LIPID ABSORPTION BY ENTEROCYTES OF THE RAINBOW-TROUT, ONCORHYNCHUS-MYKISS - DIET-INDUCED CHANGES IN THE ENDOMEMBRANOUS SYSTEM

In the trout, dietary fat is absorbed by enterocytes in the anterior segment of the intestine and the pyloric caeca. Ultrastructural analyses showed lipoprotein particles resynthesized by the endoplasmic reticulum, appearing inside this structure, as well as inside membranes of the Golgi apparatus and lamellar structures. The lamellar structures are involved in the transport of these particles to the lateral and basal intercellular spaces. In animals fed a carbohydrate-rich, low-protein diet, electron microscopic images showed a distinct arrangement of the endoplasmic reticulum, forming spiral structures in which the cisternae of the endoplasmic reticulum were tightly wound about themselves, and their membranes were fused. We interpret these results to illustrate a mode of phospholipid and glycolipid storage in the form of lipid bilayers.