A method for in vitro evaluation of protein hydrolysates for potential inclusion in veterinary diets

A candidate chicken-protein hydrolysate was subjected to high-performance size-exclusion chromatography to characterize its molecular weight profile. An inhibition ELISA assay was developed to assess the residual antigenicity, using canine serum IgG produced by dogs sensitized to the intact protein. Finally, the hydrolysate was compared to the intact protein through electrophoresis and immunoblotting. The chicken hydrolysate had a suitable molecular weight profile with 96.9% reduced to less than 10 kDa peptides. The inhibition ELISA demonstrated a residual antigenic mass of 1.5% compared with the intact protein. Immunoblotting demonstrated a strong immunoreactive band at 68-70 kDa consistent with chicken serum albumin in the intact protein, which was absent in the hydrolysate. These results demonstrate the suitability of the chicken hydrolysate for use in a protein hydrolysate diet, and provide a basis for the future comparisons of the peptide components of hydrolyzed protein diets so that veterinarians may make more informed decisions in their dietary prescriptions. (C) 2004 Elsevier Ltd. All rights reserved.