Biological mechanism
Ectotherm Skin & Vitamin D3 Production - Findings: Conversion of previtamin D3 into vitamin D3 in iguana skin was enhanced
approximately 1,100% at 25°C and 1,700% at 5°C compared with conversion in solution. The skin membrane facilitates vitamin D3 production at ectothermic body temperatures.
Evolutionary importance for the membrane enhancement of the production of vitamin D3 in the skin of poikilothermic animals
DOI: 10.1073/pnas.92.8.3124
DOI URL: https://doi.org/10.1073/pnas.92.8.3124
Access: Free full text.
Vitamin D Metabolism in Veterinary Species - Findings: Vitamin D3 is converted primarily into circulating 25-hydroxyvitamin D3,
which is used to assess vitamin D status. It is then converted into hormonally active 1,25-dihydroxyvitamin D3. Metabolism and reference values can differ substantially between species.
Vitamin D Metabolism and Profiling in Veterinary Species
DOI: 10.3390/metabo10090371
DOI URL: https://doi.org/10.3390/metabo10090371
Access: Free full text.
—----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Reptile Vitamin D3 Synthesis and Status
Leopard Gecko & UVB for D3 Synthesis - Findings: Leopard geckos exposed to low-level UVB for two hours daily had higher plasma 25(OH)D3 than unexposed geckos (61 ± 20 vs. 38 ± 8 nmol/L). Growth and weight gain did not differ during the first six months.
The nocturnal leopard gecko (Eublepharis macularius) uses UVb radiation for vitamin D3 synthesis
DOI: 10.1016/j.cbpb.2020.110506
DOI URL: https://doi.org/10.1016/j.cbpb.2020.110506
Access: Free full text.
Bearded Dragon & UVB Compared with Dietary D3 - Findings: At six months, UVB-exposed dragons had approximately 18 times the plasma 25(OH)D3 concentration of dragons receiving dietary vitamin D3 alone (178.4 ± 9.0 vs. 9.9 ± 1.3 nmol/L). Active 1,25(OH)2D3 was approximately 5.3 times higher (1.205 ± 0.100 vs. 0.229 ± 0.025 nmol/L).
Effects of vitamin D3 supplementation and UVb exposure on the growth and plasma concentration of vitamin D3 metabolites in juvenile bearded dragons (Pogona vitticeps)
DOI: 10.1016/j.cbpb.2010.02.008
DOI URL: https://doi.org/10.1016/j.cbpb.2010.02.008
Access: Free repository copy.
Bearded Dragon & Differences Between UVB Lamps - Findings: Only one of five compact UVB lamps produced a significant rise in plasma 25(OH)D3. That group reached 41.00 ± 12.85 nmol/L compared with 2.00 ± 0.00 nmol/L in controls. Wild dragons used for comparison averaged 409 ± 56 nmol/L.
A comparison of UVb compact lamps in enabling cutaneous vitamin D synthesis in growing bearded dragons
DOI: 10.1111/jpn.12728
DOI URL: https://doi.org/10.1111/jpn.12728
Access: Free repository copy.
Corn Snake & UVB for D3 Synthesis - Findings: After 28 days, mean plasma 25(OH)D3 was 196 ± 16.73 nmol/L in UVB-exposed snakes and 57.17 ± 15.28 nmol/L in controls. The UVB group increased from approximately 63 to 196 nmol/L.
Effects of ultraviolet radiation on plasma 25-hydroxyvitamin D3 concentrations in corn snakes (Elaphe guttata)
DOI: 10.2460/ajvr.69.2.294
DOI URL: https://doi.org/10.2460/ajvr.69.2.294
Access: Free article page and abstract.
Ball Python & UVB - Findings: UVB exposure did not produce a significant increase during the 70-day study. The UV group started with substantially higher 25(OH)D3 than the control group (197 ± 35 vs. 77.7 ± 41.5 nmol/L), limiting interpretation. The UV group was entirely female, while the control group was mixed-sex.
The effects of UV light on calcium metabolism in ball pythons (Python regius)
DOI: 10.1136/vr.101555
DOI URL: https://doi.org/10.1136/vr.101555
Access: Free detailed abstract.
Blanding’s Turtle & Artificial UVB - Findings: After 180 days of UVB exposure for 12 hours daily, juvenile turtles had plasma 25(OH)D3 concentrations approximately 5.5 times those of controls. The difference was significant at P < 0.001.
