<P> Fibre, especially cellulose and hemi - cellulose, is primarily broken down into the volatile fatty acids, acetic acid, propionic acid and butyric acid in these chambers (the reticulo - rumen) by microbes: (bacteria, protozoa, and fungi). In the omasum, water and many of the inorganic mineral elements are absorbed into the blood stream . </P> <P> The abomasum is the fourth and final stomach compartment in ruminants . It is a close equivalent of a monogastric stomach (e.g., those in humans or pigs), and digesta is processed here in much the same way . It serves primarily as a site for acid hydrolysis of microbial and dietary protein, preparing these protein sources for further digestion and absorption in the small intestine . Digesta is finally moved into the small intestine, where the digestion and absorption of nutrients occurs . Microbes produced in the reticulo - rumen are also digested in the small intestine . </P> <P> Regurgitation has been mentioned above under abomasum and crop, referring to crop milk, a secretion from the lining of the crop of pigeons and doves with which the parents feed their young by regurgitation . </P> <P> Many sharks have the ability to turn their stomachs inside out and evert it out of their mouths in order to get rid of unwanted contents (perhaps developed as a way to reduce exposure to toxins). </P>

The digestion of food takes place in the