Accidental salinomycin intoxication in European fallow deer (Dama dama L.).

Salinomycin, belonging to ionophore antibiotics, has been used as a feed additive for poultry for its coccidiostatic effect. Poisoning by ionophore antibiotics has been reported in cattle and other sensitive animals due to the replacement of medicated feed and/or accidental overdoses. The aim of this paper is to report the toxicity of salinomycin for fallow deer and to describe the different levels of sensitivity of cervids to this substance. In the presented case study, a medicated feed containing ivermectin used for deworming red deer and fallow deer was accidentally contaminated with sodium salinomycinate in a concentration of 252.6 mg/kg. The contaminated feed was consumed by the animals over a period of four days. The mortality of fallow deer within 12 days was 58%. No mortality was recorded in the red deer. In the affected animals, clinical signs associated with acute and congestive heart failure were observed. The biochemical examination indicated prerenal azotaemia caused by circulatory insufficiency and ion imbalance. The histological examination revealed pronounced focal acute cardiomyopathy and massive subacute myopathy in the skeletal muscles.

Mercury distribution in the great cormorant (Phalacrocorax carbo) from the Krogulna ponds and Nysa Klodzka River (Poland).

Mercury belongs among the highly hazardous substances present in the environment and represents a great health risk for many animals including predatory and piscivorous birds. The aim of this study was to assess the total mercury content in the main detoxifying organs (liver and kidney) and in the muscles of adult great cormorants (Phalacrocorax carbo) caught at two localities (the Krogulna ponds and the Nysa Klodzka River) in southern Poland. The aim was to compare the locality with the iron ore mining history (the Krogulna ponds) with a site without such load (the Nysa Klodzka River). The total mercury content in the great cormorants decreases as follows: kidneys > liver > muscle in both monitored localities and significantly differs between the localities. The average mercury content varied from 0.58 ± 0.38 mg/kg (muscle) to 1.39 ± 1.42 mg/kg (kidney) in the cormorant from the Krogulna ponds and from 1.09 ± 0.40 mg/kg (muscle) to 3.12 ± 1.55 mg/kg (kidney) in the cormorant from the Nysa Klodzka River. The accumulation of mercury does not correlate with the mining history as it was higher at the Nysa Klodzka River, but it is probably influenced by the different fish stocks in these two localities (omnivorous fish in the Krogulna ponds versus predatory fish in the Nysa Klodzka River).

Tremorgenic mycotoxin poisoning in a dog: A case report.

An eleven-year-old Pit Bull Terrier was presented to the veterinary practice with an acute onset of whole-body seizures. The clinical signs developed in a garden where the dog was kept that morning. There was a suspicion of tremorgenic mycotoxin poisoning by compost as the dog had vomited parts of compost right before the onset of the seizures and there was a pile of compost located in the garden. The dog underwent immediate decontamination following supportive treatment and recovered fully within 24 h of intensive care. The samples of the vomit and parts of the compost were cultivated. In the sample of the vomit, Penicillium sp. was found. Subsequently, tremorgenic mycotoxins paxilline, penitrem A and roquefortine C were determined chromatographically at significant concentrations in the vomit and a growth medium with cultivated Penicillium sp. The aim of this work is to describe the complex therapeutic and diagnostic approach to the patient with a suspected tremorgenic mycotoxin poisoning where a combination of mycological and chromatographic analyses was used to confirm the diagnosis. To the best of our knowledge, this is the first confirmed case of canine tremorgenic mycotoxicosis in the Czech Republic and the first reported case of paxilline poisoning in a dog.

Long-term exposure to polycyclic musk tonalide - A potential threat to juvenile zebrafish (Danio rerio)?

Polycyclic musk compounds are commonly used in personal care products to replace expensive natural fragrances. Due to their huge consumption, they have become a part of the aquatic environment. In the present study, a two-month exposure effect of tonalide on juvenile zebrafish (Danio rerio) was investigated. We determined the vitellogenin concentration to define the potential endocrine-disrupting effect of tonalide and also analysed selected indices to evaluate the induction of oxidative stress. The environmentally relevant concentration of tonalide (i.e., 500 ng/l) caused a significant decrease in the catalase activity (P < 0.05) and a significant increase (P < 0.05) in the lipid peroxidation. An increasing lipid peroxidation was also recorded for the highest concentration group tested (i.e., 50 000 ng/l). On the other hand, no significant changes were recorded in vitellogenin in all the exposed groups. Thus, based on these results, we have not demonstrated the endocrine-disrupting activity of tonalide in zebrafish. The results of the oxidative stress indices showed a significant impairment of the antioxidant defence after the two-month tonalide exposure, which could indicate part of the adaptive response to the tonalide toxicity.

