Introduction: This article presents the analysis of the correlation between the category and health status of calves and the results of their rearing and levels of selected blood parameters.Material and Methods: The study included 105 Polish Holstein-Friesian and beef (Limousine, Charolaise and Hereford) crossbred calves. Young bulls were purchased at the age of two to four weeks. The animals underwent quarantine, were dehorned, and 46 young bulls were castrated. The germ horns were removed by burning out. Castration was carried out with a bloodless method using a rubber band. The calves were kept in groups and fed a milk replacer administered via teats from automated milk-feeding stations. After the period of milk feeding, the calves were fed grass silage ad libitum and a concentrate at 2.5 kg/animal/day. The calves were weighed every two weeks. Blood for analyses was sampled at 43 d of age.Results: After the rearing period finished at the age of six months, young bulls and steers had similar body weights (176.17 and 176.55 kg) and approximate average daily weight gains from birth (0.756 and 0.767 g/day). The healthy calves at six months of age weighed 180.47 kg, whereas the animals which at least once suffered from some diseases during rearing were lighter by approx. 30 kg (P ≤ 0.01). A statistically significant (P ≤ 0.01) difference was found for the count of red blood cells and white blood cells. In comparison with healthy individuals, the diseased animals had less RBC (8.33 and 9.42 10¹²/L respectively) and more WBC (27.03 and 12.26 10⁹/L respectively).Conclusion: Castration of young bulls did not have any impact on the results of rearing and health status of the calves. The magnitude of the analysed parameters depended on the health status of the calves. Thus RBC and WBC parameters may be used to predict the health status of calves during rearing.

Introduction: This article presents the analysis of the correlation between the category and health status of calves and the results of their rearing and levels of selected blood parameters.

Introduction: The main goal of the study was to investigate the effect of KATP channel modulators on development of oxidative stress in the heart of rats showing different resistance to hypoxia.Material and Methods: The study has been performed on rats showing high- (HR) or low-resistance (LR) to hypoxia under modulators of ATP-sensitive potassium (KATP) channel opener pinacidil (0.06 mg/kg) and blocker glibenclamide (1 mg/kg) upon cobalt (Co) treatment (30 mg of cobalt chloride/kg b.w., 3 h). Changes in the oxidative stress parameters of the heart tissue, such as lipid peroxidation (LPO), level of oxidatively modified protein (OMP), and antioxidant defence system (superoxide dismutase - SOD, catalase -CAT, glutathione peroxidase - GPx, glutathione reductase - GR) as well as total antioxidant activity (TAA) were analysed.Results: Co treatment caused a significant decrease in SOD and CAT activity in the heart of LR rats and GPx activity in HR rats. It also led to a decrease in OMP level in the heart of rats with HR in comparison with controls.Conclusion: The obtained results suggest that individual resistance to hypoxia plays a crucial role in Co actions and provides evidence that the effects of KATP channel opener pinacidil in the heart are mediated through different pathways of the antioxidative system, depending on the individual resistance to hypoxia. Pinacidil exerts a protective effect on the heart tissue by preventing the LPO decrease and significantly reducing OMP levels, as well as increasing TTA in rats with LR.

Introduction: The main goal of the study was to investigate the effect of KATP channel modulators on development of oxidative stress in the heart of rats showing different resistance to hypoxia.

Introduction: The study examined the concentration of total mercury and correlation coefficients between fish size or FCF (condition factor) and the content of Hg in muscle tissue of six freshwater fish: bream (Abramis brama L.), roach (Rutilus rutilus L.), whitefish (Coregonus lavaretus L.), vendace (Coregonus albula L.), perch (Perca fluviatilis L.), and pike (Esox lucius L.). Material and Methods: The fish were caught from the Lake Pluszne located in the Olsztyn Lake District (Poland). Mercury was analysed by atomic absorption spectrometry using Milestone DMA-80 (with dual-cell). Results: The content of the element in the muscles of the examined fish was as follows: pike (0.197 mg/kg) ≈ perch (0.173 mg/kg) > vendace (0.114 mg/kg) ≈ roach (0.095 mg/kg) and roach ≈ whitefish (0.065 mg/kg), and whitefish ≈ bream (0.042 mg/kg) (p ≤ 0.05). In all cases, the content of mercury correlated positively with the body weight and total length of the fish. Only the correlation coefficients between mercury concentration and weight or length of bream were slightly higher (0.979 and 0.977 respectively, p ≤ 0.001). The length and weight relationship of the fish was also determined. Conclusion: The results showed that the levels of mercury were lower than the maximum acceptable limit established by the Commission Regulation (EC) No 629/2008 of 2 July 2008. Thus, they are safe from consumer health point of view.

