IMMUNOSTIMULATING EFFECT OF GROWTH-HORMONE - IN-VIVO ADMINISTRATION OF GROWTH-HORMONE IN RAINBOW-TROUT ENHANCES RESISTANCE TO VIBRIO-ANGUILLARUM INFECTION

In-vivo administration of purified (nGH) and recombinant (rGH) chum sa lmon, Oncorhynchus keta, growth hormone enhanced the survival of rainb ow trout, O. mykiss, against virulent Vibrio anguillarum. Macrophages obtained from rainbow trout that were treated in vivo with either GH p reparation showed enhanced stimulation of the chemiluminescent respons es induced by opsonized V. anguillarum cells and increased phagocytic activities. However, the serum bactericidal activity against V. anguil larum was not enhanced in fish injected with nGH or rGH. These finding s show that in-vivo administration of either GH preparation can effect ively prime macrophages and increase the resistance to V. anguillarum in rainbow trout. (C) 1997 Elsevier Science B.V.