Bee year: Basic physiological strategies to cope with seasonality.

Worker honey bees are subject to biochemical and physiological changes throughout the year. This study aimed to provide the reasons behind these fluctuations. The markers analysed included lipid, carbohydrate, and protein levels in the haemolymph; the activity of digestive enzymes in the midgut; the levels of adipokinetic hormone (AKH) in the bee central nervous system; the levels of vitellogenins in the bee venom and haemolymph; and the levels of melittin in the venom. The levels of all the main nutrients in the haemolymph peaked mostly within the period of maximal bee activity, whereas the activity of digestive enzymes mostly showed a two-peak course. Furthermore, the levels of AKHs fluctuated throughout the year, with modest but significant variations. These data suggest that the role of AKHs in bee energy metabolism is somewhat limited, and that bees rely more on available food and less on body deposits. Interestingly, the non-metabolic characteristics also fluctuated over the year. The vitellogenin peak reached its maximum in the haemolymph in winter, which is probably associated with the immunoprotection of long-lived winter bees. The analysis of bee venom showed the maximal levels of vitellogenin in autumn; however, it is not entirely clear why this is the case. Finally, melittin levels showed strong fluctuations, suggesting that seasonal control was unlikely.

Nitrogen factors for rainbow trout (Oncorhynchus mykiss) and brook trout (Salvelinus fontinalis) fillets.

Measures for consumer protection against food adulteration and misleading labelling are integrated into EU legislation, including methods for detecting misleading practices. Verification of the meat content is available for marine products, but not for salmonid fish due to the lack of standard nitrogen factors. This study aimed to establish nitrogen factors for rainbow trout (Oncorhynchus mykiss) and brook trout (Salvelinus fontinalis). The study analysed 340 fish from Czech fisheries obtained in the summer of 2018-2020. According to the established ISO methods, fillet samples with and without skin were analysed for their nitrogen content (protein), dry matter, ash, and fat. The recommended nitrogen factor for rainbow trout fillets with and without the skin is 3.07 ± 0.12 and 3.06 ± 0.14, respectively, and the nitrogen factor for fat-free rainbow trout fillets with and without the skin is 3.33 ± 0.15 and 3.29 ± 0.15, respectively. The recommended nitrogen factor for brook trout fillets with and without the skin is 3.16 ± 0.10 and 3.12 ± 0.09, respectively, and the nitrogen factor for fat-free brook trout fillets with and without the skin is 3.42 ± 0.13 and 3.36 ± 0.12, respectively. The established nitrogen factors will enable the analysis of the meat content to ensure that consumers purchase correctly described and labelled fish products.

The effect of sulfamethoxazole on oxidative stress indices in zebrafish (Danio rerio).

The aim of this study was to assess the impact of sulfamethoxazole (SMX) on oxidative stress indices in zebrafish (Danio rerio). The test was completed after 14 days. The tested concentrations were 50, 100 and 500 µg/L of SMX. Glutathione peroxidase, glutathione reductase, glutathione S-transferase and lipid peroxidation were investigated to determine the effects of SMX on oxidative stress in zebrafish. Lipid peroxidation gradually increased slightly (but non-significantly) at all tested concentrations during the test as compared to the control. The evaluation of oxidative stress biomarkers showed no significant changes in the activity of antioxidant enzymes in any experimental group exposed to SMX as compared to the control. The gradual increase in lipid peroxidation after 3 and 14 days in the SMX treated groups as compared to the control group indicates increasing cell membrane damage.

Spatial and Temporal Trends in Contamination of the Czech Part of the Elbe River by Mercury Between 1991 and 2016.

