Isomers of conjugated linoleic acid (CLA) are incorporated into egg yolk lipids by CLA-fed laying hens

This study was designed to determine the amount of conjugated linoleic acid (CLA) incorporated into egg lipids after dietary CLA supplementation. Single Comb White Leghorn laying hens (n = 40; 28 wk old) were randomly assigned to four treatments of varying CLA levels (0, 0.01, 0.5 and 1 g CLA/kg diet). Eggs were collected daily for 36 d. Feed consumption and body weight were monitored. CLA content of egg yolk lipid was analyzed by gas-liquid chromatography. Birds fed 0.5 and 1.0 g CLA/kg feed had significantly more CLA in the egg yolk lipid vs. control and 0.01 g CLA/kg diet groups after 7 d (P < 0.0004). Incorporation of CLA into egg lipid was highest on d 24 and 36. CLA enrichment in egg lipid in the 1.0 g CLA/kg diet group was similar to that in ruminant animal food products, similar to 3 mg CLA/g fat.