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The effects of UV light on calcium metabolism in ball pythons (Python regius)

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Abstract

Despite the popularity of keeping snakes in captivity, there has been limited investigation into the effects of UV radiation on vitamin D levels in snakes. The aim of this study was to investigate the effects of UV-b radiation on plasma 25-hydroxyvitamin D3 levels and ionised calcium concentrations in ball pythons (Python regius). Blood samples were taken from 14 ball pythons, which had never been exposed to UV-b light, to obtain baseline 25-hydroxyvitamin D3 levels and ionised calcium concentrations. Blood samples were then taken again from the same snakes 70 days later after one group (Group 1, n=6 females) were exposed to UV-b radiation daily, and the other group (Group 2, n=5 males and 3 females) were exposed to no UV-b radiation. Mean±sd 25-hydroxyvitamin D3 levels on day 0 in Group 1 were 197±35 nmol/l, and on day 70 were 203.5±13.8 nmol/l. Mean±sd 25-hydroxyvitamin D3 levels in Group 2 on day 0 were 77.7±41.5 nmol/l, and on day 70 were 83.0±41.9 nmol/l. Mean±sd ionised calcium levels at day 0 were 1.84±0.05 mmol/l for Group 1, and on day 70 were 1.78±0.07 mmol/l. Mean±sd ionised calcium levels at day 0 were 1.79±0.07 mmol/l for Group 2, and on day 70 were 1.81±0.05 mmol/l. No association was demonstrated between exposure to UV-b radiation and plasma 25-hydroxyvitamin D3 and ionised calcium concentrations. These results may provide baseline parameters for future studies in this and other snake species to determine ability to utilise UV-b light for vitamin D production.
doi: 10.1136/vr.101555
25, 2013 2013 173: 345 originally published online SeptemberVeterinary Record
J. Hedley and K. Eatwell
metabolism in ball pythons (Python regius)
The effects of UV light on calcium
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October 12, 2013 | Veterinary Record
Paper
Paper
The effects of UV light on calcium metabolism in
ball pythons (
Python regius
)
J. Hedley, K. Eatwell
Despite the popularity of keeping snakes in captivity, there has been limited investigation
into the effects of UV radiation on vitamin D levels in snakes. The aim of this study was
to investigate the effects of UV-b radiation on plasma 25-hydroxyvitamin D3 levels and
ionised calcium concentrations in ball pythons (
Python regius
). Blood samples were taken
from 14 ball pythons, which had never been exposed to UV-b light, to obtain baseline
25-hydroxyvitamin D3 levels and ionised calcium concentrations. Blood samples were then
taken again from the same snakes 70 days later after one group (Group 1, n=6 females) were
exposed to UV-b radiation daily, and the other group (Group 2, n=5 males and 3 females)
were exposed to no UV-b radiation. Mean±sd 25-hydroxyvitamin D3 levels on day 0 in Group 1
were 197±35 nmol/l, and on day 70 were 203.5±13.8 nmol/l. Mean±sd 25-hydroxyvitamin
D3 levels in Group 2 on day 0 were 77.7±41.5 nmol/l, and on day 70 were 83.0±41.9 nmol/l.
Mean±sd ionised calcium levels at day 0 were 1.84±0.05 mmol/l for Group 1, and on day 70
were 1.78±0.07 mmol/l. Mean±sd ionised calcium levels at day 0 were 1.79±0.07 mmol/l
for Group 2, and on day 70 were 1.81±0.05 mmol/l. No association was demonstrated
between exposure to UV-b radiation and plasma 25-hydroxyvitamin D3 and ionised calcium
concentrations. These results may provide baseline parameters for future studies in this and
other snake species to determine ability to utilise UV-b light for vitamin D production.
Introduction
Vitamin D is essential for the absorption of dietary calcium in near-
ly all terrestrial vertebrates (Ullrey and Bernard 1999) and a lack of
Vitamin D3 has been associated with secondary hyperparathyroidism
in lizards (Hoby and others 2010) and chelonians (McArthur 2004).
UV-b radiation in the spectrum of 290–315 nm is important in the
conversion of provitamin precursors in the skin (7-dehydrocholesterol)
to previtamin D3 (Holick 1995). Previtamin D3, in turn, is converted
to vitamin D3 (cholecalciferol) via a temperature-sensitive isomerisa-
tion (Havinga and others 1960). Cholecalciferol binds to plasma pro-
teins to be transported to the liver where it is converted to calcediol
(25-hydroxyvitamin D3). Calcediol is then transported to the kidneys
where it is converted to calcetriol (1,25 dihydroxyvitamin D3), the
active form of Vitamin D (Bentley 1976).
Different reptile species appear to have varying abilities to utilise
UV-b light to produce endogenous vitamin D3 or to absorb dietary
forms. Many lizard and chelonian species, such as iguanas, Iguana iguana
(Laing and others 2001), bearded dragons, Pogona vitticeps (Oonincx
and others 2010), panther chameleons, Furcifer pardalis (Ferguson and
others 2003) and red-eared sliders, Trachemys scripta elegans (Acierno
and others 2006), have been shown to produce endogenous vitamin
D3 in response to UV-b radiation. However, oral supplementation of
vitamin D3 to bearded dragons has been shown to be ineffective at
increasing 25-hydroxyvitamin D3 and 1,25 dihydroxyvitamin D3 to
the concentrations observed in UV-b-exposed animals (Oonincx and
others 2010), whereas black-throated monitor lizards, Varanus albigula-
ris, appear able to both use UV-b light to produce vitamin D and also
to use oral forms (Ferguson and others 2009).
