Optimisation de la teneur du lait en acides linoléiques conjugués

Objectives

Results obtained

Early results have shown that adding linseed oil and extruded linseed, which are rich in linoleic acid, to feed significantly increases the milk CLA content. At the same time, however, a vitamin E supplement would have to be added to the lipid-enriched rations to prevent the milk from becoming rancid, with falling fat levels. As long as the cattle are fed this diet, the effects are maintained over time, which suggests the possibility of supplying the industry with milk with a year-round constant CLA content. However, in summer time, the growth stage of the grass is a determining factor, though; CLA production is undeniably better with young grass. During the winter, the milk CLA concentration appears directly dependent on the diet composition, specifically on its structural value that should be between 1.3 and 1.7, and the nature of the energy supplement (fibre or starch), infuencing directly the pH of the rumen liquid. the substitution of a part of linseed by rapeseed produced in Europe did not enable to maintain a so good fatty acid pattern in the milk. The fibre content of the diets appeared as a main factor influencing the linseed effect and will be specifically investigated . Moreover, several molecules susceptible to avoid the shift of rumen bio-hydrogenation will be tersted in vivo in the future. 

Contribution

Partners

Funding

• DGARNE