Eprinomectin (EPR) is a macrocyclic lactone antiparasitic widely used in veterinary medicine. Although the off-label oral use of the pour-on formulation of EPR is known to be effective and practical, data regarding its interactions with foods or vitamin supplements that may affect intestinal absorption remain limited. This study investigated the effects of vitamin A (VA) and vitamin E (VE) on the transepithelial permeability of EPR using the Caco-2 cell monolayer model. An analytical method for EPR quantification was developed using ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). The integrity of tight junction dynamics in epithelial monolayers was monitored using transepithelial electrical resistance (TEER) throughout the 21-day differentiation protocol. Apparent permeability coefficients (Papp) were calculated in both apical-to-basolateral and basolateral-to-apical directions and compared between EPR alone and EPR combined with the vitamins. EPR alone exhibited moderate permeability across Caco-2 monolayers (7.64 ± 2.27 × 10-6 cm/s). Notably, our results demonstrate that co-treatment of EPR with VA alone, as well as co-treatment with the combination of VA and VE, significantly reduced EPR permeability in vitro (P < 0.001). These findings highlight possible food/nutrient-drug interactions relevant to veterinary oral drug administration, and additional mechanistic and in vivo studies will be necessary to clarify the underlying pathways.
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.
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.
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.
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.
Warfarin research in rats is often challenged by methodological inconsistencies and large blood volume requirements. This study aimed to validate a refined, reproducible rat model for serial prothrombin time (PT) monitoring using the CoaguChek XS, in alignment with the 3R principles, and to determine an effective warfarin sodium dosage. Male Wistar albino rats received daily oral warfarin (0.125-0.750 mg/kg) for 5 days. PT was measured using the whole-blood CoaguChek XS and two laboratory plasma assays (Innovin, Thromborel S). Agreement was assessed using Bland-Altman and Passing-Bablok regression. The CoaguChek XS consistently yielded higher PT values than laboratory tests but showed strong agreement up to 25 seconds. A daily dose of 0.125 mg/kg resulted in a stable anticoagulant effect without mortality. Doses Doses of 0.250 mg/kg and higher were toxic, causing PT prolongation beyond the device's range and high mortality within 4-7 days after the initiation of treatment. In conclusion, the CoaguChek XS is a reliable tool for experiments requiring repeated measurements. Values remain reliable up to 25 s, and 0.125 mg/kg is a safe dose for short-term studies, effectively supporting animal welfare and the 3R principles.
The present study aims to investigate the interaction between the non-steroidal anti-inflammatory (NSAID) drug meloxicam and sex hormones in seasonal polyoestrous male and female Saanen goats. It was hypothesised that sex hormones, both steroidal and peptide hormones, may influence the serum concentration of the lipophilic drug meloxicam. In the study, the relationship between plasma meloxicam concentration (μg/ml) and the levels of follicle-stimulating hormone (FSH), anti-Müllerian hormone (AMH), testosterone, oestradiol (E2), and progesterone (P4) was evaluated. For this purpose, six male and six female Saanen goats aged one year were intravenously administered a 0.5 mg/kg dose of meloxicam, and blood samples were collected at different time points (0, 5, 30 min, and 2, 8, 24, 48 h) to obtain plasma and serum. The hormone levels were determined by ELISA, following the manufacturer's instructions, and drug concentrations were measured by HPLC-UV. While the study found no direct correlation between the meloxicam levels and the sex hormones, significant sex-related differences in the hormone levels underscore the importance of considering sex-related physiological differences in veterinary pharmacology. These results will establish a scientific basis for future research on species- and sex-specific dosage adjustments.