Effects of Artificial Ultraviolet B Radiation on Plasma 25-Hydroxyvitamin D3 Concentrations in Juvenile Blanding's Turtles (Emydoidea blandingii)
DOI: 10.5818/JHMS-D-21-00039
DOI URL: https://doi.org/10.5818/JHMS-D-21-00039
Access: Free full text.
Blue-Tongued Skink & Intermittent UVB - Findings: UVB for two hours every three days increased median plasma 25(OH)D3 from 17 to 587.5 nmol/L. Exposure every seven days increased it from 23 to 51 nmol/L, although individual responses varied widely.
Intermittent ultraviolet B exposure increases plasma 25-hydroxyvitamin D3 in blue-tongued skinks (Tiliqua scincoides)
DOI: 10.2460/ajvr.25.11.0417
DOI URL: https://doi.org/10.2460/ajvr.25.11.0417
Access: Free full text.
Blue-Tongued Skink & Vitamin D Decline After UVB Withdrawal - Findings: Daily UVB exposure for either two or 12 hours increased plasma 25-OHD. Following withdrawal, concentrations returned near baseline after approximately four months in the two-hour group and seven months in the 12-hour group. Dietary D3 in the study diet did not maintain the elevated concentrations.
Measuring the Rise and Fall of Plasma 25-Hydroxyvitamin D Concentrations in Blue-Tongued Skinks (Tiliqua scincoides) Following Ultraviolet B Exposure and Withdrawal
DOI: 10.3390/vetsci12100965
DOI URL: https://doi.org/10.3390/vetsci12100965
Access: Free full text.
Hermann’s Tortoise & Natural Sunlight Compared with Artificial UV - Findings: Plasma 25(OH)D3 remained high under natural sunlight, increasing from 387.74 ± 114.56 to 411.51 ± 189.75 nmol/L. It declined under mercury-vapor lighting from 368.02 ± 119.34 to 155.69 ± 80.71 nmol/L and under fluorescent UV lighting from 313.69 ± 109.54 to 134.42 ± 51.42 nmol/L.
Plasma 25-hydroxyvitamin D3 concentrations in Hermann's tortoises (Testudo hermanni) exposed to natural sunlight and two artificial ultraviolet radiation sources
DOI: 10.2460/ajvr.73.11.1781
DOI URL: https://doi.org/10.2460/ajvr.73.11.1781
Access: Free abstract.
Hermann’s Tortoise, Pond Slider & Natural Sunlight - Findings: Hermann’s tortoises receiving sunlight in early summer averaged 22.98 ± 20.25 nmol/L vitamin D3, compared with 11.91 ± 11.52 nmol/L without sunlight. Pond sliders receiving sunlight in late summer averaged 6.77 ± 5.55, compared with 3.01 ± 4.49 nmol/L.
The effects of sex, season, and natural sunlight on plasma vitamin D3 levels in two chelonian species (Testudo hermanni, Trachemys scripta) and their interaction with calcium, phosphate, and magnesium as associated plasma compounds
DOI: 10.3389/famrs.2023.1268801
DOI URL: https://doi.org/10.3389/famrs.2023.1268801
Access: Free full text.
Rhinoceros Iguana & Seasonal Sunlight Exposure - Findings: Serum 25(OH)D3 declined approximately 85% during each of two winters without UVB or dietary vitamin D. The estimated half-life during the second winter was 69 days. Higher vitamin D status was restored outdoors when the iguanas voluntarily received approximately 1-2 J of UVB daily.
Summer and Winter Seasonal Changes in Vitamin D Status of Captive Rhinoceros Iguanas (Cyclura cornuta)
DOI: 10.5818/1529-9651-25.3.128
DOI URL: https://doi.org/10.5818/1529-9651-25.3.128
Access: Free full text.
—----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Vitamin D and Calcium Metabolism
Veiled Chameleon Gastrointestinal Vitamin D Receptors and Calcium-Absorption Proteins - Findings: Vitamin D receptor immunoreactivity was greatest in the duodenum, particularly near the bases of the villi. Calbindin-D28k was concentrated primarily in the duodenum. Groups receiving calcium and vitamins A and D, with or without UVB, had greater calbindin-D28k immunoreactivity than animals receiving no supplements or UVB alone.
