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Nutrition research on calcium homeostasis. II. Freshwater turtles (with recommendations)

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Abstract

This review reports on a decade of nutrition research into calcium (Ca) homeostasis in freshwater turtles, including research on non-nutritive factors that are essential for Ca homeostasis [i.e. ontogeny, environmental temperature and humidity, and ultraviolet (UV) light and photoreception]. Recommendations for future research include long-term research programmes in three specific areas: (1) photoreception, UV light and biosynthesis, (2) Ca homeostasis and vitamin and mineral supplementation, and (3) developmental indices, gut transit time (GTT) and energy requirements.

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... The Ca and P contents of the pellets and lyophilised beef heart were much lower than those of Gammarus and whole fish. Imbalanced diets having low Ca content lead to metabolic bone disease of nutritional origin in aquatic turtles as well (73). However, excess Ca intake (2.24% DM) may have a negative impact on the growth rate of aquatic turtles (74). ...
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Captive chelonians should be fed a natural diet to achieve a growth rate similar to that of free-ranging animals. A wide range of commercially formulated foods dedicated to chelonians is available. Feeding commercial foods has the advantage of convenience. On the other hand, species-specific information on the nutritional requirements of chelonians is not available yet. The aim of this study was to analyse and evaluate commercial pellets and feeds for chelonians. Commercial pellets (ntortoise = 7, nturtle = 7, from 6 companies) dedicated to carnivorous aquatic turtles and herbivorous terrestrial tortoises, and other aquatic turtle feeds (lyophilised beef heart, dried aquatic invertebrates, and whole frozen fish) were bought in pet shops. Whole frozen fish served as a reference feed for carnivorous aquatic turtles. The chemical composition as well as calcium (Ca) and phosphorus (P) contents were determined. Single-sample t-test was used with the label information as null hypothesis and the results of own parallel analyses for crude protein (CP), ether extract (EE), crude fibre (CF), Ca and P. The labelling of some of the pellets was deficient as nutritive values, Ca or P data were missing (tortoise pellets: 4 out of 7; turtle pellets: 5 out of 7). The label data differed significantly (p<0.05) from the results of our own analysis for 13 out of the 14 pellets. None of the tortoise pellets met the requirements of the animals completely. Because of the inadequate Ca:P ratio only one turtle pellet could be accepted. Accordingly, none of the commercial pellets can be recommended as main or only feed. Key words: nutrition; pellet; metabolic bone disease; chelonian VREDNOTENJE KOMERCIALNIH ŽELV IN KRME ZA ŽELVE Izvleček: Želve v ujetništvu je potrebno hraniti z naravno krmo, da dosežejo podobno stopnjo rasti kot živali v prosti reji. Na voljo je širok izbor komercialno pripravljene hrane za želve. Prednost hranjenja želv s komercialno hrano je priročnost, vendar podatki o prehranskih potrebah za posamezne vrste želv še niso na voljo. Namen te raziskave je bil analizirati in ovrednotiti komercialne pelete in krmo za želve. V trgovinah za živali smo od 6 podjetij kupili komercialne pelete (npeleti za vodne želve = 7, npeleti za kopenkse želve = 7) za mesojede vodne in rastlinojede kopenske želve ter drugo krmo za vodne želve (liofilizirano goveje srce, posušene vodne nevretenčarje in zamrznjene cele ribe). Zamrznjene cele ribe smo uporabili kot referenčno krmo za mesojede vodne želve. Določili smo kemično sestavo in vsebnost kalcija (Ca) ter fosforja (P). Za ničelno hipotezo smo uporabili T-test enega vzorca s podatki na etiketi in rezultate lastne paralelne analize za surove beljakovine (an gl. crude proteins, CP), ekstrakt etra (angl. ether extract, EE), surovo vlaknino (angl. crude fibre, CF), Ca in P. Oznake nekaterih peletov so bile pomanjkljive, saj so manjkali podatki o hranilnih vrednostih, Ca in P (npeleti za kopenske želve = 4 od 7, npeleti za vodne želve = 5 od 7). Podatki na etiketi so se bistveno razlikovali (p < 0,05) od rezultatov naše analize pri 13 od 14 vrst peletov. Nobeni peleti za kopenske želve niso v celoti izpolnjevali potreb živali. Zaradi neustreznega razmerja Ca : P smo kot ustrezno določili le eno izmed 7 vrst peletov za vodne želve, zaradi česar nobenih od komercialnih peletov nismo določili kot priporočljivih za glavno ali edino krmo za želve. Ključne besede: prehrana; peleti; presnovna bolezen kosti; želve
... A dietary associative effect can occur when one item of the diet affects, positively or negatively, the digestive efficiency of other nutrients (Bjorndal, 1991). This effect is more common in herbivorous and omnivorous species, and its occurrence may increase because of microbial fermentation (McWilliams, 2005). An adverse effect of dietary lignocellulose on organic matter digestibility was observed in Galapagos tortoises (Geochelone nigra) (Hatt et al., 2005); and a negative correlation has been described between the dietary cell wall content and dry matter digestibility in tortoise species, including adults of red-footed tortoises, as well as reptiles in general (Bjorndal, 1989;Barboza, 1995ab;Hatt et al., 2005;Franz et al., 2011a). ...
