EXTENDED ABSTRACT ONLY- DO NOT CITE

The proteome is the expressed protein complement of a genome in a tissue. Protein extraction followed by high resolution 2 dimensional electrophoresis, coupled with gel image analysis allows hundreds of protein to be monitored in parallel, permitting a global picture to emerge of changes in protein profile under different metabolic states. Protein spots are then subjected to further analysis leading to protein identification. A rainbow trout proteome map is being developed in which all proteins are recorded in terms of molecular weight, isoelectric point (pI) and abundance. Protein spots that are found to be of interest are excised from the gel and subjected to trypsin digestion and separation of peptides by mass spectrometry. These peptide mass fingerprints are then used to search the Genbank data base for protein identification. A proteomics approach has been used to study the protein profiles of livers of rainbow trout following different nutritional challenges. Dietary changes will result in a multitude of metabolic and gene expression responses fish, identifying proteins that are altered in their expressio