Template-Type: ReDIF-Article 1.0 Author-Name: D Mudronova Author-Workplace-Name: Department of Microbiology and Immunology, University of Veterinary Medicine and Pharmacy in Košice, Košice, Slovak Republic Author-Name: A Lagesen Author-Workplace-Name: Department of Microbiology and Immunology, University of Veterinary Medicine and Pharmacy in Košice, Košice, Slovak Republic Author-Name: E Pilipcinec Author-Workplace-Name: Department of Microbiology and Immunology, University of Veterinary Medicine and Pharmacy in Košice, Košice, Slovak Republic Author-Name: N Chomova Author-Workplace-Name: Department of Microbiology and Immunology, University of Veterinary Medicine and Pharmacy in Košice, Košice, Slovak Republic Author-Name: M Ratvaj Author-Workplace-Name: Department of Microbiology and Immunology, University of Veterinary Medicine and Pharmacy in Košice, Košice, Slovak Republic Title: Rearing system type affects baseline and post-vaccination immune gene expression in Atlantic salmon gills during smoltification Abstract: Atlantic salmon undergo critical development before sea transfer, and vaccination during this stage is routine to build protective immunity. This study compared immune responses to vaccination in smolt-stage salmon reared in flow-through (FT) versus recirculating (REC) aquaculture systems. Ten clinically healthy fish per facility were collected one week before and two weeks after intraperitoneal vaccination with commercial multivalent vaccines. Using qPCR, we compared immune gene expression in the fish gills. Before the vaccination, REC fish exhibited higher relative expression of genes coding cathelicidin-1 (cath-1), interleukin-1β (il-1β), and tumour necrosis factor-α (tnf-α) than FT fish. Fourteen days after vaccination, REC fish showed increased expression of gene coding defensin (def) and decreased expression of gene for transforming growth factorβ (tgf-β), while in FT fish, vaccination was associated with increased relative gene expression of tnf-α, tgf-β, and il-10. Within REC, cath-1 expression declined postvaccination, concurrent with an increase in il-10, suggesting a possible counter-regulatory response; in FT, the coordinated rise of pro-inflammatory (tnf-α) and anti-inflammatory (tgf-β, il-10) transcripts is consistent with an activation followed by regulatory signalling. These transcriptomic patterns imply that baseline immune gene expression and post-vaccination gill transcriptomic responses differ between rearing water systems used during smoltification in Atlantic salmon. Keywords: cytokine, vaccination, water system Journal: Veterinární medicína Pages: 271-279 Volume: 71 Issue: 7 Year: 2026 DOI: 10.17221/93/2025-VETMED File-URL: http://vetmed.agriculturejournals.cz/doi/10.17221/93/2025-VETMED.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/vet-202607-0001.txt Handle: RePEc:caa:jnlvet:v:71:y:2026:i:7:id:93-2025-VETMED Template-Type: ReDIF-Article 1.0 Author-Name: N Hodkovicova Author-Workplace-Name: Veterinary Research Institute, Brno, Czech Republic Author-Name: J Blahova Author-Workplace-Name: Faculty of Veterinary Hygiene and Ecology, University of Veterinary Sciences, Brno, Czech Republic Author-Name: K Stastny Author-Workplace-Name: Veterinary Research Institute, Brno, Czech Republic Author-Name: M Charvatova Author-Workplace-Name: Veterinary Research Institute, Brno, Czech Republic Author-Name: A Franc Author-Workplace-Name: Faculty of Pharmacy, Masaryk University, Brno, Czech Republic Author-Name: F Tichy Author-Workplace-Name: Faculty of Veterinary Medicine, University of Veterinary Sciences Brno, Brno, Czech Republic Author-Name: L Sedlackova Author-Workplace-Name: Faculty of Pharmacy, Masaryk University, Brno, Czech Republic Author-Name: J Mares Author-Workplace-Name: Faculty of AgriSciences, Mendel University in Brno, Brno, Czech Republic Author-Name: M Faldyna Author-Workplace-Name: Veterinary Research Institute, Brno, Czech Republic Author-Name: Z Svobodova Author-Workplace-Name: Faculty of Veterinary Hygiene and Ecology, University of Veterinary Sciences, Brno, Czech Republic Title: The contribution of polymer additives to microplastic toxicity: A long-term study with Oncorhynchus mykiss exposed to polystyrene microparticles with different hexabromocyclododecane content Abstract: Although microplastic toxicity in fish has been extensively studied, the role of polymer additives remains insufficiently understood. This study investigated the combined effects of polystyrene (PS) microplastics and the brominated