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

Luca Giori,Michael Ogle,Andrew C Cushing,Stephen Nelson,Nicole I Stacy,Kellie A Fecteau

doi:10.1007/s00580-019-03030-w

Abstract

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.

Highlights

Electronic supplementary material The online version of this article contains supplementary material, which is available to authorized users.Pituophis is a genus of non-venomous large-bodied constrictor snakes belonging to the Colubridae family, which is considered the largest and most structurally diverse snake group, including about 50% of all known living snake species (Uetz et al 2018; Vitt and Caldwell 2014)
Significant variation can occur within a given species due to intrinsic and extrinsic factors such as ambient environment, season, analytical methodology, physiological state, and diet (Campbell 2015c; Stacy et al 2011)
Eleven captive Louisiana pine snake (LPS) housed at Zoo Knoxville, TN, USA, were included in this study

Summary

Introduction

There is extensive variation in such data between species and even genus, and published reference data are lacking for many. Significant variation can occur within a given species due to intrinsic and extrinsic factors such as ambient environment, season, analytical methodology, physiological state, and diet (Campbell 2015c; Stacy et al 2011). Hormone analysis in snakes is not routinely performed due to lack of readily validated assays for diagnostic use and most frequently used in research studies offering insights into reproductive physiology, breeding suitability, or timing and may offer an alternative tool for sexing as demonstrated in previous studies (Edwards and Jones 2001; Jones 2011; Taylor and DeNardo 2011; Taylor et al 2004)

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