Abstract #310

# 310
RNA sequencing reveals that methionine supply during late-gestation alters neonatal Holstein heifer calf liver transcriptome profiles.
Abdulrahman S. M. Alharthi*1, Fernanda Batistel1, Valentino Palombo1, Cesar I. M. Garces1, Claudia Parys2, Juan J. Loor1, 1University of Illinois, Urbana, IL, 2Evonik Nutrition & Care GmbH, Hanau-Wolfgang, Germany.

The objectives were to investigate if increasing supply of methionine during late-pregnancy in Holstein cows affects hepatic transcriptome profiles in female offspring. Heifer calves were born to cows fed a control diet (CON) or the control plus ethyl-cellulose rumen-protected methionine (MET) for the last 28 d prepartum (0.09% of dry matter intake), and were fed and managed similarly after birth. Liver biopsies were harvested at 4 d of age from 8 calves per treatment. Extracted total RNA was sequenced using the Illumina platform, and mapped to the Bos taurus genome assembly (UMD_3.1.1). Statistical analysis was conducted using the Bioconductor edgeR package, with treatment as fixed effect and animal as random effect. Dynamic Impact Approach (DIA) analysis was performed to uncover the most-impacted cellular pathways. A total of 622 differentially expressed genes (False Discovery Rate P < 0.25, uncorrected P < 0.01) were detected. The 25 most-impacted pathways from the DIA analysis indicated that genetic information processing pathways related with transcription and translation (e.g., RNA polymerase, purine metabolism, protein processing in endoplasmic reticulum, ribosome and spliceosome) were upregulated in MET than CON calves. In contrast, critical signaling pathways related to cell cycle, cellular metabolism and immunity (e.g., protein digestion and absorption, p53 signaling pathway, PI3K-Akt signaling pathway, Jak-STAT signaling pathway, calcium signaling pathway, cytokine-cytokine receptor interaction, cellular growth and dead, cellular senescence, endocytosis and leukocyte transendothelial migration) were biologically more important and highly-upregulated in CON than MET calves. Overall, preliminary analysis indicated that molecular changes observed early after birth in response of maternal methionine supply during late-gestation are beneficial to overall hepatic function, especially in terms of metabolism and inflammatory status.

Key Words: fetal programming, liver, transcriptomics