Habituating pigs for in-pen, non-invasive biophysical skin analysis

Handling and Training of Wild Animals: Evidence and Ethics-Based Approaches and Best Practices in the Modern Zoo

There is an ethical responsibility to provide all animals living in human care with optimal and positive well-being. As animals living in zoos and aquariums frequently interact with their human caregivers as part of their daily care routines, it is both relevant and essential to consider the impact of these interactions on animal well-being. Allowing animals to have choice and control in multiple areas of their lives, such as by providing opportunities for them to voluntarily participate in their own care through, for example, positive reinforcement training, is an essential component of good animal well-being programs. This review aims to describe evidence-based approaches, ethics, and best practices in the handling and training of the many taxa held in zoos and aquariums worldwide, drawing from work in related animal care fields such as laboratories, farms, rescue, and sanctuaries. The importance of ongoing animal well-being assessments is discussed, with a particular focus on the need for continued review and refinement of processes and procedures pertaining to animal training and handling specifically. Review, enquiry, assessment, evaluation, and refinement will aim to dynamically support positive well-being for all animals.

Refining restraint techniques for research pigs through habituation

Pigs are common research models and are strong animals that can be difficult to restrain. Improper restraint can put pigs and research personnel at risk for injury and induce stress, which can affect research outcomes. This study aimed to refine restraint techniques for research pigs using habituation and operant conditioning. Forty-four (22 males, 22 females; 4 months old, ~8.1 kg) Göttingen minipigs were randomly assigned to a control (C: no interventions) or a treatment group (T). Pigs in the T group received 3 min training sessions 3 days/week for the first 14 d after arrival. Training sessions included human socialization and habituation to a hammock sling for blood collection. Blood collection occurred on day 13 for all pigs by novel technicians. Pigs were placed in the sling, blood was collected from the radial vein, and serum cortisol levels were determined (ug/dL). Pig behavior was recorded and scored for duration of time spent struggling (s) and vocalizing (s). Novel human approach tests occurred on day 12, before blood collection, and day 14, after blood collection. Pigs were scored on latency to touch the human (s) and duration of time spent in contact with the human (s). Pig weight was taken upon arrival and on day 15. Separate linear models were fitted for response variables struggle duration in sling, serum cortisol, latency to touch human, time spent in contact with human, and body weight. Fixed effects were treatment and sex. Prior to blood collection, there was no difference in response to a novel human (P > 0.05) but after blood collection, T pigs were quicker to approach (estimate: −5.352, SE: 1.72, P = 0.003) and spent more time in contact with the novel human (estimate: 3.091, SE: 1.448, P = 0.039). T pigs also had lower cortisol levels during blood collection (estimate: −2.36, SE: 0.657, P = 0.001). There was no difference in behavior while in the sling (P > 0.05). The results of the study suggest that even small investments in habituation and training pigs to study procedures is beneficial in reducing stress and improving human-animal relationships, but more time would be beneficial to promote calmer behavior in the sling.

A Case Study on the Behavioural Effect of Positive Reinforcement Training in a Novel Task Participation Test in Göttingen Mini Pigs

In laboratory animal research, many procedures will be stressful for the animals, as they are forced to participate. Training animals to cooperate using clicker training (CT) or luring (LU) may reduce stress levels, and thereby increase animal welfare. In zoo animals, aquarium animals, and pets, CT is used to train animals to cooperate during medical procedures, whereas in experimental research, LU seem to be the preferred training method. This descriptive case study aims to present the behaviour of CT and LU pigs in a potentially fear-evoking behavioural test-the novel task participation test-in which the pigs walked a short runway on a novel walking surface. All eight pigs voluntarily participated, and only one LU pig showed body stretching combined with lack of tail wagging indicating reduced welfare. All CT pigs and one LU pig displayed tail wagging during the test, indicating a positive mental state. Hence, training pigs to cooperate during experimental procedures resulted in a smooth completion of the task with no signs of fear or anxiety in seven out of eight animals. We suggest that training laboratory pigs prior to experimental procedures or tests should be done to ensure low stress levels.

Informing efficient pilot development of animal trauma models through quality improvement strategies

Poor quality data in preclinical trials can result from inconsistent and unstandardized experimental processes. Unpredictable pre-intervention variability generates unreliable data, biases outcomes and results in needless waste of animals and resources. We applied Define-Measure-Analyse-Improve-Control (DMAIC) quality improvement processes to pilot development of a swine model of trauma, haemorrhagic shock and coagulopathy. The goal was to reduce variability through protocol standardization and error reduction. Six male Sinclair swine were sequentially anesthetized, intubated, mechanically ventilated and instrumented, then subjected to multiple-hit injury, followed by fluid resuscitation monitoring and coagulation testing. Experimental tasks were defined and mapped. Performance measures were task performance times, subject stabilization time and number of task execution errors. Process improvement was assessed by reduced times and errors, and subject stability at target physiological values. Previously-overlooked performance errors and deficiencies were identified. 'Mistake-proofing' actions included personnel retraining, revisions of standard operating procedures and use of checklists. The quality improvement pilot trial produced a stable model with reduced protocol deviations. Data quality can be improved and animal waste minimized, if experimental planning incorporates strategies to ensure protocol adherence and reduced operator performance variation and errors. Properly designed pilot trials can be essential components of refinement and reduction strategies in animal-based research.

