Agnes M. Dadak

Single and combined effects of deoxynivalenol mycotoxin and a microbial feed additive on lymphocyte DNA damage and oxidative stress in broiler chickens.

The immune and intestinal epithelial cells are particularly sensitive to the toxic effects of deoxynivalenol (DON). The aim of this experiment was to study the effects of DON and/or a microbial feed additive on the DNA damage of blood lymphocytes and on the level of thiobarbituric acid reactive substance (TBARS) as an indicator of lipid peroxidation and oxidative stress in broilers. A total of forty 1-d-old broiler chicks were randomly assigned to 1 of 4 dietary treatments (10 birds per group) for 5 wk. The dietary treatments were 1) basal diet; 2) basal diet contaminated with 10 mg DON/kg feed; 3) basal diet contaminated with 10 mg DON/kg feed and supplemented with 2.5 kg/ton of feed of Mycofix Select; 4) basal diet supplemented with Mycofix Select (2.5 kg/ton of feed). At the end of the feeding trial, blood were collected for measuring the level of lymphocyte DNA damage of blood and the TBARS level was measured in plasma, heart, kidney, duodenum and jejunum. The dietary exposure of DON caused a significant increase (P = 0.001) of DNA damage in blood lymphocytes (31.99±0.89%) as indicated in the tail of comet assay. Interestingly addition of Mycofix Select to DON contaminated diet decreased (P = 0.001) the DNA damage (19.82±1.75%) induced by DON. In order to clarify the involvement of lipid peroxidation in the DNA damage of DON, TBARS levels was measured. A significant increase (P = 0.001) in the level of TBARS (23±2 nmol/mg) was observed in the jejunal tissue suggesting that the lipid peroxidation might be involved in the DNA damage. The results indicate that DON is cytotoxic and genotoxic to the chicken intestinal and immune cells and the feed additive have potential ability to prevent DNA damage induced by DON.

Genotoxic effects of deoxynivalenol in broiler chickens fed low-protein feeds

Deoxynivalenol (DON) is one of the most abundant and important trichothecenes in food and feed, and it is a significant contaminant due to its frequent occurrence at toxicologically relevant concentrations worldwide. Deoxynivalenol has negative influences on the health and performance of chicks. However, there is little information available regarding the effect of DON on DNA fragmentation in blood lymphocytes. In addition, the effects of Mycofix select (Biomin GmbH, Herzogenburg, Austria) supplementation to DON-contaminated broiler diets on lymphocyte DNA have not yet been demonstrated. Therefore, the aim of the present study was to establish the effect of DON on lipid peroxidation and lymphocyte DNA fragmentation in broilers and to evaluate the potential of Mycofix select in the prevention of toxin-mediated changes. Thirty-two 1-d-old (Ross 308 male) broiler chicks were randomly divided into 4 groups. The control group was fed a noncontaminated diet, and a second group was fed the same diet but supplemented with Mycofix select (0.25%). A third group of broilers was fed a diet artificially contaminated with 10 mg of feed-grade DON/kg of diet, and a fourth group was fed a DON-contaminated diet supplemented with Mycofix select. At the end of the feeding trial, blood was collected and the degree of lymphocyte DNA damage was measured in the plasma by comet assay. Deoxynivalenol increased (P = 0.016) the amount of DNA damage in chicken lymphocytes by 46.8%. Mycofix select protected lymphocyte DNA from the DON effects. To our knowledge, these are the first data on genotoxic effects of a moderate dose of DON on chicken lymphocytes. However, the thiobarbituric acid reactive substances level in liver and liver enzyme activity did not differ among the groups. In conclusion, the present study demonstrated that the diets contaminated with the mycotoxin DON at moderate levels in combination with low-protein feed are able to induce lymphocyte DNA damage in chickens. Supplementation with Mycofix select protected lymphocyte DNA and it was beneficial for maintaining the lymphocyte DNA integrity.

