Articles

The authors investigated the influence of housing density and bedding volume on ammonia build-up in two individually ventilated mouse cages models. While the amount of bedding had no influence on ammonia levels, smaller Type II individually ventilated cages accumulated higher ammonia levels than larger Type III individually ventilated cages, even at similar housing densities.

A mouse model to study norovirus pathogenesis is described. The murine norovirus strain WU23, originally isolated from an intestinal site, induces severe but self-resolving diarrhea in neonates, reflecting the pathology observed during human norovirus infection.

Tomsits and colleagues investigated the effects of medetomidine/midazolam/fentanyl and isoflurane/fentanyl narcosis on murine cardiac autonomic nervous activity and electrophysiology. The results show that, compared with medetomidine/midazolam/fentanyl narcosis, isoflurane/fentanyl narcosis seems to have no effect on cardiac autonomic nervous function and less influence on cardiac electrophysiology.

A large number of refinements have been studied with the aim to improve rat welfare, but more evidence is needed to fully understand their impact. This mapping review draws on the findings of 1,017 studies to show that different refinements impact different rats in different ways, and that a ‘one-size-fits-all’ approach to refinements might not be appropriate.

Using behavioral assays, transcriptome analysis and viral approaches to manipulate gene expression in the mPFC, Zhang et al. identified an important role for early growth response 2 (Egr2/Krox-20) in the development of social and cooperative behaviors in mice.

Rats undergoing the stress-enhanced fear learning procedure are usually housed in social isolation and exposed to a trauma-like experience of 15 massed electric footshocks. By showing that group-housed rats receiving fewer and lower-magnitude electric shocks still exhibit PTSD-relevant changes, this new study presents refinements of the procedure to reduce potential animal pain.

Sound levels, vibration, temperature, humidity and luminance were recorded in an animal facility that houses nonhuman primates; the findings may be used to characterize environmental conditions in similar primate facilities and inform best practices for nonhuman primate research and care.

Giannuzzi et al. present an integrated analysis of clinical features and exome and RNA sequencing data in a cohort of dogs with diffuse large B-cell lymphoma to better define the genetic landscape of this tumor and identify multiple mutations associated with the outcome.

In this article, the authors identify LanCL1 as a major male germ cell-specific antioxidant gene. Using different mouse models, they show that LanCL1 deficiency results in spermatozoal oxidative damage and impaired male fertility, while LanCL1 transgene expression protects mice against high-fat-diet-induced oxidative damage and subfertility.

In this article, Henry et al. examine how the geometry, size, opacity and depth of test chambers influence common behavioral responses in Artemia franciscana.

Survey data from 1,187 US biomedical researchers using vertebrate animals reveal diverse perspectives within the animal research community on issues of reproducibility and rigor, attrition rates in drug development, research oversight, and public engagement.

In this article, the authors characterize a new swine model of invasive pneumococcal pneumonia in mechanically ventilated pigs to mimic clinical conditions of critically ill patients.

Enchytraeus crypticus is a soil-dwelling annelid worm that has been used over the past two decades as an ecotoxicology model. Here, Mónica Amorim and colleagues present the first genome for E. crypticus. The authors identify a number of expanded gene families, including several involved with innate immunity.

In this article, the authors compared 24-h spontaneous locomotor activity in three different mouse strains (two inbred strains and one outbred strain) over a period of 2 months by using an automated recording home-cage device. Analysis of different metrics revealed strain-specific spontaneous locomotor patterns.

Long et al. examined the gut microbiome of C57BL/6 mice from two production sites of three different vendors upon receipt, and as the mice adapted to the new vivarium at the University of Connecticut Health Center. Bacterial proportional abundance varied among mice from each vendor, and mice from all vendors exhibited changes in microbial profiles over time. These findings support the need to consider the microbiome as a potential source of variation in mouse studies.

In this article, the authors evaluate the suitability and effectiveness of their micropipette-guided drug administration method as an alternative and non-invasive administration strategy for clozapine-N-oxide in chemogenetic studies using designer receptors exclusively activated by designer drugs.

Preece, Alghadban et al. explore the use of naturally sterile hybrids as an alternative to vasectomized males for the production of pseudopregnant female mice for embryo transfer. Sterile hybrids can contribute to the refinement of the procedure by avoiding a surgical intervention associated with pain and discomfort.

Poon, Y-Y et al. re-visit the effects of isoflurane on cardiovascular functions by measuring temporal changes in blood pressure, heart rate, cardiac performance, baroreflex-mediated sympathetic vasomotor tone, cardiac vagal baroreflex, functional connectivity within baroreflex neural circuits, carotid or cerebral blood flow, respiratory rate and blood gas in mice exposed to 1.5% (vol/vol) isoflurane.

Here, the authors present a new fear-conditioning paradigm in zebrafish using a robotic platform composed of three zebrafish replicas as a fear-eliciting stimulus.

Continuous motion monitoring sensitively predicts terminal endpoint in a mouse model of ovarian cancer; the use of motion metrics could reduce animal suffering and be valuable for drug efficacy testing.