Atherosclerosis risk factors in pigeon squabs

The basis for atherosclerosis susceptibility of White Carneau (WC) and resistance of Show Racer (SR) pigeons is not known. Body weight (BW), total serum cholesterol (TSC), growth of the aorta and replication of endothelial cells of the distal thoracic aorta (lesion prone site) of 1, 2 and 4 week old squabs were studied. Aortic measurements were determined morphometrically, and endothelial cell replication was quantitated by 24-hour 3H-thymidine labeling and whole-mount SEM autoradiography. From hatching to 4 weeks, BW increased more in WC than SR (22 to 473 gm in WC vs 19 to 416 gm in SR, p < 0.05) in WC than SR (197, 243 and 338 mg/dl in WC and 125, 194 and 282 mg/dl in SR). Surface area of the aorta between 1 and 4 weeks increased by 63% (109, 154 and 178 mm2) in WC and 44% (101, 140 and 146 mm2) in SR. Aortic surface area was significantly larger (0 = 0.002) in the 4 week WC than 4 week SR. 3H-thymidine labeled endothelial cells at 1, 2 and 4 weeks were 783, 387 and 53 in WC and 674, 283 and 27 cells/mm2 in SR. Endothelial replication in the 4 week WC was twice that of the SR and significantly different between breeds at 2 and 4 weeks (p = 0.04; p = 0.02, respectively). Higher TSC, endothelial cell replication and larger aortic surface area in the WC may be contributing factors to increased atherosclerosis susceptibility