Article
Tortoise husbandry includes reports of excessive growth and carapace pyramiding, although triggers still remain to be fully elucidated. Juvenile red-footed tortoises (Chelonoidis carbonaria) were fed with two different diets, one high in fiber (HF; 14.2% crude fiber; 39.2% neutral detergent fiber, NDF; dry matter basis, DMB) and one high in starch (HS; 27.7% DMB), to assess effects on energy metabolism, nutrient digestibility, and growth. A total of 20 hatchlings (10 per diet) were used to evaluate: apparent digestibility coefficients (Da) of nutrients and gross energy (GE), passage times at 5 and 11 months of age; resting and post-prandial metabolic rates at 6 and 12 months of age; growth rates; pyramiding; and estimated body composition. Animals fed HS showed higher mass-specific intake of digestible energy (113.9 ± 32.1 kJ kg⁻¹ day⁻¹ vs. 99.6 ± 35.3 kJ kg⁻¹ day⁻¹; P < 0.05), digestible DM (6.1 ± 1.8 g kg⁻¹ day⁻¹ vs. 5.0 ± 1.8 g kg⁻¹ day⁻¹; P < 0.01), shorter transit (3 ± 1 days vs. 4 ± 1 days; P < 0.01) and retention times (8 ± 2 days vs. 10 ± 2 days; P < 0.01), and higher Da of DM, starch, NDF, and GE. Crude protein Da was higher for HF. Rest and post-prandial metabolic rates, and pyramiding degree were not affected by diets. At 13 months, the animals from HS presented wider plastrons and carapaces, and higher carapace width growth rates. In addition, these animals had lower body mineral content (1.88 ± 0.15% vs. 2.15 ± 0.19%; P < 0.01) and bone density (0.13 ± 0.01 g mm⁻² vs. 0.15 ± 0.02 g mm⁻²; P < 0.02). Results provide evidence that highly digestible foods can accelerate shell growth and lower mineralization in this species.
... The sun also delivers light, including radiation in the infrared (IR) and ultraviolet (UV) spectrums. UV radiation between 290 and 315 nm (UV-B) is particularly important for reptiles because most species utilize these wavelengths to synthesize vitamin D3 which is essential for calcium metabolism (Klaphake, 2010;McWilliams, 2005). While reptiles were traditionally thought to use sunlight primarily for vision and thermoregulation, other factors such as their vitamin D3 status and the intensity of visible light also influence basking behavior (Carman, Ferguson, Gehrmann, Chen, & Holick, 2000;Ferguson et al., 2003;Hertz, Fleishman, & Armsby, 1994;Karsten, Ferguson, Chen, & Holick, 2009). ...
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Many reptiles require ultraviolet-B radiation between 290 and 315 nm (UV-B) to synthesize vitamin D3 and process dietary calcium. In captivity, exposure to too little or too much UV-B can result in health problems such as metabolic bone disease. While it is recognized that UV-B is necessary to successfully maintain many reptiles in captivity, the actual levels of UV-B that species are exposed to in nature is poorly known. We measured the UV-B exposure of two species of chameleon (Calumma brevicorne and C. nasutum) in the field in Madagascar over a period of four months. We found that both species were exposed to less UV radiation than that which was available in full sun. Only on rare occasions were chameleons observed in areas with a UV Index (UVI) greater than 3.0, and the median UVI for both species was only 0.3. There was no daily temporal pattern in UV exposure for C. nasutum, but C. brevicorne was found in areas with lower UV levels in the late afternoon when compared to late morning. Additionally, C. nasutum males showed higher UV exposure than females in late morning. Our results suggest that both C. brevicorne and C. nasutum can be classified as Ferguson Zone 1 species, and should be provided with a UV-B gradient in captivity that offers access to UV-B radiation as well as adequate shaded refuge. K E Y W O R D S Calumma, captive husbandry, Ferguson Zone, reptile lighting, UV-Index
... However, most are opportunistic carnivores or omnivores, consuming invertebrates, small vertebrates, and aquatic vegetation (Bouchard and Bjorndal, 2006;Gibbons and Avery, 1990;Luiselli et al., 2011;Ottonello et al., 2005;Rhodin et al., 2008;Spencer et al., 1998). The wide spectrum of feeding strategies among freshwater turtles and their slow metabolism may explain their high tolerance for unbalanced diets in captivity, but their longevity and the energetic expense required for shell mineralization make them vulnerable to nutritional deficiencies in captivity (McWilliams, 2005). Moreover, the nutrient requirements for most species, especially those not routinely used in large-scale turtle farming, are poorly documented. ...