Introduction: The study examined the concentration of total mercury and correlation coefficients between fish size or FCF (condition factor) and the content of Hg in muscle tissue of six freshwater fish: bream (Abramis brama L.), roach (Rutilus rutilus L.), whitefish (Coregonus lavaretus L.), vendace (Coregonus albula L.), perch (Perca fluviatilis L.), and pike (Esox lucius L.). Material and Methods: The fish were caught from the Lake Pluszne located in the Olsztyn Lake District (Poland). Mercury was analysed by atomic absorption spectrometry using Milestone DMA-80 (with dual-cell). Results: The content of the element in the muscles of the examined fish was as follows: pike (0.197 mg/kg) ≈ perch (0.173 mg/kg) > vendace (0.114 mg/kg) ≈ roach (0.095 mg/kg) and roach ≈ whitefish (0.065 mg/kg), and whitefish ≈ bream (0.042 mg/kg) (p ≤ 0.05). In all cases, the content of mercury correlated positively with the body weight and total length of the fish. Only the correlation coefficients between mercury concentration and weight or length of bream were slightly higher (0.979 and 0.977 respectively, p ≤ 0.001). The length and weight relationship of the fish was also determined. Conclusion: The results showed that the levels of mercury were lower than the maximum acceptable limit established by the Commission Regulation (EC) No 629/2008 of 2 July 2008. Thus, they are safe from consumer health point of view.

Introduction: The aim of this study was to carry out a genetic analysis of Babesia canis isolates detected in dogs in eastern Poland and to study the correlation of the protozoa variant with a specific geographical region. Material and Methods: PCR was used to identify strains of B. canis from naturally infected animals (240 dogs from four provinces: Mazowieckie, Lublin, Podlasie, and Podkarpacie) by amplifying and sequencing a fragment of the 18S rRNA gene. Results: Sequencing the PCR products led to the identification of four variants of B. canis. Two previously described protozoa variants (18S rRNA-A and 18S rRNA-B) were observed in all provinces. Additionally, in the Mazowieckie and Lublin provinces a B. canis variant which contributed to the development of acute or atypical babesiosis was observed. The fourth variant of B. canis was detected only in dogs from the Lublin province, and the course of the disease was subclinical in all dogs infected with this variant. Conclusion: These results indicate the appearance of a new fourth B. canis genotype in Poland and confirm that it is still necessary to study the relationships between the genetic structure of protozoa, geographical distribution of the parasites, and clinical course of the disease.

Introduction: The aim of this study was to carry out a genetic analysis of Babesia canis isolates detected in dogs in eastern Poland and to study the correlation of the protozoa variant with a specific geographical region. Material and Methods: PCR was used to identify strains of B. canis from naturally infected animals (240 dogs from four provinces: Mazowieckie, Lublin, Podlasie, and Podkarpacie) by amplifying and sequencing a fragment of the 18S rRNA gene. Results: Sequencing the PCR products led to the identification of four variants of B. canis. Two previously described protozoa variants (18S rRNA-A and 18S rRNA-B) were observed in all provinces. Additionally, in the Mazowieckie and Lublin provinces a B. canis variant which contributed to the development of acute or atypical babesiosis was observed. The fourth variant of B. canis was detected only in dogs from the Lublin province, and the course of the disease was subclinical in all dogs infected with this variant. Conclusion: These results indicate the appearance of a new fourth B. canis genotype in Poland and confirm that it is still necessary to study the relationships between the genetic structure of protozoa, geographical distribution of the parasites, and clinical course of the disease.

Introduction: Growing consumption of shellfish is associated with an increased risk of food poisoning. The study was carried out on live bivalve molluscs available on the Polish market between 2009 and 2013. Material and Methods: ELISA was used for the determination of the following marine biotoxins: paralytic shellfish poison (PSP), amnaesic shellfish poison (ASP), and diarrhoeic shellfish poison (DSP). The molluscs, of which seven species were examined, were obtained from wholesale companies and markets. Results: Marine biotoxins were detected below the permitted levels in 67.6% of the samples. The maximum amounts of PSP and ASP biotoxins were found in great scallops (532.6 μg/kg and 1.0 mg/kg respectively) and the peak for DSP was in blue mussels (107 μg/kg). Conclusion: The analysis of toxicological status of raw bivalve molluscs available on the market in Poland indicates that they are safe for consumers.

