Feeding Unprotected CLA Methyl Esters Compared to Sunflower Seeds Increased Milk CLA Level But Inhibited Milk Fat Synthesis in Cows (Conjugated Linoleic Acid) (Report‪)‬

INTRODUCTION Feeding lactating dairy cows diets supplemented with oilseeds rich in 18:2n-6 reduce markedly milk saturated fatty acid content and, concomitantly, enhance milk lipid 18:2cis(c)9trans(t) 11 conjugated linoleic acid (CLA) concentration (Collomb et al., 2004). The latter is the most abundant CLA isomer in the milk and is formed in the rumen during 18:2n-6 biohydrogenation (BH) and endogenously in the mammary gland from ruminally derived 18:1111 by [DELTA]9-desaturase (Griinari et al., 2000; Mosley et al., 2006). The 18:2n-6 BH rate depends on factors such as dietary forage (Sackmann et al., 2003) or dietary fat supplementation levels (Duckett et al., 2002).