Abstract #T97

# T97
Body condition score in late pregnancy is associated with abundance of hepatic microRNA involved in energy metabolism.
R. E. Bucktrout*1, H. Xia2, E. Trevisi3, M. Vailati-Riboni1, J. J. Loor1, 1Department of Animal Sciences and Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, 2College of Animal Science and Technology, Yangzhou University, Yangzhou, Jiangsu, China, 3Department of Animal Sciences, Food and Nutrition, Università Cattolica del Sacro Cuore, Piacenza, Italy.

The main objective was to evaluate associations between body condition score (BCS) in late-pregnancy, plasma biomarkers, and hepatic abundance of microRNA linked to energy metabolism during in silico and in vivo analyses. At 4 weeks before calving, 26 cows were divided into 2 groups based on BCS, BCS ≥3.50 (n = 13; HiBCS) and BCS ≤ 3.25 (n = 13; LoBCS). Dry matter intake (DMI) from −4 wk of pregnancy through 30 d in milk (DIM) and milk production during the first 30 DIM were recorded. Blood was sampled at −30, −10, 7, 15, and 30 DIM. Liver biopsies were performed at −15, 7, and 30 DIM for analysis of miR-369 5p, miR-186, and miR-200b abundance via RT-PCR after normalization with 3 internal controls. Pathway analysis using the dynamic impact approach revealed these miRNAs play a role in relation to energy metabolism by means of fatty acid metabolism, oxidative phosphorylation, gluconeogenesis, PPAR signaling, and insulin signaling. Data were subjected to repeated measures ANOVA in SAS using PROC MIXED. Main effects were BCS, time, and their interaction, while cow was the random effect. Although daily DMI did not differ prepartum, HiBCS cows averaged 1.54 kg/d (P ≤ 0.05) more DMI/d postpartum. Overall milk production was 5.34 kg/d greater (P = 0.02) in HiBCS compared with LoBCS. Cows in HiBCS also had greater (P = 0.03) overall concentrations of fatty acids, myeloperoxidase (P = 0.03), and β-hydroxybutyrate (BHB) (P = 0.06) compared with LoBCS. In contrast, LoBCS had greater plasma concentrations of alkaline phosphatase (P ≤ 0.01), tocopherol (P = 0.03), and carotene (P = 0.03). miR-186 was the most abundant of the target miRNA evaluated, but had no detectable changes in relation to BCS or time. Abundance of miR-369 5p was lower (P = 0.01) overall in cows with HiBCS. In contrast, abundance of miR-200b had a BCS × time effect (P = 0.03) due to a marked upregulation between −15 and 7 d followed by increased abundance at 30 d in cows with LoBCS. Overall, the responses in miR-369 5p and miR-200b underscore a potentially important physiological role during the periparturient period as it relates to BCS.

Key Words: BCS, microRNA (miRNA), transition period