Seasonal changes of CLA isomers and other fatty acids of milk fat from grazing dairy herds in the Azores

• Published in: Journal of the science of food and agriculture Vol. 88; no. 10; pp. 1855 - 1859
• Main Authors: Rego, Oldemiro A, Rosa, Henrique JD, Regalo, Susana M, Alves, Susana P, Alfaia, Cristina MM, Prates, José AM, Vouzela, Carlos M, Bessa, Rui JB
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 15.08.2008; Wiley; John Wiley and Sons, Limited
• Subjects: Biological and medical sciences; Cattle; Chemical compounds; CLA isomers; conjugated linoleic acid; cow feeding; dairy farms; fatty acid composition; Fatty acids; Feeds; Food industries; Food science; Fundamental and applied biological sciences. Psychology; grazing; Milk; Milk and cheese industries. Ice creams; milk composition; milk fat; milk fatty acids; Oils & fats; pasture; season; seasonal variation; silage; summer; winter; Azores; Dairy product; Lipids; dairy farms; Grazing; Fatty acids; Herd; Isomer; Pasture; Milk fat; Season; milk fatty acids; Milk; CLA isomers
• ISSN: 0022-5142; 1097-0010
• DOI: 10.1002/jsfa.3289

BACKGROUND: Season of the year associated with dietary changes has been recognized as a factor implicated in milk fat fatty acid (FA) profile in dairy cows. However, a lack of information exists concerning cows grazing all year round as is practiced in the Azores, where cows are supplemented in winter with maize silage plus concentrates, while in spring the higher grass allowance only requires supplementation with concentrate. The main objective of this study was to detect any seasonal variation of FA profile of milk fat from milk sampled in bulk tanks of 12 Azorean dairy herds.RESULTS Compared to winter milk, milk fat from spring presented a higher proportion of CLA cis-9,trans-11 (14.3 versus 9.6 g kg⁻¹ FA), C18:1 trans-11 (32 versus 22 g kg⁻¹ FA), C18:2 trans-11,cis-15 (3.7 versus 2.2 g kg⁻¹ FA), CLA trans-11,cis-13 (0.34 versus 0.23 g kg⁻¹ FA) and C18:3 n-3 (5.7 versus 5.4 g kg⁻¹ FA). The C18:2 n-6/C18:3 n-3 ratio was lower (P < 0.05) in spring. Branched-chain FA, except the anteiso-C15:0, were higher in spring, while odd-chain FA (C15:0) were higher in winter.CONCLUSION: Dairy herd management in the Azores presents a seasonal variation of milk fat FA composition, where the spring milk may present increased potential benefits for human consumers. Copyright