Analysis Of Proteome Expression Profile Of Small Intestine,Liver In Neonatal Bull Calves And Liver In Lactating Dairy Cows

With the rapid development in dairy farming in China,how to improve the health status of calves and producing high quality milk by the dairy cows have received much more attention.The physiological functions of small intestine and liver in animals play an important role in maintaining healthy production.Nevertheless,the mechanism of physiological functions of the small intestine and liver of neonatal bull calves as well as the liver of lactating dairy cows have not well characterized.Therefore,in this study,liquid chromatography–tandem mass spectrometry(LC-MS/MS)approach was employed to investigate the proteome profile of small intestine and liver,which may provide novel information to understand their mechanism of physiological function at protein level.Our results were listed as follows:1.Proteome profile in small intestine of calves.Small intestine samples were collected from the China Holstein bull calves not feeding colostrum approximately at2 h after birth.We found that a total of more than one-thousand non-redundant proteins were identified in duodenum,jejunum,and ileum,respectively.On the basis of GO annotation,most of the identified proteins were located in the cytoplasm and organelles that involved in catalytic activities and protein binding.KEGG pathway analysis revealed that the majority of the pathways corresponded to energy and immune response.The protein-protein interaction(PPI)network indicated that several proteins,such as ubiquitin-40 S ribosomal protein S27 a,serine/threonine-protein phosphatase 2A,heat shock protein 70,and eukaryotic initiation factor 4A-III were involved in more interactions than other proteins and were thus considered as central hub nodes.2.Differences in small intestinal proteins of calves.Experimental animals and tissues were treated as experiment 1.Statistical analysis showed that 178 differential expressed proteins were identified between duodenum and jejunum,218 differential expressed proteins identified between duodenum and ileum,373 differential expressed proteins identified between jejunum and ileum.In the biological processes,villin-1 and plastin-1 differentially expressed in duodenum and jejunum played an important role in regulation of microvillus length.In addition,differential expression proteins from jejunum and ileum involved in intestinal absorption,apoptotic process,and T cell costimulation had 4,26,and 3,respectively.The PPI network indicated thatseveral proteins,such as heat shock protein HSP 90-beta differential expressed between duodenum and jejunum,cytochrome c oxidase subunit 6B1 from jejunum and ileum had more interactions with other proteins in the network.3.Proteome profile in liver of calves.Experimental animals were treated as experiment 1,liver proteome of calves were mapped by LC-MS/MS approach.Results of our study were shown that most of the identified proteins involved in glucose,fatty acid,and amino acid metabolism pathway.The PPI network indicated that protein kinase C?,mitotic checkpoint protein BUB3,ubiquitin-40 S ribosomal protein S27 a,and transforming protein RhoA had more interactions with other proteins in the network.4.Proteome profile in liver of lactating dairy cows.Liver samples were collected from the China Holstein lactating dairy cows and used to map proteome profile by LC-MS/MS.We found that identified proteins,of which 16.7% featured membrane-spanning domains and 12.8% harbored signal peptides.On the basis of GO annotation,most of the identified proteins were located in the cytoplasm and organelles that involved in catalytic activities and nucleotide binding.KEGG pathway analysis revealed that the majority of the pathways corresponded to energy,lipid,and amino acid metabolism.The PPI network indicated that several proteins,such as ubiquitin-60 S ribosomal protein L40,heterogeneous nuclear ribonucleoprotein D and heat shock protein 90-alpha served as “crosstalk” nodes,which had more interactions with other proteins in the network.In summary,proteome profile of small intestine and liver from neonatal bull calves,as well as proteome profile of liver in lactating dairy cows were mapped by LC-MS/MS approach.The findings may provide novel insights into a better understanding of physiological function and adaption mechanism of small intestine and liver in calves,and liver in lactating dairy cows.