222 Corn-expressed Phytase Modulates Serum Amino Acids and Proteomics Profiles in Nursery Pigs Fed with Low-protein, -calcium, and -phosphorous Diets

Abstract Feeding pigs with very low-protein (VLP) and low-phosphorous (P) diets may be useful for decreasing the nutrients excretion to the environment; however, this practice negatively impacts the animals’ growth performance. A beneficial effect of corn-expressed phytase (CEP) on growth performance of pigs fed with VLP diets was shown by our group recently. Little is known whether this improvement is related with alterations in profile of blood proteins and amino acids (AA). The objective of this study was to investigate whether supplementation of VLP, low-calcium (Ca) and low-P diets with a CEP can influence the serum AA and proteomics profiles in pigs. Forty-eight weaned barrows were subjected into one of the following groups (n = 8/group) for 4 weeks: positive control (PC), negative control-reduced protein (NC), NC+low-dose CEP, i.e 2,000 FTU/kg (LD), NC+high-dose CEP, i.e. 4,000 FTU/kg (HD), LD with reduced Ca/P (LDR), and HD with reduced Ca/P (HDR). At week 4, blood samples were collected from all pigs. Compared to PC, NC reduced the serum leucine and phenylalanine concentrations; however, LD recovered their levels. Using trypsinolysis and mass spectrometry, 703 serum proteins were identified and quantified, wherein 25 were found to be differentially expressed among groups. Hierarchical clustering showed a clear separation in proteins identified among dietary groups. Compared to NC, 23 and 24 proteins were found to be differentially expressed in serum of LD and HD groups, respectively, with some important proteins in growth regulation such as SELENOP being upregulated and the IGFBP family being downregulated in these groups. A positive correlation was detected between growth and abundance of BGN, TLN1, PDLIM1 and COL1A2 that are involved in bone mineralization and muscle structure development. Thus, CEP improved the serum profile of some essential AA and affected the expression of proteins involved in regulation of growth in pigs fed with VLP diets.