The fatty acid composition of ewe milk or suckling lamb meat can be used to discriminate between ewes fed different diets

Abstract

Thirty-nine ewe-lamb pairs were used to evaluate the effects of the diet of lactating ewes, the type of forage (pasture vs hay) and the inclusion of 10% quebracho in the concentrate on the fatty acid (FA) profile of their milk and the meat of their suckling lambs. The estimated forage–concentrate ratio was 80:20. Milk from pasture ewes had a higher percentage of saturated FAs (SFAs; 62.3 vs 56.5), lower percentages of monounsaturated FAs (MUFAs; 30.4 vs 36.6) and n-6 polyunsaturated FAs, and a lower n-6:n-3 ratio (1.9 vs 2.3) than did that of hay ewes (P < 0.001). Meat of pasture lambs had higher percentages of total polyunsaturated FAs (PUFAs; 23.0 vs 20.4; P < 0.05) and n-3 (7.0 vs 5.0; P < 0.001) and lower percentages of MUFAs (37.9 vs 41.8; P < 0.001) and n-6:n-3 (2.0 vs 2.8; P < 0.001) than did that of hay lambs. The inclusion of quebracho increased MUFAs in milk (P < 0.05) and decreased SFAs in meat (P < 0.05). Ewes were correctly classified to the different treatments by using the FA profile of milk (100% score outcome), and to a lesser extend by using the FA profile of lamb (82–100% score outcome); de novo synthesis of FAs in lamb muscle might have reduced the classification accuracy. In conclusion, forage type had a greater effect on the FA profiles of ewe milk and the meat of suckling lambs than did the inclusion of quebracho in the concentrate. To improve the classification of meat of suckling lamb, other biomarkers should be examined. These results are relevant for ewes farmed for the production of milk as well as lambs.