Identification of Potential Serum Biomarkers for Feed Efficiency in Young Pigs

<b>Abstract Text: </b>Identification of biomarkers for feed efficiency is important for increasing overall productivity of animal production. Early indicators of feed efficiency would be of particular value. The purpose of this project was to establish serum biomarkers for feed efficiency in young pigs. Serum was collected from five week old pigs from generation 8 of the Iowa State Residual Feed Intake (RFI) project. The pigs were then finished on either a high energy low fiber diet or low energy high fiber diet. RFI was calculated using feed intake data from FIRE^&copy;Performance Testing System. Serum protein samples were analyzed using 2D Difference in Gel Electrophoresis (2D-DIGE). Separate 2D-DIGE experiments were carried for each diet using pigs from the more efficient low RFI line (n= 8) or the less efficient high RFI line (n =8). Selected proteins were identified through mass spectrometry. &nbsp;Both 2D-DIGE comparisons yielded several potential protein biomarkers for feed efficiency including gelsolin, vitronectin, serpinA3-6, and serpinA3-8. Gelsolin and vitronectin were significantly increased (13 to 57 %) in abundance in the low RFI line. SerpinA3-6 and A3-8 were identified in 14 protein spots, and the protein abundance in most of these SerpinA3-6 or A3-8 spots was more than 100% higher in the low RFI line as compared to the high RFI line pigs. These differences were consistent between the diet comparisons. SerpinA3 is a serine protease inhibitor that has promise as a biomarker to many disease states. In young pigs, an increase in serine protease inhibition could result in lower protein turnover. A decrease in protein turnover indicates less metabolic energy is being used for cellular repair and replacement. These data indicate further investigation is needed into serpinA3 as a biomarker for feed efficiency. This project was supported by Agriculture and Food Research Initiative Competitive Grant no. 2011-68004-30336 from the USDA National Institute of Food and Agriculture.

<p><b>Keywords: </b> 2D-DIGE, Residual Feed Intake, SerpinA3