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.
Key Words:
lipid metabolism; linseed oil; ω-3 fatty acids