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... Indoor-housed mother-reared primate infants of any species are also at risk of developing deficiencies and rickets, as little vitamin D is transmitted in the milk to nursing infants. Basking reptiles, including iguanas and geckos, and chelonians may also be at risk for metabolic bone disease if not provided with adequate Ultraviolet A and Ultraviolet B light exposure (McWilliams, 2005). UV light has also been studied extensively in birds, where it may play an important role in sexual signaling, prey recognition, and navigation (Prescott et al., 2003;Rajchard, 2009). ...
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The occurrence of free and glycosidic vitamin D3 and its metabolises in Cestrum diurnum leaves was investigated. The chloroform extract of the leaves (containing free vitamin D3 and its metabolites) and the chloroform-methanol (1:2) extract (containing glycosidic vitamin D3 and its metabolites) of the residue after glycosidase treatment were partially purified by column chromatography. Fractions corresponding to authentic vitamin D3, 25-hydroxy vitamin D3 (25-OH-D3) and 1,25-dihydroxy vitamin D3 (1,25-(OH)2D3) were found to be biologically active. These fractions were also analysed and quantified by HPLC. This is the first demonstration of the presence of free vitamin D3, 25-OH-D3 and 1,25-(OH)2D3 in a carcinogenic plant. Apart from the free forms, the corresponding glycosidic metabolites were also found. The concentration of free metabolises was much higher than that of the glycosidic forms.
Article
We hypothesized the vitamin D-deficient green iguanas with depleted calcium stores would seek to augment calcium intake by self-selection of a high calcium source. Eight green iguanas were offered free-choice ground oystershell in addition to their regular diet. Of these, two had not been exposed to ultraviolet (UV-B) radiation for > 5 years and were demonstrated to be vitamin D-deficient by low circulating levels of the principal vitamin D metabolite, calcidiol (25-hydroxy-cholecalciferol). The six others had been exposed to a UV-B emitting bulb for the previous 3 years and had high circulating calcidiol levels. Average daily food intake (expressed as dry matter per kg body mass) did not differ between the Low-D and High-D iguanas. The daily oystershell intake of the Low-D iguanas (0.02–0.03 g/kg) was lower than that of the High-D iguanas (0.06–0.70 g/kg), leading to a significant difference in calcium intake. The failure of iguanas to increase calcium intake in response to vitamin D-deficiency was puzzling and suggests that vitamin D, as a steroid hormone, may play some role in the expression of calcium appetite. Zoo Biol 16:201–207, 1997. © 1997 Wiley-Liss, Inc.
Article
It has been speculated that pyramiding, a condition in which the scutes of the carapace become deformed and elevated, may be caused by an imbalance in dietary calcium (Ca) and/or phosphorus (P). This was tested by feeding 48 red-eared sliders (Trachemys scripta elegans), 12–14 weeks old, one of four diets for 150 days. The control diet was 67% krill and 33% flour (DM), providing 1.38% Ca and 1.03% P. The high Ca (2.24%) and high P (2.56%) diets were created by adding limestone or sodium phosphate, respectively, to the control diet. The fourth diet contained 2.95% Ca and 2.48% P, with a Ca:P ratio similar to the control diet. Turtles were maintained in groups of four in 12 10-gallon aquariums with incandescent heat lamps and full spectrum fluorescent lamps (n = 3 tanks/diet). The incidence of pyramiding, body weight, and carapace length were measured every 50 days. Pyramiding was not induced in any group during this study, with all turtles having shells of normal shape and appearance. At the beginning of the study, the turtles weighed 8.37 ± 1.50 g (mean ± SEM), with a carapace length of 35.08 ± 1.88 mm. Those receiving the control and high Ca/high P diets grew significantly faster in body weight than the turtles receiving the high Ca diet, with the turtles on the high P diet being intermediate (control: 10.83 ± 1.49a; high Ca: 5.82 ± .78b; high P: 7.77 ± 1.94a,b; high Ca/high P: 9.01 ± 1.88a g of gain; P = 0.013). The carapaces of turtles on the high Ca diet also grew significantly slower than those of all other groups (control: 9.87 ± 1.10a; high Ca: 5.18 ± .73b; high P: 8.22 ± 2.17a; high Ca/high P: 8.20 ± 1.07a mm of gain; P = 0.010). These data suggest that oversupplementation of calcium may be detrimental to growth performance in young turtles. Zoo Biol 17:17–24, 1998. © 1998 Wiley-Liss, Inc.
