A rationale for the development of gnotobiotics

Gnotobiotic animals are used both for research and as a source of clean animal stocks. In research, reviewed by Coates (1975), gnotobiotic animals have been used to study interactions between host and micro biota and between the various elements comprising that micro-biota. Clean stocks have been used in producing breeding colonies of laboratory animals and herds of pigs free from certain pathogens. The 'conventional' laboratory animal, in common with other animal species, is a composite of the animal and its associated microbiota. The characteristics and performance of the animal itself are largely controlled by husbandry practices and the application of the principles of genetics. The microbiota, which affect the host animal, are usually only controlled to the extent of assuring the