Figure 4From: Efficacy of a polyvalent immersion vaccine against Flavobacterium psychrophilum and evaluation of immune response to vaccination in rainbow trout fry (Onchorynchus mykiss L.) Immunohistochemical detection of antigen uptake following immersion vaccination in gill of trout. Detection of F. psychrophilum antigen in gills: A unvaccinated, B day 2 pv. Brown staining indicates positive staining for antigen. Bar: 50 µm.Back to article page