Article
Leaves of Cestrum diurnum grown in Hyderabad, India were tested for vitamin D-like activity in vitamin D-deficient rat and chick and also in rachitic rat models. Vitamin D-dependent serum and bone parameters, and calcium transport by the gut which were altered in vitamin D-deficiency were restored to control levels (ie to the levels found in rats given vitamin D3 from weanling, 25 IU day−1) by incorporation of C diurnum leaf powder at a 2% level in the diet. Similarly, in rachitic rats, the extent of new bone calcification was significantly improved either by C diurnum leaf incorporation in the diet or by vitamin D3 administration. An approximate estimate of the vitamin D-like activity indicated that the plant had about 100000 IU cholecalciferol equivalents kg−1 dry leaf powder, which is three times higher than the values reported earlier. This may be because of long exposure to sunlight of the plants grown in this part of the world.
Article
In laboratory tests, young Chelydra serpentina and Trachemys scripta altered their distribution in the presence of a temperature gradient, Selection of temperatures in the gradient for hatchlings and yearlings showed that body temperatures (T(b)s) of C. serpentina were lower than T. scripta,but the difference was insignificant. Relatively low TbS could allow greater activity range and reduced metabolic maintenance cost for C. serpentina, which seldom leaves water. Published by Elsevier Science Ltd.
Article
The active vitamin D metabolite 1,25-dihydroxyvitamin D3 [1,25-D3] is thought to promote many of its actions through interaction with a specific intracellular receptor. The discovery of such receptors in monocytes and activated lymphocytes has led investigators to evaluate the role of the hormone on the immune system. The sterol inhibits lymphocyte proliferation and immunoglobulin production in a dose-dependent fashion. At a molecular level, 1,25-D3 inhibits the accumulation of mRNA for IL-2, IFN-γ, and GM-CSF. At a cellular level, the hormone interferes with T helper cell (Th) function, reducing Th-induction of immunoglobulin production by B cells and inhibiting the passive transfer of cellular immunity by Th-clones in vivo. The sterol promotes suppressor cell activity and inhibits the generation of cytotoxic and NK cells. Class II antigen expression on lymphocytes and monocytes is also affected by the hormone.When given in vivo, 1,25-D3 has been particularly effective in the prevention of autoimmune diseases such as experimental autoimmune encephalomyelitis and murine lupus but its efficacy has been limited by its hypercalcemic effect. Synthetic vitamin D3 analogues showing excellent 1,25-D3-receptor binding but less pronounced hypercalcemic effects in vivo have recently enhanced the immunosuppressive properties of the hormone in autoimmunity and transplantation.
Article
Receptor autoradiography was used for the demonstration of specific binding of the tritiated steroid hormone 1,25-dihydroxyvitamin D3 in the eyes and associated tissues of Anolis carolinensis. A 100-fold excess of non-labelled 1,25-dihyroxyvitamin D3 abolished specific nuclear binding of tracer. Nuclear [3H]-1,25-dihydroxyvitamin D3 binding was present in all animals in the retina stratum ganglionare and stratum nucleare externum as well as in the cornea; however, binding was absent in the optic nerve, except in cells of the surrounding arachnoidea. Additional cranial tissues such as chondrocytes in the sclera, parasphenoid, skeletal muscle cells, and epithelial cells of the lacrimal and Harderian glands exhibited nuclear labelling. The results suggest that 1,25-dihydroxyvitamin D3 has genomic regulatory actions that involve cell proliferation, differentiation, and functions of certain cells of the eye and associated cranial tissues. The presence of vitamin D receptors in tissues of the eye and skeletal muscle in the reptile is in part different from that observed in mammals. In general, receptors for vitamin D and related target tissues appear to be even more extensive in lizards than has been observed in rodents, which may reflect a more extensive dependency of these tissues on solar environment and active seasonal and circadian regulation.