Snakes are thought to have originally evolved from a group of liz-
ards that became subterranean and adapted to a fossorial lifestyle (Vitt
and Caldwell 2009). Despite the popularity of keeping snakes in cap-
tivity, there has, however, been limited investigation into the effects
of UV radiation on vitamin D levels in snakes, and as a consequence
many reptile care guides and popular websites recommend keeping
snakes in captivity without exposure to UV-b light (Flank 1998,
Kruzer 2012). In a previous study, exposure to UV-b light led to a sig-
nificant increase in 25-hydroxyvitamin D3 levels in colubrid snakes
(corn snakes, Elaphe guttata), suggesting that this species has evolved
and retained or recreated the ability to utilise UV-b light (Acierno and
others 2008). However, different snake species have been shown to
vary considerably in their amount of UV-b exposure in their natural
habitats (Ferguson and others 2009).
The ball python, Python regius, is one of the most common boid
species kept in captivity, and so far, no research has been performed
on the effects of UV radiation on this species. Boid snakes have fol-
lowed a different evolutionary path to colubrid snakes and retain more
primitive characteristics (Vitt and Caldwell 2009), so it is unknown if
they would be able to respond to UV-b light in the same way as corn
snakes.
The aim of this study was, therefore, to investigate the effects of
UV-b radiation on plasma 25-hydroxyvitamin D3 levels and ionised
calcium concentrations in ball pythons.
Materials and methods
Fourteen captive ball pythons were used in the study consisting of
five males and nine females, all over four years old, weighing between
Veterinary Record (2013) doi: 10.1136/vr.101555
J. Hedley, BVM&S DZooMed MRCVS,
K. Eatwell, BVSc (hons) DZooMed Dip
ECZM MRCVS,
Royal (Dick) School of Veterinary Studies
and The Roslin Institute, The University
of Edinburgh, Hospital for Small Animals,
Easter Bush Veterinary Centre, Roslin,
Midlothian EH25 9RG, UK
E-mail for correspondence:
Hedley@ed.ac.uk
Provenance: Not commissioned;
externally peer reviewed
Accepted September 3, 2013
group.bmj.com on October 11, 2013 - Published by veterinaryrecord.bmj.comDownloaded from group.bmj.com on October 11, 2013 - Published by veterinaryrecord.bmj.comDownloaded from group.bmj.com on October 11, 2013 - Published by veterinaryrecord.bmj.comDownloaded from group.bmj.com on October 11, 2013 - Published by veterinaryrecord.bmj.comDownloaded from
Paper
Veterinary Record | October 12, 2013
0.91 and 2.36 kg. These animals belonged to three local collections,
and were all due to be health screened as part of their recommended
preventative medicine protocol. Their diet and housing was standard-
ised between the collections. Snakes were housed in wooden vivaria
(115×49×43 cm) with sliding glass doors and plastic ventilation panels
in dedicated thermostatically controlled reptile rooms. Temperature
gradients of 20–30°C were maintained using heat mats towards one
end of the vivaria. Humidity was maintained within 50–80 per cent
by regular misting of the enviroment. Handling was minimised. All
snakes were standardly offered one pre-killed 25–30 g mouse once per
week as was the normal routine. All the snakes had been kept indoors
and had never previously been exposed to any supplemental or natu-
ral UV light. None of the snakes had any current health concerns. The
study was approved by the institutional Veterinary Ethics and Review
Committee.
On Day 0 (July 26, 2012) all snakes were weighed, choanal tem-
peratures were checked with an infrared thermometer (RayTemp 4,
Electronic Temperature Instruments) and a full clinical examination
was performed, before a blood sample was collected via cardiocente-
sis. Approximately 1 ml of blood was collected from each snake for
routine haematology and biochemistry. Samples were processed using
a point-of-care analyser (i-STAT 1, Abbot Diagnostics, Maidenhead,
Berkshire, UK) with a blood gas cartridge (CG8+, Abbot Diagnostics,
Maidenhead, Berkshire, UK) which had been kept in a fridge at 4°C,
but allowed to reach room temperature prior to use. The parameters
measured included pH (power of hydrogen), PaCO2 (partial pressure
of arterial carbon dioxide) (mm Hg), PaO2 (partial pressure of arte-
rial oxygen) (mm Hg), SaO2 (arterial oxygen saturation) (per cent),
Na (sodium) (mmol/l), K (potassium) (mmol/l), iCa (ionised calcium)
(mmol/l), Glu (glucose) (mg/dl), Hct (haematocrit) (per cent) and Hb
(haemoglobin) (mg/dl) in addition to total and differential white
blood cell counts which were performed manually using a phloxine
B technique to count heterophils and eosinophils (Campbell 2004).
The remaining plasma was separated and stored frozen at 20°C for
25-hydroxyvitamin D3 analysis at the end of the study.
One group of snakes (Group 1, n=6 females) were then exposed
to UV-b radiation daily. From day 1, Group 1 snakes were removed
from their usual enclosures and placed individually into commercially
available snake terrrariums where they were continually exposed to
a commonly marketed artificial UV light source (ReptiSun 5.0 UV-b
Fluorescent bulb, Zoo Med, USA) placed at a 10 cm distance from each
snake for eight hours per day. After the eight hour period the snakes
were returned to their usual enclosure for the rest of the day and over-
night. Environmental temperature was maintained within the same
range as that of the snake’s usual enclosure. UV output was measured
(mW/cm2) at weekly intervals with a Solarmeter 6.2 (Solartech, USA)
throughout the terrarium at the distance of 10 cm from the bulb at
which the snakes were basking. The remaining snakes (Group 2, n=5
males and 3 females) were maintained in their usual enclosures for the
duration of the study. The feeding regime remained the same for both
groups throughout the study.
On day 70 (October 4, 2012), snakes were re-examined, and a sec-
ond blood sample was taken for a repeat evaluation of their health sta-
tus. The same parameters were measured as previously, and separated
plasma submitted for 25-hydroxyvitamin D3 analysis.
