The gills of salmonids can easily be infested by Flavobacterium branchiophilum which is a Gram-negative bacterium present in most freshwater environments. Although it can occur in free-ranging fish it is rarely lethal and the cause of mortality in aquaculture is related to the environmental conditions of intensively reared fish. Stress has been mentioned as one of the causative agents but it seems more likely that the bacterial pressure (the amount of bacteria present on outer surface of the fish) plays a bigger role. Preventive use of Halamid therefore makes a lot of sense.
In fact the ‘hairs’ of the Flavo bacterium (the fimbriae) with which it attaches to the gill surface, cause lesions and further damage to the cells in the gill surface, leading to impaired blood circulation. Moreover, the gills start to produce mucous to fight against the infection. All of this leads to insufficient oxygen uptake and mortality. The real risk is in the speed of this process. Mortality can occur within 24 hours from the first signals.
An experienced farmer easily recognizes the clinical signs of bacterial gill disease (BGD): lethargy, loss of appetite, swimming high in the water and in a tilted position, signalling difficulty in breathing. The chances for successful curing all depend on an adequate and timely response with Halamid.
Consequently farmers look beyond treating the symptoms. They know when the risk for elevated levels of Flavo bacteria is higher and start treating preventively with Halamid. This will keep the gills clean from large scale infestation and prevents mortality due to BGD.
In recent years Axcentive research has shown that keeping the bacterial pressure under control is more important than you might think. In tropical fish farming, Vibrio bacteria for example are rarely the cause of mortality, but they create the conditions for other causative agents (eg viruses) to attack. Prevention is always better than cure.
Further information and guidelines for use can be obtained from local Halamid distributors or www.axcentive.com