Monogastrics - fat digestion

In monogastrics, some degree of fat digestion begins in the mouth due to the presence of lingual lipase and further hydrolyses occurs subsequently in the stomach due to gastric lipase, but the major site of digestion is the small intestine (about 70% of triglycerides enter the small intestine unhydrolysed). Lipase enzymes primarily hydrolyse fatty acids from the sn-1 and sn-3 positions on the triglyceride, and the sn-2 monoglycerides thus formed act as amphiphilic agents which promote formation of micelles for fat digestion and absorption through the gut mucosal cells. Fatty acids and monoglycerides are re-esterified to triglycerides in the endoplasmic reticulum before being packaged into chylomicrons and cholesterol esters for transport to tissues via the lymphatic system and bloodstream.

Digestibility of unsaturated fatty acids (USFA) is higher than saturated fatty acids in monogastrics, likely reflecting the higher affinity of poly-USFA for micelles and their lower melting point which improve their ability to be emulsified in the gut by bile acids.