Introduction: Growing consumption of shellfish is associated with an increased risk of food poisoning. The study was carried out on live bivalve molluscs available on the Polish market between 2009 and 2013. Material and Methods: ELISA was used for the determination of the following marine biotoxins: paralytic shellfish poison (PSP), amnaesic shellfish poison (ASP), and diarrhoeic shellfish poison (DSP). The molluscs, of which seven species were examined, were obtained from wholesale companies and markets. Results: Marine biotoxins were detected below the permitted levels in 67.6% of the samples. The maximum amounts of PSP and ASP biotoxins were found in great scallops (532.6 μg/kg and 1.0 mg/kg respectively) and the peak for DSP was in blue mussels (107 μg/kg). Conclusion: The analysis of toxicological status of raw bivalve molluscs available on the market in Poland indicates that they are safe for consumers.

Introduction: Although HEV infection in pigs does not pose a major economic risk to pork production, the risk of zoonotic transmission to humans is an important aspect of public health. HEV genotype 3 infections were reported in developed countries in individuals who had consumed raw meat or meat products from deer, wild boars, or pigs. The aim of the study was the analysis of the occurrence of HEV-specific antibodies among wild boars and domestic pigs in Poland. Material and Methods: A total of 290 samples from wild boars and 143 samples from pigs were tested. The antibodies were tested by ELISA. Results: The presence of anti-HEV IgG was demonstrated in 44.1% of pigs and 31.0% of wild boars. Anti-HEV IgG antibodies were detected in 1.4% of samples from pigs and in 2.1% of samples from wild boars at borderline level. The statistical analysis shows significant differences in the positive results for anti-HEV IgG between the groups of pigs and wild boars (P = 0.0263). Conclusion: Regular surveillance of the occurrence of HEV in swine and wild boars should be performed in the future.

Introduction: Although HEV infection in pigs does not pose a major economic risk to pork production, the risk of zoonotic transmission to humans is an important aspect of public health. HEV genotype 3 infections were reported in developed countries in individuals who had consumed raw meat or meat products from deer, wild boars, or pigs. The aim of the study was the analysis of the occurrence of HEV-specific antibodies among wild boars and domestic pigs in Poland. Material and Methods: A total of 290 samples from wild boars and 143 samples from pigs were tested. The antibodies were tested by ELISA. Results: The presence of anti-HEV IgG was demonstrated in 44.1% of pigs and 31.0% of wild boars. Anti-HEV IgG antibodies were detected in 1.4% of samples from pigs and in 2.1% of samples from wild boars at borderline level. The statistical analysis shows significant differences in the positive results for anti-HEV IgG between the groups of pigs and wild boars (P = 0.0263). Conclusion: Regular surveillance of the occurrence of HEV in swine and wild boars should be performed in the future.

Introduction: Chlamydia psittaci is a gram-negative obligate intracellular pathogen of birds. Poultry infections lead to economic losses and can be transmitted to humans. No vaccine is available and the bacterium-host cell interaction is not completely understood. Replicating bacteria cause pneumonia, but C. psittaci can also be non-replicating and persistent inside the cytoplasm of avian cells. RT-qPCR provides insight into the molecular pathogenesis of both active replicating and persistent Chlamydia psittaci in birds, but requires identification of stably expressed reference genes to avoid biases. Material and Methods: We investigated the expression stability of 10 C. psittaci candidate reference genes for gene expression analysis during normal growth and penicillin-induced persistence. C. psittaci Cal10 was cultured in HeLa229 and RNA was extracted. The expression level of each candidate was examined by RT-qPCR and Cq values were analysed using geNorm. Results: The genes tyrS, gidA, radA, and 16S rRNA ranked among the most stably expressed. The final selected reference genes differed according to the bacterial growth status (normal growth versus persistent status), and the time points selected during the duration of the normal chlamydial developmental cycle. Conclusion: The study data show the importance of systematic validation of reference genes to confirm their stability within the strains and under the conditions selected.

Introduction: Chlamydia psittaci is a gram-negative obligate intracellular pathogen of birds. Poultry infections lead to economic losses and can be transmitted to humans. No vaccine is available and the bacterium-host cell interaction is not completely understood. Replicating bacteria cause pneumonia, but C. psittaci can also be non-replicating and persistent inside the cytoplasm of avian cells. RT-qPCR provides insight into the molecular pathogenesis of both active replicating and persistent Chlamydia psittaci in birds, but requires identification of stably expressed reference genes to avoid biases. Material and Methods: We investigated the expression stability of 10 C. psittaci candidate reference genes for gene expression analysis during normal growth and penicillin-induced persistence. C. psittaci Cal10 was cultured in HeLa229 and RNA was extracted. The expression level of each candidate was examined by RT-qPCR and Cq values were analysed using geNorm. Results: The genes tyrS, gidA, radA, and 16S rRNA ranked among the most stably expressed. The final selected reference genes differed according to the bacterial growth status (normal growth versus persistent status), and the time points selected during the duration of the normal chlamydial developmental cycle. Conclusion: The study data show the importance of systematic validation of reference genes to confirm their stability within the strains and under the conditions selected.

