Transcriptional regulation of IL-17A and other inflammatory markers during the development of soybean meal-induced enteropathy in the distal intestine of Atlantic salmon (Salmo salar L.)

Progression of soybean meal (SBM)-induced enteropathy in Atlantic salmon (Salmo salar L.) distal intestine (DI) was studied to investigate pathophysiological mechanisms and immune responses. Seawater-adapted salmon were fed an extracted SBM-containing diet (200 g kg(-1)) from day 1-21 and compared with fish fed a fishmeal-based diet (day 0). Histological evaluation of the DI revealed signs of inflammation from day 5, which progressively increased in severity and affected more fish with increasing SBM exposure time. The expression profiles of 16 genes were analyzed by quantitative PCR. The pro-inflammatory cytokines interleukin 17A (IL-17A), IL-1 beta, interferon alpha (IFN alpha) and IFN gamma, as well as 1L-17A receptor, T-cell receptor gamma (TCR gamma), cluster of differentiation 4 alpha (CD4 alpha), CD8 beta, transforming growth factor beta (TGF beta), trypsin, protease-activated receptor 2 (PAR2) and myeloid differentiation primary response gene 88 (MyD88) were significantly up-regulated during early and/or late inflammation stages, whereas interferon-gamma-inducible lysosomal thiol reductase (GILT) was downregulated. Up-regulation of TCR gamma from day seven suggests proliferation of intraepithelial gamma delta T cells. IL-17A, up-regulated by 218-fold during early inflammation, indicates involvement of T helper 17 cells in the pathogenesis of the SBM-induced inflammatory response. (C) 2012 Elsevier Ltd. All rights reserved.