The metabolism of linoleic acid by the young lamb

Abstract

1. Groups of lambs were killed immediately after birth; others were reared on a diet of cow's milk and were killed at 10, 20 and 30 d after birth. The concentrations of 18: 2ω6 (linoleic acid) were determined in cow's milk and the concentrations of 18:2ω6, 20:4ω6 (arachidonic acid) and 20: 3ω9 (Δ^{5, 8, 11}eicosatrienoic acid) were determined in the whole carcasses of the lambs.2. The carcass of the newborn lamb contained only about 300 mg 18: 2ω6. During the first 20 d after birth, there were large increases in the 18: 2ω6 contents of the carcasses, and on the 10th and 20th days, their contents of 18: 2ω6 were similar to the dietary intakes of 18: 2ω6 at the corresponding time-intervals after birth.3. The 20: 3ω9 to 20:4ω6 ratio in the carcass of the newborn lamb was about 1.6, but after 10 d the ratio had decreased to 0.38 in spite of the fact that 18:2ω6 contributed only about 1% of the total calories in the diet.4. The minimum dietary requirements for essential fatty acids for young ruminants and for non-ruminent animals are compared.