Influence of dietary fat sources and conjugated fatty acid on egg quality, yolk cholesterol, and yolk fatty acid composition of laying hens

ABSTRACT This study was conducted to investigate the effects of dietary fats (tallow [TO] or linseed oil [LO]) or conjugated linoleic acid (CLA), singly or in combination, on laying performance, yolk lipids, and fatty acid composition of egg yolks. Three hundred 50-week-old laying hens were given one of five diets containing 2% TO; 1% TO + 1% CLA (TO/CLA); 2% LO; 1% LO + 1% CLA (LO/CLA); and 2% CLA (CLA). Laying performance, egg lipids, and serum parameters were not altered by dietary treatments. Alpha-linolenic acid or long-chain ω-3 fatty acids including eicosapentaenoic and docosahexaenoic acids were elevated in eggs of laying hens fed diets containing LO (i.e., LO or LO/CLA groups) compared with those of hens fed TO-added diets. Dietary CLA, alone or when mixed with different fat sources (i.e., TO or LO), increased the amounts of CLA in egg yolks, being the highest in the CLA-treated group. The supplementation of an equal portion of CLA and LO into the diet of laying hens (i.e., LO/CLA group) increase both CLA and ω-3 fatty acid contents in the chicken eggs.