Abstract #T146
Section: Physiology and Endocrinology
Session: Physiology & Endocrinolog II
Format: Poster
Day/Time: Tuesday 7:30 AM–9:30 AM
Location: Exhibit Hall B
Session: Physiology & Endocrinolog II
Format: Poster
Day/Time: Tuesday 7:30 AM–9:30 AM
Location: Exhibit Hall B
# T146
mRNA expression of DNA methyltransferase 1 and 3a in adipose tissue of lactating and non-lactating dairy cows.
S. Häussler1, T. Bleikamp1, L. Laubenthal1, K.-H. Südekum1, M. Hoelker1, H. Sauerwein*1, 1Institute of Animal Science, University of Bonn, Bonn, Germany.
Key Words: dairy cow, adipose tissue, DNA methylation
mRNA expression of DNA methyltransferase 1 and 3a in adipose tissue of lactating and non-lactating dairy cows.
S. Häussler1, T. Bleikamp1, L. Laubenthal1, K.-H. Südekum1, M. Hoelker1, H. Sauerwein*1, 1Institute of Animal Science, University of Bonn, Bonn, Germany.
Gene expression in cells includes the control via DNA methylation. In mammals, DNA methylation is regulated by DNA methyltransferases (Dnmts). Environmental changes, pathological processes or cellular aging can change DNA methylation patterns inducing pro-aging effects and/or age-related diseases. Moreover, stress and inflammatory conditions may decrease Dnmts activity. Based on increasing energy requirements due to lactation and parturition, high-yielding dairy cows are susceptible to metabolic disorders in the periparturient period. Around calving, dairy cows mobilize body reserves, mainly adipose tissue (AT), to meet the increased need for lactation. We hypothesized that the mRNA expression of Dnmt 1, that controls the DNA maintenance methylation, and Dnmt 3a, one of the de novo methylating enzymes, changes in AT from dairy cows due to the metabolic stress of lactation. In this study, primiparous lactating German Holstein cows and age-matched, non-pregnant, and nonlactating cows (each n = 8) were fed according to their requirements. Nonlactating cows received a straw-grass silage diet (50:50; 6.05 - 6.19 MJ NEL/kg DM) for ad libitum intake, lactating cows were fed a partial mixed ration (6.3 - 6.8 MJ NEL/kg DM) for ad libitum intake and concentrate (7.7 MJ NEL/kg DM) depending on their milk yield. Subcutaneous (sc) AT (tailhead region) was biopsied on weeks (wk) 3 and 35 postpartum (p.p.). The mRNA abundance of Dnmt 1 and 3a was quantified by qPCR in scAT. Values were compared by Student’s t-test (SPSS 24). There was no difference in the mRNA abundance of Dnmt 1 and 3a in lactating versus nonlactating cows; therefore, the time effect was tested after pooling both animal groups. From wk 3 to 35 p.p., the mRNA abundance of Dnmt1 tended to decrease 16% (P = 0.055), whereas the mRNA abundance of Dnmt 3a increased 2.2-fold (P < 0.001) from wk 3 to wk 35 p.p. The present study shows that the mRNA abundance of Dnmt 1 and 3a changes with age in bovine scAT, but seems not to be affected by lactation. Increasing expression of Dnmt 3a mRNA point to changes of the de novo methylated DNA patterns, which might compensate for cellular aging processes.
Key Words: dairy cow, adipose tissue, DNA methylation