SERUM PEPTIDE CHANGES IN CHICKENS WITH METABOLIC SKELETAL PROBLEMS ASSOCIATED WITH LAMENESS

Abstract

Serum proteins and peptides have potential as biomarkers since they form the structural and functional basis of tissues and are involved in metabolic and regulatory processes. Changes in their profiles or their breakdown products have been of interest as potential biomarkers. Tibial dyschondroplasia (TD) and femoral head separation (FHS) are two metabolic skeletal problems in poultry that cause lameness. The objective of this study was to identify serum peptide changes associated with lameness in poultry that may be predictive of the disease and may help in eliminating these hereditary defects from the genetic pool. Serum peptides were extracted from six‐wk‐old chickens with or without the above leg problems using C18 magnetic beads and analyzed by MALDI‐TOF mass spectrometry. Differentially expressed peptides were analyzed in the m/z range of 1,000–10,000 using ClinproTool™ software. Twenty two peaks from TD and 20 from FHS affected chickens were compared with their respective controls. The spectral peaks were identified using mass spectrometry followed by a data base search. Some of the peptides identified were hemostasis associated breakdown products. No differentially expressed peptide was detected in FHS but a peptide with m/z 5308.1 was elevated in chickens with TD (p⩽0.05). It was identified as a fragment of alpha 1 type‐XI isoform 1. Type XI collagen is a cartilage specific extracellular matrix protein that is involved in the organization of other collagens and maintains extracellular matrix integrity. Its breakdown product may indicate cartilage degeneration in tibial dyschondroplasia thus may serve as a surrogate marker for this problem.