Improved Deposition of Oxycarotenoids in Egg Yolks by Dietary Cottonseed Oil ,

Abstract

The effect of added dietary fat on the pigmentation of egg yolks was investigated by substituting cottonseed oil (0, 2, 4, and 6%) isocalorically for corn starch in a basal diet of white corn, soybean meal, and starch amended with a stabilized, saponified extract of marigold (Tagetes erecta) to provide 70 μg of trans- lutein per g of 0% added fat diet. Two groups of 30 hens per treatment were depleted of carotenoid stores prior to the experiment by feeding the unamended basal diet for 3 wk. After the hens had been fed the experimental diets for 21 days, five replicates of 4 eggs per pen were collected and were analyzed by HPLC for oxycarotenoid content. The diets with 0, 2, 4, and 6% fat yielded egg yolks with 45.42, 68.56, 75.57, and 80.89 μg of total oxycarotenoids per g yolk of which trans-lutein was 75, 76, 76, and 77% of the total, respectively. The minor oxycarotenoids detected were trans-lutein monoesters, trans-3′-oxolutein, trans-zeaxanthin, and cis-luteins. The yolks from hens fed the diets with 0, 2, 4, and 6% fat had scores of 10.3, 12.8, 13.2, and 13.3, respectively, according to the Roche Yolk Colour fan. Most earlier reports of positive, negative, and no effects for added dietary fat on yolk pigmentation can now be reconciled.