A PROBLEM WITH CHARACTERISTICS OF THE THIN ALBUMIN IN LAYING HENS

Industry observations indicate that a proportion of shell eggs exhibit an uncharacteristic spreading of the thin albumen when they are broke n-out for fast-food preparation. Because the height and characteristic s of the thick albumen are unaffected, the eggs are classified as Grad e A. Preliminary observations discounted effects of egg storage or con taminated feed. Two experiments were conducted with Leghorn hens over a full laying cycle, and involved different levels of protein (14, 16, 18, or 20%) and associated amino acids, or different degrees of acid- base balance (150, 200, 250, or 300 mEq/kg). In each trial, treatments were represented by eight replicate groups of four adjacently and ind ividually caged birds. Diet treatment had some effects on conventional production parameters, although there were no major effects on the ar ea of the thin albumen produced when eggs were broken out. In Experime nt 1, birds fed the highest level of protein produced eggs with the sm allest thin albumen area; however, there was considerable bird to bird variation with thin albumen area varying from 69 to 122 cm(2). Ten bi rds with compact (x 69 cm(2)) and 10 birds with spreading thin albumen (x 112 cm(2)) were inseminated with Semen from a single, unrelated ro oster. Offspring from these hens had significantly (P < 0.01) differen t thin albumen characteristics corresponding to those of their darns. Offspring producing eggs with the spreading thin albumen had the thick est eggshells as assessed by deformation measurement (P < 0.05). It is proposed that the excessively large spreading thin albumen area is ca used by eggs spending more time in the shell gland.