Statistical analysis
Data was analysed using Minitab (Minitab, Pennsylvania, USA) and
P<0.05 was taken to indicate statistical significance. Data for body
weight, ionised calcium, 25-hydroxyvitamin D3 levels and UV-b
measurements were evaluated by use of an Anderson-Darling test and
found to be normally distributed. A paired sample two-tailed t test
was used to determine whether these variables changed in individual
animals between day 0 and day 70. A two-sample t test was used to
compare the body weight, ionised calcium, 25-hydroxyvitamin D3
levels between Groups 1 and 2 at both timepoints.
The mean, sd and observed range for ionised calcium levels were
calculated using an Excel-based tool (Reference Value Advisor V.2.1,
Reference Value Advisor add in for Microsoft Excel V.2.1) (Geffre and
others 2009, 2011). The data was evaluated by use of an Anderson-
Darling test and was found to be normally distributed. Therefore, in
accordance with Reference Value Advisor V.2.1 recommendations,
the reference intervals were created parametrically. Outliers were
retained in accordance with Reference Value Advisor’s recommenda-
tions, as all snakes were clinically normal and these were not deemed
to be aberrant observations. If outliers were present, Reference Value
Advisor’s robust method was used, as this is less sensitive to the pres-
ence of outliers.
Results
All snakes remained healthy and continued feeding throughout the
duration of the study and no abnormalities were detected on rou-
tine haematological and biochemical health screening. Mean±sd
number of mice eaten by Group 1 snakes were 7.5±1.38 and by
Group 2 snakes 7.8±1.38. Mean±sd choanal temperatures were
27.1±2.0°C. Mean±sd weights at day 0 were 1.86±0.53 kg for Group
1 and 1.42±0.39 kg for Group 2. Mean±sd weights at day 70 were
1.80±0.47 kg for Group 1 and 1.46±0.37 kg for Group 2. Body
weight in Groups 1 and 2 did not differ significantly between the two
groups at the start of the study (P=0.120) or at the end of the study
(P=0.176). There were also no significant changes in body weight
within each group over the course of the study (Group 1; P=0.165,
Group 2; P=0.113).
UV-b radiation reduced over time as measured at the basking
surface from 70.86±11.78 (52–90) µW/cm2 on day 0 to 57.57±10.71
(45–71) µW/cm2 on day 70 (mean ±1sd (range)). This reduction was
statistically significant (P=0.049).
Mean±sd 25-hydroxyvitamin D3 levels on day 0 in Group 1 were
197±35 nmol/l, and in Group 2 on day 0 were 77.7±41.5 nmol/l.
Mean±sd 25-hydroxyvitamin D3 levels on day 70 in Group 1 were
203.5±13.8 nmol/l, and in Group 2 on day 70 were 83.0±41.9 nmol/l.
25-hydroxyvitamin D3 levels in Groups 1 and 2 did not differ sig-
nificantly within each group between day 0 and day 70 (Group 1;
P=0.406, Group 2; P=0.452) (Table 1). However, there were signifi-
cant differences between the two groups both at the start of the study
(P<0.001) and at the end of the study (P<0.001) with Group 1 snakes
having consistently higher 25-hydroxyvitamin D3 values at both day
0 and day 70 (Fig 1).
Mean±sd ionised calcium levels at day 0 were 1.84±0.05 mmol/l
for Group 1 and 1.79±0.07 mmol/l for Group 2. Mean±sd ionised
calcium levels on day 70 in Group 1 were 1.78±0.07 mmol/l and in
Group 2 on day 70 were 1.81±0.05 mmol/l. Ionised calcium levels in
Groups 1 and 2 did not differ significantly within each group between
day 0 and day 70 (Group 1; P=0.109, Group 2; P=0.634) (Table 2).
There were also no significant differences between the two groups
either at the start of the study (P=0.140) and at the end of the study
(P=0.497) (Fig 2). All ionised calcium data was therefore pooled for
calculation of the mean, sd and an observed interval as calculated by
Reference Value Advisor were found to be 1.81±0.06 (1.67–1.94).
TABLE 1: Plasma 25-hydroxyvitamin D
3
(25OHD
3
) concentrations
(nmol/l) in ball pythons that received (Group 1; n=6) or did
not receive (Group 2; n=8) supplemental UV radiation over the
course of the study
Sex 25OHD3 on day 0 25OHD3 on day 70
Group 1 exposed to UV-b
1 Female 224 225
2 Female 224 224
3 Female 143 177
4 Female 230 244
5 Female 173 154
6 Female 188 197
Group 2 not exposed to UV-b
7 Female 128 139
8 Female 134 127
9 Female 68.4 98.2
10 Male 32.6 44.5
11 Male 25.7 32.9
12 Male 78. 5 44.7
13 Male 4 9. 5 61.4
14 Male 105 116
Paper
October 12, 2013 | Veterinary Record
Discussion
Results of this study showed no significant effects of UV radiation on
plasma 25-hydroxyvitamin D3 and ionised calcium concentrations in
six female ball pythons. Both 25-hydroxyvitamin D3 levels and ion-
ised calcium concentrations did not differ significantly between the
group of female snakes which were exposed to UV, and the mixed
group of male and female snakes which were not.
The range of 25-hydroxyvitamin D3 levels were similar to those
previously recorded in corn snakes (Acierno and others 2008). That
study, however, indicated that exposure to UV-b light was associated
with a significant increase in 25-hydroxycholecalciferol levels. In the
current study, all snakes in Group 1 were exposed to UV-b radiation
over 70 days, and although the amount of radiation did reduce over
time, all bulbs were still emitting an output >41µW/cm2 measured
at snake level on day 70. This is greater than in the previous study
in corn snakes which showed an effect of UV-b radiation even when
exposed for only 30 days at much lower levels (~10µW/cm2).