We summarized available data concerning contamination of the Czech part of the Elbe River by mercury and assessed the potential risks to humans connected with the consumption of contaminated fish. Total mercury concentrations were evaluated in dorsal muscle of chub (Squalius cephalus) and bream (Abramis brama) that were collected at 11 sampling sites in the period from 1991 to 2016. Significant differences among sites were found for both species. The highest contamination was observed near the non-ferrous Kovohute metal works at Celakovice and also downstream from the Spolana chemical plant at Neratovice. A significant decline in contamination with time (concentrations decreasing from 1.65 to 0.22 mg kg-1; p = 0.004) was revealed in chub downstream from the Spolana plant. Calculated hazard indices (HIs) were below 1, therefore, adverse health effects on the general Czech population connected with the consumption of fish from the Elbe River were not expected.

Sodium chloride treatment effects on rainbow trout suffering from proliferative kidney disease caused by Tetracapsuloides bryosalmonae.

The aim of the present study was to evaluate the effect of a long-term sodium chloride bath on rainbow trout Oncorhynchus mykiss naturally infected by Tetracapsuloides bryosalmonae. A total of 106 infected fish were divided into 2 groups. One group was left untreated and the other was treated with sodium chloride in increasing doses up a concentration of 0.8%. After 14 d, treatment was stopped and for a further 7 d the fish response to the sodium chloride bath was observed. Cumulative mortality was significantly lower in the treated group (19.2%) compared to the untreated group (31.5%) after 21 d. This corresponded to the lower but non-significant parasite intensity in kidney and spleen in the treated group after 14 d of treatment. However, lower prevalence of parasites in both tissues was recorded in the untreated group after 21 d of treatment, but a significant difference was observed only in spleen tissue. Furthermore, significant increases in leukocytes, hemoglobin, haematocrit, ferric reducing ability of plasma, and ceruloplasmin, and significant decreases in alanine aminotransferase, aspartate aminotransferase and lactate dehydrogenase activities were noticed in the treated group compared to the untreated group. In contrast, significant decreases in lysozyme concentration in the mucus and phagocyte oxidative burst in the blood were observed in the treated group. Histopathological examination revealed proliferative and reparative changes in parenchymatous tissues in the treated group. The 14- and 21-d salt bath used in rainbow trout with proliferative kidney disease was associated with a reduction in mortality and enhanced the reparative phase in the treated group.

The effect of silver nanoparticles and silver ions on zebrafish embryos (Danio rerio).

OBJECTIVES: The aim of this study was to establish and evaluate the mortality rate, hatching rate and observe the presence of sublethal changes in zebrafish embryos after exposure to silver ions and nanoparticles. METHODS: Tests were conducted on newly fertilized zebrafish embryos, according to the modified OECD guideline 236, using a semistatic method and 96 hour incubation time. Silver nitrate and two different silver nanoparticles, stabilized with 0.01% solution of maltose and gelatine in the first case, and stabilized with polyvinylpyrrolidone, in the latter, were tested. RESULTS: Significant differences in toxicity of tested substances were recorded. The value of 96hLC50 for silver nitrate was 58.44 µg/L. The value of 96hLC50, calculated for silver nanoparticles stabilized with 0.01% solution of maltose and gelatine, was nearly 100 times higher, 4.31 mg/L. The value 96hLC50 for silver nanoparticles stabilized with polyvinylpyrrolidone exceeded 100mg/L, occurrence of sublethal effects caused by silver nanoparticles stabilized with polyvinylpyrrolidone was insignificant in most of the exposition groups, but only in this substance caused decreased hatching rate. CONCLUSION: Properties of different silver nanoparticles play an important role in levels of their toxicity and predominant mechanisms of action. In general, silver nanoparticles are less toxic for Danio rerio embryos than silver ions.

Multibiomarker Responses of Juvenile Stages of Zebrafish (Danio rerio) to Subchronic Exposure to Polycyclic Musk Tonalide.