This study aims to evaluate the response of primary cells to buparlisib, a PI3K inhibitor, at varying concentrations and exposure durations across different histological and molecular subtypes of CMGTs, and to assess PI3K/Akt/mTOR pathway activity by measuring Akt and mTOR expression. Three carcinomas (C), three sarcomas (S), and two carcinosarcomas (CS) tumours were collected from the dogs. The primary cells were produced from tissues and treated with buparlisib at different doses. Subsequently, the WST-1 assay, Annexin V, and AO/PI staining were performed sequentially to evaluate the effects of buparlisib. PI3K/Akt/mTOR signalling pathway inhibition was revealed at the gene level in C, S, and CS cells following 5 µM buparlisib treatment by RT-PCR analysis. Our results demonstrated that C1 and C2 (basal-like) cells were more sensitive than C3, CS1, and CS2 cells (luminal A) upon buparlisib treatment. Liposarcoma S2 cells responded more to buparlisib than undifferentiated S cells (S1 and S3). Buparlisib also induced apoptosis and inhibited Akt and mTOR mRNA levels in C2, C3, S2 and S3 cells (P < 0.05). A higher rate of apoptotic cell death was observed in the C histological subtype and basal-like cells, with 62.9 ± 0.8% apoptosis in C1 and 79.1 ± 0.3% in C2. The efficacy of buparlisib was more pronounced in C2 basal-like CMGT cells and liposarcoma S2 cells with the downregulation of Akt and mTOR mRNA levels (P < 0.001). Therefore, PI3K inhibitors could be used to treat CMGT, particularly the basal-like molecular subtype.
Antimicrobial resistance (AMR) represents a major global threat to both human and animal health. Within the One Health framework, farm and wild animals serve as critical reservoirs of resistant bacteria and resistance genes, which can disseminate through food, water, and the environment. The excessive and inappropriate use of antibiotics in veterinary medicine exerts selection pressure that fosters the emergence and spread of antimicrobial resistance. Current mitigation strategies aim to reduce antibiotic consumption and promote prudent use through hygiene measures, vaccination, individualised therapy, pharmacokinetic-pharmacodynamic (PK/PD) dosing optimisation, and comprehensive AMR monitoring. European legislation (EU Regulations 2019/4 and 2019/6) provides stringent guidelines on antibiotic prescription, usage, and residue limits. In this context, antibiotic combination therapy represents a promising approach to enhance antimicrobial efficacy, broaden the antibacterial spectrum, and suppress the emergence of resistance by targeting multiple bacterial pathways simultaneously. In addition to developing new drugs, renewed focus on reviving older antimicrobial molecules - supported by updated PK/PD data and optimised dosing - could provide an effective alternative in combating multidrug-resistant pathogens.
This study is based on analytical data on mycotoxin contamination in ruminant feeds in the Czech Republic over a ten-year period (2013-2023), specifically deoxynivalenol (DON), zearalenone (ZEN), T-2 toxin (T-2/HT-2), and ochratoxin A (OTA). Analyses were performed in accredited State Veterinary Institutes using validated immunochemical and chromatographic methods. Samples included forage and concentrate feeds for dairy cows, calf feed, and fattening cattle feed. During the monitoring period, DON was detected at higher concentrations, reflecting the susceptibility of field crops to Fusarium infection under local environmental conditions. Forage feeds showed significantly higher concentrations of DON (472.6 ± 13.2 µg/kg), ZEN (61.7 ± 4.4 µg/kg), and T-2/HT-2 toxin (36.7 ± 2.7 µg/kg) than concentrates for dairy cows (P < 0.05). Additionally, ZEN levels differed significantly between concentrates for dairy cows (17.1 ± 2.3 µg/kg) and calf feed (16.2 ± 3.3 µg/kg) (P < 0.05). Although mycotoxin concentrations generally remained below recommended limits, a small proportion of samples exceeded guideline values for DON (0.13%) and ZEN (0.56%). These findings highlight the importance of continued monitoring and preventive strategies to manage mycotoxin risks.
