Elżbieta Terech-Majewska

Influence of deltamethrin on nonspecific cellular and humoral defense mechanisms in rainbow trout (Oncorhynchus mykiss)

The influence of deltamethrin on the innate immunity in rainbow trout was examined. Fish were immersed in deltamethrin at doses of 1, 2, and 4 microg/L for 30 min. The results showed that deltamethrin at doses of 2 and 4 microg/L decreased phagocytic activity of spleen macrophages and proliferative response of pronephros lymphocytes at days 1, 2, and 5 after immersion. Deltamethrin at these doses decreased the lysozyme activity, total protein, and immunoglobulin levels in serum. The greatest immunosuppressive influence of deltamethrin at dose 4 microg/L was observed at the end of the study.

Intracohort cannibalism and methods for its mitigation in cultured freshwater fish

Abstract Cannibalism is a common phenomenon that occurs in over 30 fish families. Most of the species are valuable objects of aquaculture and cannibalism is highly undesirable. Cannibalism is an aggressive behaviour, which can be caused by stress induced by various population and environmental factors and can occur in two main forms: early larval and late juvenile (or adult). Each of these forms can lead to severe losses of stock. Losses are caused not only by fish eating each other, but also by an increase in the number of infections (the result of body surface damage). It is important to understand the phenomenon of cannibalism in order to properly prevent, diagnose and reduce it. The main aim of this study was to present and examine some of the well-examined methods of cannibalism mitigation. Most of the methods consist of creating rearing conditions similar to natural conditions and to reduce stress. Moreover, because of large interspecies differences, similar methods can result in different effects depending on the species. Additional studies are needed to better understand the biology of each cultured species with particular emphasis on the impact of domestication, as well as to improve fish rearing conditions.

Characterization of Yersinia enterocolitica strains potentially virulent for humans and animals in river water.

The aim of this study was to isolate and identify potentially pathogenic strains of Yersinia enterocolitica in water samples collected from the upstream section of the Drwęca River in Poland.

Influence of nematode Anguillicoloides crassus infestation on the cellular and humoral innate immunity in European eel (Anguilla anguilla L.).

Parasitic invasions are recognized as one of the primary factors responsible for decreasing populations of European eel. The aim of the present study was to determine the influence of infestation with the nematode Anguillicoloides crassus on the innate immunity in European eel (Anguilla anguilla). Anguillicoloides crassus parasitizes the swim bladder of this fish. Levels of the following immunological parameters were measured: spleen phagocyte respiratory burst activity, spleen phagocyte potential killing activity, pronephros lymphocyte proliferation stimulated by concanavaline A or lipopolisaccharide, plasma lysozyme and ceruloplasmin activity, total protein and immunoglobulin (Ig) serum levels. The analyses of the results of humoral and cellular immunity indicate that all studied parameters were statistically significant higher (p < 0.05) in non-infested fish compared to the ones with anguillicolosis except for ceruloplasmin level. These data suggest that the A. crassus infestation in European eel is responsible for a decreased immune response what could result in higher susceptibility to other pathogenic conditions.

Oxidative stress and antioxidant defence markers in muscle tissue of rainbow trout (Oncorhynchus mykiss) after vaccination against Yersinia ruckeri

Abstract Introduction: The goal of this study was to assess the influence of vaccination against enteric redmouth disease on oxidative stress biomarkers and antioxidant defence in the muscle tissue of rainbow trout (Oncorhynchus mykiss Walbaum) vaccinated against Yersinia ruckeri in the first and second month after immunisation. Material and Methods: Healthy fish were vaccinated orally with inactivated whole cells of a virulent strain of Y. ruckeri. One and two months after immunisation the muscle samples were collected. Results: No significant difference was noted in lipid peroxidation level in either the first or second month after vaccination, while aldehydic and ketonic derivatives of oxidatively modified proteins (OMB) in the vaccinated group were significantly lower in the second month compared to those in the first month after vaccination (P < 0.05). The content of ketonic derivatives of OMB in muscles in the first month after immunisation was higher compared to untreated control. All these culminated in a depletion of glutathione peroxidase (GPx) activity and low level of total antioxidant capacity (TAC). Conclusion: Correlations between catalase activity and lipid peroxidation and TAC confirmed the pivotal role of catalase in antioxidant defence during immunisation. From a broader perspective, it is suggested that immunisation of fish with Yersinia vaccine is associated with induced free radical formation and oxidative stress. Free radicals would therefore be at least partially responsible for the induction of both humoral and cellular elements of the immunity and increased protective immunity against Y. ruckeri infection.

