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Mark D. Finke - One of the best experts on this subject based on the ideXlab platform.

  • Evaluation of Various Calcium-fortified High Moisture Commercial Products for Improving the Calcium Content of Crickets, Acheta domesticus
    Journal of herpetological medicine and surgery, 2020
    Co-Authors: Mark D. Finke, Shari U Dunham, John S. Cole
    Abstract:

    ABSTRACT Crickets, Acheta domesticus, are commonly fed special diets to alter their nutrient content (especially with regards to calcium) to make them a more complete diet for insectivorous birds, reptiles, and amphibians. Typically calcium-fortified dry diets are used to increase the insects' calcium content. In this experiment we compare the moisture, calcium and phosphorus content of crickets offered a typical dry calcium-fortified Gut Loading diet and distilled water, with those fed several commercial products (two commercial “calcium-fortified cricket waters” and a calcium-fortified high moisture diet designed to provide both food and water). An unfortified dry diet served as a negative control. Crickets fed the calcium-fortified dry diet contained significantly more calcium than those fed the other treatments. Cricket phosphorus content was not affected by diet. In summary the commercial products tested were ineffective in increasing the calcium content of crickets fed these products. For that reaso...

  • Complete nutrient content of four species of commercially available feeder insects fed enhanced diets during growth
    Zoo Biology, 2015
    Co-Authors: Mark D. Finke
    Abstract:

    Commercially raised feeder insects used to feed captive insectivores are a good source of many nutrients but are deficient in several key nutrients. Current methods used to supplement insects include dusting and Gut-Loading. Here, we report on the nutrient composition of four species of commercially raised feeder insects fed a special diet to enhance their nutrient content. Crickets, mealworms, superworms, and waxworms were analyzed for moisture, crude protein, fat, ash, acid detergent fiber, total dietary fiber, minerals, amino acids, fatty acids, vitamins, taurine, carotenoids, inositol, and cholesterol. All four species contained enhanced levels of vitamin E and omega 3 fatty acids when compared to previously published data for these species. Crickets, superworms, and mealworms contained β-carotene although using standard conversion factors only crickets and superworms would likely contain sufficient vitamin A activity for most species of insectivores. Waxworms did not contain any detectable β-carotene but did contain zeaxanthin which they likely converted from dietary β-carotene. All four species contained significant amounts of both inositol and cholesterol. Like previous reports all insects were a poor source of calcium and only superworms contained vitamin D above the limit of detection. When compared to the nutrient requirements as established by the NRC for growing rats or poultry, these species were good sources of most other nutrients although the high fat and low moisture content of both waxworms and superworms means when corrected for energy density these two species were deficient in more nutrients than crickets or mealworms. These data show the value of modifying the diet of commercially available insects as they are growing to enhance their nutrient content. They also suggest that for most insectivores properly supplemented lower fat insects such as crickets, or smaller mealworms should form the bulk of the diet. Zoo Biol. 34:554–564, 2015. © 2015 The Authors. Zoo Biology published by Wiley Periodicals, Inc.

  • Complete Nutrient Content of Four Species of Feeder Insects
    Zoo Biology, 2012
    Co-Authors: Mark D. Finke
    Abstract:

    A variety of insects are commonly fed to captive insectivores but detailed nutritional analyses are only available for the most commonly fed species. Soldier fly larvae, Turkestan cockroach nymphs, tebo worms, and adult house flies were analyzed for moisture, protein, fat, ash, acid detergent fiber, neutral detergent fiber, minerals, amino acids, fatty acids, vitamins, and selected carotenoids. The acid detergent fiber was analyzed for amino acids to estimate chitin content. Nutrient content varied widely between the four insect species. Ranges for the macronutrients were as follows: moisture (60.2–74.8%), crude protein (15.5–19.7%), crude fat (1.9%–29.4%), acid detergent fiber (1.4–3.0%), neutral detergent fiber (2.6–3.8%), and ash (0.8–3.5%). Energy content ranged from a low of 918 kcal/kg for house flies to 2,977 kcal/kg for tebo worms. The chitin content of these four species ranged from 6.7 to 21.0 mg/kg. The nutrients most likely to be deficient when these species of insects are used as food for insectivores are vitamin A, vitamin D, calcium, vitamin E, thiamine, iodine, and vitamin B12. The number of nutrients deficient vs. the NRC requirements for rats on an energy basis by insect species was as follows: soldier fly larvae (3), tebo worms (15), Turkestan cockroach nymphs (5), and adult house flies (6). These data are valuable in helping assess the nutrient intake of captive insectivores and in developing Gut-Loading diets to improve the nutrient intake of captive insectivores. Zoo Biol. 32:27-36, 2013. © 2012 Wiley Periodicals, Inc.

  • evaluation of four dry commercial Gut Loading products for improving the calcium content of crickets acheta domesticus
    Journal of herpetological medicine and surgery, 2005
    Co-Authors: Mark D. Finke, Shari U Dunham, Christabel A Kwabi
    Abstract:

    ABSTRACT Crickets, Acheta domesticus, are commonly fed special diets to alter their nutrient content (especially with regard to calcium) to make them a more complete diet for insectivorous reptiles and amphibians. Calcium-fortified dry diets are used by zoos to increase a crickets' calcium content and a variety of products are available in pet stores for the hobbyist. In this experiment we compare the moisture, calcium and phosphorus content of small cricket nymphs and adult crickets offered an experimental dry calcium-fortified Gut Loading diet with those fed four commercial dry diets. An unfortified dry diet served as a negative control. Crickets fed the experimental calcium-fortified dry diet and one of the commercial products (T-Rex® Calcium Plus™ Food for Crickets) contained sufficient calcium to meet the estimated requirements of insectivorous reptiles and significantly more calcium than those fed the other treatments. Crickets fed the other three commercial products contained no more calcium than t...

  • Gut Loading to enhance the nutrient content of insects as food for reptiles a mathematical approach
    Zoo Biology, 2003
    Co-Authors: Mark D. Finke
    Abstract:

    A variety of commercially raised insects are fed to insectivorous reptiles, but information concerning appropriate diets used to feed these insects is limited. In the present study, house crickets (Acheta domesticus adults and nymphs), mealworms (Tenebrio molitor larvae), and silkworms (Bombyx mori larvae) were fed diets containing graded levels of calcium (Ca) and/or vitamin A–nutrients that are low or absent in most insects. Diets and insects were analyzed for moisture, Ca, phosphorus (P), and vitamin A. For adult crickets and cricket nymphs, body Ca and vitamin A concentrations increased in a linear fashion with increasing levels of dietary Ca or vitamin A. Ca concentrations of silkworms also increased in a linear fashion with increasing levels of dietary Ca. For mealworms, body Ca and vitamin A concentrations increased in a nonlinear fashion with increasing levels of dietary Ca or vitamin A. These regression equations, in conjunction with insect nutrient composition, allow for the calculation of the optimum nutrient concentration for Gut-Loading diets. Final recommendations were based on National Research Council (NRC) requirements for rats, adjustments for the energy content of the insects, and nutrient overages as appropriate. Gut-Loading diets for crickets (adults and nymphs) should be supplemented to contain the following nutrients, respectively: Ca (51 and 32 g/kg), vitamin A (8,310 and 5,270 mg retinol/kg), vitamin D (300 and 190 mg cholecalciferol/kg), vitamin E (140 and 140 mg RRR-a-tocopherol/kg), thiamin (31 and 21 mg/kg), and pyridoxine (20 and 10 mg/kg). Gut-Loading diets for mealworms should be supplemented to contain the following nutrients: Ca (90 g/kg), iron (51 mg/kg), manganese (31 mg/ kg), vitamin A (13,310 mg retinol/kg), vitamin D (460 mg cholecalciferol/kg), vitamin E (660 mg RRR-a-tocopherol/kg), thiamin (5 mg/kg), vitamin B12 (650 mg/kg), and methionine (29 g/kg). Gut-Loading diets for silkworms should be supplemented to contain the following nutrients: Ca (23 g/kg), iodine (0.7 mg/kg), vitamin D (140 mg cholecalciferol/kg), vitamin E (70 mg RRR-a-tocopherol/kg), and vitamin B12 (226 mg/kg). Zoo Biol 22:147–162, 2003. � c 2003 Wiley-Liss, Inc.

