methods-pairing-pair-maintenance-new-zealand-white-rabbits

Methods of Pairing and Pair Maintenance of New Zealand White Rabbits (<em>Oryctolagus Cuniculus)</em> Via Behavioral Ethogram, Monitoring, and Interventions

New Zealand White (NZW) laboratory rabbits (Oryctolagus cuniculus), as well as their ancestors the European Rabbit, are a social species that exhibit ...

University of Michigan

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Although guinea pigs (Cavia porcellus) have been used in research for more than a century and remain the most prevalent USDA-covered species, little has been elucidated regarding the recognition of clinical pain or analgesic efficacy in this species. We sought to assess pain in guinea pigs by using newer, clinically relevant methods that have been validated in other rodent species: the behavioral ethogram and cageside proxy indicator. In this study, 10 male guinea pigs underwent electronic von Frey testing of nociception, remote videorecording of behavior, and cageside assessment by using time-to-consumption (TTC) of a preferred treat test. These assessments were performed across 2 conditions (anesthesia only and castration surgery under anesthesia) at 3 time points (2, 8, and 24 h after the event). The anesthesia only condition served to control for the nonpainful but potentially distressing components of the surgical experience. Compared with those after anesthesia only conditions, subtle body movements were increased and nociceptive thresholds were decreased at 2 and 8 h after surgery. At 24 h, neither subtle body movement behaviors nor nociceptive thresholds differed between the 2 conditions. In contrast, TTC scores did not differ between the anesthesia only and surgery conditions at any time point, underscoring the challenge of identifying pain in this species through cageside evaluation. By comparing ethogram scores with measures of nociception, we validated select behaviors as pain-specific. Therefore, our novel ethogram allowed us to assess postoperative pain and may further serve as a platform for future analgesia efficacy studies in guinea pigs.

Validation of a Behavioral Ethogram for Assessing Postoperative Pain in Guinea Pigs (Cavia porcellus).

Guinea pigs (Cavia porcellus) are a frequently used species in research, often involving potentially painful procedures. Therefore, evidence-based recommendations regarding analgesia are critically needed to optimize their wellbeing. Our laboratory examined the efficacy of carprofen and extended-release (ER) buprenorphine, alone and as a multimodal combination, for relieving postsurgical pain in guinea pigs. Animals were assessed by using evoked (mechanical hypersensitivity), nonevoked (video ethogram, cageside ethogram, time-to-consumption test), and clinical (weight loss) measurements for 96 h during baseline, anesthesia-analgesia, and hysterectomy conditions. In addition, ER buprenorphine was evaluated pharmacologically. Guinea pigs treated with a single analgesic showed increased mechanical sensitivity for at least 96 h and indices of pain according to the video ethogram for as long as 8 h, compared with levels recorded during anesthesia-analgesia. In contrast, animals given both analgesics demonstrated increased mechanical sensitivity and behavioral evidence of pain for only 2 h after surgery compared with anesthesia-analgesia. The cageside ethogram and time-to-consumption tests failed to identify differences between conditions or treatment groups, highlighting the difficulty of identifying pain in guinea pigs without remote observation. Guinea pigs treated with multimodal analgesia or ER buprenorphine lost at least 10% of their baseline weights, whereas weight loss in carprofen animals was significantly lower (3%). Plasma levels for ER buprenorphine exceeded 0.9 ng/mL from 8 to 96 h after injection. Of the 3 analgesia regimens evaluated, multimodal analgesia provided the most effective pain control in guinea pigs. However the weight loss in the ER buprenorphine-treated animals may need to be considered during analgesia selection.

Evaluation of Pain Assessment Techniques and Analgesia Efficacy in a Female Guinea Pig () Model of Surgical Pain.

Murine orthotopic cancer models often require surgery, potentially causing pain or distress. However, analgesics are often withheld because they may alter tumour development. Two orthotopically implanted cancers were investigated in mice pre-treated with meloxicam (10 mg/kg), buprenorphine (0.2 mg/kg) or saline (1 ml/kg). Tumours were imaged and welfare was assessed using body weight, behaviour and nociceptive responses. In study 1, BALB/c mice were inoculated with 4T1 mammary carcinoma or saline during surgery or anaesthesia. As pre-treatment with a single buprenorphine dose appeared beneficial to cancer growth consistency, a second cohort of mice additionally received saline or buprenorphine at 12 and 24 h. Surgery resulted in increased mammary tumour growth and lung metastases. These unwanted effects were lessened by buprenorphine pre-treatment, especially when given repeatedly. Mammary tumour-bearing mice became less active and nociceptive thresholds declined over time, indicating some discomfort as tumours grew. In study 2, C57BL/6 mice received B16 melanoma. This non-surgical model was used to determine whether meloxicam or buprenorphine affected cancer seeding of the lungs. While meloxicam reduced B16 lung seeding, buprenorphine did not. Mechanical thresholds decreased as cancer developed in mice bearing melanoma, but the magnitude of this was insufficient to conclude that there were any significant welfare concerns. This study highlights the scientific value in utilising non-surgical models, where possible. When surgery must be performed at the time of tumour inoculation, the effects of this should be controlled with appropriate analgesics to enhance the value and possibly translation of the research.

Jennifer Lofgren

Unit for Laboratory Animal Medicine,
Refinement and Enrichment Advancements Laboratory

University of Michigan

Methods of Pairing and Pair Maintenance of New Zealand White Rabbits (Oryctolagus Cuniculus) Via Behavioral Ethogram, Monitoring, and Interventions

Jennifer Lofgren

Unit for Laboratory Animal Medicine,Refinement and Enrichment Advancements Laboratory

University of Michigan

Methods of Pairing and Pair Maintenance of New Zealand White Rabbits (Oryctolagus Cuniculus) Via Behavioral Ethogram, Monitoring, and Interventions

Unit for Laboratory Animal Medicine,
Refinement and Enrichment Advancements Laboratory