Article
We described the diet of Emydura macquarii, an omnivorous turtle from south-eastern Australia, compared its digestive performance on diets of fish or plants at two temperatures, and related how both diet and temperature affect its food selection in nature. Filamentous algae constituted 61% of the stomach content of E. macquarii. The turtles rarely fed on motile prey, but selected carrion from the lagoon bottom and terrestrial insects (Diptera, Hymenoptera and Coleoptera) trapped on the surface of the water. Digestive efficiency of E. macquarii was affected little by body temperature, in contrast to consumption rates and rates of passage which were strongly influenced by both temperature and diet. In combination, these responses resulted in a slower rate of digestion at 20°C than at 30°C. Digestive efficiency of E. macquarii on a herbivorous diet at 30°C (49%) was about half that of turtles on a carnivorous diet (91%), but they had longer transit times (118 h on the plant diet versus 70 h). Lower consumption rates and longer mean retention times in turtles fed plants compared those fed fish relate to slower digestive processing of the plant. Rapid processing and higher consumption rates of fish by E. macquarii resulted in higher energy gains compared to turtles consuming plants (almost 100 times more energy at 30°C). The laboratory results suggest that fish carrion and aquatic and terrestrial invertebrates are probably essential dietary items of E. macquarii in the wild, because its metabolic requirements cannot be met from aquatic macrophytes alone.
Article
Ultraviolet-A radiation (320-400 nm) is scattered rapidly in water. Despite this fact, UV is present in biologically useful amounts to at least 100 m deep in clear aquatic environments. Discovery of UV visual pigments with peak absorption at around 360 nm in teleost cone photoreceptors indicates that many teleost fishes may be adapted for vision in the UV range. Considering the characteristic absorption curve for visual pigments, about 18% of the downwelling light that illuminates objects at 30-m depth would be available to W-sensitive cones. Strong scattering of UV radiation should produce unique imaging conditions as a very bright UV background in the horizontal view and a marked veiling effect that, with distance, obscures an image. Many teleosts have three, or even four, classes of cone cells mediating colour vision in their retina and one can be sensitive to UV. These UV-sensitive cones contain a visual pigment based on a unique opsin which is highly conserved between fish species. Several powerful methods exist for demonstration of UV vision, but all are rather demanding in terms of technique and equipment. Demonstration that the eye lacks W-blocking compounds that are present in many fish eyes is a simpler method that can indicate the possibility of UV vision. The only experimental evidence for the use of UV vision by fishes is connected to planktivory: detection of UV-opaque objects at close range against a bright UV background is enhanced by the physical properties of UV light. Once present, perhaps for the function of detecting food, UV vision may well be co-opted through natural selection for other functions. Recent discovery that UV vision is critically important for mate choice in some birds and lizards is a strong object lesson for fish ecologists and behaviourists. Other possible functions amount to far more than merely adding a fourth dimension to the visible spectrum. Since UV is scattered so effectively in water, it may be useful for social signalling at short range and reduce the possibility of detection by other, illegitimate, receivers. Since humans are blind to UV light, we may be significantly in error, in many cases, in our attempts to understand and evaluate Visual aspects of fish behaviour. A survey of the reflectance properties of skin pigments in fishes reveals a rich array of pigments with reflectance peaks in the UV. For example, the same yellow to our eyes may comprise two perceptually different colours to fish, yellow and UV-yellow. It is clearly necessary for us to anticipate that many fishes may have some form of UV vision. (C) 1999 The Fisheries Society of the British Isles.
Article
Thesis (M.A.)--State University of New York, College at Buffalo, 1988. Includes bibliographical references (leaves 48-58).
Article
The exchange of water between a chelonian egg and its subterranean environment is influenced by numerous factors, the most important of which are (1) structure of the calcareous layer of the eggshell, (2) water potential and temperature in the nest, and (3) fraction of the eggshell that actually contacts soil in the nest cavity. Eggs with relatively porous shells tend to absorb large quantities of water from cool, moist environments and to lose large amounts of water to warm, dry ones. Net water-exchange by such eggs also tends to be more favorable (&equals; positive) when soil contacts the entire eggshell than when a large fraction of the shell is exposed to air trapped inside the nest cavity. In contrast, eggs with relatively impermeable shells usually exchange only small amounts of water with their environment, regardless of the physical conditions that prevail inside the nest. The pattern of net water-exchange, together with size (and water content) of the freshly laid egg, determines the amount of water that is available to sustain the embryo. An embryo having access to a relatively large reserve of water will consume more of its yolk and grow to larger size before hatching than will an embryo having access to a smaller reserve of water. Large, well-hydrated hatchlings may survive better than small, dehydrated animals during the trek overland from nest to water. If so, a cooler, wetter nest will also be a better nest.
