Replacement of barley by oats and enzyme supplementation in diets for laying hens, 2: Interior quality and chemical composition of eggs
Aimonen, E.M.J. (Helsingfors Univ. (Finland). Inst. foer Husdjurslaera) | Uusi-Rauva, E.
A total of 864 eggs were analysed for physical and chemical egg quality traits and fatty acid composition. The eggs were from a performance trial in which the replacement of increasing portions of barley in the diet by oats and the effect of multi-enzyme supplementation (Avitzyme, Cultor Ltd.) were studied during the first six laying months. Almost all physical and chemical egg quality traits and the main fatty acids in the yolk were significantly affected by hens' age in a linear and quadratic manner. The trend was for increasing yolk, albumen and shell weights, so that the percent of yolk in the whole egg weight increased and albumen and shell percentages decreased as the hens grew older. Yolk solids and lipid concentrations increased, but yolk colour turned lighter during the laying period. Albumen height, Haugh units, shell weight per shell area and shell thickness decreased. The replacement of barley by oats in diets had no influence on the gross physical or chemical composition of the eggs. The enzyme treatment had a small but significant negative effect on all shell quality traits except the percentage of cracked eggs. Yolk colour points were higher on diets with the enzyme. The percentage of oleic acid in egg yolk increased while the proportion of other fatty acids decreased as the hens grew older. The concentration of linoleic acid increased and that of palmitic, palmitoleic and oleic acids decreased with increasing dietary level of oats. The enzyme supplementation had no influence on the fatty acid composition of the yolk.Show more [+] Less [-]