Biochemical and Weight Changes of Mottled Yolks in Eggs from Hens Fed Nicarbazin

INTRODUCTION YOLK mottling has been observed for many years but the physical and chemical alterations of the yolk associated with this phenomenon have not received particular attention. The only data were those which characterized a sample of mottled areas, removed from boiled yolks, as having a higher protein-fat ratio than a sample of non-mottled yolks (Almquist, 1933). When nicarbazin, a coccidiostat, was fed at levels above 0.005 percent to laying hens, there was an increase in the incidence and degree of yolk mottling above that observed in eggs from non-medicated hens (Polin, Ott and Siegmund, 1957). Some of the yolks were analyzed to determine the changes associated with mottling, and the results are reported herein. EXPERIMENTAL The eggs used in this experiment were obtained from White Plymouth Rock and White Leghorn hens. Some of these birds were kept in single cage batteries at the laboratory while others were at a . . .