Autologous, homologous, and heterologous red blood cell transfusions in cockatiels (Nymphicus hollandicus)

The use of heterologous blood transfusions in birds is controversial. The purpose of this study was to determine the survival of fluorescent-labeled red blood cells (RBCs) after single and multiple transfusions in compatible cross-matched groups of birds. Twenty cockatiels (Nymphicus hollandicus) were equally divided into four transfusion groups: an autologous or control group (transfusion to same bird); a homologous group (cockatiel to cockatiel), a heterologous group of two species in the same taxonomic family (blue-fronted Amazon parrot [Amazona aestiva] to cockatiel), and a heterologous group of two species in different orders (pigeon [Columba livia] to cockatiel). Donor blood (1 ml) was centrifuged and the plasma discarded. The washed RBCs were stained with a fluorescent dye and transfused into recipient cockatiels. Three RBC transfusions using the same donor-recipient pairs were administered at 0, 7, and 9 weeks, and then serial blood samples were analyzed by using flow cytometry to measure fluorescent-labeled RBCs remaining in circulation over time. The fluorescent-labeled RBC half-life was significantly longer in the autologous and homologous groups (range, 10.5 to 16.8 days) than in the two heterologous groups (range, 0.1 to 2.6 days) after all three transfusions (P < .001 for all comparisons). No difference was found in half-life of RBCs between the two heterologous groups after any of the transfusions or between the autologous and homologous groups after transfusions 1 and 2. After transfusion 3, the half-life was longer in the autologous group than in the homologous group (P < .001). We conclude that fluorescent-labeled RBC survival is comparable after autologous and homologous avian transfusions; however, heterologous transfusions result in significantly shorter half-life of transfused RBCs, regardless of taxonomic relatedness. Therefore, heterologous transfusions in birds may not be efficacious.