Elżbieta Terech-Majewska, Alicja Bernad, Joanna Pajdak-Czaus, Patrycja Schulz, Andrzej K. Siwicki
ABSTRACT. Fish diseases hinder the development of aquaculture significantly. Currently, the foundation of maintaining fish in good health rests on the importance of monitoring for any potential epizootic. Gram negative microorganisms remain the largest group of pathogenic agents responsible for disease states in fishes. It is especially important to identify mixed infections in which several bacterial factors, parasites and bacteria, and viruses and bacteria are identified. Infections of this type have different clinical presentations and run different courses. Frequently, the choice of therapies and courses of treatment is also difficult. The aim of the study was to evaluate the causes of disease states at a selected rainbow trout (Oncorhynchus mykiss) aquaculture facility based on the results of a two-year monitoring study conducted in 2014-15. No viruses were confirmed at the facility, and the disease states were mainly caused by bacteria and parasites. In 2014, a total of 19 tests were conducted, while 18 were conducted in 2015. Diseased states were most frequently detected in the fish during the summer months of July to September (57.89% in 2014, 50% in 2015). P. fluorescens, A. hydrophila complex, P. orysihabitans, Ch. indologenes, S. putrefaciens, Flavobacterium spp., and Enterococcus spp. were isolated from the samples collected. The most commonly identified parasite was Ichthyophthirius multifiliis. Mixed infections of parasites and A. hydrophila complex, P. fluoresens, P. orysihabitans, and Pantoea spp. were the most common. Given the complexity of most of the cases identified at the selected facility, it was concluded that targeted prevention based on continuous monitoring and modern disease prevention methods for fish cultured under controlled conditions is very important.
Keywords: rainbow trout, mixed infections, laboratory diagnostics
Przyjęto po recenzji 9.10.2017 r.