Influence of feeding and UVB exposition on the absorption mechanisms of calcium in the gastrointestinal tract of veiled chameleons (Chamaeleo calyptratus)
DOI: 10.1111/jpn.12206
DOI URL: https://doi.org/10.1111/jpn.12206
Access: Free full text.
—----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Amphibian Vitamin D3 Synthesis and Development
Amphibians & Vitamin D3 and UVB - Findings: Amphibians can obtain vitamin D3 through UVB exposure or diet. The review connects inadequate vitamin D with nutritional metabolic bone disease and possible reproductive and immune effects, while emphasizing that excessive UV can injure amphibians at every life stage.
Ultraviolet radiation and Vitamin D3 in amphibian health, behaviour, diet and conservation
DOI: 10.1016/j.cbpa.2009.06.008
DOI URL: https://doi.org/10.1016/j.cbpa.2009.06.008
Access: Free detailed abstract.
Oriental Fire-Bellied Toad & UVB - Findings: Serum 25(OH)D3 was higher under UVB, approximately 88.2-88.7 nmol/L, than without UVB, approximately 73.6-74.1 nmol/L. UVB accelerated development of adult coloration, while dietary calcium interacted with growth and skeletal outcomes.
Impacts of UVB provision and dietary calcium content on serum vitamin D3, growth rates, skeletal structure and coloration in captive oriental fire-bellied toads (Bombina orientalis)
DOI: 10.1111/jpn.12203
DOI URL: https://doi.org/10.1111/jpn.12203
Access: Free repository record.
Amazonian Milk Frog & UVB During Development - Findings: Frogs receiving daily UVB had greater body mass (1.35 ± 0.06 vs. 1.16-1.17 g), vertebral length (0.97 ± 0.01 vs. 0.89-0.90 cm), and femur length (1.12 ± 0.017 vs. 1.04-1.05 cm).
Ultraviolet B radiation (UV-B) and the growth and skeletal development of the Amazonian milk frog (Trachycephalus resinifictrix) from metamorphosis
DOI: 10.5897/JPAP.9000026
DOI URL: https://doi.org/10.5897/JPAP.9000026
Access: Free article page.
Mallorcan Midwife Toad Larvae & UVB - Findings: UVB did not significantly affect serum vitamin D3, calcium, phosphorus, growth, pigmentation, or total body mineral content under the tested conditions.
Impacts of UVB provision on serum vitamin D3, pigmentation, growth rates and total body mineral content in Mallorcan midwife toad larvae (Alytes muletensis)
DOI: 10.19227/jzar.v8i1.434
DOI URL: https://doi.org/10.19227/jzar.v8i1.434
Access: Free full text.
—----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Vitamin D Synthesis in Invertebrates
Insect Species & UVB-Induced Vitamin D Synthesis - Findings: Higher UVB irradiance increased vitamin D3 in migratory locusts, house crickets, and yellow mealworms, but not in black soldier fly larvae. Vitamin D3 increased from undetectable to 226 IU/kg in locusts, from 41 to 124 IU/kg in house crickets, and from 50 to 3,067 IU/kg in mealworms. Mealworms reached approximately 6,400 IU/kg after 32 hours of cumulative exposure.
Evidence of vitamin D synthesis in insects exposed to UVb light
DOI: 10.1038/s41598-018-29232-w
DOI URL: https://doi.org/10.1038/s41598-018-29232-w
Access: Free full text.
Black Field Cricket & UVB During Calcium Gut-Loading - Findings: Vitamin D3 remained below the detection limit throughout 48 hours of UVB exposure. The Ca:P ratio increased from 0.17 to approximately 0.40 after 24 hours on the high-calcium diet but did not increase further during the second 24 hours. All accumulated calcium was lost within 24 hours after removal of the calcium-rich food.
Calcium Accumulation and Loss and Vitamin D3 Content of Feeder Black Field Crickets (Gryllus bimaculatus) Fed on a High Calcium Diet with and without UVB Irradiation
DOI: 10.3390/jzbg2030027
DOI URL: https://doi.org/10.3390/jzbg2030027
Access: Free full text.
Powdered Mealworms, Crickets and Locusts & UVB Fortification - Findings: UVB-treated yellow mealworm powder contained 8.95-18.24 µg vitamin D3/g dry matter. UVB-treated migratory locust and two-spotted cricket powders did not contain quantifiable vitamin D3 under the tested conditions.
