title: Acute depigmentation of fertile brown eggs in a commercial layer operation.
abstract: Rapid depigmentation of brown eggs is an infrequent but startling event in the commercial egg industry that can result in significant economic losses. Loss of shell pigment in brown-shelled eggs is caused by various factors. In many cases, the exact cause of flock-wide pigment loss remains undetermined. A rapid decline in shell pigmentation was observed in 2 flocks of Hyline brown layers. The lack of evidence of an infectious disease process suggested a feed or management problem. On the basis of a small-scale, "in-house" feeding trial, the feed was identified as the cause of depigmentation. Feed analysis by liquid chromatography with mass spectrometry confirmed the presence of 4,4'-dinitrocarbanilide, a major component of nicarbazin (NCZ). There was no evidence of increased mortality, and only a slight but transient drop in the egg production was observed. Depigmentation effects were rapidly reversed after replacing the feed with NCZ-free feed.
authors.affiliation: California Animal Health and Food Safety Laboratory System, School of Veterinary Medicine, University of California, Davis, 1550 N Soderquist Avenue, PO Box 1522, Turlock, CA 95381, USA.
authors.forename: Bruce R
authors.initials: BR
authors.lastname: Charlton
authors.forename: Asheesh K
authors.initials: AK
authors.lastname: Tiwary
authors.forename: Arthur A
authors.initials: AA
authors.lastname: Bickford
authors.forename: Mike
authors.initials: M
authors.lastname: Filigenzi
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D000818:Animals; D002224:Carbanilides / Q000009:adverse effects* / Q000032:analysis*; D002645:Chickens; D004528:Egg Shell / Q000187:drug effects* / Q000378:metabolism; D005260:Female; D010860:Pigments, Biological / Q000378:metabolism*
chemical_list: D002224:Carbanilides; D010860:Pigments, Biological; C039493:4,4'-dinitrocarbanilide