Richard F Preziosi - One of the best experts on this subject based on the ideXlab platform.

  • The effect of different UV and calcium provisioning on health and fitness traits of red-eyed tree frogs (Agalychnis callidryas)
    Journal of Zoo and Aquarium Research, 2014
    Co-Authors: Rachael E. Antwis, Richard F Preziosi, Andrea Fidgett
    Abstract:

    In response to global amphibian declines and extinctions, the IUCN has recommended the establishment of ex situ conservation breeding programmes. However, there are a limited number of studies that scientifically assess amphibian husbandry practices, even at a basic level of nutrition and lighting. One component of captive husbandry that is increasingly discussed is the provision of ultraviolet radiation (UVR), which is required for the synthesis of vitamin D3 and subsequent assimilation of calcium and phosphorous from the diet. Here we used two methods of UV provision (“background UV” and “background UV with UV boost”) and two calcium Gut-Loading diets (5% and 10%) to assess the effects on a range of fitness measures in the red-eyed tree frog (Agalychnis callidryas). We found no effects of either UV treatment or calcium diet on growth, body condition or cutaneous bacterial communities of frogs, although subsequent to the UV boost, frogs had a significantly greater fungal load in comparison to frogs that were not UV-boosted. There were negligible differences in the breeding success of females according to UV exposure. Provision of the UV boost was not demonstrated to provide any real advantages for A. callidryas in terms of growth or breeding success. In addition, there were no benefits of a 10% calcium diet over a 5% calcium diet (in conjunction with regular dusting). Further studies that investigate the UV requirements of other amphibian species and ecotypes are required, particularly in conjunction with naturalistic cricket Gut-Loading diets.

  • differences in carotenoid accumulation among three feeder cricket species implications for carotenoid delivery to captive insectivores
    Zoo Biology, 2012
    Co-Authors: Victoria Ogilvy, Andrea Fidgett, Richard F Preziosi
    Abstract:

    There are a limited number of feeder-invertebrates available to feed captive insectivores, and many are deficient in certain nutrients. Gut-Loading is used to increase the diversity of nutrients present in the captive insectivore diet; however, little is known about delivery of carotenoids via Gut-Loading. Carotenoids may influence health and reproduction due to their roles in immune and antioxidant systems. We assessed interspecific variation in carotenoid accumulation and retention in three feeder-cricket species (Gryllus bimaculatus, Gryllodes sigillatus and Acheta domesticus) fed one of three diets (wheat-bran, fish-food based formulated diet, and fresh fruit and vegetables). Out of the three species of feeder-cricket in the fish-food-based dietary treatment group, G. bimaculatus had the greatest total carotenoid concentration. All cricket species fed the wheat-bran diet had very low carotenoid concentrations. Species on the fish-food-based diet had intermediate carotenoid concentrations, and those on the fruit and vegetable diet had the highest concentrations. Carotenoid retention was poor across all species. Overall, this study shows that, by providing captive insectivores with G. bimaculatus crickets recently fed a carotenoid-rich diet, the quantity of carotenoids in the diet can be increased.

