Due to the design of the rodent digestive system, most rodents must consume their food twice before nutrients can be efficiently absorbed. Rodents are primarily herbivores that consume large amounts of plant cellulose that is difficult to digest. When food is initially ingested by a rodent, it is softened in the stomach and is carried to the small intestine and then a large, post-digestive cecum that houses a dense collection of bacteria. The activity of the bacteria is able to break down molecules of cellulose into simple starches and sugars, but once the material has reached the part of the digestive tract in which the bacterial flora is located, it is past the point where it can be absorbed into the body. In order to obtain nutrients that would be otherwise lost, the rodent reingests the fecal pellets it produces. On the second trip through the system, a larger proportion of nutrients are absorbed from the pellets so that rodent digestion is overall about 80 percent efficient.

Alexa Fluor 488 conjugated to a lectin isolated from the red kidney bean (Phaseolus vulgaris) was utilized to target glycoproteins present in the sample of rat stomach tissue depicted in the digital image above (yielding green emission). The specimen was also stained for F-actin and nuclear DNA with Alexa Fluor 568 (red emission) conjugated to phalloidin and Hoechst 33258 (blue emission), respectively. Images were recorded in grayscale with a 12-bit digital camera coupled to either a Nikon E-600 or Eclipse 80i microscope equipped with bandpass emission fluorescence filter optical blocks. During the processing stage, individual image channels were pseudocolored with RGB values corresponding to each of the fluorophore emission spectral profiles.