Introduction: The aim of the study was to optimise and compare two multiplex PCR assays for the detection of Listeria spp. and Listeria monocytogenes in biological samples including the liver, brain, and blood. Material and Methods: Three strains of L. monocytogenes and single strains of each of the species: L. ivanovii, L. innocua, L. grayi, L. welshimeri, and L. seeligeri were used. Additionally, five other species of bacterium were used to evaluate the specificity of the tests. Results: Specific amplification products were obtained for both multiplex PCR assays, which confirmed the tested strains as Listeria spp. and L. monocytogenes, respectively. Isolates of other species did not yield PCR products. Conclusion: Both multiplex PCR assays proved to be significantly sensitive and highly-specific methods for the detection of Listeria strains.

Introduction: The aim of the study was to optimise and compare two multiplex PCR assays for the detection of Listeria spp. and Listeria monocytogenes in biological samples including the liver, brain, and blood. Material and Methods: Three strains of L. monocytogenes and single strains of each of the species: L. ivanovii, L. innocua, L. grayi, L. welshimeri, and L. seeligeri were used. Additionally, five other species of bacterium were used to evaluate the specificity of the tests. Results: Specific amplification products were obtained for both multiplex PCR assays, which confirmed the tested strains as Listeria spp. and L. monocytogenes, respectively. Isolates of other species did not yield PCR products. Conclusion: Both multiplex PCR assays proved to be significantly sensitive and highly-specific methods for the detection of Listeria strains.

Introduction: The study objective was to develop and evaluate a new TaqMan multiplex real-time PCR method for Salmonella, L. monocytogenes, and verotoxigenic Escherichia coli (VTEC) detection in slaughtered animal carcasses.Material and Methods: The procedure included an enrichment step, DNA extraction, and two multiplex real-time PCRs. The first PCR detected the invA and hly genes of Salmonella and L. monocytogenes respectively, the second the vtx1, vtx2, and eae genes of VTEC.Results: The validation of this method resulted in 100% relative sensitivity, specificity, and accuracy as compared to the reference ISO methods. The limit of detection per swab sample was established at 1 cfu for Salmonella and L. monocytogenes and 2 cfu for VTEC. The authors analysed 265 slaughterhouse-collected swabs from cattle, pig, and poultry carcasses. Among 125 from cattle, 51 were positive for VTEC, 29 for Salmonella, and 1 for L. monocytogenes. Among swabs from pig carcasses (n = 95), three, two, and one sample were positive for these pathogens respectively. None of the microorganisms tested for was identified in 45 samples of poultry origin.Conclusion: The obtained results showed that the method developed can rapidly identify the main bacterial pathogens that may contaminate carcasses of food-producing animals.

Introduction: The study objective was to develop and evaluate a new TaqMan multiplex real-time PCR method for Salmonella, L. monocytogenes, and verotoxigenic Escherichia coli (VTEC) detection in slaughtered animal carcasses.

Introduction: In the present study, some of the commercial fish farms located in the Black Sea region of Turkey, were screened for bacteria between 2012 and 2014.Material and Methods: The bacterial agents isolated from fish were identified by classical biochemical tests and the rapid diagnostic tests (API 20 E and API 20 Strep). All strains were further identified by sequencing of the 16S rRNA genes. The strains were also investigated for resistance to different antimicrobials by the disc diffusion method. Antibiotic resistance genes, including tetracycline (B), β-lactam (ampC, blaTEM, blaPSE), florfenicol (floR), erythromycine (ereA, ereB), sulphonamide (sulI, sulII), and trimethoprim (dhfr1) genes, were determined by the PCR method.Results:Vibrio anguillarum, Vibrio fluvialis, Photobacterium damselae subsp. piscicida, Pseudomonas luteola, Lactococcus garvieae, Streptococcus iniae, Aeromonas hydrophila, and Yersinia ruckeri were isolated from marine and freshwater cultured fish. According to the results of disc diffusion, all isolates were sensitive to florfenicol, trimethoprim+sulfamethoxazole, oxitetracycline, and enrofloxacin, and resistant to lincomycin, penicillin G, and amoxicillin. Also, sulI, sulII, and floR resistance genes were detected in the bacteria.Conclusion: The results of the study open up the opportunity to perform further investigations which could determine the possible role of ARGs in fish pathogens.

Introduction: In the present study, some of the commercial fish farms located in the Black Sea region of Turkey, were screened for bacteria between 2012 and 2014.