There are various possible explanations for the results of this
study. Ball pythons are nocturnal snakes (Leck and Klingenberg 2000),
so less likely to need the ability to utilise UV-b light, whereas corn
snakes have more diurnal or crepuscular habits, so will be exposed
to some natural sunlight (Love and Love 2000). Gender may have
accounted for the elevated 25-hydroxycholecalciferol levels in Group 1
snakes. In green iguanas, reproductively active females were found to
have elevated 25-hydroxycholecalciferol levels compared with males
(Nevarez and others 2002). The reproductive status of the snakes in
this study was not evaluated, but the study was performed between
July and September which is the season that some of these snakes had
produced eggs in previous years.
Mean, sd and reference intervals for ionised calcium as calculat-
ed by Reference Value Advisor were found to be 1.81±0.06 (1.67–
1.94) which is higher than recorded values in iguanas (Dennis
and others 2001) and similar to recorded values in Testudo species
(Eatwell 2009). Ionised calcium levels did not vary between the two
groups despite differences in 25-hydroxyvitamin D3 levels. Ionised
calcium is, however, physiologically maintained within a tight ref-
erence range so changes in this would not be expected despite dif-
ferences in 25-hydroxyvitamin D3. Ionised calcium levels have not,
to the authors knowledge, been published previously in any snake
species.
Although no significant effects of UV-b exposure on plasma
25-hydroxyvitamin D3 and ionised calcium concentrations were
demonstrated in this study, exposure to UV light has been shown
to have other beneficial effects in reptiles. Behavioural changes have
been demonstrated in iguanids and agamids (Moehn 1974), and
increased activity levels in corn snakes exposed to UV light (Nail
2011). The potential positive behavioural effects of UV-b radiation
in ball pythons have not been examined before and would be a use-
ful future study. In this study, snakes were only exposed to UV-b
radiation for eight hours per day due to time limitations, but a more
natural photoperiod would be 12 hours UV-b:12 hours darkness,
and the effect of different photoperiods would also need further
investigation.
It is important to be aware of possible side effects of supplying
excessive UV light. Photokeratoconjunctivitis and photodermatitis
have been reported in a ball python associated with exposure to a UV
bulb (Gardiner and others 2009). That bulb, however, had a much
higher UV-b output than the bulbs tested in this study, and a dispro-
portionately high output of UV-b below 300 nm which is within
the action spectra for photokeratoconjunctivitis, photodermatitis
and DNA damage (Setlow 1974). Body weight in the two groups did
not differ significantly over the course of the study, and all snakes
remained clinically healthy, so there was no evidence of problems
with UV exposure at the level used in this study.
The effects of UV-b radiation on ball pythons would ideally be
obtained by assessment of two randomised gender-balanced groups.
One limitation of this study is that only female snakes were exposed
to UV-b radiation. Future studies would be necessary to examine
larger numbers of snakes and investigate the effect of UV-b radiation
on the different genders. Further studies would also be necessary to
examine the effect of environmental temperature in combination
with UV-b radiation.The pythons in the current study were provided
with a temperature gradient of 20–30°C, and measured choanal tem-
peratures were 27.1±2.0°C (mean±sd), but higher temperatures may
be necessary for production of cholecalciferol.
250
200
150
100
Plasma 250HD3 concentrations (nmol/L)
50
0
Group 1 day 0Group 2 day 0Group 1 day 70 Group 2 day 70
FIG 1: Boxplot to illustrate plasma 25-hydroxyvitamin D3 (25OHD3)
concentrations (nmol/l) in ball pythons that received (Group 1; n=6)
or did not receive (Group 2; n=8) supplemental UV radiation over
the course of the study
TABLE 2: Ionised calcium concentrations (mmol/l) in ball pythons
that received (Group 1; n=6) or did not receive (Group 2; n=8)
supplemental UV radiation over the course of the study
Sex Ionised Ca day 0 Ionised Ca day 70
Group 1 exposed to UV-b
1 Female 1.8 1.73
2 Female 1.9 1.85
3 Female 1.79 1.8
4 Female 1.81 1.84
5 Female 1.91 1.81
6 Female 1.84 1.67
Group 2 not exposed to UV-b
8 Female 1.8 1.8
9 Female 1.75 1.79
10 Female 1.71 1.88
11 Male 1.86 1.8
12 Male 1.79 1.7 7
13 Male 1.75 1.7 3
14 Male 1.92 1.8
15 Male 1.74 1.89
1.95
1.90
1.85
1.80
Ionised calcium (mmol/L)
1.75
1.70
Group 1 day 0Group 2 day 0Group 1 day 70 Group 2 day 70
FIG 2: Boxplot to illustrate ionised calcium concentrations (mmol/l)
in ball pythons that received (Group 1; n=6) or did not receive
(Group 2; n=8) supplemental UV radiation over the course of the
study
Paper
Veterinary Record | October 12, 2013
In conclusion, no association has been demonstrated between
exposure to UV-b radiation and plasma 25-hydroxyvitamin D3 and
ionised calcium concentrations in the female ball pythons in this
study. These results may, however, provide baseline parameters for
future studies in this and other snake species to determine ability to
utilise UV-b light for vitamin D production.
Acknowledgements
The authors would like to thank the staff at Edinburgh Butterfly
and Insect World, Five Sisters Zoo and the Exotic Animal Teaching
Facility at the Royal (Dick) School of Veterinary Studies, Edinburgh
for their help with this study, and Dr Darren Shaw for advice on the
statistics.
