Abstract #314
Section: Physiology and Endocrinology (orals)
Session: Physiology & Endocrinology 2
Format: Oral
Day/Time: Tuesday 10:15 AM–10:30 AM
Location: Room 262![](/2019/images/btn-find-it.png)
Session: Physiology & Endocrinology 2
Format: Oral
Day/Time: Tuesday 10:15 AM–10:30 AM
Location: Room 262
![](/2019/images/btn-find-it.png)
# 314
Nitrogen metabolism and insulin signaling targets in adipose tissue of Holstein cows during the periparturient period differ by body condition score.
Y. Liang*1, E. Trevisi2, J. Loor1, 1University of Illinois at Urbana-Champaign, Urbana, IL, 2Università Cattolica del Sacro Cuore, Piacenza, Italy.
Key Words: insulin resistance, amino acid transporter, transition cow
Nitrogen metabolism and insulin signaling targets in adipose tissue of Holstein cows during the periparturient period differ by body condition score.
Y. Liang*1, E. Trevisi2, J. Loor1, 1University of Illinois at Urbana-Champaign, Urbana, IL, 2Università Cattolica del Sacro Cuore, Piacenza, Italy.
The periparturient period is characterized by increased insulin resistance status in dairy cows. In non-ruminants, excessive fat deposition is associated with decreased insulin sensitivity and alterations in amino acid (AA) metabolism in adipose tissue. The hypothesis was that abundance of AA transporters, components of the urea cycle, and insulin signaling targets differs by prepartal body condition score (BCS) in dairy cows. Twenty 2 multiparous Holstein cows were divided by BCS before parturition (−30 d prepartum) into a BCS ≤ 3.25 (LoBCS, n = 11) or BCS ≥ 3.50 (HiBCS, n = 11) group. Adipose tissue obtained on d −15, 7, and 30 relative to calving date was used for RT-PCR analysis. Blood was obtained at −30, −15, 7, 10, and 30 d relative to calving date for energy balance biomarker analysis. The statistical model in SAS included the fixed effect of treatment, time and its interaction. There was no difference in prepartal DMI and milk yield between groups (P > 0.05). A treatment × time interaction was observed for postpartal DMI due to greater responses in LoBCS cows (P < 0.05). A treatment × time was observed for the plasma concentrations of fatty acids (NEFA) due to greater (P < 0.05) responses in HiBCS cows. Compared with LoBCS, HiBCS cows had greater (P < 0.05) plasma concentrations of glucose and hydroxybuyrate (BHBA). Among 6 AA transporters measured, HiBCS cows had greater overall (P < 0.05) mRNA abundance of high-affinity cationic (SLC7A1) and sodium-coupled AA transporters (SLC38A1). Abundance of arginino-succinate lyase (ASL) and arginase 1 (ARG1) (P < 0.05) also was greater overall in HiBCS cows, suggesting that adipose tissue in those cows had greater urea cycle activity. Abundance of protein kinase B1 (AKT1) was upregulated (P < 0.05) in HiBCS cows suggesting enhanced insulin signaling. Overall, the data indicate that BCS is associated with unique profiles of targets related to insulin sensitivity and nitrogen utilization in adipose tissue of dairy cows. The significance of these findings in the context of physiologic adaptations during the periparturient period merit further research.
Key Words: insulin resistance, amino acid transporter, transition cow