THE EFFECT OF HENS AGE AND WEIGHT CLASSES ON THE INTERNAL COMPOSITION OF EGGS
Nikolova Nedeljka, Kostadinov Tosho, Nastova Rodne
In this study there were tested the effect of hen's age and egg weight classes on internal composition of eggs (mass and chemical composition of albumen and yolk). As test material we used eggs from two groups of Isa Brown hybrid hens, younger layers to 45 weeks and older layers with more than 45 weeks of age. Equal number of eggs were collected from five weight classes of eggs (C, B, A, S and SS), which whom were examined the mass of albumen and yolk in separate classes of eggs and percentage content of individual parameters for determining chemical composition of albumen and yolk in both age groups. Obtained results were statistically processed by applying different models of Least Squares Means Harvey (1990). The influence of hen's age on the mass and the chemical composition of albumen and yolk and was not statistically significant in any of their parameters. Although, younger hens had average lower mass of yolk (16.72 g) and consequently lower values of its chemical composition unlike the older hens (17.02 g). An examination of effect of egg weight classes on the internal composition of eggs also showed no statistical significance. But differences in mass of albumen and yolk by egg weight classes were evident. Namely, the lowest values of albumen mass had eggs of C weight class (36.14 g) and the highest values had egg of SS weight class (40.71 g), which indicates right ratio of albumen mass with egg weight classes.
Key words: hen's age, weight classes, albumen, yolk, chemical composition