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... UVB still is a controversial subject amongst herpetoculturalists, especially in snake husbandry. Snakes lack pineal glands which lizards possess, and are thought to contribute and drive basking behaviors needed to ensure enough UVB radiation has occurred for Vitamin D 3 synthesis and calcium uptake [41][42][43][44]. Herpetologists deduced that snakes likely do not require UVB radiation in D 3 synthesis decades ago, and this has since become herpetoculture dogma. ...
... Recent experimentation with UVB exposure in snakes challenges this determination, and has consistently demonstrated elevated vitamin D 3 levels in blood plasma and higher calcium deposition in bones after UVB exposure [37,39,40]. A single study conducted on P. regius, a mainstay of private herpetoculture, determined that no significant differences in vitamin D 3 plasma levels occurred in response to UVB exposure [42], which many in herpetoculture interpret to mean UVB is not necessary or beneficial for P. regius or snake welfare. ...
... What is interesting is the number of herpetoculturalists who gravitated to this single article [42] and readily cite it to support not supplying UVB to their charges, and fail to acknowledge the other three articles on snakes that demonstrate a "positive" physiological response to UVB. Natural history driven evidence-based approaches could add inference to this issue. ...
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Article
Herpetocultural practices are based on norms driven by economy of space and time for keepers, with little scientific inference backing their practice. In recent years, a subset of herpetoculturalists have promoted evidence-based husbandry that relies on science and experimental design to generate husbandry practice. A theoretical framework and protocol are proposed herein that enables any individual who has access to the internet the ability to use various outlets of natural history information (scientific literature databases, social media sources, and weather websites) and previously published husbandry reports as evidence to drive the creation of novel herpetocultural practice. A case study is provided which compares readily available information on the care of Hydrodynastes gigas (false water cobra), such as online care sheets for the species, with the proposed evidence based herpetocultural protocol founded on natural history information and published care and captive breeding reports. Results were assessed for protocol efficacy and determined that the natural history informed evidence-based approach increased animal welfare and generated new information specific to the natural history of H. gigas.
... 11,13,[32][33][34][35] For instance, consequences of low UVB exposure include low plasma or hepatic vitamin D concentration and metabolic bone disease, evaluated by the measurement of bone mineral density via micro-computed tomography, 36 histology 37 or dual-energy X-ray absorptiometry. 38,39 A third approach is to determine if increasing the amount of UVB to which the animal is exposed can increase the plasma concentration of 25-hydroxycholecalciferol. 32,33,[40][41][42] In this approach, however, it is assumed that the highest calcidiol concentration is necessarily the best, which has not yet been demonstrated. In some species, higher calcidiol has been associated with an increased frequency of shedding, up to once weekly in leopard geckos (Eublepharis macularius), which is more frequent than the shedding frequency observed in wild geckos. ...
... In addition, in many species, hepatic and plasma concentrations are not necessarily correlated and it is unknown which parameter is the most accurate to evaluate the status of an animal. 40 A more comprehensive approach to determine an optimal UVB dose should ideally include medical and behavioral parameters, and information about the amount of UVB free-ranging animals are exposed to. ...
Article
Many animals under human care are kept indoors to prevent infectious diseases vectored by wildlife, facilitate environment control, or due to the lifestyle of their owners. However, ultraviolet radiation has documented effects on animal vision, vitamin synthesis, immunity, behavior, psychogenic disorders and on their environment. Ultraviolet-emitting lights are commercially available and the documentation of their effect on indoor-housed animals is increasing. This article reviews published information about ultraviolet effects in vertebrate animals from veterinary and ethological perspectives, and techniques used to assess ultraviolet exposure across animal taxa.
... 2 In another study using ball pythons (Python regius), no relationship between UVb exposure and vitamin D concentrations was found. 9 However, in the previously mentioned study, the snakes had access to UVb lamp for only 70 days with an unknown spectral power distribution; hence, it is unknown whether the UVb lamp emitted wavelengths effective in D3 synthe- Table 1. ...
... 5,12 Ball pythons exposed to UVb did not increase 25-OH-D 3 levels compared to unexposed counterparts. 9 This could have been due to a lack of suitable UVb radiation provided in that study or inhomogeneous starting concentrations, or it could indicate a difference in synthesizing capacity between Burmese pythons and ball pythons. Ball pythons are suggested to require a higher UV index than Burmese pythons when comparing their natural habitat. ...
Article
Deficiency of vitamin D can contribute to health complications that present as metabolic bone disease. The aim of this small-scale study was to determine if a high UVb irradiance would affect an increase in plasma vitamin D3 concentrations in Burmese pythons (Python bivittatus). There have been inconsistent results throughout the literature concerning the usefulness of UVb radiation regarding vitamin D3 synthesis. Blood samples of four healthy Burmese pythons were taken at day 0 and day 310. After the first blood sample was taken, an Arcadia Superzoo T5 ASZ01 lamp was fitted in the enclosure. For 310 days, the pythons were exposed to UVb radiation. Blood plasma vitamin D3 concentrations were considerably higher after UVb exposure. This study indicates that a period of 10 mo of UVb exposure can result in an increased vitamin D3 status in Burmese pythons. Answering whether these elevated levels have health benefits for Burmese pythons (and possibly other snake species) requires further studies.
... Evidence surrounding the use of UVB lighting to permit vitamin D synthesis is mixed, with one study on corn snakes (Pantherophis guttata) suggesting that this type of lighting is beneficial, 21 and another study showing no difference in vitamin D absorption in ball pythons (Python regius) that received UVB lighting compared to a control group that did not. 22 Several authors have proposed that, in the absence of fuller data, exposure to naturalistic levels of UVB for snakes offers reasonable general practice. 13 20 23-25 ...