Synthetic polycyclic musks, widely used as additives in personal care products, are present in both biotic and abiotic matrices of the aquatic environment at concentrations of ng/l to µg/l. Although they are determined at comparatively low concentrations, these levels are biologically relevant and pose a significant growing risk as stressors to aquatic organisms. The purpose of our study was to evaluate the effects of 28-day-long exposure to polycyclic musk tonalide in zebrafish juvenile stages (Danio rerio) using selected biomarkers. Environmentally relevant concentrations of tonalide caused significant changes in selected enzyme activities in the experimental groups exposed to the highest concentrations. The activity of glutathione S-transferase and lipid peroxidation increased significantly (p < 0.05) after exposure to the highest concentration (50,000 ng/l) compared with the control. A similar trend was observed in catalase activity; there was a significant increase (p < 0.05) after exposure to two highest concentrations of tonalide (5000 and 50,000 ng/l). In addition, a statistically significant decrease (p < 0.05) in glutathione reductase activity was found in the lowest test concentration of tonalide (50 ng/l). None of the tested concentrations resulted in histopathological changes in liver, kidney, skin, or gill. Furthermore, no effects on body weight, body length, specific growth rate, and behavior were observed. Our results showed that tonalide exposure induced profound changes in the activities of antioxidant and detoxifying enzymes, such changes representing an adaptive response of the fish organism to tonalide toxicity.

Stacked Bt maize and arthropod predators: exposure to insecticidal Cry proteins and potential hazards.

Genetically engineered (GE) crops with stacked insecticidal traits expose arthropods to multiple Cry proteins from Bacillus thuringiensis (Bt). One concern is that the different Cry proteins may interact and lead to unexpected adverse effects on non-target species. Bi- and tri-trophic experiments with SmartStax maize, herbivorous spider mites (Tetranychus urticae), aphids (Rhopalosiphum padi), predatory spiders (Phylloneta impressa), ladybeetles (Harmonia axyridis) and lacewings (Chrysoperla carnea) were conducted. Cry1A.105, Cry1F, Cry3Bb1 and Cry34Ab1 moved in a similar pattern through the arthropod food chain. By contrast, Cry2Ab2 had highest concentrations in maize leaves, but lowest in pollen, and lowest acquisition rates by herbivores and predators. While spider mites contained Cry protein concentrations exceeding the values in leaves (except Cry2Ab2), aphids contained only traces of some Cry protein. Predators contained lower concentrations than their food. Among the different predators, ladybeetle larvae showed higher concentrations than lacewing larvae and juvenile spiders. Acute effects of SmartStax maize on predator survival, development and weight were not observed. The study thus provides evidence that the different Cry proteins do not interact in a way that poses a risk to the investigated non-target species under controlled laboratory conditions.

Effect of T-2 toxin-contaminated diet on common carp (Cyprinus carpio L.).

The T-2 toxin, a fungal metabolite produced by Fusarium molds, occurs in a range of agriculture products. Reduced availability of fish meal has led to increasing use of cereals as a source of protein in commercial aquaculture feeds, which has increased the potential for mycotoxin contamination. The purpose of this study was to investigate toxicity of T-2 toxin intake in common carp (Cyprinus carpio L.) using haematological, biochemical and immunological parameters and oxidative stress indices. In a four-week feeding trial, fish were fed a commercial diet with 5.3 mg/kg T-2 toxin added. Ingestion of contaminated diet did not lead to mortality of fish, probably due to lower feed intake. On the other hand, it significantly affected haematological variables such as haematocrit, haemoglobin, red blood cell counts leading to anemia and white blood cell counts leading to leukopenia due to lymphopenia. Plasma glucose concentration and alanine amino transferase activity showed a significant increase while triglycerides concentration decreased. Activity of ceruloplasmin was significantly decreased in plasma. Further, liver glutathione S-transferase activity was significantly increased and catalase activity decreased, in parallel with a significant increase in caudal kidney catalase activity and a decrease in glutathione peroxidase activity. Finally, lipid peroxidation (detected as malondialdehyde) was significantly increased in the liver and caudal kidney. Changes in non-specific immune response and cytokine levels in head kidney indicated immune system sensitivity to T-2 toxin. Overall, the results demonstrate that this feed-borne mycotoxin is able to induce anaemia and oxidative stress and cause changes in the immune response of common carp.

Accumulation of Mercury in The Tissues of the Great Cormorant (Phalacrocorax carbo) From Common Carp.