Laparoscopic-assisted implantation of a urinary catheter in male sheep

OBJECTIVE-To evaluate a laparoscopic technique for implantation of a urinary catheter in the right paramedian area in male sheep and to determine feasibility, benefits, and risks for this technique. DESIGN-Evaluation study. ANIMALS-6 Healthy male sheep (mean +/- SD body weight, 42.16 +/- 11.95 kg [92.75 +/- 26.29 lb]). PROCEDURES-Each sheep was anesthetized and positioned in dorsal recumbency. A 10-mm laparoscope was inserted in the right paramedian area between the xiphoid and preputial orifice. After creation of capnoperitoneum, grasping forceps were inserted in the left paramedian area at the level of the teats and used to immobilize the urinary bladder. A pigtail balloon catheter was implanted transcutaneously in the right paramedian area between the preputial orifice and teats and directed into the urinary bladder by use of laparoscopic guidance. The catheter was removed 10 days after implantation. Fourteen days after initial surgery, a second laparoscopy was performed to evaluate pathologic changes. RESULTS-Inadvertent insertion of the first trocar into the rumen of 1 sheep was the only intraoperative complication encountered. Laparoscopic-assisted implantation of the urinary catheter was successfully performed in all sheep. No postoperative complications were detected. CONCLUSIONS AND CLINICAL RELEVANCE-Laparoscopic-assisted implantation of a urinary catheter in the right paramedian area was successfully performed and may be a feasible method for use in sheep. This method can be considered as an alternative to tube cystotomy performed by laparotomy.

Llamas and alpacas in Europe: Endoparasites of the digestive tract and their pharmacotherapeutic control

There are distinctive specifications for veterinary medical care of South American camelids (SACs), namely, llamas, alpacas, vicunas and guanacos. Camelids are classified as food-producing animals, but as veterinary medicinal products are often only licensed for domestic food-producing species such as horses, goats, sheep and cattle, treatment of SACs generally requires off-label use of drugs. Endoparasitism is a major health concern in camelids and can result in severe clinical diseases and economic losses. There is still a lack of work on the pharmacokinetics, safety and efficacy for most antiparasitic drugs used in SACs. Even when choosing an appropriate route of administration, several aspects must be considered such as the fact that pour-on formulations are largely ineffective in camelids due to the unique features of llama and alpaca skin and hair that result in extremely low drug bioavailability. This review focuses on the main endoparasites of the digestive tract in llamas and alpacas in Europe and pharmacotherapeutic options based on current knowledge.

Establishing an efficacious dose rate of monepantel for treating gastrointestinal nematodes in llamas under field conditions

In Europe, the importance of domesticated South American Camelids (SAC), llamas ( Lama glama ) and alpacas ( Lama pacos ), has grown, especially in recent years, due to their rising popularity and the associated increase in their numbers. SACs are classified as ‘food producing animals’ within the European Union. Thus, special guidelines need to be followed in the case of pharmacological treatment. For llamas and alpacas, drugs are used in an extra-label manner, since appropriate veterinary medicinal products are only authorised for domestic food-producing species such as horses, goats, sheep or cattle, but not for camelids. Endoparasitism is a major health concern in SACs causing severe clinical diseases and economic losses. Especially, gastrointestinal nematode (GIN) infections are common in llamas and alpacas kept in Europe. This is not surprising given that camelids often share grazing with sheep, goats and cattle, or are kept on pastures previously used for ruminants. Cross-transmission between host species can take place (Bishop and Rickard 1987) and GIN common to sheep and cattle have been documented in camelids as well (Leguia 1991, Rickard 1994, Fowler 2010). There are several classes of anthelmintics frequently used in all ruminants, including benzimidazoles, macrocyclic lactones, imidazothiazoles and hydropyrimidines. For anthelmintic drugs, very few data are published on proper dose regimen in SACs. It is difficult to estimate whether anthelmintic drugs applied at dose rates and routes suggested for horses, sheep or cattle lead to drug levels able …

Immunomodulation during and after castration under inhalation anaesthetic without genotoxic effects on equine lymphocytes

Genotoxic DNA damage due to inhalation anaesthesia has been demonstrated in human lymphocytes. In order to evaluate anaesthesia-associated changes in cell-mediated immunity on the basis of a potential DNA damage as a health risk in horses, single cell gel electrophoresis and lymphocyte proliferation assay were performed on equine lymphocytes which were obtained before, during and after regular castration under inhalation anaesthetic. No significant lymphocytic DNA damage due to isoflurane anaesthesia was observed, whereas lymphocyte proliferative reactivity and lymphocyte counts decreased significantly (p≤0.05) during and after anaesthesia. The present study thus indicates that the combined anaesthesia does not result in significant DNA damage, which hence cannot be held responsible for the observed changes in the immune response of equine lymphocytes. However, the recognized compromises of immune function ought to be considered especially in immunologically challenged animals.

