The influence of the location of a nest box in an individually ventilated cage on the preference of mice to use it

The improvement of housing conditions for mice by using environmental enrichment materials is of high concern for the scientific community. Plastic, autoclavable nest boxes are commercially available and ready to use for specific cases such as in individually ventilated cages, metabolic cages, or during toxicological studies. The aim of this study was to see if the location of the nest box within the cage could influence the mice to prefer and use it. Located on the cage floor or hung from the cage lid, a nest box (MPLEX, Otto Environmental, Milwaukee, Wisconsin), enriched the cages. The study concluded that the location of the nest boxes in the individually ventilated cage plays a significant role in the mice preferring to use it or to avoid it. It is also important to use environmental enrichment items that provide animals with the possibility of expressing their preferences and manipulating them in a way to cope better with their environmental conditions.

Eradication of Helicobacter bilis and H. hepaticus from infected mice by using a medicated diet

Infection of laboratory mice with Helicobacter spp. is a serious problem for many laboratory animal facilities worldwide. Rederivation and antibiotic treatment are two of the most common methods used to eliminate the bacterial infection from rodent colonies. Forty-seven newly imported mice were suspected to be positive for Helicobacter infection based on PCR analysis of pooled fecal samples from sentinel animals. We treated the mice with a medicated feed containing four antibiotic compounds (amoxicillin, clarithromycin, metronidazole, omeprazole). After eight weeks of continuous administration the animals were negative for H. bilis and H. hepaticus. Frequent retesting of the animals for up to one year proved that the mouse colony remained negative for Helicobacter spp.