Seasonal variation in blood biochemistry of long term captive Mediterranean tortoises (Testudo graeca and T hermanni)

Evaluation of changes in serum biochemical parameters in zarudny's spur-thighed tortoises (Testudo graeca zarudnyi) influenced by gender and season

BACKGROUND

The Zarudny's spur-thighed tortoise or Iranian tortoise (Testudo graeca zarudnyi) has just been reported from Iran so far. Therefore, the purpose of this study was to determine the effects of season and gender on serum biochemical parameters of this valuable species in Iran.

RESULTS

This study was performed on 20 clinically healthy adult Zarudny's spur-thighed tortoises. Blood samples were collected from the jugular vein and then serum biochemical parameters and body weight were measured in autumn and winter. The following biochemical parameters were measured: total cholesterol, triglyceride, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, very low-density lipoprotein, total protein, creatinine, urea, glucose, calcium, inorganic phosphorus, total bilirubin, uric acid, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and lactate dehydrogenase. Urea concentration increased significantly at emergence from hibernation. Also, in winter, total protein, phosphorous, creatinine, total bilirubin concentrations and alkaline phosphatase activity decreased significantly compared to autumn, but aspartate aminotransferase and lactate dehydrogenase activities were significantly higher than in autumn. There was no significant difference for the parameters mentioned above by gender, except for phosphorous. Phosphorous concentration in females was significantly higher than that of males in autumn. Cholesterol and low-density lipoprotein cholesterol levels in females were significantly higher than males in autumn and winter.

CONCLUSIONS

The present study is the first study that monitors the serum biochemical parameters of adult Zarudny's spur-thighed tortoises based on season and gender. Seasonal reference intervals should be used for biochemical parameters in this valuable species. Also, sex-specific reference intervals for phosphate and cholesterol are necessary.

Hemoparasite occurrence and hematological/serum chemistry variations in Podocnemis vogli turtles: A comparative analysis between wild-residing infected specimens and captive non-infected counterparts

Reptiles show a high occurrence of hemoparasites in the wild; however, little is known about the impact of such infections on their hosts' physiology and health status. Podocnemis vogli is an ancient turtle distributed in South America, frequently infected by blood parasites. Specifically, we analyzed the hematological and serum chemistry parameters of 78 wild turtles. We compared these values with those obtained from non-infected turtles of the same species in ex-situ conditions, considering factors such as sex and coinfections. Two orders of hemoparasites were detected under microscopic analyses: Adelorina, represented by Haemogregarina sp. (98.72 ± 0.28%), and Haemosporida, represented by Haemocystidium sp. (30.77 ± 1.16%), the latter genus being always in coinfection with Haemogregarina. Significant differences were observed in 20 parameters between infected (free living) and uninfected (living in captivity) turtles. The ALP, PCV, Hb, and MCV were significantly different by sex; albumin, cholesterol, creatinine, percentage of heterophils, lymphocytes, and basophils differed in coinfection. This is the first report of reference intervals of P. vogli in the wild and the first study comparing hematological and blood biochemistry values between hemoparasite-infected and uninfected P. vogli turtles. However, the limited knowledge of these parameters in wild reptiles and the wide range of interval values makes it difficult to determine any significant impact on turtle health. Nevertheless, this study highlights the need for more in-depth research to explore the potential effects of blood parasite infections on turtles, including immune response and coevolution studies.

The Amount of Food Ingested and Its Impact on the Level of Uric Acid in the Blood Plasma of Snakes

In mammals, lipemic blood from sampling too soon after an animal feeds can have substantial effects on biochemical values. Plasma biochemical values in reptiles may be affected by species, age, season, and nutritional state. However, fasting status is not routinely considered when sampling reptile blood. Assessing uric acid levels in snakes is an important part of the diagnosis of the renal disease. However, the use of this biochemical indicator is undervalued without knowledge of natural uric acid fluctuations and the lack of differentiation from pathological changes. This study aimed to look at the relationship between snake feeding and uric acid concentrations. The investigation aims to better understand the feed-induced changes that occur and render the analysis of this biochemical parameter a more potent diagnostic tool. The study used ten snakes belonging to seven species, and basal uric acid values were evaluated by blood biochemical analysis before feeding. The snakes were fed in two rounds, with successive blood sampling and monitoring of uric acid changes carried out for each. The snakes were fed approximately 50% more with the second round of feeding to investigate the relationship between food supply and uric acid level. The findings show feeding led to substantial elevations in uric acid values, whereby postprandial concentrations were significantly elevated for up to 8 days after feeding. The findings show the significant changes in uric acid levels that occur after feeding and the similarities between postprandial rises in uric acid and those reported in snakes with renal disease. To minimize misdiagnosis and differentiate transient postprandial hyperuricemia from pathological increases, it is recommended that sufficient anamnestic data on time since the last feeding be collected, as well as repeated samples following weeks of fasting. This knowledge is crucial because the amount of feed in terms of intensity and volume has a significant effect on uric acid levels in the blood of snakes.

