Factors Affecting Egg Yolk Pigmentation

Egg yolk color is an important indicator of egg quality and can significantly impact the competitiveness of egg products in the market. The use of feed additives is a common method to enhance egg yolk color. With the widespread application of colorants, it is crucial to scientifically understand and analyze the factors influencing egg yolk pigmentation.

The factors affecting egg yolk pigmentation can be broadly classified into two categories: poultry-related factors and external factors. Poultry-related factors include diseases, poultry breeds and age, and insufficient yolk development time. For example, poultry diseases can hinder yolk formation or reduce the time required for yolk development, thereby affecting yolk coloration. Research has shown that when chickens are infected with coccidiosis, the utilization rate of lutein is only 70% compared to normal conditions. Poultry breeds and age also influence yolk pigmentation as different breeds have variations in pigment metabolism and deposition capabilities. Some breeds exhibit higher absorption and utilization efficiency of pigments, while others may not perform as well. Additionally, the age of the chicken can affect its digestive and absorption rates. Moreover, under normal circumstances, complete yolk pigmentation takes around 10 days as pigment deposition increases with the development of follicles in the ovary. 

To achieve a high level of pigment deposition in the yolk, it is generally recommended to feed a pigmented diet for two weeks before egg production to ensure complete color development.External factors include feed contamination with mycotoxins, temperature, humidity, light intensity, inappropriate levels of vitamin A in the feed, as well as the timing and duration of feed additive usage. Residual substances like mycotoxins in feed can negatively impact poultry metabolism and pigment deposition. Environmental factors such as temperature, humidity, and light intensity can affect poultry digestion and the stability of pigments. 

Delayed addition of colorants in the feed or prolonged exposure to air can result in oxidation and reduced coloration levels. Insufficient vitamin A in the chicken's body can lead to the conversion of carotenoids to vitamin A to meet the nutritional requirements, thereby affecting the degree of pigment deposition.Therefore, when using poultry feed additives, it is essential to consider both poultry-related and external factors and develop a well-designed plan for colorant usage to maximize the effectiveness of egg yolk pigmentation.