyte competence: evidence that reduced transcript abundance for follistatin is associated with poor developmental competence of bovine oocytes

Patel¹,

Bettegowda²,

Ireland³

et al. 2007

Reproduction

Self Cite

109

113

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“…Culture of embryos in vitro results in embryos fundamentally different from those produced in vivo, particularly for ruminants [3,4]. In general, the longer in vitro culture, the more deviation occurs relative to embryos recovered in vivo; this phenomenon appears to be exacerbated when in vitro oocyte maturation and in vitro fertilization procedures precede embryo culture [5,6].…”

Section: Introductionmentioning

confidence: 99%

Serum free embryo culture medium improves in vitro survival of bovine blastocysts to vitrification

et al. 2008

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The aim of this study was to examine the effects of co-culture with Vero cells during the in vitro maturation (IVM) and three culture media, B2 + 5% fetal calf serum (FCS) on Vero cells, synthetic oviduct fluid (SOF) + 5% FCS, and SOF + 20 g L À1 bovine serum albumin (BSA), on the developmental competence of the embryos and their ability to survive vitrification/warming. We also tested the effect of morphological quality and the age of the embryo on its sensitivity to vitrification. The IVM system neither affects the embryo development up to Day 7 nor survival rates after vitrification. The culture of embryos in SOF + FCS and in Vero cells + B2 allowed obtaining more Day 6 and Day 7 blastocysts, and a higher % of Day 7 blastocysts vitrified than culture in SOF + BSA. Contrarily, on Day 8, more blastocysts were vitrified in SOF + BSA than in SOF + FCS. Blastocysts quality affected development after vitrification/warming, and Day 7 embryos showed higher survival rates than their Day 8 counterparts. Day 7 blastocysts produced in Vero cells or in SOF + BSA survived at higher rates than those produced in SOF + FCS at 24 and 48 h after warming. Embryo culture with BSA allows obtaining hatching rates after vitrification/warming higher than those obtained after coculture with Vero cells in B2 and FCS. Moreover, this system provides hatching rates from Day 8 blastocysts comparable to those obtained on Day 7 in Vero cells. Further studies, including embryo transfer to recipients, are needed to clarify factors affecting the freezability of in vitro produced bovine embryos. #

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“…However, current in vitro production protocols are inefficient at producing viable embryos (Lonergan et al 2001), partly due to abnormal oocyte cytoplasmic maturation in vitro (Krisher & Bavister 1998). Optimisation of in vitro maturation (IVM) protocols is vital not only for generating viable embryos but also to support the development of subsequent offspring into normal adults (Eppig & O'Brien 1998).…”

Section: Introductionmentioning

confidence: 99%

Fluctuations in bovine ovarian follicular fluid composition throughout the oestrous cycle

Orsi

Gopichandran²,

Leese³

et al. 2005

Reproduction

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Bovine oocyte maturation in vitro frequently results in abnormal cytoplasmic maturation and failure to acquire developmental competence. This is, in part, likely to be due to the non-physiological nutritional milieu to which oocytes are exposed. Improvements in oocyte developmental potential may be achieved by modelling nutrient profiles on those of preovulatory follicular fluid (FF). However, little is known about fluctuations in FF nutrient levels according to follicle dominance and oestrous cyclicity. This study therefore characterised the carbohydrate and amino acid profile of FF according to these parameters, and compared preovulatory FF composition with that of maturation medium. Carbohydrate concentrations (n 5 121) were determined enzymatically whilst amino acid profiles (n 5 40) were determined by reverse-phase HPLC. Pyruvate and glucose concentrations were unaffected by follicle dominance, whereas Stage III -IV lactate profiles were higher in non-dominant FF (P < 0.01). While most dominant FF amino acid concentrations were affected by oestrous stage, only glutamate, alanine, leucine and lysine levels fluctuated in non-dominant FF. Glucose and lactate concentrations were significantly negatively correlated, whereas most amino acids were significantly positively correlated with each other. Maturation medium had higher pyruvate and lower lactate concentrations than preovulatory FF (P < 0.001), whereas glucose level was similar. All amino acid levels (except histidine, taurine, alanine and tryptophan) differed significantly between maturation medium and preovulatory FF. These data indicated that FF composition varies throughout the oestrous cycle. Preovulatory FF nutrient profile differed from that of maturation medium, perhaps accounting for the poor developmental competence of in vitro matured oocytes. These data may contribute to the formulation of a nutritionally more physiological maturation medium.

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Factors influencing oocyte and embryo quality in cattle

Cited by 80 publications

References 81 publications

Functional genomics studies of oocyte competence: evidence that reduced transcript abundance for follistatin is associated with poor developmental competence of bovine oocytes

Functional genomics studies of oocyte competence: evidence that reduced transcript abundance for follistatin is associated with poor developmental competence of bovine oocytes

Serum free embryo culture medium improves in vitro survival of bovine blastocysts to vitrification

Fluctuations in bovine ovarian follicular fluid composition throughout the oestrous cycle

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