Conjugated linoleic acid: A mixture of bio- active fatty acids in milk fat of ruminants

Conjugated linoleic acid (CLA) present in ruminant milk, have several health benefits including anticarcinogenic, antiatherogenic, immuno-modulating, growth promotion and lean body mass promotion. In the present work we have investigated the content of one dominant (c9, t11-CLA), one intermediate (t10, c12-CLA) and the three minor CLA isomers (t11, c13- , t7, c9- CLA) in ruminant milk from three districts of Sindh. A total of 167 milk samples were collected throughout the year from Dairy Farms in Thatta, Dadu and Hyderabad, Sindh. The results show strong variation in CLA content, depending on ruminant milk and season. The mean CLA concentration was higher in cow’s milk fat ranging from 8.81 -10.99 mg /g followed by sheep 8.39 – 9.10 mg /g, goat 5.90 -6.35 mg /g and buffalo milk fat 5.10 – 6.22 mg /g respectively. Summer milk fat contains 7.60 – 24.00 % higher content of total CLA as compared to winter milk in all ruminants. The differences in CLA contents are possibly due to the different activity of desaturase enzymes among ruminants, while seasonal variations in milk CLA concentrations reflect the availability of green pasture and its quality.