Vitamin D Fortification of Selected Edible Insect Species Through UVB-Treatment
Published DOI: 10.1016/j.foodchem.2024.138679
Published DOI URL: https://doi.org/10.1016/j.foodchem.2024.138679
Preprint DOI: 10.2139/ssrn.4634714
Preprint DOI URL: https://doi.org/10.2139/ssrn.4634714
Access: Free manuscript through SSRN.
Black Soldier Fly Larvae, Dietary Sterols & UVB - Findings: Mushroom-fed larvae accumulated 702 ± 95 mg/kg fresh weight of ergosterol, compared with 444 ± 56 mg/kg in the mushrooms. After one hour of UVB, larvae contained 46 ± 2 mg/kg vitamin D2 and 10.9 ± 0.5 mg/kg vitamin D3. Neither vitamin was detectable before UVB exposure.
Feeding black soldier fly (Hermetia illucens) larvae with mushrooms and then exposing them to UVB produces larvae extremely rich in vitamins D2 and D3
DOI: 10.1016/j.fufo.2025.100692
DOI URL: https://doi.org/10.1016/j.fufo.2025.100692
Access: Free full text.
—----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
UV Exposure and Species Requirements
Reptile and Amphibian UVB Provision - Findings: The UV-Tool groups species according to natural basking and microhabitat behavior and assigns suitable ultraviolet-index zones. Its central husbandry principle is to provide a usable UV gradient with access to shade rather than exposing the entire enclosure uniformly.
How much UVB does my reptile need? The UV-Tool, a guide to the selection of UV lighting for reptiles and amphibians in captivity
DOI: 10.19227/jzar.v4i1.150
DOI URL: https://doi.org/10.19227/jzar.v4i1.150
Access: Free full text.
Screens, Glass, Acrylic and UVB Transmission - Findings: Fourteen enclosure materials were evaluated. General UV-meter readings did not always accurately represent biologically effective vitamin-D-producing radiation through UV-transmitting acrylic. Measurements through screen material corresponded more closely with biologically effective attenuation.
Evaluation of UVB reduction by materials commonly used in reptile husbandry
DOI: 10.1002/zoo.20148
DOI URL: https://doi.org/10.1002/zoo.20148
Access: Free abstract.
—----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
UV Spectrum and Lamp Safety
UVB LEDs & Nonnatural Spectra - Findings: Eighteen LED lamps were evaluated. Their spectra differed substantially from sunlight, and some emitted abnormally short-wavelength UVB or UVC associated with eye and skin injury. All lacked substantial output in the 315-335 nm region involved in natural regulation of vitamin D3 photoproducts.
UVB-emitting LEDs for reptile lighting: Identifying the risks of nonsolar UV spectra
DOI: 10.1002/zoo.21806
DOI URL: https://doi.org/10.1002/zoo.21806
Access: Free abstract.
Problematic UV Lamps & Reptile Eye Injury - Findings: This conference report documented photokeratoconjunctivitis in more than 80 reptiles following exposure to certain compact UV lamps. - This paper was moved and must be relocated or have a permalink posted.
PHOTO-KERATO-CONJUNCTIVITIS IN REPTILES
DOI: 10.5555/20093041829
DOI URL: https://doi.org/10.5555/20093041829
Access: Free bibliographic record. Conference literature.
—----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
UV Dose, Temperature and Amphibian Safety
Striped Marsh Frog & Interaction Between UVB and Temperature - Findings: At 15°C, high UV exposure produced 68.4% mortality, approximately 20 times that of the low-UV treatment. Growth reduction under high UV was 81.3%, compared with 18.4% under low UV.
Effects of ultraviolet-B radiation on physiology, immune function and survival is dependent on temperature: implications for amphibian declines
DOI: 10.1093/conphys/coaa002
DOI URL: https://doi.org/10.1093/conphys/coaa002
Access: Free full text.
Green Tree Frog & UV Irradiance Compared with Cumulative Dose - Findings: Treatments delivering the same cumulative UV dose at different irradiances produced different effects on growth, coloration, swimming performance, and survival. Cumulative dose alone was insufficient to predict the biological response.
Ultraviolet-B irradiance and cumulative dose combine to determine performance and survival
DOI: 10.1016/j.jphotobiol.2021.112276
DOI URL: https://doi.org/10.1016/j.jphotobiol.2021.112276
Access: Free abstract.
