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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 #417433
Research Project: Applying Nutritional Strategies to Improve Early Embryonic Development and Progeny Performance in Beef Cows

Location: Livestock Bio-Systems

Title: Methionine and guanidinoacetic acid supplementation influence bovine oocyte quality during in-vitro maturation

Author
item Snider, Alexandria - Alex
item Rempel, Lea
item Miles, Jeremy
item Cushman, Robert - Bob
item Crouse, Matthew

Submitted to: IETS
Publication Type: Abstract Only
Publication Acceptance Date: 7/30/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: During oocyte maturation and early embryonic development, methylation can influence the quality of the oocyte and subsequent embryo. If methylation is reduced, then this leads to abnormal oocyte maturation and reduced embryo quality. Methionine (Met) is an important one-carbon metabolite that can increase methylation, while guanidinoacetic acid (GAA) sequesters methyl groups leading to global methylation deficiency. Our hypothesis is supplementation of GAA will lead to methyl deficiency and incorporation of Met will improve methylation status in the matured oocyte. Follicles (2-7mm) were aspirated from slaughterhouse ovaries to obtain cumulus oocyte complexes (n = 800/treatment) and matured for 23 hr in maturation medium containing: Control, Met (21 µM), GAA (20 mM), or Met + GAA. After maturation, a subset of oocytes was randomly selected for transcript abundance analysis of markers associated with methylation and oocyte quality, 5-methylcytosine analysis, and chromatin and microtubule analysis. The remaining oocytes underwent in-vitro fertilization with sex-sorted male semen then in-vitro embryo culture. Percent cleavage and blastocyst rate, microtubule distribution and chromatin configuration were collected and analyzed using the GLIMMIX procedure of SAS, while 5-methycytosine and transcript abundance was analyzed using the MIXED procedure of SAS with the main effect of supplementation as fixed effects and replication as random effect. A reduction (P < 0.05) in 5-methylcytosine was observed in Met and GAA supplementation alone and increased when supplemented together. Transcript abundance of BMP15, CEPT1, and COX2 were significantly reduced (P < 0.05) in the GAA group compared to the control group, while a tendency for transcript reduction was observed for CHPT1 and CPEB4. A significant interaction (P < 0.05) between Met and GAA was observed for DNMT3A and DNMT3B with a reduction in the Met and GAA supplementation alone and increased in Met + GAA supplementation. Microtubule distribution abnormalities were increased (P < 0.05) with GAA supplementation compared to the control group, while no differences were observed for the combined supplementation. No differences were observed in Met, GAA, or the Met + GAA for cleavage or blastocyst rate. Taken together, there appears to be a negative impact of Met and GAA on global methylation and oocyte quality. When Met is added in combination with GAA, the negative influence observed with Met or GAA alone is reduced in the oocytes. Using this model, we can begin to understand the implications of supplementing one-carbon metabolites during in-vitro maturation and start to understand long-term implications on early embryonic development. USDA is an equal opportunity employer and provider.