flame retardant hexabromocyclododecane (HBCD) on the health of rainbow trout (Oncorhynchus mykiss) following six weeks of dietary exposure. Fish were exposed to PS particles with varying HBCD content (0.0 mg/g - PS-HBCDfree, 0.2 mg/g - PS-HBCDlow, 1.0 mg/g - PS-HBCDhigh) or to HBCD alone (HBCDonly). The combination of PS and HBCD induced the most pronounced biological responses at molecular, biochemical and histological levels. In the liver, oxidative stress and upregulation of pro-inflammatory cytokines (il8, il2), together with increased catalase expression, were observed in PS- and/or PS-HBCD-exposed groups, indicating an imbalance in antioxidant defence. Histopathology confirmed liver dystrophy and renal lesions, while elevated vitellogenin expression suggested endocrine disruption. Although HBCD accumulation was confirmed only in the HBCDonly group, the polymer-bound form caused comparable physiological alterations, supporting its contribution to combined toxicity. Overall, the study demonstrates that PS microparticles can act as vectors enhancing the bioactivity of embedded additives such as HBCD, resulting in complex multi-organ effects and emphasising the importance of assessing additive-polymer interactions when evaluating the environmental risks of microplastics. Keywords: diet, fish, plastic, pollution, rainbow trout, toxicology Journal: Veterinární medicína Pages: 280-294 Volume: 71 Issue: 7 Year: 2026 DOI: 10.17221/95/2025-VETMED File-URL: http://vetmed.agriculturejournals.cz/doi/10.17221/95/2025-VETMED.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/vet-202607-0002.txt Handle: RePEc:caa:jnlvet:v:71:y:2026:i:7:id:95-2025-VETMED Template-Type: ReDIF-Article 1.0 Author-Name: K Matejickova Author-Workplace-Name: Department of Infectious Diseases and Preventive Medicine, Veterinary Research Institute, Brno, Czech Republic Author-Name: J Motlova Author-Workplace-Name: Department of Infectious Diseases and Preventive Medicine, Veterinary Research Institute, Brno, Czech Republic Author-Name: H Novotna Author-Workplace-Name: Department of Infectious Diseases and Preventive Medicine, Veterinary Research Institute, Brno, Czech Republic Author-Name: Z Mikulkova Author-Workplace-Name: Tekro, spol. s r.o., Prague, Czech Republic Author-Name: P Ginterova Author-Workplace-Name: Tekro, spol. s r.o., Prague, Czech Republic Author-Name: M Jerabek Author-Workplace-Name: Tekro, spol. s r.o., Prague, Czech Republic Author-Name: L Pojezdal Author-Workplace-Name: Department of Infectious Diseases and Preventive Medicine, Veterinary Research Institute, Brno, Czech Republic Title: Efficacy of five peroral therapeutics against Ichthyophthirius multifiliis infestation in salmonids Abstract: Ichthyophthirius multifiliis is a widespread parasitic ciliate causing significant losses in intensive freshwater aquaculture. This study evaluated the efficacy of medicated feed containing amprolium hydrochloride (2 mg/kg b.w./day), clopidol (2 mg/kg b.w./day), praziquantel (20 mg/kg b.w./day), toltrazuril (50 mg/kg b.w./day), and doxycycline (40 mg/kg b.w./day) administered at different stages of infection in experimentally infected brook trout fingerlings. Doxycycline and praziquantel demonstrated high protective efficacy (0-5% mortality) when applied during parasite exposure or the preclinical stage of infection. In contrast, amprolium hydrochloride, toltrazuril, and clopidol showed limited or no protective effect. The timing of administration was critical, and prophylactic use of effective compounds via feed may offer a practical strategy for controlling I. multifiliis outbreaks. These findings support the potential of doxycycline and praziquantel as oral chemotherapeutics in aquaculture, warranting further investigation for therapeutic use in advanced infection stages. Keywords: amprolium, brook trout, clopidol, doxycycline, praziquantel, toltrazuril Journal: Veterinární medicína Pages: 255-262 Volume: 71 Issue: 7 Year: 2026 DOI: 10.17221/99/2025-VETMED File-URL: http://vetmed.agriculturejournals.cz/doi/10.17221/99/2025-VETMED.