Article
Background A large number of snakes are kept as pets in Western societies. Few studies have been undertaken to assess keeping practices of snakes by private owners in Australia. Therefore, there is concern that some owners may not understand even basic husbandry requirements. The aim of this preliminary study was to identify the most common practices used by snake owners in Victoria, Australia. Method An online survey asked 251 snake owners to describe ways in which they attempt to meet their snake’s environmental, behavioural, dietary, social and health needs. Results Fewer than half of participants had an enclosure large enough for the snake to fully stretch out, and just over half had an enclosure large enough to meet the requirements in the Victorian Code of Practice. Only 60 per cent of owners correctly identified their snake’s activity patterns based on information about wild snakes of the same species. Conclusion Educational campaigns may help improve outcomes for snakes in the future, but more research is needed about captive snake husbandry, to provide an evidence base for informing snake management recommendations.
... Although originally focused on lizards (Allen et al., 1999;Laing and Fraser, 1999;Carman et al., 2000;Laing et al., 2001;Ferguson et al., 2003Ferguson et al., , 2005Oonincx et al., 2010), more recent examples in chelonians (Acierno et al., 2006;Selleri and Di Girolamo, 2012) and a snake species (Acierno et al., 2008) also suggest that UVB can play an important role in the circulating concentrations of 25-hydroxyvitamin D 3 in these reptiles too. However, it should not be assumed that UVB light is a requirement for vitamin D regulation in all diurnal vertebrates, as dogs and cats do not use this method for acquiring vitamin D and a recent study in captive ball pythons (Python regius) found that UVB had no impact on circulating 25-hydroxyvitamin D 3 concentrations in that species (How et al., 1994;Hedley and Eatwell, 2013). These findings re-affirm that we must evaluate each species separately to determine how they acquire vitamin D such that, when in captivity, we can provide appropriate husbandry and care to minimize the likelihood for iatrogenic disease (e.g., NSHP). ...
Article
Ultraviolet B radiation (UVB) is required by many vertebrates to stimulate the photobiochemical synthesis of vitamin D. Vitamin D plays many important roles in the body, including assisting in the absorption of calcium at the level of the intestines. Deficiencies in vitamin D can lead to the development of nutritional disease. Leopard geckos (Eublepharis macularius) are naturally nocturnal to crepuscular; therefore, it is not known whether they benefit from UVB radiation. The purpose of this study was to measure 25-hydroxyvitamin D3 concentrations in leopard geckos exposed to short duration UVB light. Twelve adult, male leopard geckos were used for this study. Blood samples were collected from the cranial vena cava to establish baseline 25-hydroxyvitamin D3 concentrations. Once the baseline samples were collected, the animals were randomly divided into two groups. The animals provided UVB radiation were exposed to non-UVB producing light for 12 h and UVB for 2 h, whereas animals in the control group only received non-UVB producing light for 12 h. Exposure to the UVB light occurred for 2 h per day: 1 h at 0600 h and 1 h at 1800 h to mimic dawn and dusk, respectively. An additional blood sample was collected 30 days after the initiation of UVB exposure. There was a significant difference (F = 9.7, P = 0.012) in 25-hydroxyvitamin D3 concentrations between the two groups, with UVB exposed geckos having significantly higher concentrations. The results of this study demonstrate that short duration exposure to UVB light can lead to increased circulating 25-hydroxyvitamin D3 concentrations in leopard geckos.
Article
Vitamin D is an essential hormone that can be acquired via the diet, exposure to ultraviolet B (UVB) radiation, or a combination of both. Studies in reptiles suggest that the acquisition of vitamin D can vary between species; thus, species-specific evidence-based research should be pursued to develop appropriate husbandry recommendations. The objective of this study was to determine whether artificial UVB could be used to increase circulating 25-hydroxyvitamin D3 (25-OHD3) concentrations in juvenile Blanding’s turtles (Emydoidea blandingii). Sixteen juvenile turtles from an on-going headstart program at the DuPage County Forest Preservation District (Wheaton, IL, USA) were used for this study. The turtles were randomly divided into two groups of eight using a random number generator. The treatment group was exposed to three compact UVB fluorescent bulbs (23 watts) 12 hours/day for 6 months, while the control group was not provided supplemental UVB lighting. Bulbs were placed 15.2 cm (6 inches) from the water surface. A radiometer was used to measure UVB radiation 15.2 cm from the bulb surface on days 0 and 180. Blood samples were collected at a single time point (day 180) to measure 25-OHD3 concentrations. There was a significant difference (P < 0.001) in plasma 25-OHD3 concentrations between groups, with 25-OHD3 concentrations being 5.5 times higher in the UVB group compared with the controls. Based on the results of this study, the authors recommend exposing juvenile Blanding’s turtles to artificial UVB as part of their standard care.
Chapter
When reptiles are presented for emergencies, patient stabilization is the first priority as with other species. Diagnostic tools that provide instantaneous results can be valuable to triage patients, identify problems, devise treatment plans, and assess prognosis. Obtaining baseline data upon presentation also allows for monitoring the patient's progress and response to treatment over time. This chapter reviews the application of such diagnostic tools to the critical reptile patient.
Article
Over the last 10 years, exotic animal clinical pathology has been evolving, improving health assessment in avian, mammal, fish, reptile, and amphibian patients. These advances are reviewed in this article. Species-specific reference intervals for blood parameters are becoming more available (eg, for ionized calcium, endocrine panels, and vitamin D plasmatic concentrations). In addition, new technologies are being developed to facilitate targeted metabolite detection and result acquisition by veterinarians. Novel techniques, biomarkers, and clinical changes related to disease have been described in avian, mammal, fish, reptile and amphibian species. The use of mobile applications may also be helpful.
