Effects of Methisoprinol on Innate Immunity Parameters in Intensively Reared European Eel (Anguilla anguilla)

Stress and chemotherapeutics can negatively affect the immune system of fish in intensive culture. Methods of prevention include immunonutrition. The present study examined the influence of dietary supplementation with the synthetic compound methisoprinol on selected nonspecific immune parameters in intensively cultured juvenile European eel (Anguilla anguilla). The fish were fed a commercial pellet containing 0 (control) or 200 mg methisoprinol/kg feed. After four weeks, the following immunological parameters were measured: respiratory burst activity and potential killing activity of the phagocytes, lymphocyte proliferation after stimulation by concanavaline A or lipopolisaccharide, and serum lysozyme activity, ceruloplasmin activity, total protein, and total immunoglobulin. Except for serum ceruloplasmin activity and total protein, all immune parameters were significantly higher (p<0.05) in the methisoprinol-treated group than in the control, strongly suggesting that four weeks of feeding methisoprinol to juvenile eels might improve innate immunity

UDN-like disease in spawners of salmonid fishes from the Rega, Parsęta, Wieprza, and Słupia rivers in 2009-2012

Since 2007 in Poland, skin lesions have been observed in salmon (Salmo salar L.) and sea trout (Salmo trutta L.) entering Pomeranian rivers to spawn. The clinical picture of affected fish resembled ulcerative dermal necrosis (UDN), a disease of unknown etiology affecting mainly the scalps of wild salmonids. The aim of the 2009-2012 study was to determine with microbiological tests the etiological agent of the skin lesions observed in salmonids entering the Pomeranian rivers. During the study, a total of 13 species of Gram-negative bacteria belonging mainly to the Yersiniaceae, Enterobacteriaceae, and Pseudomonadaceae families were isolated and identified from the skin and kidneys of diseased fish. The Gram-positive bacteria isolated were aerobic, hemolytic granules of the genus Streptococcus. Mycological examinations on damaged fish body surfaces revealed yeasts of the genus Rhodotorula and fungi of the family Saprolegniaceae. The results of our study did not permit us to identify unequivocally the direct cause of the fish diseases analyzed since all the bacteria isolated during the study are normally found in aquatic environments. Some of the isolated bacteria identified were assumed to be potentially pathogenic to fish. The fungal infections observed were probably secondary and only exacerbated ongoing disease processes

In vitro study of Lactobacillus plantarum properties as a potential probiotic strain and an alternative method to antibiotic treatment of fish

The presence of lactic acid bacteria (LAB) favors the stabilization of intestinal flora, facilitates digestion, improves the assimilability of fodder, and has an immunomodulatory effect on the immune system. According to current research, the application of LAB following antibiotic treatment prevents the development of opportunistic bacteria inhabiting the digestive tract. In the study the potential probiotic properties of Lactobacillus plantarum strains, which can be administered as an alternative to antibiotic treatment in aquaculture, were investigated under in vitro conditions. The strains of L. plantarum were characterized for important properties such as the ability to grow in the presence of 10% fish bile, a tolerance of low pH, and antagonism to pathogens dangerous for fish such as Aeromonas salmonicida and Pseudomonas fluorescens; therefore, they meeting the criteria for strains with probiotic properties. In view of currently increasing resistance to antibiotics and a decrease of their efficiency, probiotic bacteria can serve to support immunity to infections in the future

Immune-enhancing activity of potential probiotic strains of Lactobacillus plantarum in the common carp (Cyprinus carpio) fingerling

Introduction: Immune-potentiating functions of Lactobacillus plantarum strains in the common carp were evaluated

Effect of Different Routes of Vaccination against Aeromonas salmonicida on Rearing Indicators and Survival after an Experimental Challenge of Pikeperch (Sander lucioperca) in Controlled Rearing

Bacterial diseases are a significant problem in the controlled rearing of fish. Furunculosis (Aeromonas sp.), flavobacteriosis (Flavobacterium sp.), and pseudomonadosis (Pseudomonas sp.) are currently the most frequently identified diseases in recirculating aquaculture systems of various fish species. Such a situation is also observed in pikeperch rearing. Due to the emerging difficulties of effective prophylaxis using commercial vaccines, interest in the use of autovaccinations is increasing, not only in ichthyopathology but also in other veterinary fields. Our research aimed to assess the effect of the vaccination method on the overall condition of the fish and survival after the experimental infection with Aeromonas salmonicida. Pikeperch were vaccinated by (1) bath, (2) a single i.p. injection, or (3) feed. The fish were measured and weighed on day 0 and after 28 and 56 days of the experiment. Specific growth rate, daily growth rate, condition factor, and feed conversion ratio were calculated. On days 7, 14, 21, and 28 of the experiment, ceruloplasmin and lysozyme levels were rated. In addition, a challenge test was performed. The obtained results showed that the method of vaccination is important and affects the growth of fish, the overall condition of fish, and survival after experimental infection