Factors affecting plasma chemistry values of the Spanish Imperial Eagle, Aquila adalberti

Abstract

Studies in endangered raptors have given reference values for some blood constituents of metabolic, veterinary, ecological and/or taxonomic interest. However, the variations in such values with physiological and external factors are poorly known. In the present study, the influence of sex, age, nutritional state and local environment was tested on up to 19 plasma variables in the Spanish Imperial Eagle (Aquila adalberti). Our results showed that differences between sexes were not significant for any of the studied parameters. However, age had a significant effect on a number of metabolites, inorganic ions and enzyme activities. In particular, age- related differences in glucose, triglyceride, lactate dehydrogenase, creatine phosphokinase and creatinine values between chick and (sub)adult eagles were found. In addition, some metabolic responses of subadult birds to fasting and refeeding were quite similar to those found in other raptors. Finally, nestlings inhabiting different geographic areas also differed in relation to the values of several plasma parameters, those dissimilarities probably accounting for quantitative and qualitative differences in their respective diets.