Full-text available
Article
We studied the effects of ultraviolet B (UVB) exposure or administration of dietary vitamin D on serum vitamin D, serum 25-hydroxyvitamin D3 (25[OH]D), calcium, and phosphorus in juvenile blackthroated monitor lizards(Varanus albigularis) deprived of all sources of vitamin D for 87 days. Deprivation resulted in significant decreases of circulating levels of 25(OH)D (25-35%), vitamin D3 (73-76%), calcium (6%), and phosphorus (16%). The half-life of circulating 25(OH)D during deprivation was estimated to be from 128-139 days. After deprivation, eight monitors were given a single dose of UVB from exposure for l0-20 minutes to a Spectroline UVB lamp. The dose resulted in an average of 14.2% conversion of provitamin D, to previtamin D, and photoproducts within in vitro models. When administered once every week for 92 days, the dose failed to significantly modify the decline of serum 25(OH)D; however, the decline of vitamin D, seemed to level off. The overall effect of the UVB dosing was weak, and more frequent doses are probably needed to restore and maintain vitamin D status. Conversely, the oral administration of doses of vitamin D, averaging 10,000 IU/kg and administered orally once every week for 92 days to an additional eight vitamin D-deprived juvenile monitors, stopped the decline of 25(OH)D and caused a large increase (600%) in circulating levels of vitamin D, compared to predeprivation levels. Doses of dietary vitamin D, used in the post-deprivation phase of our study quickly restored a normal vitamin D status but were too high for maintenance and could possibly expose the animals to eventual intoxication. The predeprivation levels of vitamin D by (1) daily exposure to UVB gradients generated with a Westron 100-watt mercuryvapor lamp (averaging a daily maximum of l6% conversion of provitamin D to previtamin D, and photoproducts within ln vitio models), and (2) feeding monitors crickets gut-loaded with a commercial vitamin D-supplemented diet along with whole mice maintained the vitamin D status.
Full-text available
Article
International recommendations for determination of reference intervals have been recently updated, especially for small reference sample groups, and use of the robust method and Box-Cox transformation is now recommended. Unfortunately, these methods are not included in most software programs used for data analysis by clinical laboratories. We have created a set of macroinstructions, named Reference Value Advisor, for use in Microsoft Excel to calculate reference limits applying different methods. For any series of data, Reference Value Advisor calculates reference limits (with 90% confidence intervals [CI]) using a nonparametric method when n≥40 and by parametric and robust methods from native and Box-Cox transformed values; tests normality of distributions using the Anderson-Darling test and outliers using Tukey and Dixon-Reed tests; displays the distribution of values in dot plots and histograms and constructs Q-Q plots for visual inspection of normality; and provides minimal guidelines in the form of comments based on international recommendations. The critical steps in determination of reference intervals are correct selection of as many reference individuals as possible and analysis of specimens in controlled preanalytical and analytical conditions. Computing tools cannot compensate for flaws in selection and size of the reference sample group and handling and analysis of samples. However, if those steps are performed properly, Reference Value Advisor, available as freeware at http://www.biostat.envt.fr/spip/spip.php?article63, permits rapid assessment and comparison of results calculated using different methods, including currently unavailable methods. This allows for selection of the most appropriate method, especially as the program provides the CI of limits. It should be useful in veterinary clinical pathology when only small reference sample groups are available.
Chapter
This chapter introduces some extinct amphibian and reptilian taxa and discusses the history of the clades that compose the modern herpetofauna. The origin of terrestriality was quickly followed by an eruption of new species with new lifestyles and body forms. Although amphibian (anamniote) diversification began earlier, amniotes were the dominant group by the mid-Permian in terms of number of species and individuals, based on the fossil record. Tetrapods largely disappeared from the fossil record at the end of the Devonian. They next appeared en masse in the Upper Mississippian and Lower Pennsylvanian when fossils representing lowland lake and swamp assemblages reappeared. More than a dozen clades are recognized, and they include several groups of anthracosaurs, at least three amphibian groups, and the enigmatic Crassigyrinus. Unlike subsequent tetrapods, all known early tetrapods had more than five digits; Acanthostega had eight digits on its forefeet. In the Pennsylvanian, many new tetrapod groups appeared: geophyrostegid and limnoscelid anthracosaurs, eryopoid amphibians, and nectrideans and three groups of microsaurs. This fauna lived predominantly in the lowlands.
Article
It has been recognized in both the popular and scientific literature that ultraviolet light plays a part in the lives of lizards. It has generally been assumed that ultraviolet light helps prevent or cure rickets although there have been suggestions in the literature that light quality may influence behavior. In this study, behavioral changes induced by ultraviolet light included threats to conspecifics in Dipsosaurus dorsalis and Crotaphytus collaris as well as an increase in the frequency of assertion displays in Dipsosaurus and an increased frequency of head nods in Agama agama. One of the more important physical factors in the environment of desert lizards is light.
Article
This paper summarizes the results of recent investigations into the photochemical isomerizations in the vitamin D field which were the subject of further research in our laboratories during the last decade. A new scheme is proposed showing the various reactions occurring during irradiation of a provitamin D. The quantum yields of these reactions at 2537 Å were determined. On the basis of these data the effect of the wavelength of the light used on the yields of products is explained. Emission spectra of ergosterol and its photoisomers were measured at 80°K. No phosphorescence was observed. Some aspects of the mechanism of the photochemical cyclizations, ring openings and the cis/trans isomerization are discussed.