The aim of this work is to assess mercury content in the great cormorant in the Trebon region pond systems (Czech Republic) in terms of its potential to accumulate mercury from common carp. Selected tissues samples were taken from 51 cormorants and 30 common carp. In the food chain the cormorant was found to have the potential to accumulate mercury, where the muscle total mercury was roughly 35 times higher compared to the total mercury content in the carp muscle as its food. A statistically significantly higher overall mercury content (p < 0.01) has been found in the kidney and liver (2.23 ± 0.30, 2.12 ± 0.22 mg/kg) compared to other tissues examined in cormorants. The proportion of muscle methylmercury in the total mercury content of the cormorant was within the range 64.3%-87.3%. The results can help us to gain a better understanding of how mercury is distributed and accumulated in the aquatic food chain.

Challenges facing European agriculture and possible biotechnological solutions.

Agriculture faces many challenges to maximize yields while it is required to operate in an environmentally sustainable manner. In the present study, we analyze the major agricultural challenges identified by European farmers (primarily related to biotic stresses) in 13 countries, namely Belgium, Bulgaria, the Czech Republic, France, Germany, Hungary, Italy, Portugal, Romania, Spain, Sweden, UK and Turkey, for nine major crops (barley, beet, grapevine, maize, oilseed rape, olive, potato, sunflower and wheat). Most biotic stresses (BSs) are related to fungi or insects, but viral diseases, bacterial diseases and even parasitic plants have an important impact on yield and harvest quality. We examine how these challenges have been addressed by public and private research sectors, using either conventional breeding, marker-assisted selection, transgenesis, cisgenesis, RNAi technology or mutagenesis. Both national surveys and scientific literature analysis followed by text mining were employed to evaluate genetic engineering (GE) and non-GE approaches. This is the first report of text mining of the scientific literature on plant breeding and agricultural biotechnology research. For the nine major crops in Europe, 128 BS challenges were identified with 40% of these addressed neither in the scientific literature nor in recent European public research programs. We found evidence that the private sector was addressing only a few of these "neglected" challenges. Consequently, there are considerable gaps between farmer's needs and current breeding and biotechnology research. We also provide evidence that the current political situation in certain European countries is an impediment to GE research in order to address these agricultural challenges in the future. This study should also contribute to the decision-making process on future pertinent international consortia to fill the identified research gaps.

Effects of therapeutic formalin bath on selected indices in fish.

OBJECTIVES: The aim of this study is to assess the effects of a treatment bath in a formalin solution on fish, focusing on haematological, biochemical and histopathological profiles. METHODS: A total of 96 common carps (Cyprinus carpio) were randomly assigned to eight groups. Four experimental groups were placed in the test solution for 60 minutes. The concentration of the formalin bath was 0.17 ml/l (38% formaldehyde), with the water temperature of 20°C. The effects of the bath were monitored immediately (E0) and 24 hours (E24h), 48 hours (E48h) and 10 days (E10d) after the bath. There was a control group (C0, C24h, C48h, C10d) for each of the experimental groups. RESULTS: Histopathological indices were strongly affected. Extensive changes were found on gill and skin immediately and also after 24 h, 48 h and 10 d of the formalin treatment bath. A plurality of mucinous elements was observed on the skin. Moreover, structural devastation of lamellas and numerous mucinous cells were observed on the gill. Changes were also found in haematological and biochemical indices. CONCLUSIONS: It can be concluded that after applying the treatment bath in the formalin solution, the monitored profiles were affected immediately after the bath and also after 10 days (histopathological changes of skin and gill). Such significant impact of therapeutic formalin bath should be considered in treatment of fish.

The Effects of Salicylic Acid on Juvenile Zebrafish Danio rerio Under Flow-Through Conditions.

The aquatic environment is becoming increasingly contaminated with pharmaceuticals. Salicylic acid (SA), which can be used individually or appear as a degradation product of the widely used acetylsalicylic acid was chosen for testing. Juvenile zebrafish Danio rerio were subjected to OECD test No. 215 (fish, juvenile growth test) with salicylic acid concentrations of 0.004; 0.04; 0.4; 4 and 40 mg/L. Specific growth rate (SGR), histological changes, and parameters of oxidative stress were evaluated. SA had no effects on histological changes, SGR, glutathione reductase, and lipid peroxidation. Increased catalytic activity of GPx was found at 0.04 mg/L compared to control, increased catalytic activity of catalase was found at 0.04 and 4 mg/L compared to control, and increased catalytic activity of glutathione-S-transferase was found at 0.004 and 0.04 mg/L compared to control (P < 0.05). Juvenile zebrafish turned out to be relatively insensitive to both environmentally relevant (0.004 mg/L) and higher concentrations of salicylic acid.

