Study On Factors Involved In Egg Yolk Pigmentation And Colorants

The prtsent study was conducted to determine the effects of minerals, basal diets, some natural colorants, drugs and breeds on egg yolk pigmentation. At the same time, the comparison trial was adopted to determine the time that egg yolks were pigmented, and a additive using to pigment egg yolks was got. The results showed that: 1. The formation of egg yolk thicken layer by layer. In term of yolk surface, it take 10 days that the pigmentation was stable. However, the stabilized deposition of inner pigments varied from 18 to 20 days. The results indicated that storage period had in- significant effect on yolk color. 2. Minerals including zinc, selium, and iodine were important factors involved in pigmentation of egg yolk. When supplement of zinc, selium or iodine was as twice as control (zinc, 50mg/kg; selium, 0. 1mg/kg; iodine, 0.3mg/kg) respectively, the yolk color was i~p to 8 degree or above, which conform to international regulation of egg ex- port or import. There was not significant difference in deposition of minerals among treatments with the exception of calcium. The supplement of selium or iodine as twice as control ilmproved the deposition of selium or iodine, which was credible basis on de- veloping functional food. 3. The composition of basal diet affected yolk color, when one third wheat, or one third rice, or one second wheat, or one second rice were substituted for yellow corn, the yolk color decreased to 5, 4, 3, 2 degree respectively. When the egg yolk color was 2 or 3 degree. the egg could not export and be edible based on international regulations. Supplement of Lukangding Red (200mg/kg) + Lukangding Yellow (100mg/kg) en- hanced the yolk color degree from 3 to 8. 4. Some natural colorants have significant pigment. Supplement of 0. 8% natural peper mail, or 2% dried cow feceal meal or 4% alfalfa grass meal evaluated the yolk col- or up to 9 degree, which that of the control was 6 degree. The diets supplemented 4% alfalfa grass meal not only improved pigmentation of egg yolk, but also increased vita- min A content and decreased cholesterol content. Supplement of 0. 6% natural peper mail or 2% dried cow feceal meal affected feed intake due to poor palstability. 5. There Were no significant effects of supplement oxyteracycline, chloteracycline and arsanilic acid on egg yolk color with 6 degree level. In 300mg/kg JSS treatment, the yolk color was 6 degree too. While added 500mg/kg JMH into the basal diet, the egg yolk color was up to 9 degree. Supplement of oxytetracycline + JMH or chlortetracy dine + JMH in the basal diet, the egg yolk color was up to 8 and 6 degree respectively and decreased one and three color unit respectively than that of JMH treatment. Added oxytetracyclimne + JSS or chlortetracycline + JSS, the egg yolk color was up to 8 and 6degree respectively. When added arsanilic acid + JSS, the egg yolk color was up to 7 degree and improved one color unit than that of JSS treatment. When added arsanilic acid +JMH to basal diet, the egg yolk color was up to 8 degree and decreased one color unit than that of JMH treatment. 6. Breed of layers is important factor influencing pigment of egg yolk. The Hisex brown ?egg layers deposited the pigments more efficiently than the Hy ?line white ? egg layers. Their egg-yolk color was six and five degree respectively. Supplemented 4% alfalfa grass meal, the egg yolk color of browngg and whitegg was up to nine and six degree respectively and improved three and one...