In vitro antimicrobial activity of ethanolic extracts obtained from Ficus spp. leaves against the fish pathogen Aeromonas hydrophila

Abstract The main goal of this study was to determine in vitro antimicrobial activity of ethanolic extracts obtained from the leaves of various Ficus species against Aeromonas hydrophila isolated locally from infected rainbow trout (Oncorhynchus mykiss Walbaum) with the aim of providing scientific rationale for the use of the plant in the treatment of bacterial infections induced by Aeromonas spp. in fish. Antimicrobial susceptibility testing was done on Muller-Hinton agar with the disc diffusion method. In the present study, most ethanolic extracts proved effective against the A. hydrophila tested, with 10-12 mm inhibition zones observed. A. hydrophila demonstrated the highest susceptibility to F. pumila. Among various species of Ficus with moderate activity against A. hydrophila, the highest antibacterial activities were noted for F. benghalensis, F. benjamina, F. deltoidea, F. hispida, and F. lyrata. Thus, Ficus can be used as a natural antiseptic and antimicrobial agent in veterinary practice. Further investigations need to be conducted to isolate and identify the bioactive compounds that can then be subjected to detailed pharmacological studies and the development of clinical applications. The alarming rate of increasing resistance in bacterial pathogens in aquaculture environments means that medicinal plants with antibacterial properties are very important as natural resources of new active compounds.

Impact of brewer’s yeast extract and levamisole in diets with vegetable oils on the growth, chemical composition, and immunological and biochemical blood parameters of pikeperch (Sander lucioperca)

The impact of applying NuPro® (40 g/kg feed) and levamisole (300 mg/kg feed) in European pikeperch (Sander lucioperca) diets with vegetable oils on growth, immunological, hematological, and blood chemical parameters was assayed. The fish were fed the feed containing sunflower and linseed oils (48 and 21 g/kg feed) (group VO) or this feed with levamisole (group VOL) or NuPro® (group VON). The fourth group was fed the feed with fish oil added in the amount of 69 g/kg feed (group FO). The pikeperch were reared for 56 days. Feeding the fish feed supplemented with levamisole or NuPro® increased the immunological responses of the phagocytes and lymphocytes, lysozyme activity, and total gamma-globulin levels. The feed supplemented with NuPro® resulted in decreased aspartate and alanine aminotransferase and alkaline phosphatase activity. Vegetable oils in the feed were linked to increased contents of linoleic acid in fish bodies. The quantity of eicosapentaenoic and docosahexaenoic acids was significantly the highest in group FO. The immunological index obtained in group VON indicated that the diet supplemented with brewer’s yeast extract (NuPro®) was the most advantageous when feeding juvenile pikeperch feeds with vegetable oils.

Improving disease prevention and treatment in controlled fish culture

Abstract The aim of the work was to evaluate long-term results of studies focusing on improving methods for preventing and treating fish diseases using selected natural and syntetic immunomodulators and vaccines in fish culture. Simultaneously, attention is drawn to infectious or environmental threats against which appropriately composed immunoprophylaxis can be used in production cycles. Fish culture is intensifying in Poland and globally, which means that the role of prevention and well-designed prophylaxis is of increasing significance to the prevention and treatment of fish diseases. Currently, 33 fish species are cultured in Poland as stocking material or for production. The primary methods for preventing diseases in controlled fish culture are ensuring the welfare of fish and other prophylactic methods, including immunoprophylaxis. Many infectious and non-infectious threats that can cause direct losses and limit fish culture are present in the aquatic environment. Fish diseases generally stem from the simultaneous action of many factors that coincide and are difficult to distinguish. Pesticides (organochlorine insecticides, organophosphorus herbicides), aromatic hydrocarbons, pentachlorophenol, heavy metals, and chemotherapeutics are particularly toxic to fish. Biodegradation, which is continual in aquatic environments, is a process by which toxic and other substances that negatively affect fish become bioavailable and impact the immune system, the functioning of which is a specific bioindicator of environmental quality. Innate immunity plays a key role in the defense against disadvantageous factors, which also include pathogens. Immunomodulation methods can protect resistance mechanisms, thereby increasing disease prevention and treatment in controlled fish culture.