Contaminants formed after the use of pesticides raise concerns for human health and aquatic ecosystems, i. a., due to their high persistence in surface waters and their further migration to other components of the environment. In our study, we compared the effect of the insecticide Mospilan SP and its active substance acetamiprid on the aquatic crustacean Artemia franciscana. The concentration was 367.44 mg/l for Mospilan SP LC50 after 120 h, and 102.82 mg/l after 144 hours. The concentration was 148.04 mg/l for the active substance acetamiprid LC20 after 144 h and 28.84 mg/l after 168 hours. The commercial insecticide Mospilan SP showed a significant suppressive effect on the measured morphological parameters (body length and body width), with statistically significant differences observed after 10 days of exposure. When comparing the changes after the application of the insecticide and the active substance, it is impossible to confirm the same effect on the morphological parameters within the given time intervals. The objective of the study was to examine morphological changes at sublethal concentrations, as these changes can provide a more sensitive indication of the adverse effects of commercial products and active substances on morphological parameters.
Honeybee health is a key factor in sustainable apiculture, with the most significant colony losses attributed to the mite Varroa destructor and microsporidia of the genus Nosema spp. The aim of this review article is to summarise current knowledge on the use of pharmaceuticals and preparations in the prevention and treatment of these diseases and to highlight promising alternatives to synthetic acaricides. Commonly used active substances such as amitraz and pyrethroids show decreased efficacy in many countries due to the development of resistance. Therefore, organic acids (formic, oxalic, and lactic), essential oils, and plant extracts are increasingly used as environmentally friendly, residue-free alternatives. Some plant preparations and extracts have been shown to be effective against Nosema ceranae. In addition to therapeutic interventions, the importance of preventive measures and immune support through supplements containing vitamins, amino acids, and probiotics is emphasised. The article highlights the need for integrated bee health management combining pharmacological, natural, and biotechnological approaches to limit resistance development, minimise residues in bee products, and promote overall colony vitality.
Allergic asthma is a widespread disease with elevated eosinophil levels. Although corticosteroids are widely prescribed for allergic asthma, numerous patients experience limited sensitivity and side effects. Loranthus tanakae Franch. & Sav., a traditional herbal plant, has anti-inflammatory and antioxidant properties in pulmonary inflammation caused by Asian sand dust and cigarette smoke condensate. To assess the protective effects of L. tanakae, we examined the influence of an L. tanakae ethanol extract (LTE) in ovalbumin (OVA)-induced asthma. Mice received intraperitoneal sensitisation with OVA, and challenged using OVA inhalation. LTE was consecutively orally gavaged for 6 days. Following sacrifice, the bronchoalveolar lavage fluid (BALF) and lung tissue was analysed. The LTE treatment considerably reduced inflammatory cell counts, proinflammatory cytokine levels in the BALF, and immunoglobulin E, compared with the OVA group, along with a reduction in airway hyperresponsiveness. The LTE also improved airway inflammation and suppressed mucus hypersecretion in the lung tissues. Additionally, the expression of MMP-9 and activation of ERK, JNK, and p38 were notably diminished in the LTE groups. This study revealed reduced airway inflammation in OVA-induced asthma via suppressing the MMP-9 and mitogen-activated protein kinase-associated factors. Consequently, our findings demonstrated that LTE is suggested as a potential remedy for allergic asthma.
Two probiotic (Lactiplantibacillus plantarum) supplementation strategies (continuous and cyclic) were evaluated for their ability to enhance resistance of rainbow trout (Oncorhynchus mykiss) to Aeromonas salmonicida infection. Neither of these strategies improved post-challenge survival. Instead, cyclic administration resulted in a significantly higher mortality rate (73%) compared with continuous supplementation (52%) and the control group (46%). One week post-challenge, most haematological, plasma biochemical, and immune parameters showed no significant difference between treatments, though fish receiving cyclic supplementation did exhibit a reduced lymphocyte count. However, three weeks post-challenge, this same group showed a significant decrease in total phagocyte number and in the proportion of phagocytes within white blood cells. IgM concentrations were significantly lower in both probiotic-supplemented groups than in the control group. In the cyclic group, reductions in interleukin-10 and elevations in total protein levels were also observed. Microbiome analysis of gut content three weeks post-challenge revealed a marked decline in microbial diversity in both probiotic-treated groups. These findings indicate that, under the experimental conditions, probiotic supplementation did not provide protection against A. salmonicida infection and that cyclic administration may disrupt immune homeostasis and intestinal microbial stability, ultimately compromising host resilience.
