Assessments on the digestibility of oxidized compounds from [1-14C] linoleic acid using a combination of...

The aim of this study was to evaluate the digestibility coefficients of different groups of oxidized fatty acids by applying a methodology based on chromatographic techniques. After thermoxidative treatment, oxidized labelled linoleic acid was isolated and included at 1% in the experimental diets. Male 250-300 g Wistar rats were fed ad lib for seven days. Lipids extracted from diets and faeces were analyzed using a combination of chromatographic methods and radioactivity measurements to determine the specific digestibilities of four groups of altered fatty acids: oxidized monomers non-polar dimers, oxidized dimers and polymers. Mean digestibility coefficients of oxidized monomers, dimers and polymers were 91.0, 74.5 and 69.8%, respectively. In contrast, non-polar dimers were poorly absorbed. The presence of unaltered labelled fatty acids in faeces indicated that structural modifications may have been taken place prior to absorption, and oxidized fatty acids seem to be the main compounds affected.