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/vet-202607-0003.txt Handle: RePEc:caa:jnlvet:v:71:y:2026:i:7:id:99-2025-VETMED Template-Type: ReDIF-Article 1.0 Author-Name: I Toulova Author-Workplace-Name: Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, Faculty of Veterinary Hygiene and Ecology, University of Veterinary Sciences Brno, Brno, Czech Republic Author-Workplace-Name: Department of Zoology, Fisheries and Hydrobiology, Faculty of AgriSciences, Mendel University in Brno, Brno, Czech Republic Author-Name: V Vaibarova Author-Workplace-Name: Department of Infectious Diseases and Microbiology, Faculty of Veterinary Medicine, University of Veterinary Sciences Brno, Brno, Czech Republic Author-Name: I Papezikova Author-Workplace-Name: Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, Faculty of Veterinary Hygiene and Ecology, University of Veterinary Sciences Brno, Brno, Czech Republic Author-Workplace-Name: Department of Zoology, Fisheries and Hydrobiology, Faculty of AgriSciences, Mendel University in Brno, Brno, Czech Republic Author-Name: K Matejickova Author-Workplace-Name: Department of Infectious Diseases and Preventive Medicine, Veterinary Research Institute, Brno, Czech Republic Author-Name: I Mikulikova Author-Workplace-Name: Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, Faculty of Veterinary Hygiene and Ecology, University of Veterinary Sciences Brno, Brno, Czech Republic Author-Workplace-Name: Department of Zoology, Fisheries and Hydrobiology, Faculty of AgriSciences, Mendel University in Brno, Brno, Czech Republic Author-Name: H Novotna Author-Workplace-Name: Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, Faculty of Veterinary Hygiene and Ecology, University of Veterinary Sciences Brno, Brno, Czech Republic Author-Workplace-Name: Department of Zoology, Fisheries and Hydrobiology, Faculty of AgriSciences, Mendel University in Brno, Brno, Czech Republic Author-Workplace-Name: Department of Infectious Diseases and Preventive Medicine, Veterinary Research Institute, Brno, Czech Republic Author-Name: M Palikova Author-Workplace-Name: Department of Ecology and Diseases of Zoo Animals, Game, Fish and Bees, Faculty of Veterinary Hygiene and Ecology, University of Veterinary Sciences Brno, Brno, Czech Republic Author-Workplace-Name: Department of Zoology, Fisheries and Hydrobiology, Faculty of AgriSciences, Mendel University in Brno, Brno, Czech Republic Title: An experimental challenge model for infecting African catfish (Clarias gariepinus) with Edwardsiella tarda Abstract: Edwardsiella tarda is an important fish pathogen that causes outbreaks leading to significant losses in aquacultural species such as African catfish (Clarias gariepinus). In order to study host-pathogen interactions and design preventive strategies, it is essential to prepare a reliable experimental infection model. The aim of this study was to develop a reproducible immersion challenge model for E. tarda infection in C. gariepinus. The present study consisted of preliminary experiments and a main experiment evaluating the different routes of infection and the bacterial concentrations and exposure durations in an immersion bath. Preliminary experiments demonstrated that infection could be induced by either intraperitoneal injection or immersion bath, and that infection was more successful at higher concentrations. The main experiment involved two concentrations (108 and 2 × 108 CFU/ml) of immersion bath and two immersion durations (1 and 2 h), each repeated twice. The fish were monitored for clinical signs and mortality throughout the experiment and samples were collected on day 10 post-infection for haematological, immunological, and pathological assessment. High-dose immersion reliably induced infection, with disease progression depending on bacterial concentration and exposure duration. This established model is a practical and reproducible tool for future studies on the pathogenesis and immunity of C. gariepinus, as well as the use of immunostimulants and therapeutics. Keywords: bacterial infection, edwardsiellosis,  immersion bath, intraperitoneal injection Journal: Veterinární medicína Pages: 263-270 Volume: 71 Issue: 7 Year: 2026 DOI: 10.17221/102/2025-VETMED File-URL: http://vetmed.agriculturejournals.cz/doi/10.17221/102/2025-VETMED.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/vet-202607-0004.txt Handle: RePEc:caa:jnlvet:v:71:y:2026:i:7:id:102-2025-VETMED Template-Type: ReDIF-Article 1.0 Author-Name: M Faldyna Title: Editorial for the Thematic Issue on Fish Health and Disease Management II Journal: Veterinární medicína Number: 0 Volume: 71 Issue: 7 Year: 2026 File-URL: http://vetmed.agriculturejournals.cz/artkey/vet-202607-0005_editorial-for-the-thematic-issue-on-fish-health-and-disease-management-ii.php File-Format: text/html File-URL: http://vetmed.agriculturejournals.cz/pdfs/vet/2026/07/05.pdf File-Format: Application/pdf Handle: RePEc:caa:jnlvet:v:71:y:2026:i:7:id:vet-202607-0005