Effects of body mass and genotype on avian degenerative joint disease pathology and articular cartilage proteoglycan distribution.
OBJECTIVE
The objective of this study was to investigate the role of body mass and genotype in the development of avian degenerative joint disease (DJD).


METHODS
Layer strain and broiler strain fowl, fed either ad libitum or on a restricted diet, were kept under identical conditions for up to a year. At various time points cartilage samples were taken from the distal tibiotarsus (DTT), proximal tarsometatarsus, antitrochanter and proximal humerus. All samples were assessed for gross morphology and histopathology, and in some samples the cartilage proteoglycan distribution was investigated by Safranin O staining.


RESULTS
Layer strain fowl did not develop DJD. Heavy ad libitum fed broiler strain fowl developed DJD earlier and more severely than lighter, feed restricted, broiler strain fowl. The articular surface of the DTT was worst affected by DJD. Safranin O staining of DTT samples (age 180 days) from the ad libitum fed broilers revealed variable proteoglycan distribution in the articular cartilage. Some areas were intensely stained throughout all zones, whereas other areas showed no staining in any zone. Age matched, non-diseased DTT samples from feed restricted broilers showed a more consistent staining pattern with little staining in the surface zone and more in the middle and deep zones.


CONCLUSIONS
These data indicate that avian DJD is body mass mediated in broiler strain fowl, and that proteoglycan distribution is altered in diseased cartilage.
Department of Biochemistry, University of Edinburgh, U.K.
J M
JM
Anderson-MacKenzie
D J
DJ
Hulmes
B H
BH
Thorp
D000818:Animals; D001835:Body Weight; D002358:Cartilage, Articular / Q000378:metabolism* / Q000473:pathology; D002645:Chickens; D004396:Coloring Agents; D005838:Genotype; D006614:Hindlimb / Q000378:metabolism / Q000473:pathology; D007596:Joints / Q000378:metabolism / Q000473:pathology; D010003:Osteoarthritis / Q000235:genetics / Q000378:metabolism / Q000473:pathology / Q000662:veterinary*; D010619:Phenazines; D011201:Poultry Diseases / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D011509:Proteoglycans / Q000235:genetics / Q000378:metabolism*; D013045:Species Specificity
D004396:Coloring Agents; D010619:Phenazines; D011509:Proteoglycans; C009195:safranine T