Table 1.

Main complications in microbiota research using human individuals [5].

Complications in Human Host Models	Solutions
Variation in host genome	To control genotype variations in in vivo animal models To study individual human genome projects To look for interpersonal variations between monozygotic and dizygotic human twins
Environmental exposures (toxins, antibiotics, diet)	All of these can be controlled in in vivo animal models
Tractability	In vivo animal models offer the possibility of examining remote regions of the gut
Difficult-to-replicate experiments due to unique microbiota of each individual	Possibility of transplanting the same microbiota into multiple animal hosts