Seasonal hematology and plasma biochemistry reference range values of the yellow-marginated box turtle (Cuora flavomarginata)

The yellow-marginated box turtle (Cuora flavomarginata) is critically endangered and very few studies have been performed to aid the conservation effort. This study reports the first complete analysis of blood parameters for this species and will provide a reference for future conservation studies. Hematology and biochemistry reference range values were established from 52 (18 males and 35 females) clinically healthy yellow-marginated box turtles (C. flavomarginata). In order to investigate the gender and seasonal differences in these ranges, blood samples were collected from the jugular veins of the turtles in January, April, July, and October to represent the four seasons. To detect significant variation (P < 0.05), data were analyzed using repeated measurements of analysis of variance. Significant gender differences were observed in red blood cell mass parameters, absolute eosinophils, absolute monocytes, alkaline phosphatase, aspartate aminotransferase, blood urea nitrogen, calcium, uric acid, cholesterol, creatine kinase, glucose, phosphorus (P), total protein, and triglycerides. Marked seasonal variations were noted in red blood cell mass parameters, absolute monocytes, albumin, alkaline phosphatase, aspartate aminotransferase, blood urea nitrogen, uric acid, creatine kinase, creatinine, glucose, P, and triglycerides. Primary reasons for the differences between gender and season were associated with reproduction and temperature change. Cuora flavomarginata has lower alanine aminotransferase values compared with other chelonians.

Hematologic and plasma biochemical reference values of the yellow pond turtle Mauremys mutica and the effects of sex and season

Background

The International Union for Conservation of Nature considers the yellow pond turtle Mauremys mutica to be an endangered species. Hematologic analyses are useful tools for monitoring the health, disease processes, and physiologic status of reptiles by clinicians and conservationists. The objectives of this study were to measure plasma biochemical values in healthy captive yellow pond turtles, determine reference values, and evaluate the effects of sex and season on the results. Blood samples were taken from the jugular vein of 53 adult captive individuals (18 males and 35 females) in four different months that represented summer, winter, fall, and spring in Taiwan. Plasma biochemical assays were performed using an automatic analyzer. Descriptive statistics and distributions of each data variable were analyzed using SAS software.

Results

Hematological and plasma biochemical reference values of the yellow pond turtle were determined in this study. There were no significant sex differences in hematological values; however, there were seasonal differences, and interactions between sex and season were observed. In females, lactate dehydrogenase, uric acid, calcium, cholesterol, and triglyceride concentrations were significantly higher than in males. There were seasonal differences but no sex and season interactions in serum biochemical values.

Conclusions

This information can serve as baseline reference data for future health assessment studies of free-ranging and captive M. mutica, and for epidemiologic, conservation, and captive-breeding studies.

Characterization and quantification of the influence of season and gender on plasma chemistries of Hermann's tortoises (Testudo hermanni, Gmelin 1789)

The present study is the first to monitor plasma chemistries of a group of 30 Hermann's tortoises (HTs) over two summer seasons to characterize and quantify seasonal and gender-related influences. The following analytes were analyzed: ALT, ALP, AST, BA, CA, CHO, CK, LDH, GLU, GLDH, P, TP, TRIG, urea and uric acid. Two-way repeated-measures ANOVA, mean values, confidence intervals were calculated. The overall results showed distinct patterns and somewhat unexpected results concerning the plasma chemistry changes induced by season and gender in a majority of routine biochemical analytes. TRIG, CHO, CA, and P were significantly higher in females. AST, ALT, BA, LDH and GLDH showed an increase in males in midsummer. ALP showed a significant and analogous seasonal variation for both sexes. GLU showed a moderate increase during midsummer. Uric acid and urea concentrations showed a distinct seasonal variation. For some analytes, fitted curves could be calculated describing the seasonal variation.

Plasma biochemical reference values in clinically healthy captive bearded dragons (Pogona vitticeps) and the effects of sex and season

BACKGROUND

Bearded dragons are one of the most popular pet lizard species, and biochemical reference values are useful for health management of these reptiles.

OBJECTIVES

The objectives of this study were to measure plasma biochemical values in healthy captive bearded dragons, determine reference values, and evaluate the effects of sex and season on the results.

METHODS

Blood samples were collected from 100 captive healthy bearded dragons in Tokyo during the summer and winter. Plasma biochemical measurements were performed using a dry-slide automated biochemical analyzer. The data were then compared based on sex and season using 2-way ANOVA.

RESULTS

Globulin, cholesterol, and calcium concentrations of females were higher in both summer and winter compared with the values obtained for males. Both males and females had higher uric acid concentrations in winter than in summer. When compared with males, females had a higher chloride concentration in summer and a higher total protein concentration and aspartate aminotransferase activity in winter. Potassium concentration in males was lower in winter than in summer, whereas in females cholesterol concentration was lower in winter than in summer.

