PSV-13 - Characterization of the relative abundance of duodenal mRNA related to genes involved in copper absorption in different breeds of sheep

Abstract: The objective of this experiment was to characterize relative expression of mRNA related to genes involved in Cu absorption in the duodenum of different breeds of sheep. Opportunistic liver and small intestine samples were collected from three harvested market weight Lincoln and Suffolk wether lambs (3-4 moths of age) fed a low quality forage based diet. A 5 cm sample of the duodenum (15 cm aboral from the pyloric sphincter) was collected from each lamb at the time of slaughter. Samples were immediately excised, sliced open, and washed with a PBS solution. The mucosal lining of the intestine was scraped with a scalpel blade to collect enterocytes. The scraped enterocytes were placed into a conical tube containing RNAlater. Furthermore, a one cm cubed sample from the center of the right lobe of the liver was collected from each lamb, washed with PBS solution, and stored in a conical tube until liver Cu concentrations could be determined. All intestinal and liver samples were stored at 4°C until transported back to the laboratory. Total enterocyte RNA was extracted and purified using TRI reagent and RNeasy. Primers for antioxidant 1 (ATOX1), Cu transporting alpha-polypeptide Atpase (ATP7A), Cu transporting beta-polypeptide Atpase (ATP7B), and Cu transporter1 (CTR1), were designed for real time PCR analysis. Liver Cu concentrations were lower (P < 0.05) in Lincoln (225.3 ± 23.1 mg Cu/kg DM) compared to Suffolk lambs (342.1 ± 31.2 mg Cu/kg DM). The relative mRNA expression of ATOX1 (P < 0.05), ATP7B (P < 0.01), and CTR1 (P < 0.04) in duodenal enterocytes were lower in Lincoln compared to Suffolk lambs. These data indicate that Cu absorption from the duodenum may be different in these breeds of sheep. Further research examining the impact of dietary Cu dose on genes involved in Cu absorption in different breeds of sheep as well as identification and quantification of proteins involved in Cu absorption, is warranted.