  • Differences in carotenoid accumulation among three feeder-cricket species: implications for carotenoid delivery to captive insectivores.
    Zoo Biology, 2011
    Co-Authors: Victoria Ogilvy, Andrea Fidgett, Richard F Preziosi
    Abstract:

    There are a limited number of feeder-invertebrates available to feed captive insectivores, and many are deficient in certain nutrients. Gut-Loading is used to increase the diversity of nutrients present in the captive insectivore diet; however, little is known about delivery of carotenoids via Gut-Loading. Carotenoids may influence health and reproduction due to their roles in immune and antioxidant systems. We assessed interspecific variation in carotenoid accumulation and retention in three feeder-cricket species (Gryllus bimaculatus, Gryllodes sigillatus and Acheta domesticus) fed one of three diets (wheat-bran, fish-food based formulated diet, and fresh fruit and vegetables). Out of the three species of feeder-cricket in the fish-food-based dietary treatment group, G. bimaculatus had the greatest total carotenoid concentration. All cricket species fed the wheat-bran diet had very low carotenoid concentrations. Species on the fish-food-based diet had intermediate carotenoid concentrations, and those on the fruit and vegetable diet had the highest concentrations. Carotenoid retention was poor across all species. Overall, this study shows that, by providing captive insectivores with G. bimaculatus crickets recently fed a carotenoid-rich diet, the quantity of carotenoids in the diet can be increased. Zoo Biol 30:1-9, 2011. � 2011 Wiley-Liss, Inc.

Victoria Ogilvy - One of the best experts on this subject based on the ideXlab platform.

  • differences in carotenoid accumulation among three feeder cricket species implications for carotenoid delivery to captive insectivores
    Zoo Biology, 2012
    Co-Authors: Victoria Ogilvy, Andrea Fidgett, Richard F Preziosi
    Abstract:

    There are a limited number of feeder-invertebrates available to feed captive insectivores, and many are deficient in certain nutrients. Gut-Loading is used to increase the diversity of nutrients present in the captive insectivore diet; however, little is known about delivery of carotenoids via Gut-Loading. Carotenoids may influence health and reproduction due to their roles in immune and antioxidant systems. We assessed interspecific variation in carotenoid accumulation and retention in three feeder-cricket species (Gryllus bimaculatus, Gryllodes sigillatus and Acheta domesticus) fed one of three diets (wheat-bran, fish-food based formulated diet, and fresh fruit and vegetables). Out of the three species of feeder-cricket in the fish-food-based dietary treatment group, G. bimaculatus had the greatest total carotenoid concentration. All cricket species fed the wheat-bran diet had very low carotenoid concentrations. Species on the fish-food-based diet had intermediate carotenoid concentrations, and those on the fruit and vegetable diet had the highest concentrations. Carotenoid retention was poor across all species. Overall, this study shows that, by providing captive insectivores with G. bimaculatus crickets recently fed a carotenoid-rich diet, the quantity of carotenoids in the diet can be increased.

  • THE INFLUENCE OF CAROTENOIDS ON FITNESS RELATED TRAITS IN ANURANS: IMPLICATIONS FOR EX SITU CONSERVATION
    2011
    Co-Authors: Victoria Ogilvy
    Abstract:

    Amphibians are facing an extinction crisis, and in many cases it has become necessary to conserve species in captivity. Unfortunately, our understanding of the nutritional requirements of amphibians in captivity is currently limited. There have been anecdotal reports that captive bred amphibians have duller skin colouration than wild members of the same species. Many amphibians use carotenoid pigments in skin colouration. Carotenoids are yellow-red pigments synthesised by photosynthetic tissues, however vertebrates cannot synthesise them de novo and rely entirely on dietary sources. Reduced colour in captive bred amphibians could therefore result from limited carotenoid availability in the diet. Limited access to carotenoids could have further negative consequences on health and reproductive success since carotenoids are known to function in the immune, antioxidant and reproductive systems of other vertebrate taxa. The role of carotenoids in amphibian fitness is currently unknown, and the aim of this PhD was to assess the importance of carotenoids to anuran amphibians. Skin colour may be influenced by carotenoid availability, and it was therefore important to establish a suitable method for quantifying skin colour in amphibians. In Chapter 1 I assessed two methods for colour quantification, including digital photography and spectrometry. Neither method was significantly more accurate than the other, however I chose to use photography for my studies for reasons of practicality. In Chapters 2 and 3 I assessed the role of carotenoids in the reproductive systems of wild frogs. I found that carotenoid-based skin colouration was involved in the breeding behaviour of wild Agalychnis moreletii frogs. I found positive assortative mating by colour in that frogs were found mating with individuals with similar carotenoid-based colouration. This assortative mating by colour may be driven by mutual mate choice, or may have evolved to prevent mismatched pairing with a sympatric and phenotypically similar species (A. callidryas). I then analysed the carotenoid composition of eggs produced by wild A. moreletii and Phyllomedusa trinitatis, which are tree frogs with similar reproductive ecology but different egg deposition strategies: Agalychnis moreletii deposits green eggs on the surface of leaves while P. trinitatis wraps pale cream eggs in leaves. The concentration and diversity of carotenoids was significantly higher in A. moreletii than P. trinitatis and potential ecological explanations for this are discussed.In Chapter 4 I investigated carotenoid availability in the diet of captive amphibians by analysing the carotenoid composition of commonly used feeder-invertebrates. I assessed interspecific variation in carotenoid accumulation in three feeder-cricket species (Gryllus bimaculatus, Gryllodes sigillatus and Acheta domesticus), which were all fed one of three diets (wheat-bran, fish-food based diet, fresh fruit and vegetables). All three cricket species were a poor source of carotenoids unless they were Gut-loaded on a carotenoid-rich diet. Nutrient retention over a two-day period was poor across species. Finally, there were significant interspecific differences in Gut-Loading capacity, with G. bimaculatus having the greatest capacity. This study shows that carotenoid availability to captive amphibians will be limited unless they are fed specific feeder invertebrate species, recently Gut-loaded on carotenoid-rich foods. In Chapters 5, 6 and 7 I assessed the influence of carotenoids on fitness related traits in captive anurans. I firstly assessed colour degradation in captive-reared A. moreletii frogs and looked at whether skin colour could be improved through increased carotenoid availability in the diet. I found that carotenoid-based skin colour degraded quickly in captivity but could be improved through dietary supplementation with carotenoids, however there was a critical period during post-metamorphic growth for deposition of carotenoids in the skin. Next, I investigated the effect of carotenoids on larval growth and development, and post-metamorphic growth, development, skin colour and reproductive success in captive A. callidryas frogs. I found no direct effect of carotenoids during larval stages, however there were carry-over effects on post-metamorphic growth and skin colour. Increased post-metamorphic carotenoid availability positively influenced growth, skin colour and reproductive success. Similarly to A. moreletii, there was a critical period during post-metamorphic growth for deposition of carotenoids in the skin. Finally, I examined the protective potential of carotenoids in Silurana (Xenopus) tropicalis tadpoles that were exposed to ultraviolet (UV) light. Exposure to UV light significantly reduced tadpole survival and there was no evidence that carotenoids afforded any protection. Nevertheless, in tadpoles that were not exposed to enhanced UV light, carotenoids increased survival. Furthermore, carotenoids had a significantly positive effect on the developmental rate of tadpoles in both UV limited and UV enhanced environments. The studies in this PhD show that carotenoid availability has important consequences on fitness related traits in anuran amphibians, which include effects on growth, skin colour, reproductive success and survival. Carotenoid availability to captive amphibians will, however, be low unless they are provided with feeder invertebrates that have been recently Gut-loaded on carotenoid-rich foods. These findings should be considered when recommendations are made on the nutritional requirements of amphibians in captivity as they could significantly improve the fitness of captive-bred individuals, and thus increase the success of ex situ conservation programmes.

