Effects of cadmium, mercury, and selenium on reproductive indices in male lesser scaup (Aythya affinis) in the western Boreal forest.

Combined lesser scaup (Aythya affinis) and greater scaup (A. marila) populations decreased from the 1980s to the 1990s and have not recovered. Factors limiting reproduction, including effects of contaminants and trace elements, have been highlighted as a concern in female scaup, but no studies have examined possible effects on male scaup. We examined the effects of cadmium, mercury, selenium, and corticosterone on pair status and on male reproductive indices, including testosterone, testes mass, and seminiferous tubule diameter, in male lesser scaup collected in the western boreal forest near Yellowknife, Northwest Territories, May and June, during 2004 and 2005. Male scaup that were larger in size (p = 0.048) and with better body condition (p = 0.038) were more likely to be paired. No relations were observed between independent variables and testosterone and testes mass. However, results suggested that seminiferous tubule diameter is influenced by a complex array of biologic and toxicologic parameters, which differ depending on pair status. Tubule diameters of paired male scaup were negatively influenced by hormones, whereas contaminants influenced diameter in unpaired male scaup. The effects of selenium were attenuated when bound with cadmium but not mercury. When selenium concentrations were high (greater than median value), there was a positive effect of cadmium on tubule diameter (R(2) = 0.30, n = 10, p = 0.007) but a negative relation with mercury (R(2) = 0.15, n = 10, p = 0.09). Seminiferous tubule diameter may be a sensitive indicator of sublethal effects of contaminants. This study showed contaminant and trace element effects at concentrations lower than threshold levels associated with major toxic effects. This study also demonstrated the complex nature of biologic systems and the importance of considering interactions to accurately characterize effects of metals.

Cardiopulmonary effects of propofol and a medetomidine-midazolam-ketamine combination in mallard ducks.

OBJECTIVE: To compare safety of propofol with a medetomidine-midazolam-ketamine (MMK) combination as an anesthetic agent in mallard ducks. ANIMALS: 12 healthy adult female mallard ducks. PROCEDURE: Each duck was anesthetized twice in a crossover study design with 5 days between randomized treatments. Ducks were given medetomidine (50 micrograms), midazolam (2 mg), and ketamine (10 mg) in combination, i.v., or propofol (10 mg, i.v., followed by 1- to 4-mg boluses). Systolic, diastolic, and mean arterial pressures, heart and respiratory rates, and esophageal temperature were recorded before anesthesia and every 5 minutes after induction for 30 minutes, and at 5 minutes after reversal with atipamezole (250 micrograms) and flumazenil (25 micrograms; MMK group) or last bolus (propofol group). Arterial blood samples from 8 ducks were collected before anesthesia, 5, 10, 15, 30 minutes after induction, and after reversal or last bolus. RESULTS: 8 ducks survived the MMK anesthesia; 1 duck died and 3 ducks required resuscitation to prevent death. All ducks survived propofol anesthesia. Ducks anesthetized with either anesthetic agent had a significant increase in arterial carbon dioxide tension and decrease in arterial oxygen tension, arterial pH, and esophageal temperature. Ducks given MMK had a decrease in mean arterial pressure and respiratory rate, whereas ducks given propofol had an increase in respiratory rate. Rapid reversal of the effects of MMK was achieved with atipamezole and flumazenil. All physiologic variables, except esophageal temperature in the propofol group, returned to approximate baseline values after reversal or last bolus. CONCLUSIONS: The MMK combination in unsafe for use in ducks. Ducks can be anesthetized safely with propofol but should be monitored and ventilated artificially.

Evaluation of isoflurane and propofol anesthesia for intraabdominal transmitter placement in nesting female canvasback ducks.

Heart rate, occurrence of apnea, body temperature, quality of anesthesia and nest abandonment were compared during either propofol or isoflurane anesthesia of nesting female canvasback ducks (Aythya valisineria) at 15 to 18 days of incubation. One hundred eighteen canvasbacks were assigned randomly to three treatments so that nest abandonment could be compared among treatments from May to July 1995 and 1996. Sterile dummy silicone implants were placed during an abdominal laparotomy while ducks were anesthetized with either propofol or isoflurane, or ducks were flushed from the nest but not captured (control). Propofol was delivered through an intravenous catheter, while isoflurane was delivered in oxygen. Propofol provided smooth, rapid induction and recovery, whereas ducks recovering from isoflurane tended to struggle. At the nest, ducks in the propofol group were given additional boluses until they were lightly anesthetized, whereas birds that received isoflurane were released. All birds survived surgery but one death occurred prior to surgery in 1995 using propofol during a period without ventilation and monitoring. Adequate artificial ventilation is recommended to prevent complications. Heart rate declined significantly in both years during isoflurane anesthesia and in 1995 during propofol anesthesia but not 1996. During both isoflurane and propofol anesthesia, body temperature declined significantly over time. Nest abandonment was significantly different among treatments and occurred in all treatment groups in both years, but propofol (15%) and control groups (8%) had lower than expected abandonment compared to isoflurane (28%). Propofol offers several advantages over isoflurane for field use; equipment is easily portable, lower anesthetic cost, and ambient temperature does not alter physical characteristics of the drug. Advantages over isoflurane, including lower nest abandonment following intraabdominal radio transmitter placement, make propofol a good anesthetic choice for field studies.

Fish, amphibian, and reptile analgesia.