Efficacy and safety of oral praziquantel against Dicrocoelium dendriticum in llamas.

Dicrocoelium dendriticum can cause severe pathological changes of the liver and bile system in camelids, and therapeutic options for treatment are limited. To address this problem, the efficacy of two different dose rates of praziquantel was investigated in llamas suffering from natural D. dendriticum infections. 53 llamas were examined under field conditions on two occasions: before and two weeks after treatment. At the beginning of the study, the animals were weighed, randomly allocated to one of the treatment groups (n=21 each) or the control group (n=11) and dosed orally using a praziquantel-containing paste (250 mg/ml) at a dose of either 25 mg (group 1) or 50 mg (group 2) per kg of body weight. Criteria for efficacy were faecal egg count reduction (FECR) and extensity effect. Animals treated with 25 mg/kg of body weight showed a FECR of 85%. Therapy with 50 mg/kg led to a FECR of 91%. Almost twice the number of animals of group 1 (33%) still shed eggs two weeks after treatment compared with group 2. The results of this study indicate that 50 mg/kg oral praziquantel is required for efficacious dosing and that this dose rate is safe in llamas and thus is recommended for the treatment of camelids naturally infected with D. dendriticum.

Metabolic changes associated with anaesthesia and cherry poisoning in a pony

OBSERVATIONS A case of a pony with severe cyanide intoxication as a result of cherry ingestion is presented. General anaesthesia was performed for colic surgery. Severe metabolic lactate acidosis in combination with a high arterial oxygen partial pressure and clinically good peripheral perfusion parameters were the remarkable signs during anaesthesia. Severe hypothermia was obvious during recovery. Ten hours post-surgery the pony was euthanized as a result of neurological signs. The diagnosis of cyanide intoxication was made post-mortem. CONCLUSION Cherry ingestion can lead to lethal cyanide intoxication in horses indicated by severe nonhypoxic lactic acidosis during anaesthesia.

Use of endoscopy for examination of the sacral epidural space in standing cattle

OBJECTIVE To develop an epiduroscopic technique for use in standing cattle and describe the endoscopically visible anatomic structures of the epidural space in the sacrococcygeal area. ANIMALS 6 healthy nonlactating, nonpregnant cows (mean +/- SD age, 60 +/- 18.5 months; mean weight, 599.7 +/- 63.87 kg) and 3 bovine cadavers. PROCEDURES Cadavers were used to allow familiarization with the equipment and refinement of the technique. Following these experiences, procedures were performed in live animals. Each cow was restrained in a stock. After sedation with xylazine (0.03 mg/kg, IV), 2% lidocaine hydrochloride (0.25 mg/kg) was injected epidurally in the first intercoccygeal or the sacrococcygeal intervertebral space. By use of an introducer set (guidewire and dilation trocar and shaft), a flexible endoscope (length, 75 cm; diameter, 2.3 mm) was inserted through the dilation shaft into the epidural space. To obtain an optimal view, small amounts of air were insufflated into the epidural space through the working channel of the endoscope via a syringe with special filter. RESULTS Anatomic structures of the epidural space that were viewed by means of the endoscopic procedure included blood vessels, connective tissue, fat, nerves, and the spinal dura mater. No adverse events were detected during epiduroscopy, and it was tolerated well by all 6 cows. CONCLUSIONS AND CLINICAL RELEVANCE In ruminants, epidural structures can be viewed via endoscopy. Such epiduroscopic procedures may be useful in anatomic studies as well as for the diagnosis of disease or therapeutic interventions in ruminants.

Pharmacokinetics and clinical efficacy of lidocaine in cattle after intranasal administration during rhinotracheobronchoscopy.

*Institute of Pharmacology and Toxicology, Department of Basic Sciences, University of Veterinary Medicine, Vienna, Austria; Clinic for Ruminants, Department for Farm Animals and Herd Management, University of Veterinary Medicine, Vienna, Austria; Department of Clinical Pharmacy and Diagnostics, University of Vienna, Vienna, Austria; Institute of Medical Physics and Biostatistics, Department of Basic Sciences, University of Veterinary Medicine, Vienna, Austria; Clinic for Anaesthesiology and Perioperative Intensive Care, Department of Small Animals and Horses, University of Veterinary Medicine, Vienna, Austria