Blood biochemical profile of the South American rattlesnake (Crotalus durissus terrificus) in captivity

Original paper

BLOOD BIOCHEMICAL PROFILE OF THE SOUTH AMERICAN RATTLESNAKE (Crotalus durissus terrificus) IN CAPTIVITY

J. C. TROIANO1, E. G. GOULD³, R. ALTHAUS², G. MALINSKAS²,J. A. GOULD³, J. HEKER¹, J. C. VIDAL¹, E. AMANTINI³, C. SIMONCINI¹

1 Area de Iología, Museo de Ciencias Naturales "Bernardino Rivadavia", Avenida Angel Gallardo 470 (1405), Buenos Aires, Argentina; 2 Cátedra de Química Biológica, Facultad de Agronomía y Veterinaria de Esperanza, Universidad Nacional del Litoral, Rvdo. Padre Luis Kreder 2805 (3080) Esperanza , Santa Fe , Argentina; 3 Fundación de Estudios Biológicos - Gral Urquiza 1940/42 -(1243) Buenos Aires -Argentina.

ABSTRACT: Blood samples were collected from 180 healthy specimens of the South American rattlesnake, Crotalus durissus terrificus, in captivity. All animals were in good clinical condition. Normal biochemical reference values were established for the following: total proteins, albumin, globulins, uric acid, creatinine, urea, glucose, triglycerides, cholesterol, total lipids, calcium, phosphorus, potassium, sodium, chloride, magnesium, GOT (AST), GPT (ALT), and alkaline phosphatase (ALP). Samples were obtained by venipuncture of the ventral tail vein. Values were compared with published data for Boidae, Elapidae, and Viperidae.

KEY WORDS: blood, biochemistry, Crotalus durissus terrificus, captivity.

INTRODUCTION

Determination of normal blood biochemical values in a population kept in captivity is an essential step to estimate health condition. This procedure is routinely employed for mammals and birds, but not usually for snakes.

Normal hematological and biochemical data for snakes in captivity are generally available. This is not true for South American snakes, especially Crotalinae.

To establish normal biochemical data for the South American rattlesnake, Crotalus durissus terrificus, in captivity blood samples from 180 snakes were collected for analysis.

MATERIALS AND METHODS

One hundred and eighty healthy

Crotalus durissus terrificus snakes of varying ages and both sexes, captured in Argentina (deparasitized upon arriving at the snake farm and then quarantined for one month) were kept in individual wooden boxes at 22-28°C, 40-60% humidity, and natural day/night cycles as in the different seasons of the year.

All the specimens fed spontaneously on living prey, one adult mouse (20-25 g) for a week and received filtered water ad libitum. All the samples were obtained in 1999. Blood sampling was performed by removing the snakes from the boxes using a metallic hook and firmly restraining the head and the rest of the body by two operators. The use of anesthetics or sedative agents, known to induce significant alterations in the hematological values (6), was avoided. Blood (2.0 ml) was collected by a third operator by venipuncture of the caudal vein (13) using disposable 21G-needles fitted to sterile 2.5 ml syringes.

The blood samples were transferred to clean glass tubes and the serum was obtained. Total proteins, albumin, and globulins were determined by the Biuret method; uric acid was determined in a sample of serum deproteinized with tungstic acid and calcium carbonate by uricase and peroxidase, resulting in quinoneimine dye. Creatinine was determined using creatinine picrate method; urea was determined spectrophotometrically at 505 nm by the formation of indophenol blue. Triglycerides and glucose were measured at 505 nm by the formation of quinonein dye. Cholesterol was determined spectrophotometrically by the 4p-benzoquinone monophenazone reaction. Total lipids were measured at 530 nm by ethyl-vainillin reaction. ALT and AST were determined spectrophotometrically by the formation of 2.4 dinitrophenylphosphate. ALP was determined at 405 nm by hydrolysis of nitrophenylphosphate. Phosphorous was determined at 630 nm by the formation of phosphomolibdate; calcium was measured at 570 nm by reaction with cresolphtalein-complexone; chloride was measured at 460 nm by the complex formation with sulphocyanide; magnesium at 520 nm by the complex formation with magon. Potassium and sodium were measured by flame spectrophotometry. All reagents used in these biochemical determinations were provided by Wiener Laboratorios, Argentina. Blood chemical values are expressed in SI Units (9).

RESULTS

The different determinations performed in serum (expressed in SI Units) (9), are shown in Table 1.

DISCUSSION/CONCLUSION

The amount of total proteins, albumin, and globulins are within the range of variation described in other Crotalus species (C. atrox, C. horridus, C. rubber, and C. viridis) (4,8) and some other viperid snakes (Vipera ammodytes, V. berus, V. lebetina, Agkistrodon intermedius, Echis carinatus, Agkistrodon piscivorus, and Bitis arietans) (7,10,11,15) but lower than those reported for Boidae (3,5,16,17).

Total lipids, cholesterol, and triglycerides are within the range described for other Crotalus species such as Crotalus horridus and C. oreganus (4), but lower than those reported for Bitis arietans (15), Crotalus atrox (4), and Boidae (3,17).

Serum glucose concentration is similar to that reported for Boidae (3,5,17), but lower than those reported for elapid species, although the latter were obtained by a different, less precise method (2).

Urea concentration found in C. d. terrificus is within the range described for other ophidian species (8) and lower than that observed in Crocodylia, since snakes do not produce urea as a final product of nitrogen. In fact, nitrogen is directed to purine biosynthesis, resulting in uric acid and this metabolic route appears to play an essential role in water balance. Uric acid concentration in C. d. terrificus is within the range reported in Boidae (3,17). Determination of uric acid concentration is particularly important, since it allows early detection of hyperuricemia (uric gout), resulting in urate deposition in tissues and organs and eventually death, to which C. d. terrificus is particularly susceptible (14). Serum concentrations of sodium, chloride, and potassium are similar to those found in other species, such as captive and free-ranging Boidae (3,5,17), Colubridae (1,11), Elapidae (2), Viperidae (10,12, 15), and other Crotalus species (4).

Concentrations of magnesium, phosphorous, and calcium are within the range of variation described for Crotalus atrox, C. horridus, C. oreganus (4), other Viperidae (12,15), Elapidae (2), and some Boidae of Eunectes genus (3,17), but lower than those obtained with Python regius and Boa constrictor constrictor (5, 16). Concentration of serum enzymes (GOT, GPT, and ALP) are within the range described by other authors for Boa constrictor and Python regius (16) as well as in an autochthonous Boidae, Eunectes notaeus (17).

With the exception of total proteins, albumin, globulins, lipids, cholesterol, and triglycerides all biochemical values are within the range described for Elapidae, Viperidae, Crotalinae, but lower than those reported for Boidae.

Data in this paper can be a useful tool in establishing normal biochemical values for captive Crotalus durissus terrificus and for comparison with the free-ranging population for conservational or veterinary purposes.

Received 27 September 2000

Accepted 4 December 2000

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Publication Dates

• Publication in this collection
  08 Oct 2002
• Date of issue
  Dec 2001

History

• Accepted
  04 Dec 2000
• Received
  27 Sept 2000