Fatty acid and enzymatic compositional changes in the pancreas of rats fed dietary n-3 and n-6 polyunsaturated fatty acids

Abstract

The influence of n-3 and n-6 PUFA on the fatty acid composition and the enzyme content of zymogen granules of the normal exocrine pancreas was tested on rats. The animals were fed on different diets comprising 5% fish oil (FO), safflower oil (SFO), and evening primrose oil (EPO) used singly or in combination as dietary fats. The results were compared with those from animals fed 5% hydrogenated beef tallow (HBT). The fatty acid composition and digestive enzyme content were analyzed after a 6-wk feeding period. Differences in the pancreatic fatty acid profiles were related to the fatty acid composition of the ingested fats. Equivalent levels of n-3 fatty acids and 20:3n-6 were obtained with either EPO or FO fed singly or in combination. Similar results were observed with SFO/FO. Higher C20:3n-6/C20:4n-6 ratios were obtained with the oil mixtures. An increase in amylase levels, but a decrease in serine protease (Band 21 kdalton) levels, was associated with EPO. An elevation in procarboxypeptidase levels paralleled an increase in 18:0 levels, whereas the proportion of lipase (Band 49 kdalton) varied inversely with the proportion of C20:3n-6. The SFO/FO mixture elevated the proportions of protease II and proelastase. These results suggest that specific fatty acids influence the proportion of specific digestive enzymes in the zymogen granules.