Article
The photoproduction of vitamin D in the skin was essential for the evolutionary development of terrestrial vertebrates. During exposure to sunlight, previtamin D3 formed in the skin is isomerized to vitamin D3 (calciol) by a temperature-dependent process. Since early land vertebrates were poikilothermic, the relatively slow conversion of previtamin D3 to vitamin D3 at ambient temperature put them at serious risk for developing vitamin D deficiency, thus leading to a poorly mineralized skeleton that could have ultimately halted further evolutionary development of vertebrates on land. We evaluated the rate of isomerization of previtamin D3 to vitamin D3 in the skin of iguanas and found the isomerization rate was enhanced by 1100% and 1700% at 25 degrees C and 5 degrees C, respectively. It is likely that the membrane entrapment of previtamin D3 in its s-cis,s-cis conformation is responsible for the markedly enhanced conversion of previtamin D3 to vitamin D3. The membrane-enhanced production of vitamin D3 ensures the critical supply of vitamin D3 to poikilothermic animals such as iguanas.
Article
The effect of exposure of bacterial suspensions to UV radiation by means of the dose-response curves was assessed. The D37 and D10 values were used for subsequent statistical analysis of the results. The aim of this article is to evaluate the sensitivity to UV radiation of several microorganisms of different habitats (Rhizobium meliloti, Rhodobacter sphaeroides, Escherichia coli, and Deinococcus radiodurans), two mutants with nonfunctional SOS DNA repair system (R.meliloti recA - and E. coli recA -), and a mutant in the synthesis of carotenoids (R. sphaeroides crtD). The results reveal that D. radiodurans was an extremely resistant bacterium, R. meliloti was more resistant than R. sphaeroides, and E. coli was the most sensitive bacterium tested. The high sensitivity of recA - mutants was also verify. Moreover, it seems that the possession of pigments had no important effect in the sensitivity of R. sphaeroides to UV radiation.
Article
Structural homology between the high-affinity thyroxine (T4)-binding protein (TBP) in the plasma of the turtle, Trachemys scripta, and vitamin D-binding proteins (DBP) of mammals prompted an investigation of plasma vitamin D binding in the turtle. Several lines of evidence indicate that the TBP represents the primary binding protein for 25-OH-cholecalciferol (D3) in the turtle plasma. D3-binding protein in whole plasma migrates in the same position as TBP by size-exclusion chromatography and polyacrylamide gel electrophoresis; it is electrophoretically distinct from sex hormone-binding proteins. D3 binding to purified TBP alone is enhanced (up to sevenfold) in the presence of plasma proteins, including albumin; with this correction, the D3-binding activity of plasma corresponds to expected TBP titers. Plasma selectively stripped of TBP by affinity chromatography and purified turtle albumin have only trace D3-binding activity. Variations in physiological state (thyroidal status, age, and sex) previously associated with variable T4 binding (and TBP levels) in T. scripta show correlated variability in plasma D3 binding. D3 binding is also highly correlated with T4 binding (r = 0.81; P < 0.001) for plasma samples taken from 30 adults representing 10 different species of Trachemys. D3 binding in plasma exhibits a high-affinity site (Ka = 2.3 x 10(8) M-1) and a second lower-affinity (Ka = 2 x 10(6) M-1), higher-capacity site; capacities are highly variable. Purified TBP has a comparable high affinity (Ka = 2.8 x 10(8) M-1), with a capacity close to 1 mol/mol. Binding of T4 and D3 are not competitive, indicating separate binding sites for the two ligands; in fact, T4 tends to enhance the affinity and the capacity for D3. A single protein in turtle plasma ("TBP/DBP") functions in the transport of two different hormones normally served by two distinct binding proteins (representing different multigene families) in mammals. These results have implications for the mediation of T4 effects on growth.
Article
Ten clinically healthy green iguanas (Iguana iguana) imported from South America were examined, and haematological and biochemical measurements were made on samples of blood. This paper describes the methods of blood sampling, handling and laboratory analysis, and presents the results as a set of normal blood ranges for the green iguana.
Article
Vitamin D binding protein (DBP) was isolated from the plasma of the snapping turtle, Chelydra serpentina (mixed sex adult), and compared with the previously characterized dual function binding plasma protein that binds both thyroxine (T4) and vitamin D (tsTDBP) in an emydid turtle, Trachemys scripta. Purification of Chelydra serpentina DBP (csDBP) was accomplished by ion exchange chromatography, preparative polyacrylamide gel electrophoresis, and reverse-phase high-performance liquid chromatography. Estimates of increased purification (ca. 71-fold), recovery (ca. 1.5%), and corresponding plasma concentration (ca. 0.6 mg/ml) are confounded by interference with other proteins. A protein was identified that showed the same high affinity for 25-OH-cholecalciferol (vitamin D3) as the tsTDBP, and the two exhibited similar heat resistances in binding. The csDBP and tsTDBP had similar molecular weights by SDS-PAGE (ca. 58 kDa), showed immunological cross reactivity, and differed by only three residues, representing conservative substitutions, in the 30 NH2-terminal amino acid sequence. A slightly lesser homology (up to 89% similarity based on conservative substitutions) was seen with three mammalian DBPs. However, unlike tsTDBP, the DBP from the snapper did not bind T4. These data support the view that the DBP of emydid turtles secondarily evolved a second T4 binding site, and this is probably independent of the D3 binding domain.
