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Supplementing Grazing Dairy Ewes with Plant‐Derived Oil and Rumen‐Protected EPA+DHA Pellets Enhances Health‐Beneficial n−3 Long‐Chain Polyunsaturated Fatty Acids in Sheep Milk

Nguyen, Quang V., Le, Van H., Nguyen, Don V., Malau‐Aduli, Bunmi S., Nichols, Peter D., Malau‐Aduli, Aduli E. O.
European journal of lipid science and technology 2018 v.120 no.6 pp. e1700256
Carthamus tinctorius, canola, canola oil, dairy sheep, diet, docosahexaenoic acid, eicosapentaenoic acid, ewe milk, ewes, fatty acid composition, grazing, lactation, linseed, milk fatty acids, omega-3 fatty acids, pellets, rice bran, rumen, sires
This study investigates the impact of supplementing dairy ewes in mid lactation with rumen‐protected (RPO) pellets containing eicosapentaenoic acid (EPA, 20:5n−3) and docosahexaenoic acid (DHA, 22:6n−3) or pellets infused with 50 mL kg⁻¹ DM of either canola (CO), rice bran (RBO), flaxseed (FSO), or safflower (SFO) oils on enhancing the concentration of n−3 long‐chain (≥C₂₀) polyunsaturated fatty acids (n−3 LC‐PUFA) in milk. It is hypothesized that including these oils in the diet of grazing dairy ewes will improve milk fatty acid (FA) composition by increasing levels of n−3 LC‐PUFA. Sixty grazing dairy ewes balanced by sire breed and parity are randomly allocated to one of 6 treatments: 1) Control: commercial pellets without oil inclusion; 2) pellets containing 50 mL kg⁻¹ DM of CO; 3) RBO; 4) FSO; 5) SFO; and 6) RPO at the rate of 1 kg day⁻¹ for each ewe for 8 weeks. Weekly bulked daily milk FA analysis shows RPO has the most efficiency at elevating n−3 LC‐PUFA content by twofold, threefold, and fivefold greater concentrations of EPA, DPA, and DHA, respectively, than the control (0.17 vs 0.08%, 0.23 vs 0.08%, 0.19 vs 0.04%) (P < 0.0001). FSO improves levels of EPA (0.11%) and DPA (0.15%), while CO increases DPA (0.13%) (P < 0.0001). FSO and RPO reached the “source” and good “source” of n−3 LC‐PUFA (ΣEPA + DHA + DPA) contents of 35.1 and 61.7 mg 250 mL⁻¹, respectively. These findings recommend that rumen protected pellets containing EPA + DHA, flaxseed, and potentially canola oil supplements, can be used to improve the content of n−3 LC‐PUFA in dairy ewe milk. Practical Applications: The results promote the potential for production of premium quality and health‐beneficial fresh milk through dietary supplementation of grazing dairy ewes with plant‐derived oil and rumen‐protected EPA + DHA. Interactions between supplemented diets and week of supplementation on the concentrations of LA (a), ALA (b), EPA (c), DHA (d), and DPA (e) in milk.