Plasma Peptide YY and Pancreatic Polypeptide in Dogs After Long-Term Adaptation to Dietary Fats of Different Degrees of Saturation: Olive and Sunflower Oil

Abstract

Mongrel dogs from weaning to 6 months of age were fed on one of two diets that differed only in the type of fat content (virgin olive oil or sunflower seed oil) to compare plasma levels of peptide YY (PYY) and pancreatic polypeptide (PP) in the basal period and in response to food. Under resting conditions, blood concentrations of both peptides, measured by specific radioimmunoassays, were significantly higher in the olive oil group. Food intake was not followed by any marked or significant changes in PYY or PP circulating levels, although some rises were observed. On the other hand, plasma PYY reached significantly greater values throughout the postprandial period in the dogs fed on the diet containing olive oil, whereas no differences were recorded between the groups as far as PP is concerned. Our results demonstrate that long-term intake of diets enriched in monounsaturated fatty acids (olive oil) produces significantly higher basal levels of PYY and PP, as well as significantly higher PYY levels in response to food compared with diets containing sunflower oil. The differences, traceable to the composition of the two types of dietary fat supplied, explain the attenuated pancreatic secretory activity observed by us previously in this animal species. This mechanism may be responsible, at least in part, for the adaptation of pancreatic secretion to the quality of dietary fat.