PSXIII-18 The use of proteomic analysis to understand copper trafficking proteins in sheep.

Abstract Seven Rambouillet-crossbred wethers were used to investigate the effect of copper supplementation on Cu concentrations and protein abundances in plasma, bile, liver, duodenum, jejunum, and ileum tissues. Liver biopsies and plasma were collected from each animal prior to the initiation of the experiment for initial Cu concentration analysis. Wethers were blocked by BW and assigned to 1 of two treatments: 1) control: no supplemental Cu (n=3) and 2) +Cu: 12 mg of supplemental Cu/kg DM (n=4). Ground corn was used as a carrier and fed in a separate feed container daily before the delivery of feed. After receiving treatments for 28d, all wethers were transported to a USDA-inspected abattoir and harvested. Following harvest, blood, bile, liver, duodenum, jejunum, and ileum samples were collected for Cu concentration analysis. Additional liver and duodenum samples were collected for proteomic analysis. Data were analyzed as a randomized block design using the MIXED procedure in SAS with individual animals as the experimental unit. Animals in the +Cu group had a greater (P < 0.02) copper concentration in plasma, liver, and jejunum than the control group. Ileum tissues contained greater (P < 0.01) copper concentration in the control group than in the +Cu group. Bile, and duodenum Cu concentrations were similar (P > 0.10) across treatments. There is no difference (P > 0.80) in protein abundance for all proteins in the liver and duodenum. In the liver, there were 5 and 28 proteins exclusively present in the control and +Cu group, respectively. In the control group, proteins associated with cell carcinoma suppression, cellular structural and formation and sulfur metabolism were identified. Whereas hepatic proteins involved in metabolism and energy production, immune and cellular regulation, protein processing and disease development were present in the +Cu group. Twenty-three proteins were exclusively found in the duodenum of the control group impacting metabolism and cellular processes, growth and regulation, immune response and reproductive function. While 20 proteins related to nutrient metabolism, cellular maintenance and transport and immune function were exclusively present in the +Cu group. Additionally, the SWEET glucose transporter was only found in animals that received the +Cu treatment, suggesting a potential increasing in glucose absorption from the small intestine. Future research is needed to better understand the impact of copper supplementation on sheep, as the reason for the exclusive presence of proteins in one treatment but not the other remains unclear.