Article
Individual variation in physiological traits may have important consequences for offspring survivorship and adult fitness. Variance in offspring phenotypes is due to interindividual differences in genotype, environment, and/or maternal effects. This study examined the contributions of incubation environment, maternal effects, and clutch identity to individual variation in metabolic rates in the common snapping turtle, Chelydra serpentina. We measured standard metabolic rate, as determined by oxygen consumption, for 246 individuals representing 24 clutches at 15 degrees and 25 degrees C, and we measured standard metabolic rates additionally for 34 individuals at 20 degrees and 30 degrees C. Standard metabolic rate for 34 snapping turtles measured at 15 degrees, 20 degrees, 25 degrees, and 30 degrees C increased with increasing temperature. Mean standard metabolic rate for 246 individuals was 0.247 microL O(2) min(-1) g(-1) at 15 degrees C and 0.919 microL O(2) min(-1) g(-1) at 25 degrees C. At 15 degrees C, mass at hatching, individual mass, and egg mass had no significant effects on metabolic rate, but at 25 degrees C, mass at hatching, individual mass, and egg mass did have significant effects on metabolic rate. Incubation temperature had no significant effect on metabolic rate at 15 degrees, but it did have a significant effect at 25 degrees C. Clutch identity had a significant effect on metabolic rate at both 15 degrees and 25 degrees C. Interindividual variation in standard metabolic rate due to incubation temperature, and especially clutch identity, could have large effects on energy budgets. Results suggest that there were both environmental and genetic effects on standard metabolic rate.
Article
We tested two hypotheses: first, that the inferior anoxia tolerance of the softshell turtle, Apalone spinifera, compared to the western painted turtle, Chrysemys picta bellii, is related to its less mineralized shell, and second, that turtle bone, like its shell, stores lactate during prolonged anoxia. Lactate concentrations of blood, hindlimb bone, and shell were measured on normoxic Apalone and Chrysemys and after anoxic submergence at 10 degrees C for 2 and 9 d, respectively. Blood and shell concentrations of Ca(2+), Mg(2+), Na(+), K(+), and inorganic phosphate (P(i); for shell only) were also measured. Because a preliminary study indicated lactate distribution in Chrysemys throughout its skeleton during anoxia at 20 degrees C, we used hindlimb bones as representative skeletal samples. Apalone shell, though a similar percentage of body mass as Chrysemys shell, had higher water content (76.9% vs. 27.9%) and only 20%-25% as much Ca(2+), Mg(2+), CO(2), and P(i). When incubated at constant pH of 6.0 or 6.5, Apalone shell powder released only 25% as much buffer per gram wet weight as Chrysemys shell. In addition, plasma [Ca(2+)] and [Mg(2+)] increased less in Apalone during anoxia at an equivalent plasma lactate concentration. Lactate concentrations increased in the shell and skeletal bone in both species. Despite less mineralization, Apalone shell took up lactate comparably to Chrysemys. In conclusion, a weaker compensatory response to lactic acidosis in Apalone correlates with lower shell mineralization and buffer release and may partially account for the poorer anoxia tolerance of this species.
Article
We dissected hearts from near-term embryos and hatchlings of common snapping turtles (Chelydridae: Chelydra serpentina) whose eggs had incubated on wet or dry substrates, and then dried and individually weighed the heart and yolk-free carcass from each animal. Hearts and carcasses of prenatal and neonatal animals grew at different rates, and the patterns of growth by both heart and carcass differed between wet and dry environments. Hearts grew faster, both in actual mass and in mass adjusted for variation in body size, in embryos and hatchlings whose eggs were incubated on dry substrates than in animals whose eggs were held on wet media. This finding is consistent with a hypothesis that embryos incubating in dry settings experience hypovolemia secondary to dehydration and that enlargement of the heart compensates, in part, for the associated increase in viscosity of the blood. Embryonic turtles seemingly exhibit the same plasticity and response that would be expected from other vertebrate ectotherms subjected to the physiological challenges associated with desiccation and an associated reduction in blood volume.
