Submitted to: Midwestern Section of the American Society of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: 12/19/2012
Publication Date: 3/1/2013
Citation: Rempel, L.A., Miles, J.R. 2013. Methylation patterns in fetal tissues generated from gilts inseminated with fresh or cryopreserved semen [abstract]. Journal of Animal Science. 91 (Supplement 2):123-124 (Abstract #P103).
Technical Abstract: Environmental influences, such as pollutants, climate, or diet, can alter the epigenetic configuration of gametes. The objective of our study was to evaluate differences in methylation activity of fetal placenta and liver from porcine pregnancies derived from fresh or frozen/thawed semen. Thirty cyclic gilts were single-time inseminated following an altrenogest/gonadotropin synchronization procedure. Pregnant gilts were harvested at d 28 of gestation and placental and liver tissues were collected from the smallest, average and largest littermate fetuses. Genomic DNA was isolated and 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) was measured using an ELISA technique. Pregnancy data and litter statistics were analyzed with GLIMMIX and GLM procedures, respectively. Methylation data were analyzed with MIXED procedures. No differences (P >/= 0.13) in litter and piglet traits were detected between gilts bred with fresh semen (9 pregnant/15 bred) or gilts bred with frozen/thawed semen (6 pregnant/15 bred). No global methylation differences (P >/= 0.12) were identified in fetal liver. Percent activity of 5mC was not different (P = 0.93), but its catalyzed product, 5hmC, and the ratio of 5mC:5hmC were different (P = 0.09 and P = 0.05, respectively) in placenta derived from fresh semen insemination versus frozen/thawed. Activity of DNA can be impacted by 5hmC, which inhibits DNA methyltransferase (DNMT)1-mediated methylation of target cytosine and 5hmC has reduced affinity for various methyl-CpG-binding proteins potentially affecting transcription activity in promoter regions. Further investigations into the mechanisms yielding hydroxymethylcytosine differences in placenta derived from fresh versus frozen/thawed semen are merited. USDA is an equal opportunity provider and employer.