Aspen shaving versus chip bedding: effects on breeding and behavior

Abstract

The choice of laboratory cage bedding material is often based on both practical and husbandry issues, whereas behavioral outcomes rarely appear to be considered. It has been noted that a breeding success difference appears to be associated with the differential use of aspen chip and aspen shaving bedding in our facility; therefore, we sought to analyze breeding records maintained over a 20-month period. In fact, in all four mouse strains analyzed, shaving bedding was associated with a significant increase in average weanlings per litter relative to chip bedding. To determine whether these bedding types also resulted in differences in behaviors associated with wellbeing, we examined nest building, anxiety-like, depressive-like (or helpless-like), and social behavior in mice housed on chip versus shaving bedding. We found differences in the nests built, but no overall effect of bedding type on the other behaviors examined. Therefore, we argue that breeding success, perhaps especially in more challenging strains, is improved on shaving bedding and this is likely due to improved nest-building potential. For standard laboratory practices, however, these bedding types appear equivalent.

Living inside the box: environmental effects on mouse models of human disease

“…A wide variety of bedding types continue to be used to house mice in these boxes. The different bedding types can affect breeding ( Iturrian and Fink, 1968 ; Jackson et al, 2015 ; Tanaka et al, 2014 ), overall health ( Becker et al, 2010 ; Ferrecchia et al, 2014 ; Horn et al, 2012 ; Potgieter and Wilke, 1996 ) or metabolism. This can lead to a wide variety of disorders, including cancer ( Jacobs and Dieter, 1978 ; Li et al, 2009 ; Nielsen et al, 1986 ; Schoental, 1974 ; Torronen et al, 1989 ; Vesell, 1967 ; Vlahakis, 1977 ).…”

Evaluation of the neutrophil:lymphocyte ratio as an indicator of chronic distress in the laboratory mouse

“…When designing studies that use animal models, it has been recognized that the results are more translatable to human disease when the subjects are healthy with minimal stressors [1][2][3][4][5][6] . But, not all stress is bad, so it is critical that evaluations of animal well-being differentiate between distress (that which results in decreases in animal well-being as the animal is unable to cope or adapt) and eustress (stressors which enhance the functioning of the animal) 7,8 .…”

Bedding Material Affects Mechanical Thresholds, Heat Thresholds, and Texture Preference

“…It has long been known that different bedding materials can affect the wellbeing and sexual behavior of mice 25,28,48,55 , but the potential effects on the evoked and non-evoked somatosensory behavior assays have been little studied. Through the combination of a variety of evoked and non-evoked assays, and acute and chronic tissue inflammation, we have shown that the bedding type can markedly affect animal behavior.…”

“…The animal facility at our institute typically uses an Aspen wood chip bedding called Sani-Chips® (Fig 1A), which when touched feels somewhat prickly with sharp edges, even though the wood pieces are small. The Aspen chips are dried to about 8% moisture content and then screened to the specifications which include a size range from 8 to 20 mesh of the National Institute of Health 28 . The Aspen Sani Chips® we use come from P.J.…”

“…ALPHA-Dri® is reported to be about ten times more absorbent than other wood chip bedding 52 like Aspen bedding. It is comprised of pure, virgin paper cellulose, which is virtually free of confounding contaminants 28 . We noted that animals nest more readily in the TEK-Fresh bedding as compared to Aspen or Pure-o’Cel ™ bedding as shown in photos from animals in our study (Fig 1F–H) and its soft quality is thought to enhance environmental enrichment and encourages nest building 1,6,45 .…”