CONCLUSIONS

Biochemical values that differed based on sex and season in bearded dragons were similar to those in other lizards. These differences reflect physiologic differences in reproductive status in females and seasonal changes in temperature and hydration status. Plasma biochemical values established for bearded dragons in this study will be useful in the diagnostic assessment of captive animals.

The Effects of Feeding on Hematological and Plasma Biochemical Profiles in Green (Chelonia mydas) and Kemp's Ridley (Lepidochelys kempii) Sea Turtles

In mammals, lipemic blood from sampling too soon after an animal feeds can have substantial effects on biochemical values. Plasma biochemical values in reptiles may be affected by species, age, season, and nutritional state. However, fasting status is not routinely considered when sampling reptile blood. In this paper, we evaluated 2-hour postprandial blood collection in two sea turtle species to investigate the effects of feeding on hematological and plasma biochemical values. Feeding had no significant effects on hematological values in either species, nor did it have an effect on plasma biochemistry values in Kemp's ridley sea turtles. In postprandial green turtles, total protein, albumin, ALP, AST, ALT, amylase, and cholesterol increased significantly, and chloride decreased significantly. Although statistically significant changes were observed, the median percent differences between pre- and postprandial values did not exceed 10% for any of these analytes and would not likely alter the clinical interpretation.

Comparison of total calcium, ionised calcium and albumin concentrations in the plasma of captive tortoises (Testudo species)

Plasma total calcium, ionised calcium and albumin levels in Hermann's tortoises (Testudo hermanni), spur-thighed tortoises (Testudo graeca), marginated tortoises (Testudo marginata) and Horsfield's tortoises (Testudo horsfieldi) were investigated. The animals were captive adults maintained under natural unfiltered sunlight in the UK with no dietary sources of cholecalciferol. Analysis of total calcium data showed statistically significant seasonal elevations in females in August compared with March (P=0.003), and statistically significant elevations in females compared with males at all sampling points (March P=0.036, June P=0.003 and August P<0.0001). These differences in values became more prominent as the summer progressed. Albumin values did not appear significantly affected by season. However, males had significantly higher albumin levels than females in the August samples. A correlation between total calcium and ionised calcium was confirmed but there was no correlation between total calcium and albumin values. Total calcium levels were a poor indication of ionised calcium levels, which constituted between 18 and 57 per cent of the total calcium value.

SHORT-TERM BIOLOGICAL VARIATION OF CLINICAL CHEMICAL VALUES IN DUMERIL'S MONITORS (VARANUS DUMERILI)

Plasma biochemical values are routinely used in the medical management of ill reptiles, and for monitoring the health of clinically normal animals. Laboratory tests, including clinical biochemical values, are subject to biological and analytical variation, the magnitude of which determines the utility of population-based reference ranges for the detection of abnormal results in the individual animal. Nested analysis of variance of repeated measurements allows the variance to be broken into within-individual, between-individual, and analytical variation. When the within-individual variation is large and the interindividual variation is low, a sample may be accurately classified as normal or abnormal based on a population-based reference interval. However, if the intraindividual variation is low and the interindividual variation high, population-based reference intervals are of limited value as the ranges for an individual encompass only a part of the conventional reference interval. Between-lizard, within-lizard, and analytical components of variance were assessed by nested analysis of variance for 16 commonly measured plasma biochemical parameters in eight healthy adult Dumeril's monitors (Varanus dumerili). Albumin, cholesterol, phosphate, calcium, sodium, and total protein demonstrated levels of individuality suggesting that comparison of a single measurement to a conventional population-based reference range may be too insensitive to detect small but significant alterations in the value for that animal. Only for potassium and AST did the index of individuality suggest that the use of reference values may be warranted. Uric acid, globulin, glucose, and amylase fell in a gray zone, where population-based ranges should be used with caution. The critical difference indicates the difference between two consecutive analytical results that may be safely ascribed to natural variation. In the present study critical difference varied from 7 and 11%, respectively, for sodium and chloride to 75 and 125% for uric acid and AST.