Pain perception and appropriate behavioral responses are important for survival. The conservation of the opioid ligand and receptor suggests evolution of opioid receptors mediating antinociception throughout vertebrate phylogeny. Fish, amphibians, and reptiles have appropriate neurologic components, display the appropriate behavior in response to a painful stimulus, and possess antinociceptive mechanisms to modulate pain. Because pain perception in these species is therefore likely to be analogous to that of mammals, invasive and painful procedures should always be accompanied by appropriate analgesia and anesthesia. Although specific doses have not been established in clinical trials, clinicians should attempt to provide lower vertebrates with appropriate analgesia during painful procedures. Further experimental and clinical investigations are necessary to expand the current veterinary literature in the area of pain and analgesia in lower vertebrates such as fish, amphibians, and reptiles.

Amphibian pain and analgesia.

Analgesics are often not provided to amphibians because the presence and severity of pain may not be recognized in these animals. In addition, there is little information on the mechanism of action of analgesic agents in amphibians. However, amphibians possess appropriate neurologic components for transmitting pain from peripheral receptors to the central nervous system and antinociceptive mechanisms to modulate pain. They are capable of displaying behavioral and physiologic modification of pain systems in response to analgesic pharmacologic agents. Therefore, pain perception in amphibians is likely analogous to that in mammals and invasive, potentially painful procedures should be accompanied by appropriate analgesia and anesthesia. Although specific doses have not been established in clinical trials, basic research into the mechanisms and regulation of endogenous opioid systems demonstrates the potential clinical benefit for the use of opioids in these animals. Other analgesics such as alpha2-agonists, ketamine, and tricaine methanesulfonate have also demonstrated analgesic potential.

Pharmacodynamics of flunixin and ketoprofen in mallard ducks (Anas platyrhynchos).

Flunixin (FLX) and ketoprofen (KET) are potent nonsteroidal anti-inflammatory drugs (NSAIDs) used to alleviate pain and decrease inflammation. These drugs block access of arachidonic acid to its binding site on the cyclooxygenase enzyme, thus preventing conversion to thromboxane A2 and subsequent degradation to thromboxane B2 (TBX). Consequently, plasma TBX may be used to estimate duration of NSAID action. Sixteen adult mallard ducks (Anas platyrhynchos) were randomly assigned to three treatment groups: control (n = 4), FLX 5 mg/kg (n = 6), or KET 5 mg/kg (n = 6). Blood samples were taken 1 hr prior to and just before (0 hr) injection and 0.25, 0.5, 1, 2, 4, 6, 12, 24, 36, and 48 hr after injection. Plasma samples were analyzed for corticosterone and TBX. The feces were tested for the presence of hemoglobin and the ducks were euthanized for complete necropsy at the end of the study. Samples of muscle, kidney, liver, proventriculus, and intestine were taken for histologic analysis. Thromboxane was suppressed significantly in all birds following administration of either FLX or KET for 4 hr and decreased for approximately 12 hr compared with baseline samples (-1 and 0 hr). In the control group, TBX gradually declined over time. None of the ducks showed evidence of gastrointestinal bleeding, but the FLX group had muscle necrosis present at injection sites. FLX and KET likely exert pharmacological effects for at least 12 h. Although degree of TBX inhibition cannot be correlated absolutely with degree of analgesia or anti-inflammatory effects, it is possible that these effects are present during this time. This work suggests that FLX and KET can potentially be used as anti-inflammatory and analgesic agents in waterfowl. However, because of muscle necrosis at the injection site, we do not recommend parenteral use of FLX in ducks.

Cutaneous mycoses in chameleons caused by the Chrysosporium anamorph of Nannizziopsis vriesii (Apinis) Currah.

A dermatophyte-like fungus was isolated from skin biopsies of three different species of captive chameleon in which fungal elements had been observed by histologic examination. An adult Parson's chameleon (Chamaeleo parsonii) presented with vesicles that became crusty brown lesions on the limbs and body. Skin biopsies revealed fungal hyphae in the affected epidermis and underlying dermis. The lesions regressed fully after oral administration of itraconazole. An adult jewel chameleon (Chamaeleo lateralis) from the same private collection presented with localized black skin lesions and died while being treated with itraconazole. A pulmonary granuloma was also present in this chameleon at autopsy. Cultures obtained from skin and lung lesions yielded the same fungus. A third isolate was obtained from a skin biopsy of a Jackson's chameleon (Chamaeleo jacksoni) with deep ulcerative cutaneous lesions located at the base of the tail. The fungus, in all three cases, has been identified as the Chrysosporium anamorph of Nannizziopsis vriesii, a poorly known ascomycetous species recorded previously from the skin of a lizard and from soil, on the basis of its keratinolytic activity, resistance to cycloheximide, strongly restricted growth at 37 degrees C, formation of clavate or pyriform single-celled or two-celled aleurioconidia, and alternate and fission arthroconidia.

Ascites and hepatic cirrhosis in a cockatiel (Nymphicus hollandicus).

A mature, female cockatiel (Nymphicus hollandicus) was examined because of respiratory difficulties. Clinical and laboratory findings included ascites and evidence of hepatic disease (i.e., increased plasma bile acid concentrations, aspartate aminotransferase, and alkaline phosphatase activities). Plasma protein electrophoresis results were consistent with chronic-active inflammation. The albumin-to-globulin (A:G) ratio, calculated from plasma electrophoresis, was 0.3. Postmortem examination revealed severe hepatic fibrosis and a diffuse, interstitial, granulomatous lipid pneumonia.