Table 1.

Uses of CD1 colonies with standardized, complex GM profiles.

Uses of Standardized Complex Microbiota Colonies
	Advantage(s)	Disadvantage(s)
CMTR Surrogates	•  Natural vaginal transfer of GM •  Complete transfer of GM •  First generation pups available for study of early life events	•  Expertise for embryo transfer •  High cost of rederivation/embryo transfer
GM donors for axenic mice	•  Stable complex GM that represent those in contemporary colonies	•  High cost of gnotobiotic studies
GM donors via fecal transplant (post antibiotic)	•  Moderate cost	•  Success limited to transfer of high richness GM to low richness GM (opposite transfers ineffective) •  Incomplete transfer
Cross fostering surrogates	•  Ease of use •  Low cost •  Early (w/in 24 hr) transfer of GM	•  Requires timed mating •  Non-vaginal GM transfer •  Incomplete transfer resulting in hybridized GM •  Need for second generation pups for early life events
GM donors via co-housing	•  Ease of use •  Low cost	•  Incomplete transfer resulting in hybridized GM •  Need for second generation pups for early life events