Evaluation of mercury contamination in dogs using hair analysis.

OBJECTIVES: The present work is aimed at assessing the mercury contamination of dogs through the analysis of hair. For the determination of the total mercury in dogs, we chose skin derivatives--hair. The content of total mercury was also measured in the pelleted feed. METHODS: Dogs were divided into two groups. The first group (group A) was fed granular feed containing fish and the second group (group B) granular feed free of fish. A total of 131 hair and granular feed samples were collected. The total mercury in hair and granular feed samples was measured using atomic absorption spectrophotometry on AMA 254. RESULTS: The values of the total mercury content in the hair of dogs had a median value of 0.0375 mg.kg(-1) in group A and of 0.0336 mg.kg(-1) in group B. No statistically significant difference was found between the groups (p>0.05). The median values of the total mercury were 0.0048 mg.kg(-1) in group A and 0.0017 mg.kg(-1) in group B, respectively. A highly statistically significant difference between the groups was found (p<0.01). CONCLUSIONS: No correlation was obtained between the total mercury content in the hair of dogs and granulated feed (rs=0.2069, p>0.05). The reason may be a content of various mercury species in feed samples or a human failure (nonobservance of the prescribed diet).

Degradation rate of praziquantel and fenbendazole in rainbow trout following oral administration.

OBJECTIVES: The aim of this study was to evaluate and compare the rate of degradation and elimination of praziquantel and fenbendazole antiparasitics following oral administration to salmonids. In addition, we determine whether the length of the legal withdrawal period is sufficient for complete elimination of antiparasitic residue from the body. The use of these drugs in fish is currently considered off-label and data on degradation are not available for rainbow trout. METHODS: The model species for this experiment was the rainbow trout (Oncorhynchus mykiss) and praziquantel and fenbendazole were chosen for experimental therapy. Both drugs were administered into the gastrointestinal tract using a stomach tube. Concentrations of fenbendazole and praziquantel were established through high performance liquid chromatography-tandem mass spectrometry. RESULTS: Our results show that concentrations of praziquantel and fenbendazole reach their maximum in the body within 24 hours of administration, with concentrations dropping sharply over the following 24 hours. With one exception, when trace amounts of both substances were found in blood plasma, the drugs were completely degraded and eliminated from the body by the end of the experiment (corresponding to 497.6 degree days). CONCLUSIONS: Praziquantel and fenbendazole both show a high rate of degradation and elimination from fish. As both substances were eliminated from the body within the required withdrawal period (i.e. within 500 degree days) they can be safely used based on current knowledge of their therapeutic effect for treating helminth infections.

Oxidative stress indices and histopathological effects of the nonsteroidal antiinflammatory drug naproxen in adult zebrafish (Danio rerio).

OBJECTIVES: The aim of this study was to investigate the effects of the nonsteroidal antiinflammatory drug naproxen on adult zebrafish (Danio rerio). METHODS: Three months old zebrafish (Danio rerio) were exposed to naproxen at concentrations of 0.001, 0.1 and 5 mg.L(-1). We focused on the changes in oxidative stress indices during and at the end of the experiment and histopathological examination of tissues after a two week long exposure period. RESULTS: We found that a 3 day long exposure to naproxen causes mild oxidative stress and affects detoxification in zebrafish, which is demonstrated by the increased activity of glutathione peroxidase and glutathione S-transferase at 0.001 and 0.1 mg.L(-1) of naproxen, respectively. After a 7 day long exposure to 0.1 and 5 mg.L(-1), more potent effects on enzymes occur. However, these effects are only short lasting. At the end of the experiment, the activities of the target enzymes recover back to homeostatic baseline levels. Except catalase, which is induced only after a two week long exposure to the environmental concentration of naproxen. Despite the fact that naproxen causes mild oxidative stress in zebrafish, exposure to this drug does not result in lipid peroxidation. Histopathological examination revealed obvious changes to the gills and liver even at exposure to the environmental concentration of naproxen. CONCLUSION: This study demonstrates that the environmental concentration of naproxen can slightly influence both the antioxidant defense system and histopathology of non-target fish.