Ichthyophthiriosis, caused by Ichthyophthirius multifiliis, is a major threat in salmonid aquaculture. This study evaluated the efficacy of orally administered standard doxycycline and controlled-release doxycycline formulations in experimentally infected brook trout (Salvelinus fontinalis). Fish received medicated feed for 10 days starting seven days post-infection. Controlled-release doxycycline achieved the highest survival rate (84.2%), followed by standard doxycycline (73.7%), while no control fish survived after day 25 post-infection. Both drug formulations eliminated trophonts from the skin and gills by 20 days post-treatment. Despite a 2.5-fold lower dietary dose, the controlled-release doxycycline achieved a tissue concentration equivalent to ~32% of that of standard doxycycline, with similar retention rates. Levels of doxycycline residues in water declined over time for both groups, indicating limited environmental release. These results demonstrate the effective mitigation of ichthyophthiriosis with orally administered doxycycline and the enhancement of antiparasitic efficacy and reduction of drug load in tissues and the environment via controlled-release technology, supporting its potential as a sustainable medicated feed strategy in salmonid aquaculture.
This study assessed the effect of a 24-hour bath with praziquantel (2 and 4 mg/l) on grass carp (Ctenopharyngodon idella) by monitoring the haematological parameters, plasma biochemical profile, and oxidative stress indices. Fish were sampled at 24-, 48-, 72-, and 96-hours post-exposure (hpe). The haematological analysis revealed a significant increase (P < 0.05) in the white blood cell count immediately after treatment at both concentrations, with no subsequent changes. Within the plasma biochemical profile, a significant decrease (P < 0.05) was observed only in chloride (24 hpe at 2 mg/l; 72 hpe at both concentrations) and in magnesium (48 hpe at 2 mg/l). The oxidative stress responses indicated that the gill was the most responsive tissue. In the gill, the catalase and glutathione-S-transferase activities increased significantly (P < 0.05) at 48 hpe at 4 mg/l. Lipid peroxidation in the gill decreased at 48 hpe but increased at 72 hpe following exposure to 4 mg/l. In the hepatopancreas, the glutathione peroxidase activity significantly decreased at 48 hpe at 2 mg/l. In the plasma, significant changes (P < 0.05) were detected only in the ceruloplasmin activity, which decreased at 72 hpe in the 2 mg/l group. These findings provide essential baseline data supporting the potential future application of praziquantel in aquaculture.
Gyrodactylosis, caused by monogenean parasites of the genus Gyrodactylus, poses a significant threat to aquaculture, particularly under intensive farming conditions. This study evaluated the in vitro effectiveness of three veterinary anthelmintics - fenbendazole (FBZ), levamisole hydrochloride (LHC), and ivermectin (IVM) - against four Gyrodactylus species collected from wild cyprinid hosts. Parasite survival was monitored over 48 h at 6-7 °C. LHC showed the highest efficacy at both tested concentrations (30 and 50 mg/l), achieving near-complete mortality within 8 hours. FBZ and IVM were significantly less effective, with 23% and 33% of parasites surviving, respectively. Species-specific differences in drug susceptibility were observed, particularly with FBZ and IVM, with G. carassii showing consistently higher sensitivity than G. laevis, G. rutilensis, and G. vimbi. Lower water temperatures probably contributed to reduced drug efficacy and prolonged parasite survival. These findings highlight the importance of species-level evaluation and temperature considerations when selecting anthelmintic treatments for gyrodactylosis. In vitro testing under controlled conditions offers valuable insights into parasite susceptibility and complements in vivo approaches. Further research incorporating broader parasite diversity, temperature ranges, and pharmacological profiles is recommended to optimise treatment strategies in aquaculture.
