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Abstract

Objective—To establish a safe and effective endoscopic technique for collection of liver biopsy specimens from lizards by use of a 2.7-mm rigid endoscope system that is commonly available in zoologic veterinary practice.

Design—Prospective study.

Animals—11 subadult male green iguanas (Iguana iguana).

Procedures—Each lizard was anesthetized, and right-sided coelioscopic examination of the right liver lobe and gallbladder was performed. Three liver biopsy specimens were collected from each lizard by use of a 2.7-mm rigid endoscope and 1.7-mm (5-F) biopsy forceps. Biopsy samples were evaluated histologically for quality and crush artifact. Ten days following surgery, all iguanas were euthanatized and underwent full necropsy examination.

Results—For all 11 iguanas, the right liver lobe and gallbladder were successfully examined endoscopically, and 3 biopsy specimens of the liver were collected without complications. Mean ± SD durations of anesthesia and surgery were 24 ± 7 minutes and 6.8 ± 1.0 minutes, respectively. At necropsy, there was no evidence of trauma or disease associated with the skin or muscle entry sites, liver, or any visceral structures in any iguana. All 33 biopsy specimens were considered acceptable for histologic interpretation; in most samples, the extent of crush artifact was considered minimal.

Conclusions and Clinical Relevance—By use of a 2.7-mm rigid endoscope, liver biopsy procedures can be performed safely, swiftly, and easily in green iguanas. Biopsy specimens obtained by this technique are suitable for histologic examination. For evaluation of the liver and biopsy specimen collection in lizards, endoscopy is recommended.

Full access
in Journal of the American Veterinary Medical Association

Objective

To determine percentage of false-positive test results for assays used by regulatory agencies to detect antibiotic residues in tissues.

Design

Prospective study.

Animals

426 dairy cows.

Procedure

Dairy cows scheduled for culling that were identified as being unlikely to have antibiotic residues in tissues on the basis of strict inclusion criteria were used. A sample of kidney obtained from each cow at slaughter was tested on-site, using the swab test on premises (STOP; 97 samples) or the fast antibiotic screening test (FAST; 329 samples). Frozen samples (n = 1,278) of liver, muscle, and kidney were thawed and retested at a federal laboratory, using the same screening assays. Kidney and liver samples (n = 852) were also tested using the 7-plate bioassay confirmation test used for confirmation and identification of antibiotic residues.

Results

Results of screening assays performed onsite were negative. When frozen samples were retested, 20 (12 liver, 7 kidney, and 1 muscle) had positive FAST results, but none had positive STOP results. Of the samples tested with the 7-plate bioassay confirmation test, 4 liver samples had results indicating a tetracycline (n = 3) or an unidentified microbial inhibitor (1) as a residue.

Clinical Implications

Results suggest it is unlikely that regulatory action will be taken against producers sending untreated cattle to market. However, because results of the FAST and 7-plate bioassay confirmation test were positive when applied to frozen tissue, use of assays based on microbial inhibition may not be valid for confirmation of residues. (J Am Vet Med Assoc 1999;214:1048–1050)

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To characterize hematologic and clinical consequences of chronic dietary consumption of freeze-dried garlic at maximum voluntary intake in horses.

Animals—4 healthy sex- and age-matched horses.

Procedure—An initial garlic dose (0.05 g/kg, twice daily) was fed to 2 horses in a molasses carrier as part of their normal ration and was gradually increased to maximum voluntary intake (0.25 g/kg, twice daily) over 41 days. Dietary supplementation then continued for a total of 71 days. Two control horses were fed molasses with no garlic with their ration. Blood samples were collected weekly and analyzed for hematologic and biochemical changes, including the presence of Heinz bodies. Recovery of affected blood values was followed for 5 weeks after termination of dietary supplementation with garlic.

Results—At a daily dose of > 0.2 g/kg, horses fed garlic developed hematologic and biochemical indications of Heinz body anemia, as characterized by increases in Heinz body score (HBS), mean corpuscular volume (MCV), mean corpuscular hemoglobin, platelet count, and serum unconjugated and total bilirubin concentrations and decreases in RBC count, blood hemoglobin concentration, mean corpuscular hemoglobin concentration, and serum haptoglobin concentration. Recovery from anemia was largely complete within 5 weeks after termination of dietary supplementation with garlic. Heinz body score and MCV remained high at the end of the 5-week recovery period.

Conclusions and Clinical Relevance—Horses will voluntarily consume sufficient quantities of garlic to cause Heinz body anemia. The potential for garlic toxicosis exists when horses are chronically fed garlic. Further study is required to determine the safe dietary dose of garlic in horses. (Am J Vet Res 2005;66:457–465)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine pharmacokinetics of meloxicam in healthy green iguanas following PO and IV administration and assess potential toxicity.

Animals—21 healthy green iguanas (Iguana iguana).

Procedures—To assess pharmacokinetics, 13 iguanas were administered a single dose (0.2 mg/kg) of meloxicam PO and, 14 days later, the same dose IV. To assess potential toxicity, 4 iguanas were given meloxicam at a dosage of 1 or 5 mg/kg, PO, every 24 hours for 12 days, and results of histologic examination were compared with results for another 4 iguanas given a single dose of meloxicam (0.2 mg/kg).

Results—There were no significant differences between PO and IV administration with regard to terminal half-life (mean ± SD, 12.96 ± 8.05 hours and 9.93 ± 4.92 hours, respectively), mean area under the curve to the last measured concentration (5.08 ± 1.62 μg•h/mL and 5.83 ± 2.49 μg•h/mL), volume of distribution (745 ± 475 mL/kg and 487 ± 266 mL/kg), or clearance (40.17 ± 10.35 mL/kg/h and 37.17 ± 16.08 mL/kg/h). Maximum plasma concentration was significantly greater following IV (0.63 ± 0.17 μg/mL) versus PO (0.19 ± 0.07 μg/mL) administration. Time from administration to maximum plasma concentration and mean residence time were significantly longer following PO versus IV administration. Daily administration of high doses (1 or 5 mg/kg) for 12 days did not induce any histologic changes in gastric, hepatic, or renal tissues.

Conclusions and Clinical Relevance—Results suggested that administration of meloxicam at a dose of 0.2 mg/kg IV or PO in green iguanas would result in plasma concentrations > 0.1 μg/mL for approximately 24 hours. (Am J Vet Res 2010;71:1277–1283)

Full access
in American Journal of Veterinary Research