Determination of Fatty Acids Profile in Original Brown Cows Dairy Products and Relationship with Alpine Pasture Farming System

SIMPLE SUMMARY: In the world context of climate change and increasing food needs, it is of vital importance to preserve genetic resources in production ecosystems. On the Italian Alps that means conservation of local cattle breeds and maintaining of traditional alpine agro-pastoral practices. In particular, positive effects, such as preservation of fauna and flora biodiversity and greater appreciation by tourists, have been shown to correlate with mountain pastures. This study aimed to evaluate the relationships between different fatty acids in Original Brown cows’ milk and cheese as well as the pattern of fatty acids that most contributes to discriminate between two different farming systems, in which the main difference was the practice, or not, of alpine summer-grazing. A multivariate statistical approach was used. Results indicated that the diet fed to animals, by influencing ruminal fermentation process and mammary gland de novo synthesis, is responsible for defining fatty acids characteristic profiles in dairy products. Findings also suggest that it is possible to build a reliable model based on specific fatty acids concentrations in order to identify pasture-raised or not dairy products. By this way, farmers who practice traditional agro-pastoral system could be easily recognized and adequately remunerated. ABSTRACT: This study aimed to evaluate the relationships between fatty acids and the pattern that most contributes to discriminate between two farming systems, in which the main difference was the practice, or not, of alpine summer-grazing. Milk and cheese were sampled every month in two farms of Original Brown cows identical under geographical location and management during no grazing season point of view in the 2018 season. Fatty acids concentrations were determined by gas chromatography. The principal component analysis extracted three components (PCs). Mammary gland de novo synthetized fatty acids (C14:0, C14:1 n9, and C16:0) and saturated and monosaturated C18 fatty acids (C18:0, C18:1 n9c) were inversely associated in the PC1; PC2 included polyunsaturated C18 fatty acids (C18:2 n6c, C18:3 n3) and C15:0 while conjugated linoleic acid (CLA n9c, n11t) and fatty acids containing 20 or more carbon atoms (C21:0, C20:5 n3) were associated in the PC3. The processes of rumen fermentation and de novo synthesis in mammary gland that are, in turn, influenced by diet, could explain the relationships between fatty acids within each PC. The discriminant analyses showed that the PC2 included the fatty acids profile that best discriminated between the two farming systems, followed by PC3 and, lastly, PC1. This model, if validated, could be an important tool to the dairy industry.