In 3 test groups (11 pigs in each group), rations with an identical fatty acid pattern of the fat in the fodder (except C 17 acids) with a high energy level (energy concentrations = 131%), medium energy level (energy concentrations = 100%) and low energy level (energy concentrations 90 or 82%, resp.) were used. In the course of the investigation the fatty acid spectrum was studied by analyzing spinal fat biopsy specimen. An interrelation was found to exist between the energy supply and the fatty acid spectrum in the depot fat. When identical quantities of heptadecenoic and heptadecanoic acids were added to the fodder, a high energy level resulted in a reduced C17 acid content in the spinal fat, whereas a low energy level led to an increased C17 acid content in the spinal fat. Different energy concentrations caused a change in the contents of oleic acid, linoleic acid and linolenic acid in the spinal fat. With changed energy concentrations, the C16 and C18 acid content showed variations compared with the group given standard fodder. The myristin acid content showed almost no change.