Evaluation of Potential Sustainable Bedding Substrates Focusing on Preference, Behavior, and Stress Physiology in Rats—A Pilot Study

SIMPLE SUMMARY: The use of animals in research is currently a very controversial and emotionally discussed topic; however, to date, animals still play a pivotal and fundamental role in the advancement of biomedical research. Housing conditions of laboratory animals are especially important, as they constitute an overarching factor independent of the respective experiments. In this pilot study, we investigated different types of bedding, i.e., substrates which are used to house laboratory rats. Bedding is a crucial environmental factor for rats as it has a significant influence on their well-being and the animals tend to have a lifelong exposition to a single type of substrate. Our objective for this pilot study was to evaluate corncob and spelt as ecological alternatives to the most commonly used aspen wood chip bedding. Although the rats’ behavior was not changed by different types of bedding substrates, we detected that the rats liked to consume spelt, which could potentially lead to confounding results, when the animals are tested for certain scientific hypotheses. Therefore, this is a crucial factor to consider when planning an experiment that fulfills high-quality scientific outcomes while simultaneously complying with important animal welfare considerations. ABSTRACT: Ensuring optimal housing conditions for laboratory animals is a crucial prerequisite for high-quality and ethically justifiable in vivo science. In addition to guaranteeing animal welfare and promoting scientific validity, environmental sustainability is also increasingly gaining attention in laboratory animal facilities. Consequently, comprehensive management of such aspects is one of the core tasks of any research vivarium. Hygienic monitoring and adhering to standardized experimental protocols have been highlighted in the past; nevertheless, various environmental aspects of housing animals still need to be evaluated in greater depth. In this pilot study, we aimed at assessing the suitability of spelt and corncob as economical and ecologically friendly bedding substrates as compared with commonly used aspen wood chips. Therefore, following a descriptive study design, we examined the preferences of male and female Wistar rats for corncob and spelt under specific conditions. In addition, we evaluated potential effects on behavior, metabolism, and stress physiology. The type of bedding did not seem to influence behavior in the observed parameters but did have time- and sex-dependent effects on blood glucose. Furthermore, housing animals on spelt led to a significant reduction in food consumption, probably compensated for by the intake of spelt, and although it did not influence glucose levels, it may have certainly impacted the nutrient supply. Our descriptive pilot study, therefore, highlights the importance of a thorough condition-associated evaluation of even seemingly marginal environmental factors, when balancing potential cost-benefit advances in sustainability and questions of standardization and reproducibility of experimental protocols.