Effects of Energy and Protein Content in the Diet on Milk Yield and Milk Fatty Acid Profile in Dairy Ewes



The primary obiective of this trial was to evaluate the effect of energy and protein content in the diet on the FA profile of milk fat from ewes, especially polyunsaturated fatty acids Omega 3 (C18:3, EPA, C22:3, C22:5 and DHA) and CLA (conjugated linoleic acid C18:2 n-9c, 11t ). A secondary obiective was to effect with different level energy and protein on diet of caracteristics fermentation ruminal, yield and quality of sheep milk. Consequently, experimental diets were constituted by a 2 x 2 factorial arrangement of energy level in diets (Low – 0,90 UFL/kg DM vs. High – 0,97 UFL/kg DM) and protein level (Low – 14% CP vs. High – 16% CP). On a dry matter (DM) basis, forage: concentrate ratios were 73 : 27 (low energy diets) and 57 : 43 (high energy diets).
Increased levels of protein and energy of diet in lactating sheep, influenced positively the quantitative and qualitative production of milk and, in particular, the profile of fatty acids. Nutritional quality of sheep milk has been improved as a result of declining the degree of fats saturation, by reducing the proportion SFA which are responsible for the occurrence of cardiovascular diseases in humans, and increasing share of PUFA and especially those of Omega 3 type (C18:3, EPA, C22:3, C22:5 and DHA) and CLA (conjugated linoleic acid – C18:2 n-9cis, 11trans), which have an important role in preventing and combating cardiovascular disease, and CLA has anticancerous and antidiabetic effect. The highest milk quality, analyzed through the influence on human health, determined by a high content of Omega 3 fatty acids and CLA, was obtained from sheep fed with a ration of high energy and protein level (0,97 UFL/kg and 16% CP of DM). At the same lot it has been also recorded the best proportion PUFA n-6/n–3 and the lowest atherogenicity index of milk fats.


PUFA Omega 3; CLA; milk fat; energy and protein in the diet; dairy ewes.

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DOI: http://dx.doi.org/10.15835/buasvmcn-asb:66:1-2:3326

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