Staphylococcus hyicus is one of the causative agents of exudative epidermitis in pigs. The aim of this study was to establish a porcine challenge model of a skin infection caused by S. hyicus to assess the effectiveness of a medicinal product intended for local application. Based on the results of the presence of toxin encoding genes and antimicrobial resistance (detected resistance to clindamycin, penicillin, ampicillin, erythromycin and tetracycline), three field strains were selected for the trial. At D0, six surface defects were created on the back of six piglets. The defects were inoculated with bacteria at two different concentrations: 1 × 108 or 1 × 109 CFU/ml. Every day throughout the experiment, the pigs were monitored, and their rectal temperatures were measured. On D4, D9, and D14, a visual evaluation and indirect bacteriological imprints of the defects were performed. Crusts were present from D9, and a lower bacterial concentration led to reduced secretion and crust formation. Based on the results of bacterial cultivation of the indirect imprints, however, S. hyicus was present in greater amounts in the wound defects infected with the lower bacterial concentration. As there were differences in the obtained results among the strains used, it can be concluded that the strain marked as CAPM 6689 seems to be the most applicable and the lower concentration was enough for the infection development.
Drone brood homogenate (DBH), a nutrient-rich bee product, has received limited scientific attention despite its potential immunomodulatory and gut-protective properties. This study evaluated the effects of a dietary DBH supplementation on the intestinal barrier-related gene expression, phagocytic activity, and lymphocyte subpopulations in pigs. Eighteen weaned pigs were assigned to three groups (control, DBH100, DBH200) and fed DBH at 0, 100, or 200 mg/kg feed for 18 days. The gene expression of tight junction markers (occludin, claudin-1) and mucosal integrity-associated proteins (lumican, OLFM4) was assessed in the ileum by qRT-PCR. Phagocyte function and peripheral blood lymphocyte subpopulations were analysed by flow cytometry. DBH200 significantly upregulated the occludin, claudin-1, lumican, and OLFM4 expression, indicating enhanced intestinal barrier support. The phagocytes from both DBH-treated groups exhibited an increased engulfing capacity and an elevated oxidative burst index, though the percentage of active phagocytes was only weakly affected. The DBH supplementation did not alter the total T (CD3+) or B (CD21+) cells; however, both DBH groups showed a significantly increased CD4+ : CD8+ lymphocyte ratio, which is consistent with immune stimulation. These findings suggest that DBH may beneficially modulate the gut barrier integrity and selected components of innate and adaptive cellular immunity in pigs.
Non-steroidal anti-inflammatory drugs (NSAIDs) are a cornerstone in the management of canine osteoarthritis (OA), despite concerns regarding their long-term safety. Among non-pharmacological alternatives, pulsed electromagnetic field (PEMF) therapy has gained attention for its potential analgesic and anti-inflammatory effects, although veterinary-specific evidence remains limited. This randomised, controlled pilot study compared the clinical efficacy of PEMF therapy versus NSAID treatment (Mavacoxib) in 16 dogs with clinically and radiographically confirmed OA. Dogs were randomly assigned to receive either a 12-session PEMF protocol over 45 days or a standard Mavacoxib regimen. Clinical evaluations included pain scores (VAS), pain on palpation, lameness severity (NRS), gait analysis (GLS and TPI), muscle circumference, and radiographic progression. Assessments were performed at baseline (T0), 30 days (T1), and 60 days (T2). PEMF therapy showed earlier improvements in pain, lameness, and muscle mass, and a favourable trend in joint mobility. No significant differences were detected in gait or radiographic parameters between groups. These preliminary findings suggest that PEMF is non-inferior to NSAIDs and highlight its potential role in multimodal OA management. Limitations include a small sample size and a short follow-up. Further studies are needed to confirm these preliminary results in larger cohorts.
