Reduction
Reduction in number of laboratory animals in experiments.
Reduction is being achieved by:

an appropriate design of the experiment

a choice of appropriate species and strains

a choice of adequate statistics

sharing of experimental animals

genetic and microbiological standardization of
experimental animals.
Microbiology
Gnotobiotic animals – positive determination of micro-flora
(germ-free, one-germ associated...)
Specified pathogen free – negative determination of microflora.
Conventional
Genetics
Outbred – every animal is genetically unique
Inbred – all animals are genetically identical, multiple
brother x sister breeding
Coisogenic strains – two strains differ each other just in one
chromosomal locus
Transgenic animals – addition or deletion of one gene
Replacement
Replacement of animal by in vitro methods (cell and tissue
culture), invertebrates, plants or micro-organisms, computer
simulations or men.
Refinement
Refinement of experimental methods, caging and breeding.
Handling, adequate size of the cage, light/dark cycle,
temperature (usually 20 – 24 oC), humidity (40 –70 %), toys...
Adequate anaesthesia and analgesia, minimal tissue damage.