Prevention of soya-induced enteritis in Atlantic salmon (Salmo salar) by bacteria grown on natural gas is dose dependent and related to epithelial MHC II reactivity and CD8α+ intraepithelial lymphocytes.
An experiment was carried out to study the preventive effect of bacterial meal (BM) produced from natural gas against plant-induced enteropathy in Atlantic salmon (Salmo salar). Salmon were fed a diet based on fish meal (FM) or seven diets with 200 g/kg solvent-extracted soyabean meal (SBM) to induce enteritis in combination with increasing levels of BM from 0 to 300 g/kg. Salmon fed a SBM-containing diet without BM developed typical SBM-induced enteritis. The enteritis gradually disappeared with increasing inclusion of BM. By morphometry, no significant (P>0.05) differences in the size of stretches stained for proliferating cell nuclear antigen were found with 150 g/kg BM compared with the FM diet. Increasing BM inclusion caused a gradual decline in the number of cluster of differentiation 8 α positive (CD8α+) intraepithelial lymphocytes, and fish fed BM at 200 g/kg or higher revealed no significant difference from the FM diet. Histological sections stained with antibody for MHC class II (MHC II) showed that fish with intestinal inflammation had more MHC II-reactive cells in the lamina propria and submucosa, but less in the epithelium and brush border, compared with fish without inflammation. There were no significant (P>0.05) differences in growth among the diets, but the highest levels of BM slightly reduced protein digestibility and increased the weight of the distal intestine. In conclusion, the prevention of SBM-induced enteritis by BM is dose dependent and related to intestinal levels of MHC II- and CD8α-reactive cells.
Department of Animal and Aquacultural Sciences, Aquaculture Protein Centre, CoE, Norwegian University of Life Sciences, Ås, Norway. odd-helge.romarheim@umb.no
Odd H
OH
Romarheim
Dyveke L
DL
Hetland
Anders
A
Skrede
Margareth
M
Øverland
Liv T
LT
Mydland
Thor
T
Landsverk
D000818:Animals; D001419:Bacteria / Q000254:growth & development*; D016827:CD8 Antigens / Q000032:analysis; D004751:Enteritis / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary*; D004848:Epithelium / Q000276:immunology; D005393:Fish Diseases / Q000209:etiology / Q000276:immunology / Q000517:prevention & control*; D000949:Histocompatibility Antigens Class II / Q000032:analysis / Q000276:immunology; D007422:Intestines / Q000276:immunology / Q000382:microbiology / Q000473:pathology; D008214:Lymphocytes / Q000276:immunology*; D009929:Organ Size; D020317:Salmo salar; D013025:Glycine max / Q000009:adverse effects*
D016827:CD8 Antigens; C431698:CD8alpha antigen; D000949:Histocompatibility Antigens Class II