|Packialakshmi, Balamurugan - University Of Arkansas|
|Liyanage, Rohana - University Of Arkansas|
|Lay, Jackson - University Of Arkansas|
|Okimoto, Ron - Cobb-Vantress, Inc|
Submitted to: Biomarker Insight
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/1/2014
Publication Date: 1/14/2015
Citation: Packialakshmi, B., Liyanage, R., Lay, J., Okimoto, R., Rath, N.C. 2015. Prednisolone-induced predisposition to femoral head separation and the accompanying plasma protein changes in chickens. Biomarker Insight. 10:1-8.
Interpretive Summary: Meat-type poultry suffer from leg problems due to their fast growth which lead to their lameness. One of the causes of poultry lameness is due to the separation of their thigh bone from the hip joint cartilage which is called femoral head separation (FHS). It is a production and welfare problem in poultry industry. To eliminate the birds prone to this leg problem requires diagnosis ahead of time with some markers. Blood is a good source of markers associated with health problems. We wanted to identify whether there are biomarkers by comparing blood proteins of heathy and FHS-prone birds. We used a chemical called prednisolone to induce femoral head weakness by injecting it at 5 wk of age which increased the incidence of this leg problem. We then compared the blood protein profiles of healthy and diseased birds with a technique called mass spectrometry. Our results showed that 2 peptides coming from the breakdown of HDL, a cholesterol carrying protein, were elevated in disease prone birds and there were certain proteins which support blood vessel growth and maintain the integrity of growth region of femur near hip joint were absent. We suggest that monitoring the levels of these proteins may predict the susceptibility of the birds to femoral head problems.
Technical Abstract: Femoral head separation (FHS) is an idiopathic bone problem that causes lameness and production losses in commercial poultry. In a model of prednisolone induced susceptibility to FHS, the changes in plasma proteins and peptides were analyzed to find possible biomarkers. Plasma from control and FHS-susceptible birds were depleted of their high abundant proteins by acetonitrile precipitation then subjected to cation exchange, and reverse phase (RP) fractionations. Analysis with Matrix Assisted Laser Desorption Ionization-Time-of-Flight Mass Spectrometry (MALDI-TOF-MS) showed several differentially expressed peptides two of which were isolated by RP-HPLC and identified as the fragments of Apolipoprotein A-I. The acetonitrile fractionated plasma proteins were subjected to reduction/alkylation, and trypsin digestion followed by liquid chromatography and tandem mass spectrometry which showed the absence of protocadherin 15, vascular endothelial growth factor-C, certain transcription- and ubiquitin mediated proteolytic factors in FHS prone birds. It appears that prednisolone induced dyslipidemia, vascular, and tissue adhesion problems may be consequential to FHS.