Effect of different levels of pigment and fat sources on blood and egg yolk cholesterol and yolk colour of laying hens

Abstract

Egg yolk colour has always been regarded as an important egg quality characteristic and recently has had an even more important role in the marketing of eggs. One of the dietary factors influencing egg yolk colour is dietary fat. Dietary fat has been reported to have a positive or negative effect. Mackay et al (1963) reported that the addition of 4% animal fat improve egg yolk pigmentation. Hamilton and Parkhurst (1990) found that fats with lowering melting point resulted in higher oxycarotenoid level in yolk. An investigation of the role for dietary fat in yolk pigmentation appeared worthwhile because the sources of fat are different in the formulation of diets and because yolk pigmentation is an economically important quality factor. The objective of the present study was to investigate the influence of three sources of fat and levels of pigment on yolk colour and performance of laying hens.