Evaluation of vitamin D concentrations in Uro-mastyx spp. with and without radiographic evidence of dystrophic mineralization
  • B L Raphael
  • S B James
  • R A Cook
Raphael, B. L., James, S. B. & Cook, R. A. (1999): Evaluation of vitamin D concentrations in Uro-mastyx spp. with and without radiographic evidence of dystrophic mineralization. Proceedings of the American Association of Zoo Veterinarians 1999: 20–23
The pineal complex of reptiles: physiological andbehavioral Ecology and Evolution 9: 313–333. roles The common diseases of captive reptiles: their symptoms, treatment, and prevention
  • G Tosini
  • J O Truitt
Tosini, G. (1997): The pineal complex of reptiles: physiological andbehavioral Ecology and Evolution 9: 313–333. roles. Ethology, Truitt, J. O. (1962): The common diseases of captive reptiles: their symptoms, treatment, and prevention. Coral Gables, FL: privately published
Metabolic bone disease
  • Dc Washington
  • Smithsonian Institution
  • T H Boyer
Washington, DC: Smithsonian Institution. Boyer, T. H. (1996): Metabolic bone disease. In Reptile medicine and surgery: 385–392.
Reptile lighting: a current perspective
  • Gehrmann
Gehrmann, W. H. (1996): Reptile lighting: a current perspective. Vivarium 8: 44–45.
Nutrient composition of whole prey commonly fed to reptiles and amphibians
  • Dierenfeld
Dierenfeld, E. S. & Barker, D. (1995): Nutrient composition of whole prey commonly fed to reptiles and amphibians. Proceedings of the Association of Reptilian and Amphibian Veterinarians 1995: 3–15.
Food preferences, feeding practices and nutritional problems of captive reptiles
  • Kollias
Kollias, G. V. & Gentz, E. J. (1996): Food pref-erences, feeding practices and nutritional problems of captive reptiles. Proceedings of the Association of Amphibian and Reptilian Veterinarians 1996: 107–110.
An illuminating discussion of vitamin D, ultraviolet radiation and reptiles
  • Bernard
Bernard, J. B. & Ullrey, D. E. (1995): An illumi-nating discussion of vitamin D, ultraviolet radiation and reptiles. Proceedings of the Association of Rep-tilian and Amphibian Veterinarians 1995: 40–42.
Head starting Blanding's tur-tles (Emydoidea blandingii): a strategy for enhance-ment of a fragmented population
  • G V Kollias
  • M M Zgola
  • T K Weinkle
  • A B Breisch
Kollias, G. V., Zgola, M. M., Weinkle, T. K. & Breisch, A. B. (1997): Head starting Blanding's tur-tles (Emydoidea blandingii): a strategy for enhance-ment of a fragmented population. Proceedings of the American Association of Zoo Veterinarians 1997: 306–307.
Turtles, tor-toises and terrapins
  • D R Mader
Mader, D. R. (Ed.). Philadelphia, PA: W. B. Saunders Co. Boyer, H. B. & Boyer, D. M. (1996): Turtles, tor-toises and terrapins. In Reptile medicine and surgery: 61–78.
Clinical nutrition of reptiles and amphibians
  • Donoghue
Donoghue, S. (1995): Clinical nutrition of reptiles and amphibians. Proceedings of the Association of Reptilian and Amphibian Veterinarians 1995: 16–37.
© The Zoological Society of London Analysis of the maintenance diet offered to lories and lorikeets (Psittaciformes; Loriinae)
Int. Zoo Yb. (2005) 39: 85–98 © The Zoological Society of London Analysis of the maintenance diet offered to lories and lorikeets (Psittaciformes; Loriinae)
Evaluation of vitamin D concentrations in Uromastyx spp. with and without radiographic evidence of dystrophic mineralization Diseases of reptiles Visceral gout in birds and reptiles
  • B L Raphael
  • S B James
  • R A Cook
  • H Reichenbach-Klinke
  • E K A Elkan
Raphael, B. L., James, S. B. & Cook, R. A. (1999): Evaluation of vitamin D concentrations in Uromastyx spp. with and without radiographic evidence of dystrophic mineralization. Proceedings of the American Association of Zoo Veterinarians 1999: 20–23. Reichenbach-Klinke, H. & Elkan, E. (1965): Diseases of reptiles. Hong Kong: TFH Publications. Slifka, K. A. (1997): Visceral gout in birds and reptiles. In Proceedings of the ninth Dr. Scholl conference on the nutrition of captive wild animals: 134–139.
Spain and 3 Rainforest Clinic for Birds
  • Loro Researcher
  • Parque
Researcher, Loro Parque Fundación, Tenerife, Spain and 3 Rainforest Clinic for Birds, PO Box 508, Loxahatchee, Florida 33470, USA