Applicability of a Spectrophotometric Method for Assessment of Oxidative Stress in Poultry

Oxidative stress is discussed as being related to health, welfare, and also to product quality. Recently, a spectrophotometric method based on the Fenton reaction (reactive oxygen metabolites, ROM) has been proposed to characterize pro-oxidative stressors in body fluids by determining early products of oxidation from proteins, lipids and nucleic acids. The applicability of this method for blood samples from various bird species was tested. The validity of the method for mammalian domestic animals was demonstrated by linearity yielded with increasing amounts of serum. In contrast, serum obtained from chicken yielded ROM concentrations below the limit of detection when serum volumes comparable to mammalian samples were used. Applying higher amounts of serum was not increasing the optical density readings in a linear way. To assess whether the lack of sensitivity and linearity is a problem limited to chicken or poultry in general, we tested sera from laying hens, turkey, duck, goose, pheasant, pigeon, and guinea fowl. For most of the species tested, the method could not be validly applied. There is no reason to assume that oxidative stress in birds may not exist, therefore we conclude that bird specific matrix effects hinder the valid application of the ROMs test in poultry.