51-Chromium Labeled Erythrocyte Half-time Disappearance from Adult Sinclair (S-1) Miniature Swine

Half-time disappearance of ⁵¹Cr-labeled erythrocytes from 20 adult miniature swine was measured. Seven males and 13 females from 388 to 418 days of age, having a mean weight of 55kg were studied. Five ml of blood collected from each animal were labeled with 75 µCi ⁵¹Cr at room temperature for 60 to 90 min. Following injection of the labeled erythrocytes into each animal, blood samples were collected every four to six days. Specific activity was measured and half-time disappearance determined by linear regression. The results were compared with values obtained from the same animals tested at two earlier ages. No significant (P <0.05) difference in erythrocyte half-time disappearance was detected between males and females at the three different ages. Mean (±SEM) erythrocyte half-time disappearance values were: 20 to 46 days of age, 19.58 (±0.59) days; 79 to 109 days of age, 23.56 (±1.18) days; and 388 to 418 days of age, 22.35 (±0.72) days. A significant (P <0.01) difference in erythrocyte half-time disappearance was found between the miniature swine tested at 20 to 46 days of age and those tested at either 79 to 109 or 388 to 418 days of age. No significant (P <0.05) difference in erythrocyte half-time disappearance was found between the two older age groups.