Chapter
AnorexiaCloacal Organ ProlapseCutaneous and Subcutaneous LesionsCystic CalculiDiarrhoeaDystociaEar InfectionsEctoparasitesEndoparasitesFollicular StasisFrost DamageGoutHeat DamageHepatic DiseaseHepatic LipidosisHypervitaminosis AHypothyroidism/HypoiodinismHypovitaminosis AHypovitaminosis B1 (THIAMINE)Lower Digestive Tract DiseaseIntestinal Impaction/ObstructionEnteritis and ColitisFungal EnteritisAmoebiasisBalantidium and NyctotherusCoccidiansCryptosporidiosisTrichomonas/FlagellatesHexamitaMetazoan ParasitesAscaridsOxyurids (PINWORMS)ProatractisOther Metazoan ParasitesNeoplasia of the Digestive TractLower Respiratory Tract InfectionsMaladaptationMetabolic Bone Disease (MBD) and Nutritional Secondary HyperparathyroidismMetastatic Calcinosis/PseudogoutPosterior Paresis or WeaknessPost-Hibernation Anorexia (PHA)Renal DiseaseSepticaemiaSight ProblemsSteatitisStomatitisUpper Respiratory Tract Disease (URTD)/Runny-Nose Syndrome (RNS)Viral DiseaseWeight Abnormalities—OverweightWeight Abnormality—UnderweightYolk Coelomitis
Article
Nutritional metabolic bone disease (NMBD) is one of the most frequently observed pathological conditions in herpetoculture. To develop guidelines for NMBD prevention in growing veiled chameleons (Chamaeleo calyptratus), 56 hatchlings were divided into 6 groups [group UV, with UVB exposure; group No: no supplements; group CaAUV: with calcium (Ca), vitamin A, UVB; group CaA: with Ca, vitamin A; group CaADUV: with Ca, vitamin A, cholecalciferol, UVB; and group CaAD, with Ca, vitamin A, cholecalciferol] and reared for 6 mo on locust-based diets. The nutrient composition of the locusts' diet and the locust-based diet for the chameleons was determined. The diagnosis included the detailed description of clinical findings, histopathology, measurements of serum Ca, 25-hydroxycholecalciferol (25-OHD(3)), liver 25-OHD(3), vitamin A, bone mineral density, and bone mineral concentration. Chameleons that received no dietary supplementation of Ca, vitamin A, and cholecalciferol developed NMBD. When Ca and vitamin A were supplemented, the chameleons did not develop NMBD, independently of additional UVB and dietary cholecalciferol. The best prevention for NMBD was achieved by chameleons that received locusts gut-loaded with 12% Ca and dusted with 250,000 IU/kg (75 mg/kg) vitamin A and 25,000 IU/kg (0.625 mg/kg) cholecalciferol plus provision of long (10 h/d), low irradiation exposure (3-120 μW/cm(2)) to UVB. Chameleons that were fed diets low in vitamin A, cholecalciferol, and Ca were diagnosed with fibrous osteodystrophy. We noticed an interaction of vitamin A and cholecalciferol supplementation in the storage of vitamin A in the liver and formation of colon calcifications. From these findings, recommendations for the rearing of juvenile chameleons were derived.
Article
The effectiveness of dietary vitamin D3 and UVb exposure on plasma vitamin D metabolites in growing bearded dragons (Pogona vitticeps) was studied. A total of 84 (40 males and 44 females) newly hatched bearded dragons were allocated to six levels of oral vitamin D3 supplementation (0 to 400%) or six UVb exposure times (2 to 12 h). At 3 and 6 months of age, blood samples were obtained from each animal and analysed for 25(OH)D3 and 1,25(OH)2D3. At 3 months of age, plasma concentrations of 25(OH)D3 did not increase with increasing vitamin D3 supplementation unlike the 1,25(OH)2D3. At 6 months of age, plasma concentrations of both 25(OH)D(3) and 1,25(OH)2D3 increased with increasing vitamin D(3) supplementation. Plasma concentrations in UVb-exposed animals were 18 times higher for 25(OH)D3 (178.4+/-9.0 vs. 9.9+/-1.3 nmol/L) and 5.3 times higher for 1,25(OH)2D3 (1.205+/-0.100 vs. 0.229+/-0.025 nmol/L) than in vitamin D(3) supplemented animals at 6 months of age. This study shows that 2h of UVb exposure enables adequate physiological concentrations of plasma vitamin D metabolites to be maintained in growing bearded dragons. Oral supplementation of vitamin D(3) is ineffective in raising plasma concentrations of 25(OH)D3 and 1,25(OH)2D3 to concentrations observed in UVb-exposed animals.
Article
A male ball python (Python regius) and a female blue tongue skink (Tiliqua spp.) of unknown age were evaluated for anorexia, lethargy, excessive shedding, corneal opacity (python), and weight loss (skink) of approximately three weeks' duration. These animals represented the worst affected animals from a private herpetarium where many animals exhibited similar signs. At necropsy, the python had bilateral corneal opacity and scattered moderate dysecdysis. The skink had mild dysecdysis, poor body condition, moderate intestinal nematodiasis, and mild liver atrophy. Microscopic evaluation revealed epidermal erosion and ulceration, with severe epidermal basal cell degeneration and necrosis, and superficial dermatitis (python and skink). Severe bilateral ulcerative keratoconjunctivitis with bacterial colonization was noted in the ball python. Microscopic findings within the skin and eyes were suggestive of ultraviolet (UV) radiation damage or of photodermatitis and photokeratoconjunctivitis. Removal of the recently installed new lamps from the terrariums of the surviving reptiles resulted in resolution of clinical signs. Evaluation of a sample lamp of the type associated with these cases revealed an extremely high UV output, including very-short-wavelength UVB, neither found in natural sunlight nor emitted by several other UVB lamps unassociated with photokeratoconjunctivitis. Exposure to high-intensity and/or inappropriate wavelengths of UV radiation may be associated with significant morbidity, and even mortality, in reptiles. Veterinarians who are presented with reptiles with ocular and/or cutaneous disease of unapparent cause should fully evaluate the specifics of the vivarium light sources. Further research is needed to determine the characteristics of appropriate and of toxic UV light for reptiles kept in captivity.