Bodden Carina, Wewer Maximilian, Kästner Niklas, Palme Rupert, Kaiser Sylvia, Sachser Norbert, Richter S Helene
Department of Behavioural Biology, University of Münster, Münster, Germany; The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia.
Department of Behavioural Biology, University of Münster, Münster, Germany.
Physiol Behav. 2021 Jan 1;228:113220. doi: 10.1016/j.physbeh.2020.113220. Epub 2020 Oct 26.
The use of millions of mice in scientific studies worldwide emphasises the continuing need for a reduction of sample sizes, however, not at the expense of scientific validity. Split-plot designs have been suggested to enhance statistical power while allowing a reduction of animal numbers in comparison to traditional experimental designs. Recently, a promising approach of a split-plot design has been implemented and proven useful using mixed-strain housing of at least three different mouse strains. However, the impact of co-housing different strains of mice in one cage on animal welfare has still to be defined. This study aimed at comparing the effects of mixed-strain and same-strain housing of female C57BL/6J and DBA/2N mice on welfare and behaviour in two experimental phases. In a first phase, mice were housed in either mixed- or same-strain pairs. Home cage behaviour, activity rhythm, body weight, and faecal corticosterone metabolites were assessed. Furthermore, tests for anxiety-like and exploratory behaviour as well as spatial learning were performed. In a second phase, sociability was investigated in newly formed mixed-strain quartets. Mixed-strain housing did not induce alterations in anxiety, locomotion, learning, stereotypic behaviour, and stress hormone levels. However, changes in social behaviours and activity rhythm were observed. Increased agonistic and decreased socio-positive behaviours might point towards mild impacts on welfare in C57BL/6J mice under co-housing conditions. Altogether, scientific research may greatly benefit from co-housing mice of different strains within the same cages (e.g. for the realisation of a split-plot design), provided that strains are carefully selected for compatibility.
全球范围内数百万只小鼠被用于科学研究，这凸显了持续减少样本量的必要性，然而，这不能以牺牲科学有效性为代价。有人建议采用裂区设计来提高统计效力，同时与传统实验设计相比可减少动物数量。最近，一种有前景的裂区设计方法已经得到应用，并通过至少三种不同小鼠品系的混合饲养证明是有用的。然而，将不同品系的小鼠同笼饲养对动物福利的影响仍有待确定。本研究旨在比较雌性C57BL/6J和DBA/2N小鼠在混合品系和同品系饲养两种情况下，在两个实验阶段对其福利和行为的影响。在第一阶段，小鼠以混合品系或同品系配对饲养。评估其笼内行为、活动节律、体重和粪便皮质酮代谢物。此外，还进行了焦虑样行为、探索行为以及空间学习的测试。在第二阶段，对新形成的混合品系四小鼠组进行社交性研究。混合品系饲养并未引起焦虑、运动、学习、刻板行为和应激激素水平的改变。然而，观察到了社交行为和活动节律的变化。攻击行为增加和社交积极行为减少可能表明在同笼饲养条件下对C57BL/6J小鼠的福利有轻微影响。总之，只要仔细选择相容性好的品系，将不同品系的小鼠同笼饲养（例如用于实现裂区设计）可能会使科学研究受益匪浅。
