Rat digs: the effects of crowding and cage size on rat growth

The extent to which laboratory and housing conditions affect rodents is always a concern in experimental studies. Not only can the housing environment influence an animal's welfare, it may also have a confounding effect on the data acquired in the research. As yet, there is no consensus about the ideal range in rats for two housing parameters, cage size and cage density. Here, Yildiz et al. examine the effects of those two parameters on the growth, organ development, metabolic profile, and hemogram of juvenile Sprague-Dawley rats. Their study indicates that larger cages and higher population densities depress the body weight and weights of several organs in rats. In addition, their research suggests that larger group size and population density are more detrimental to female than male growth. See page 28

Rat urine collection on a budget

Urine and fecal matter can provide important data for a variety of studies in laboratory animals, but sample collection in many instances is by no means straightforward. Some methods of urine collection, for instance, may even require invasive procedures, such as vesicle puncture or catheterization. Moreover, obtaining samples that are uncontaminated by blood cells, drinking water, or other substances can be a challenge. Demirkan and Melli describe an apparatus they have devised to collect fecal and urine samples from rats (or, with modifications, mice). The devise is inexpensive, easy to assemble, and simple to operate. See page 39

Keeping the bugs in: caging for research with high-risk pathogens

In the last few years, it seems that research involving select agents has become all the rage. To a certain extent, concerns about bioterrorism and emerging diseases have played a role in fomenting the recent spike in select-agent research. Because animal research involving microorganisms classified as select agents must be conducted under ABSL-3 and -4 conditions, the recent spate of new studies and federal funding has also initiated a surge in the biocontainment caging options available for that research. In their article, Maher and Young describe some of the ABSL-3 and -4 cage and rack systems currently on the market. See page 42