Flii neutralizing antibodies improve wound healing in porcine preclinical studies

Wound healing is an important area of widely unmet medical need, with millions of procedures carried out worldwide which could potentially benefit from a product to improve the wound repair process. Our studies investigating the actin-remodeling protein Flightless I (Flii) show it to be an important regulator of wound healing. Flii-deficient mice have enhanced wound healing in comparison to Flii overexpressing mice which have impaired wound healing. For the first time, we show that a Flightless I neutralizing monoclonal antibody (FnAb) therapy is effective in a large animal model of wound repair. Porcine 5 cm incisional and 6.25 cm(2) excisional wounds were treated with FnAb at the time of wounding and for two subsequent days. The wounds were dressed in Tegaderm dressings and left to heal by secondary intention for 7 and 35 days, respectively. At the relevant end points, the wounds were excised and processed for histological analysis. Parameters of wound area, collagen deposition, and scar appearance were analyzed. The results show that treatment with FnAb accelerates reepithelialization and improves the macroscopic appearance of early scars. FnAbs have the potential to enhance wound repair and reduce scar formation.

In vitro permeation of a pegylated naltrexone prodrug across microneedle-treated skin

Microneedles (MN) are a useful tool for increasing skin permeability to xenobiotics. Previous research showed marked improvement in the percutaneous flux of naltrexone (NTX) hydrochloride by the use of MN skin pretreatment alone; however, for better therapeutic effect, further enhancement is desired. The goal of this in vitro study was to combine microneedle skin pretreatment with the use of a highly water-soluble PEGylated naltrexone prodrug (polyethyleneglycol-NTX, PEG-NTX) to investigate its transdermal transport at varying concentrations. Solubility and stability of the prodrug were investigated. In vitro diffusion experiments employing MN-treated minipig skin were used to evaluate the performance of the PEGylated prodrug. The results revealed substantial deviation from ideal behavior, with the flux through MN-treated skin having a nonlinear relationship to the prodrug concentration in the donor solution. While in the lower concentration range tested the prodrug flux increase was proportional to the concentration increase, at high concentrations it showed no such dependence. Accounting for the decrease in the effective prodrug diffusivity accompanying the increase in viscosity, as predicted by the Stokes-Einstein equation, provided a rationale for the observed flux values. Increasing the viscosity of the donor solution is hypothesized to afford a curvilinear permeation profile for the PEGylated NTX prodrug.

Evaluation of Barrier Creams Against Sulphur Mustard: (II)In VivoandIn VitroStudies using the Domestic White Pig

Previous studies in our laboratory have demonstrated that barrier creams, comprising perfluorinated polymers, are effective against the chemical warfare agent sulphur mustard (SM) when evaluated using human skin in vitro. The purpose of this follow-up study was to further evaluate three candidate (perfluorinated) barrier creams against SM (vapour) using the domestic white pig. The severity and progression of the resulting skin lesions were quantified daily for three weeks post-exposure using biophysical measurements of transepidermal water loss (TEWL) and skin reflectance spectroscopy (SRS). Skin biopsies obtained post-mortem were evaluated by light microscopy and additional skin samples were obtained from adjacent (unexposed) skin sites for a comparative in vitro skin absorption study. Samples of SM vapour within the dosing chambers were measured ex vivo to ascertain the exposure dose (Ct). The three creams were highly effective against SM in vivo (Ct approximately 5000 mg.min.m(-3)): After 3 weeks, barrier cream pre-treated sites were not significantly different from control (unexposed) skin when evaluated by TEWL, SRS or histology. In contrast, skin exposed to SM without pre-treatment showed evidence of persistent damage that was consistent with the slow healing time observed in humans. The amount of SM absorbed in vitro in untreated pig skin was similar to that required to cause comparable lesions in human skin (8-20 and 4-10 microg.cm(-2), respectively), further validating the use of pigs as a toxicologically-relevant dermal model for SM exposure.

Lipids and skin barrier function--a clinical perspective

The stratum corneum (SC) protects us from dehydration and external dangers. Much is known about the morphology of the SC and penetration of drugs through it, but the data are mainly derived from in vitro and animal experiments. In contrast, only a few studies have the human SC lipids as their focus and in particular, the role of barrier function in the pathogenesis of skin disease and its subsequent treatment protocols. The 3 major lipids in the SC of importance are ceramides, free fatty acids, and cholesterol. Human studies comparing levels of the major SC lipids in patients with atopic dermatitis and healthy controls have suggested a possible role for ceramide 1 and to some extent ceramide 3 in the pathogenesis of the disease. Therapies used in diseases involving barrier disruption have been sparely investigated from a lipid perspective. It has been suggested that ultraviolet light as a treatment increases the amount of all 3 major SC lipids, while topical glucocorticoids may lead to a decrease. Such effects may influence the clinical outcome of treatment in diseases with impaired barrier function. We have, therefore, conducted a review of the literature on SC lipids from a clinical perspective. It may be concluded that the number of human studies is very limited, and in the perspective of how important diseases of impaired barrier function are in dermatology, further research is needed.

Harmonising the definition of refinement

Russell and Burch's Three Rs (replacement, reduction and refinement) remain the cornerstone for principles guiding humane experimental research. However, the concept of refinement has evolved considerably since its first inception and there have been numerous interpretations, some of which are regressive from the original definition. In this paper we examine the interpretations of refinement, and propose a harmonised progressive definition that is in line with changes in animal ethics and animal welfare science. Our definition should be applied to all aspects of refinement: those related to housing, husbandry and care, techniques used in scientific procedures, periprocedural care, health and welfare monitoring, and experimental design. We argue not only that the concept should include the avoidance or minimisation of adverse effects experienced at any time during the life of an animal destined for use in a laboratory, but also that it should be applied to the founder animals. Furthermore, we take a proactive stance and argue that refinement should include enhancing well-being through environmental enrichment. The acceptance and application of this new definition by legislative authorities and in guidelines would represent a significant step forward for animal welfare.