Effects of strain and age of layer chickens on mineral contents of egg yolk and albumen

Abstract

This study evaluated the effects of strain (genotype) and age on the mineral composition of egg yolk and albumen of the domestic chicken. A total of 810 eggs were used in a 3 X 3 factorial ar-rangement of treatments involving the Lohmann White, Lohmann Brown and White Leghorn which were 31, 40 and 53 weeks old. Data obtained were subjected to the analysis of variance (ANOVA) using the General Linear Model procedure in Minitab (version 18). Phosphorous was highest in yolks from the White Leghorn (4433.4 μg/g) than in yolks from the Lohmann Brown (4402.4 μg/g) and Lohmann White (4397.5 μg/g) strains. Iron content of egg yolk was significantly (p < 0.05) different among all the layers with the highest in the Lohmann Brown (77.0 μg/g) fol-lowed by the Lohmann White (37.2 μg/g) and lowest in the White Leghorn (21.7 μg/g). There was significant (p < 0.05) effect of layers’ age on all the mineral elements of the chicken yolk except calcium, while all but phosphorous could be substantially affected by hen-age in the albumen. Copper and zinc concentrations of the yolk significantly increased from week 31 (0.7 and 21.2 μg/g) to week 40 (1.2 and 28.9.2 μg/g) to week 53 (1.9 and 39.5 μg/g) correspondingly. Chicken strain and age interactions were detected for all minerals in the egg parts with the exception of calcium in the yolk. The results denote that yolk from White Leghorn at week 40 had about 5% more potas-sium than at weeks 31 and 53, comparable to the observation made for the same element where the yolk from the Lohmann White at week 40 had about 11% more potassium than at weeks 31 and 53. In summary, there are variations in the mineral contents of egg yolk and albumen of layer chick-ens by virtue of their genetic constitution and ages. Consequently, farmers must produce from the best strains (genotypes) at the appropriate hen-ages to make mineral contents of eggs meet the needs of specific consumers and products. The outcomes will therefore be beneficial for dieticians to recommend quality eggs for persons with specific mineral challenges and also assist the manu-facturing industry to choose eggs for particular products.