Prepare red dye (Carminered dye, Sigma #C1022) in 0,5% methylcellulose (Sigma #M7027).

Take the animal and administer the red dye by oral gavage.

After oral gavage, individualize the animals in separate boxes without bedding.

Monitor the animal boxes for a total time of 4h.

Register the time when the animals defecate the first dyed fece (stained red).

Represent the time until first dyed fece as the transit time of the animals.