Fish Nutrition and Feed Technology (2+1)

Unit 14 - Digestive enzyme, digestibility and factors affecting digestibility

14.4.Fat digestion

The liver plays an important role in fat digestion. The bile that is produced in the liver and stored in gall bladder is released when food arrives in the intestine. It contains gallic acid of high surface activity and these emulsify the fats, breaking large fat drop lets in to very small droplets there by increasing the surface area and making them more accessible to fat splitting enzymes, which are termed as lipolytic enzymes or lipases.

Lipase activity has been found in extracts of the pancreas, pyloric caecae and upper intestine, but necessarily in all these sites in all the species. Unlike in protein or carbohydrate digestion, lipases show relatively little substrate specificity and many will catalyse hydrolysis of almost any organic ester. Thus the progressive breakdown of a fat through various intermediate stages is often catalysed by a single lipase and there is not a precise succession of different enzymes as in proteolysis.