  • Differences in carotenoid accumulation among three feeder-cricket species: implications for carotenoid delivery to captive insectivores.
    Zoo Biology, 2011
    Co-Authors: Victoria Ogilvy, Andrea Fidgett, Richard F Preziosi
    Abstract:

    There are a limited number of feeder-invertebrates available to feed captive insectivores, and many are deficient in certain nutrients. Gut-Loading is used to increase the diversity of nutrients present in the captive insectivore diet; however, little is known about delivery of carotenoids via Gut-Loading. Carotenoids may influence health and reproduction due to their roles in immune and antioxidant systems. We assessed interspecific variation in carotenoid accumulation and retention in three feeder-cricket species (Gryllus bimaculatus, Gryllodes sigillatus and Acheta domesticus) fed one of three diets (wheat-bran, fish-food based formulated diet, and fresh fruit and vegetables). Out of the three species of feeder-cricket in the fish-food-based dietary treatment group, G. bimaculatus had the greatest total carotenoid concentration. All cricket species fed the wheat-bran diet had very low carotenoid concentrations. Species on the fish-food-based diet had intermediate carotenoid concentrations, and those on the fruit and vegetable diet had the highest concentrations. Carotenoid retention was poor across all species. Overall, this study shows that, by providing captive insectivores with G. bimaculatus crickets recently fed a carotenoid-rich diet, the quantity of carotenoids in the diet can be increased. Zoo Biol 30:1-9, 2011. � 2011 Wiley-Liss, Inc.

Andrea Fidgett - One of the best experts on this subject based on the ideXlab platform.

  • The effect of different UV and calcium provisioning on health and fitness traits of red-eyed tree frogs (Agalychnis callidryas)
    Journal of Zoo and Aquarium Research, 2014
    Co-Authors: Rachael E. Antwis, Richard F Preziosi, Andrea Fidgett
    Abstract:

    In response to global amphibian declines and extinctions, the IUCN has recommended the establishment of ex situ conservation breeding programmes. However, there are a limited number of studies that scientifically assess amphibian husbandry practices, even at a basic level of nutrition and lighting. One component of captive husbandry that is increasingly discussed is the provision of ultraviolet radiation (UVR), which is required for the synthesis of vitamin D3 and subsequent assimilation of calcium and phosphorous from the diet. Here we used two methods of UV provision (“background UV” and “background UV with UV boost”) and two calcium Gut-Loading diets (5% and 10%) to assess the effects on a range of fitness measures in the red-eyed tree frog (Agalychnis callidryas). We found no effects of either UV treatment or calcium diet on growth, body condition or cutaneous bacterial communities of frogs, although subsequent to the UV boost, frogs had a significantly greater fungal load in comparison to frogs that were not UV-boosted. There were negligible differences in the breeding success of females according to UV exposure. Provision of the UV boost was not demonstrated to provide any real advantages for A. callidryas in terms of growth or breeding success. In addition, there were no benefits of a 10% calcium diet over a 5% calcium diet (in conjunction with regular dusting). Further studies that investigate the UV requirements of other amphibian species and ecotypes are required, particularly in conjunction with naturalistic cricket Gut-Loading diets.

  • differences in carotenoid accumulation among three feeder cricket species implications for carotenoid delivery to captive insectivores
    Zoo Biology, 2012
    Co-Authors: Victoria Ogilvy, Andrea Fidgett, Richard F Preziosi
    Abstract:

    There are a limited number of feeder-invertebrates available to feed captive insectivores, and many are deficient in certain nutrients. Gut-Loading is used to increase the diversity of nutrients present in the captive insectivore diet; however, little is known about delivery of carotenoids via Gut-Loading. Carotenoids may influence health and reproduction due to their roles in immune and antioxidant systems. We assessed interspecific variation in carotenoid accumulation and retention in three feeder-cricket species (Gryllus bimaculatus, Gryllodes sigillatus and Acheta domesticus) fed one of three diets (wheat-bran, fish-food based formulated diet, and fresh fruit and vegetables). Out of the three species of feeder-cricket in the fish-food-based dietary treatment group, G. bimaculatus had the greatest total carotenoid concentration. All cricket species fed the wheat-bran diet had very low carotenoid concentrations. Species on the fish-food-based diet had intermediate carotenoid concentrations, and those on the fruit and vegetable diet had the highest concentrations. Carotenoid retention was poor across all species. Overall, this study shows that, by providing captive insectivores with G. bimaculatus crickets recently fed a carotenoid-rich diet, the quantity of carotenoids in the diet can be increased.

