Establishment of Selected Baseline Blood Chemistry and Hematologic Parameters in Captive and Wild-Caught African White-Backed Vultures (Gyps Africanus)

Abstract

ABSTRACT:Despite the devastating collapse of three vulture populations on the Asian subcontinent as a result of their exposure to diclofenac, there is little available information on the normal physiology of many vulture species, including the African White-backed Vulture (Gyps africanus). Such information is needed to fully understand mechanisms for toxicity and to identify and prevent future health problems. The aim of this study was to establish baseline parameters for hematologic and selected serum chemistry parameters for this model species for further studies into the toxicity of diclofenac. Captive nonreleasable and wild African White-backed Vultures were used to determine reference values. For hematology, erythrocyte counts, hemoglobin concentration, hematocrit, packed cell volume, mean corpuscular volume, mean corpuscular hemoglobin concentration, and total and differential leukocyte counts were measured. Chemical analytes measured included sodium, potassium, calcium, albumin, and globulin concentrations, aspartate aminotransferase, creatine kinase, and alanine aminotransferase activities. Uric acid and urea concentrations and the urea:uric acid ratio also were evaluated. Values are presented as means, standard deviations, and reference intervals. The serum chemistry parameters selected may provide a starting point for the evaluation of changes in renal and hepatic function; these organ systems are most severely affected by diclofenac. Results were also compared with values reported for G. africanus nestlings, and from these results it is evident that the clinical pathologic parameters are age related. This indicates that the use of nestling values for the evaluation of clinical pathologic findings in adults may be unreliable and could lead to incorrect assumptions.

Diclofenac toxicity in Gyps vulture is associated with decreased uric acid excretion and not renal portal vasoconstriction

“…This difference was not significant (p = 0.4) and also within the normal range established for the White-backed vulture (Naidoo et al, 2008b). While both MLX and DF appeared to induce an increase in plasma UA (n = 4/drug) (Fig.…”

Hematocrit and Plasma Chemistry Values in Adult Collared Scops Owls (<i>Otus lettia</i>) and Crested Serpent Eagles (<i>Spilornis cheela hoya</i>)

“…The HCT values of adult captive collared scops owls and adult captive crested serpent eagles were similar and lay within the ranges described for captive individuals of other raptors [13,17,19,21,30,35]. In general, male birds are thought to have higher HCT than females, partly due to the erythropoietic effect of androgens [37,35].…”

“…As Spagnolo et al [35] aptly pointed out, it is essential to guarantee a high chance of survival to release animals and to avoid the introduction of pathogens into the environment. Successful survival and prevention strategies could benefit from combining clinical examinations with analyses to detect hematologic and biochemical abnormalities in rehabilitated animals prior to their release [30,35].…”

Opportunistic infection of Aspergillus and bacteria in captive Cape vultures (Gyps coprotheres)

“…In our case, we compared the blood parameters with those of Polo et al [16] , and the variations were not conclusively suggestive of aspergillosis. However, we noted the elevation of alanine amino transferase and aspartate amino transferase, enzymes that are often associated with physiological harm such as trauma, stress, toxicity or hepatocellular injury [17] . The vultures in the present case underwent a series of physical capture events within the zoo during sampling.…”