Effect of Echium oil supplementation on milk fatty acid profile in lactating dairy goats

Plant seeds of the genus Echium (Boraginaceae) contain high amounts of n3 polyunsaturated fatty acids (PUFA), predominantly alpha-linolenic and stearidonic acids. They may therefore be considered promising to increase, in ruminant products, the content of long-chain n3 PUFA (EPA and DHA), well known for their ability to lower cardiovascular disease risk in humans. This study aimed to assess the effects of dietary supplementation of Echium plantagineum (Ep) oil (unprotected against ruminal biohydrogenation) on the fatty acid (FA) profile of goat milk. Twenty-four Camosciata goats were divided into two groups and fed for 44 days a 70:30 forage:concentrate diet supplemented (Ep group, Echium) or not (C group, control) with 40 mL Ep oil. Individual milk samples were collected at 11, 22, 33, and 44 days following supplementation and analysed for their FA profile. Data were statistically treated as a repeated measure design. Echium oil supplementation decreased (p<0.001) the n6/n3 FA ratio and the concentrations of odd-chain, branched-chain and total saturated FA, including lauric (−33%), myristic (−24%) and palmitic (−20%) acids, thus significantly diminishing the atherogenicity index of milk. The Ep diet increased milk content (g 100g-1 fat) of total monounsaturated FA (25.42 vs. 21.16; p<0.001), total polyunsaturated FA (6.30 vs. 3.76; p<0.001), total C18:1 trans FA (7.76 vs. 1.99; p<0.001), total C18:2 trans FA (3.66 vs. 1.19; p<0.001), total conjugated linoleic acids (2.22 vs. 0.67; p<0.001) and total n3 FA (1.33 vs. 0.68; p<0.001). EPA was higher in Ep than C milk (0.024 vs. 0.017; p<0.001) while DHA was undetectable in all analyzed milk samples. Data suggest that dietary supplementation of ruminally unprotected Ep oil can significantly ameliorate the nutritional quality of lipids in goat milk. However, one serving (250 mg) of Ep milk just provided 1.84 mg of beneficial long-chain n3 PUFA (EPA+DHA).