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ARS Home » Plains Area » Clay Center, Nebraska » U.S. Meat Animal Research Center » Livestock Bio-Systems » Research » Publications at this Location » Publication #417245
Research Project: Applying Nutritional Strategies to Improve Early Embryonic Development and Progeny Performance in Beef Cows

Location: Livestock Bio-Systems

Title: Guanidinoacetic acid supplementation negatively affects bovine cumulus-oocyte complexes during in-vitro maturation

Author
item Snider, Alexandria
item KAPS, MARTIM - University Of Veterinary Medicine
item Rempel, Lea
item Miles, Jeremy
item Cushman, Robert
item Crouse, Matthew

Submitted to: Reproduction, Fertility and Development
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/19/2025
Publication Date: 12/4/2025
Citation: Snider, A.P., Kaps, M., Rempel, L.A., Miles, J.R., Cushman, R.A., Crouse, M.S. 2025. Guanidinoacetic acid supplementation negatively affects bovine cumulus-oocyte complexes during in-vitro maturation. Reproduction, Fertility and Development. 37(18). Article RD25084. https://doi.org/10.1071/RD25084.
DOI: https://doi.org/10.1071/RD25084

Interpretive Summary: Assisted reproductive technologies have increased use by the beef cattle industry. The current rate of in-vitro produced embryos is suboptimal, due to altered DNA methylation during in-vitro oocyte maturation. The current study investigated the level of guanidinoacetic acid during in-vitro oocyte maturation to determine if there is a threshold concentration to negatively impact oocyte quality. The addition of 20 mM guanidinoacetic acid showed a negative impact on oocyte quality and early embryonic development. This information provides a model to study levels of DNA methyl inhibition during early embryonic development in-vitro and subsequent fetal development.

Technical Abstract: Methylation is an important part of oocyte maturation and early embryonic development. Altered methylation status leads to poor oocyte quality and altered embryonic development. One specific metabolite, guanidinoacetic acid (GAA), sequesters methyl-groups to make creatine, causing a methyl deficient state. Understanding how GAA influences oocyte methylation status increases knowledge of oocyte maturation in vitro. Aims. The objective of this study was to determine the threshold concentration of GAA supplementation negatively impacting oocyte quality. We hypothesized that supplementation of GAA reduces quality of oocytes and alters early embryonic development in a dose dependent manner. Methods. Immature cumulus oocyte complexes were collected from slaughterhouse ovaries and matured in vitro with GAA (0 mM, 5 mM, 10 mM or 20 mM) incorporated into the medium. Matured oocytes were randomly collected to determine microtubule distribution and transcriptomic analysis, or fertilized and developed embryos in vitro. Key results. Incorporation of GAA during in vitro maturation negatively impacted oocyte quality and early embryonic development. Specifically, supplementation of 5 mM GAA reduced S-adenosyl-L-methionine production (P < 0.05), increased transcripts within the creatine pathway in oocytes (P < 0.05) and impaired chromosome arrangement (P < 0.05). Reduction in total cells was observed in blastocysts from the 5 mM and 20 mM GAA group. Conclusions. Incorporation of 5 mM GAA to the in vitro maturation medium negatively impacted oocyte and subsequent early embryonic development. The 20 mM supplementation demonstrated negative implications, but the methylation pathway was not impacted. Implications. Further research is warranted to investigate other potential mechanisms that are impacted by eliciting a methyl donor deficient status in matured oocytes.