HEMATOLOGIC AND PLASMA BIOCHEMICAL CHANGES ASSOCIATED WITH FENBENDAZOLE ADMINISTRATION IN HERMANN'S TORTOISES (TESTUDO HERMANNI)

Toxicosis associated with benzimidazole anthelmintics has been reported with increasing frequency in zoologic collections. Clinical signs, clinicopathologic abnormalities, and gross and histologic lesions are primarily the result of damage to the gastrointestinal and hematopoietic systems. Profound leukopenia, especially granulocytopenia, is the most common and severe clinicopathologic change associated with benzimidazole administration. Death usually occurs from overwhelming systemic bacterial and/or fungal infections secondary to severe immunosuppression. In this 125-day study, six male Hermann's tortoises (Testudo hermanni) were treated orally with two 5-day courses of fenbendazole 2 wk apart at a dosage of 50 mg/kg. Serial blood samples were used to assess hematologic and plasma biochemical changes before, during, and following the treatment period. Although the tortoises remained healthy, blood sampling indicated an extended heteropenia with transient hypoglycemia, hyperuricemia, hyperphosphatemia, and equivocal hyperproteinemia/hyperglobulinemia, which were considered to be in response to fenbendazole administration. Changes in several other clinicopathologic parameters appeared to correlate with fenbendazole administration. The hematologic and biochemical changes seen in the healthy animals in this study should be considered when treating compromised tortoises with fenbendazole. Hematologic and plasma biochemical status of tortoises/reptiles should be determined before treatment and monitored during the treatment period. The risk of mortality of an individual from nematode infection should be assessed relative to the potential for metabolic alteration and secondary septicemia following damage to hematopoietic and gastrointestinal systems by fenbendazole.

Effects of blood processing techniques on sodium and potassium values: a comparison between Aldabra tortoises (Geochelone gigantea) and Burmese mountain tortoises (Manouria emys)

BACKGROUND

Hematologic and plasma biochemical evaluations are routinely used in evaluating the chelonian patient, but appropriate processing techniques have been minimally defined.

OBJECTIVES

This study was designed to compare the effects of temperature, time, anticoagulant, and species on sodium and potassium values in the Aldabra tortoise (Geochelone gigantea) and the Burmese mountain tortoise (Manouria emys).

METHODS

Blood samples from 7 Aldabra tortoises and 8 Burmese mountain tortoises were collected into tubes without anticoagulant and tubes containing lithium heparin. Sodium and potassium concentrations were measured by flame photometry in serum and plasma harvested immediately after collection and from aliquots of whole blood stored at 4 degrees C and 25 degrees C for 5 to 120 minutes.

RESULTS

In Aldabra tortoises, storage time and temperature had no significant effect on potassium concentrations in heparinized blood and in blood without anticoagulant. However, sodium concentrations in serum and plasma decreased significantly in samples without anticoagulant stored at 4 degrees C and 25 degrees C and in heparinized samples stored at 4 degrees C. In Burmese mountain tortoises, potassium concentrations in serum and plasma increased significantly with time in samples without anticoagulant and in heparinized samples stored at 4 degrees C and 25 degrees C, but the increases were less at 4 degrees C. Sodium concentrations in serum and plasma decreased significantly in blood without anticoagulant and heparinized blood stored at 4 degrees C and 25 degrees C.

CONCLUSIONS

Storage of blood samples with and without anticoagulant at 4 degrees C significantly improved the stability of potassium and sodium concentrations in both species of tortoises. Early separation of red cells from serum or plasma after blood collection is especially important to ensure the reliability of potassium measurements.

Diseases of the reptile pancreas

A great deal of research is still needed to better understand the reptile pancreas especially with regard to diagnosis and treatment. However, vigilant clinicians and pathologists have important roles to play in expanding our knowledge base in this field, and are encouraged to share their findings through publications and presentations.

Temporal, population, and sexual variation in hematocrit of free-living desert tortoises: correlational tests of causal hypotheses

Hematocrit (packed cell volume, PCV) varies seasonally in some vertebrates and often differs between the sexes and among conspecific populations. Such variation in PCV may reflect variation in nutritional health, requirements for oxygen transport (metabolic rate), or hydration. The relative importance of these influences was tested with serial measurements of PCV in two Mojave Desert populations of the desert tortoise (Gopherus agassizii) over two activity seasons, during a period with large seasonal differences in availability of food and water. Hematocrit varied widely (range = 14–40, CV = 20%), reflecting differences between populations, between sexes, between years, and over time within years. Causal hypotheses were tested by correlating PCV with physiological indicators of nutritional health (blood urea nitrogen), oxygen requirements (field metabolic rate), and hydration (length-relative mass, water-influx rate, urine osmolality, plasma sodium, and plasma osmolality). Results indicated a dominant influence of dehydration-induced hemoconcentration during this extreme drought period, although all correlations were relatively weak. Circumstantial evidence is marshalled to suggest longer term effects of nutrition (at seasonal, yearly, and population levels of variation) and perhaps oxygen requirements (driving sexual dimorphism). All these simultaneous and sometimes opposing effects interact in complex ways to produce the patterns of variation observed, and these interactions render PCV a poor indicator of physiological state in desert tortoises.

Sample collection and clinical pathology of reptiles

Clinical pathology techniques can guide the clinician to diagnose and treat the reptile patient successfully. Text, tables, pictures, and diagrams in this article describe blood and cytology collection techniques and interpretation for the common pet reptile species.