RESUMO
Effective pain relief in animals relies on the ability to discern pain and assess its severity. However, few objective measures exist to assess the presence and severity of pain in axolotls, and few resources are available regarding drugs and appropriate doses to provide pain relief in this species. This study evaluated behavioral tools for cageside pain assessment and validated a reproducible and reliable quantitative method to evaluate analgesic efficacy in axolotls. Animals were divided into control and treatment groups (n = 6 per group); treatment groups received buprenorphine through injection (50 mg/kg every 24 h for 48 h intracelomically) or butorphanol immersion (0.50 or 0.75 mg/L every 24 h for 48 h). Qualitative behavioral tests, adapted from other amphibian studies, included tapping on the home tank, directing water jets or physically touching specific anatomic points on the animal, and placing a novel object in the home tank. Quantitative methods used to produce noxious stimuli were the acetic acid test and von Frey aesthesiometers. Animals that were treated with analgesics did not demonstrate a significant difference compared with controls during behavioral assessment at 1, 6, 12, 25, 30, and 48 h after analgesia administration. The acetic acid test revealed a reproducible, concentration-dependent pain response. However, a significant difference in the AAT response was not observed between control and treated groups with the tested analgesics and doses.
Assuntos
Ambystoma mexicanum , Analgesia/métodos , Analgésicos/farmacologia , Manejo da Dor/veterinária , Medição da Dor/veterinária , Dor/veterinária , Analgésicos/administração & dosagem , Animais , Comportamento Animal , Buprenorfina/administração & dosagem , Buprenorfina/farmacologia , Butorfanol/administração & dosagem , Butorfanol/farmacologia , Ciência dos Animais de Laboratório , Dor/prevenção & controle , Medição da Dor/métodosRESUMO
Axolotls (Ambystoma mexicanum) from a research colony presented with multifocal, white chalky to gray skin lesions, a diffuse whitish to blue hue to the integument, and friable gill filaments. Skin scrapings and wet mounts revealed Chilodonella, Ichthyobodo, and a trichodinid species. The average overall burden (that is, all 3 species) per axolotl ranged from 0 to 25 parasites per 40 × field (p40f; mean ± 1 SD, 2.6 ± 5.5), with a prevalence of 12%, 60%, and 48%, respectively. Concurrent with husbandry modifications, axolotls were treated with an 8-h static immersion bath that contained 0.025 mL/L 37% formaldehyde. Chilodonella organisms were no longer observed after the initial treatment, and Ichthyobodo decreased from 2.4 ± 5.6 to 0.6 ± 1.8 organisms p40f. However, the average overall burden increased 4-fold to 10.5 ± 9.8 parasites p40f, and the trichodinid organisms increased 13-fold from 0.8 ± 2.3 to 10.4 ± 9.2 organisms p40f. A second treatment consisted of an 8-h immersion bath that contained 0.05 mL/L 37% formaldehyde on 2 consecutive days. A significant change was noted in the average overall burden of 0.5 ± 1.1 parasites p40f, a greater than 5- and 21-fold decrease from pretreatment and after the initial treatment, respectively. No significant change between the first and second treatment was observed for Ichthyobodo, with 0.6 ± 1.2 organisms p40f, but this number represented a significant decrease from pretreatment. After the second treatment, the trichodinid organism was detected in only one axolotl, with a low overall burden of 0.2 ± 0.4 organisms p40f and resulting in a significant decrease in the trichodinid count to 0.01 ± 0.04 organisms p40f. Treatment with formalin (37% formaldehyde), in conjunction with husbandry improvements, was effective in significantly reducing ectoparasite burden and eliminating clinical symptoms in axolotls but did not fully eliminate all protozoa.