Hematology, plasma biochemistry, and hormonal analysis of captive Louisiana pine snakes (Pituophis ruthveni): effects of intrinsic factors and analytical methodology

Blood analyte data are useful in health assessments and management of reptiles. There is a knowledge gap for blood analyte data of the endangered Louisiana pine snake (LPS; Pituophis ruthveni). The objectives of this study were to provide baseline hematology, plasma biochemical, and hormone data of captive LPS, to compare the data in juvenile and adult snakes and in adult snakes by sex, and to investigate methodological differences in hormone (serum vs. plasma) and protein analyses (total solids versus total protein). Blood samples from apparently healthy captive LPS were analyzed for hematology and plasma biochemistry (n = 11) and plasma and serum hormone analyses (n = 9). Packed cell volume (PCV) and absolute heterophils were significantly higher in adult compared with juvenile LPS, while PCV, white blood cell count, and absolute lymphocytes were higher in adult males compared with adult females. Significantly higher plasma concentrations were found in adults compared with juveniles for calcium, total protein, total solids, albumin, globulins, and bile acids. No significant differences were observed in 17β-estradiol measured in serum and plasma when comparing adults and juveniles and for 17β-estradiol in adult males and females. Plasma concentrations of 17β-estradiol were significantly lower than in serum. Serum testosterone in two adult males was 8.33 and 35.53 nmol/L, respectively, while it was undetectable in females and juveniles (n = 5). This study is the first to provide baseline information on blood analytes in endangered LPS, which will be useful for individual animals in managed care and as baseline for future population-level assessments.