Frequently Asked Questions

How do you manage playpen biosecurity?

We do not share playpens between holding rooms or animals under different biosecurity levels to mitigate the risk of infection transmission. Objects placed in the playpen are autoclaved before use. Following this, objects and the base layer of woodchip are only washed or changed when they become visually dirty. To our knowledge we have not transmitted unwanted infections between animals or between humans and animals.

Guidance document coming soon.

How can we adapt playpens for higher biosecurity level units?

Animals can go into the playpen in their home cage groups. We suggest creating autoclavable bags of standardized playpen enrichment that can be placed into the playpen and then removed, the playpen cleaned and items replaced at a frequency compatible with management requirements between animals or cohorts.

What food rewards do you use for rats and mice?

We have used 5TUL reward pellets from TestDiet, mealworms, yoghurt drops, chocolate O’s, fruity gems, star puffs, rainbow foraging bits, wheat grains, fruit and nut foraging mix and sunflower seeds. Scattering these in the homecage/playpen adds an additional rewarding component of foraging. We also use condensed milk (10 – 20 %), peanut butter or strawberry milkshake (50 %) as part of our habituation to oral dosing. We are aiming to investigate the use of other food rewards, including protein-based or sugar-free rewards, soon.

How do you deal with bitter compounds when oral dosing?

Not all drugs are compatible with oral dosing in palatable solutions due to pharmacokinetic issues or problems associated with the taste or effects of the drug being tested which can stop animals ingesting due to an aversive association being formed. There are several different approaches that can be taken when dealing with compounds that have an aversive taste. The percentage of palatable solution can be increased, the dose volume can be increased (reducing concentration of aversive tasting drug/ml) or there are some products which can reduce/neutralise the taste of the drug. It is helpful to also give animals regular doses of the vehicle to reduce any association being formed between the vehicle and the drug which can reduce consumption (although this does not work for all drugs as some have an odour which the animals can detect even when the vehicle concentration is increased). We are currently investigating the utility of bitter drug powder in increasing the palatability of aversive tasting drugs.

How can the refined restraint methods be applied to rodents that must be handled within a change station or isolator?

Mice

We would recommend habituating mice to a vetbed for dosing procedures using positive reinforcement. If mice cannot be touched with the hands, they can be tube handled onto the vetbed and gently scruffed using the scruff guard. For SC injections, animals should be ideally held on the vet bed so their feet remain in contact with the surface. For IP injections, the position of the animal should be maintained to as near a natural position as possible e.g. with some of the feet in contact with vetbed and tilted only as much as is needed to clear access and not tilted behind the vertical or fully inverted.

Rats

Similarly to above, we recommend habituating rats to a vetbed for dosing procedures using positive reinforcement. Our refined rat IP dose hold can be amended to the vetbed rather than against the body. Keeping the abdominal area relaxed for injection can be achieved via the same hold, with the rat’s weight against the vetbed rather than the handler.