  • Differences in carotenoid accumulation among three feeder-cricket species: implications for carotenoid delivery to captive insectivores.
    Zoo Biology, 2011
    Co-Authors: Victoria Ogilvy, Andrea Fidgett, Richard F Preziosi
    Abstract:

    There are a limited number of feeder-invertebrates available to feed captive insectivores, and many are deficient in certain nutrients. Gut-Loading is used to increase the diversity of nutrients present in the captive insectivore diet; however, little is known about delivery of carotenoids via Gut-Loading. Carotenoids may influence health and reproduction due to their roles in immune and antioxidant systems. We assessed interspecific variation in carotenoid accumulation and retention in three feeder-cricket species (Gryllus bimaculatus, Gryllodes sigillatus and Acheta domesticus) fed one of three diets (wheat-bran, fish-food based formulated diet, and fresh fruit and vegetables). Out of the three species of feeder-cricket in the fish-food-based dietary treatment group, G. bimaculatus had the greatest total carotenoid concentration. All cricket species fed the wheat-bran diet had very low carotenoid concentrations. Species on the fish-food-based diet had intermediate carotenoid concentrations, and those on the fruit and vegetable diet had the highest concentrations. Carotenoid retention was poor across all species. Overall, this study shows that, by providing captive insectivores with G. bimaculatus crickets recently fed a carotenoid-rich diet, the quantity of carotenoids in the diet can be increased. Zoo Biol 30:1-9, 2011. � 2011 Wiley-Liss, Inc.

Claire Vergneau-grosset - One of the best experts on this subject based on the ideXlab platform.

  • Evaluation of β‐carotene assimilation in leopard geckos (Eublepharis macularius)
    Journal of Animal Physiology and Animal Nutrition, 2018
    Co-Authors: Ophélie Cojean, Stéphane Lair, Claire Vergneau-grosset
    Abstract:

    Although leopard geckos (Eublepharis macularius) are commonly kept under human care, their vitamin requirements are largely unknown. Many invertebrate preys display a low vitamin A concentration; thus, Gut-Loading insects with vitamin A or carotenoids is a common practice. The objective of this prospective experimental study was to investigate whether dietary supplementation with β-carotene, including prey Gut-Loading, leads to sufficient vitamin A hepatic storage and prevents epithelial squamous metaplasia development in leopard geckos. Ten clinically healthy female leopard geckos were randomly divided in two groups with various supplementations: a group receiving vitamin A supplementation and a group receiving β-carotene. Insects were Gut-loaded continuously with a supplement containing vitamin A or β-carotene, depending on the group. Oral supplementation with cod liver oil or carrot juice was administered weekly to each lizard from "vitamin A group" and "carotenoid group" respectively. After 10 weeks of supplementation, surgical hepatic biopsies were obtained in three geckos of each group while the two remaining geckos were euthanized to undergo complete necropsy. Hepatic vitamin A concentration was determined for each lizard (n = 10) by ultra-performance liquid chromatography. Histopathology revealed hepatocellular vacuolization and vitellogenic follicles in five females. Epithelial squamous metaplasia was not observed in any of the geckos. Hepatic vitamin A concentration was significantly higher in the carotenoid-supplemented group than in the vitamin A-supplemented group (p = 0.03). Our results suggest that in leopard geckos, dietary supplementation with β-carotene allows sufficient vitamin A hepatic storage.