Rockrose and quebracho condensed tannins have a minor impact on the fatty acid profile of goat milk and cheese without altering animal performance and composition of products

Abstract

This study was carried out to test the hypothesis that the inclusion of condensed tannins (CT) from rockrose (Cistus ladanifer L.) and quebracho (Schinopsis lorentzii) in dairy goat diets supplemented with vegetable oil rich in polyunsaturated fatty acids (PUFA) can increase the potentially healthy fatty acids (FA) in milk and cheese fat, without compromising animal performance and milk and cheese composition. A feeding experiment was conducted with 18 Serpentina goats distributed into three dietary treatments: C) Basal diet (Control); R) Basal diet supplemented with CT from rockrose; and Q) Basal diet supplemented with CT from quebracho. Basal diet was composed of forage and concentrate at a ratio of 25:75 and supplemented with 50 g/kg dry matter (DM) of soybean oil. Basal diet was offered at level of 800 g/head and day, and hay was offered ad libitum. Individual milk yield, chemical composition and FA profile were analyzed on days 0, 7, 14 and 21 of the experimental period. In the last week of experiment, milk of five consecutive milking from each goat was pooled to make fresh cheese, and cheese was analyzed for chemical composition and FA profile. The inclusion of CT from rockrose and quebracho in goat diets did not affect the milk yield or the milk and cheese chemical composition. Both CT sources had a minor impact on milk and cheese FA profile, limited to a reduction of some branched-chain FA in milk and cheese and a reduction of 18:1 trans-10 in milk. Rockrose CT also reduced the contents of 18:1 trans-9 in milk compared to control diet. The basal diet used in present work, containing 250 g/kg DM of dehydrated Lucerne, low-starch ingredient replacing part of the cereals and supplemented with PUFA-rich vegetable oil, resulted in goat milk and cheese with high levels of FA with potential health benefits. However, the rockrose and quebracho CT did not increase PUFA, 18:1 trans-11 and 18:2 cis-9, trans-11 levels in milk and cheese.