The diet of free-roaming Australian Central Bearded Dragons (Pogona vitticeps)

An Update on Companion Inland Bearded Dragon (Pogona vitticeps) Nutrition

Evidence-based recommendations for the amount, type, and frequency of food items and supplements are lacking for bearded dragons. General recommendations based on ecological data, a few studies, and experts in the field are to: provide at least 50% high-fiber plant matter dusted in pure calcium and less than 50% adult and lower fat larval insects gut loaded with an 8% calcium diet and dusted with pure calcium, provide ultraviolet B lighting for vitamin D3 synthesis, provide multivitamins on a weekly basis, or monthly at minimum, provide a water dish large enough to soak and drink.

Prevalence and risk factors of hepatic lipid changes in bearded dragons (Pogona vitticeps)

Hepatic lipidosis is a common disease of captive bearded dragons (Pogona vitticeps). Diagnosis, prevention, and treatment of this condition are challenging, as there is minimal information in the literature. Our study determined the prevalence and epidemiological risk factors associated with the grade and severity of hepatic lipid changes in bearded dragons submitted for necropsy in 2 North American institutions. A total of 571 postmortem cases were retrieved, and from each pathology report the demographic data (age, sex) and the list of final diagnoses were extracted. For each case diagnosed with hepatic lipidosis, the archived sections of liver were reviewed and the severity of lipid change was stratified using a standardized histologic grading system. Descriptive statistics were used to estimate the prevalence of each grade and severity class. Associations between grade and severity, as well as demographic data and concurrent diseases, were explored using ordinal logistic regression analysis. On multiple logistic models, the occurrence of infectious disease and neoplasia was associated with decreased grade and severity of hepatic lipid changes, while the female sex and adult age were associated with an increased grade and severity. None of the other variables were significantly associated with hepatic lipid changes. These results suggest that reproductively active females and adult bearded dragons are predisposed to increasing hepatic lipid changes, while those with an underlying disease process have reduced hepatic lipid accumulation and changes, possibly due to increased fat catabolism. Data in this study can serve to benchmark the prevalence of hepatic lipidosis in bearded dragons and allow further investigations.

Historical and future climate change fosters expansion of Australian harvester termites, Drepanotermes

Past evolutionary adaptations to Australia's aridification can help us to understand the potential responses of species in the face of global climate change. Here, we focus on the Australian-endemic genus Drepanotermes, also known as Australian harvester termites, which are mainly found in semiarid and arid regions of Australia. We used species delineation, phylogenetic inference, and ancestral state reconstruction to investigate the evolution of mound-building in Drepanotermes and in relation to reconstructed past climatic conditions. Our findings suggest that mound-building evolved several times independently in Drepanotermes, apparently facilitating expansions into tropical and mesic regions of Australia. The phylogenetic signal of bioclimatic variables, especially limiting environmental factors (e.g., precipitation of the warmest quarter), suggests that the climate exerts a strong selective pressure. Finally, we used environmental niche modeling to predict the present and future habitat suitability for eight Drepanotermes species. Abiotic factors such as annual temperature contributed disproportionately to calibrations, while the inclusion of biotic factors such as predators and vegetation cover improved ecological niche models in some species. A comparison between present and future habitat suitability under two different emission scenarios revealed continued suitability of current ranges as well as substantial habitat gains for most studied species. Human-mediated climate change occurs more quickly than these termites can disperse into newly suitable habitat; however, their role in stabilizing arid ecosystems may allow them to mitigate effects on some other organisms at a local level.

Managing the Health of Captive Groups of Reptiles and Amphibians

Managing the health of reptile and amphibian collections is centered on providing appropriate environmental parameters, husbandry conditions, and nutrition as well as maintaining good welfare and careful collection planning. Disease transmission is reduced through quarantine, appropriate diagnostic testing, and annual veterinary health assessment."

Dietary enrichment of edible insects with omega 3 fatty acids

Edible insects are advocated as sustainable and healthy food and feed. However, commercially produced insects are often low in n-3 fatty acids and have suboptimal n-6/n-3 ratios. A certain amount and proportion of these FAs is required to optimize human health. Flaxseed oil consists primarily (57%) out of alpha-linolenic acid. An experiment was conducted to quantify the effect of flaxseed oil provision on fatty acid composition and to determine the quantity needed to attain a beneficial n-6/n-3 ratio. Three species were used in the experiment: house crickets (Acheta domesticus [L.]), lesser mealworms (Alphitobius diaperinus [Pfanzer]) and black soldier flies (Hermetia illucens [L.]). These were provided with either a control diet or a diet enriched with 1%, 2%, or 4% flaxseed oil during their larval/nymphal stage. Fatty acid profiles of diets and insects were determined via GC-MS. The three species had distinct fatty acid profiles on all four diets, but responded similarly to flaxseed oil addition. For each percent added to the diet, the alpha-linolenic acid content of the insects increased by 2.3%-2.7%. Four percent addition increased the n-3 fatty acid content 10-20 fold in the three species and thereby strongly decreased n-6/n-3 ratios from 18-36 to 0.8-2.4. A ratio below 5 is considered optimal for human health and was achieved by 2% flaxseed oil inclusion for house crickets and lesser mealworms, and at 1% inclusion for black soldier flies. Adding a source of n-3 fatty acids to insect diets can thus improve the nutritional quality of insects.

Characterization and phylogeny of bitter taste receptor genes (Tas2r) in Squamata

The perception of bitter taste is linked to the detection of toxins. Therefore, it facilitates avoiding the consumption of potential toxins in the diet. At the molecular level, bitter taste is mediated by taste 2 receptors (Tas2rs). Studies on Tas2r have made major advances in recent years. However, little is known about Tas2rs in Squamata, the second largest order of extant vertebrates. To explore the repertoire and phylogenetic relationships among Tas2r genes in Squamata, we identified and characterized Tas2rs from genome assemblies of 15 Squamata species. We observed considerable Tas2r contraction and expansion in the suborders Serpentes and Lacertilia, respectively. Phylogenetic and reconciliation analysis suggested that lineage-specific gene gains and losses could have led to the Tas2r contraction and expansion in Squamata. Different Tas2r repertoires in Serpents and Lacertilia also reflect their oral anatomical features and taste behaviors. Our findings offer novel perspectives into the study of taste and dietary protection in Squamata species.

Evidence-Based Reptile Housing and Nutrition

The provision of a good light source is important for reptiles. For instance, ultraviolet light is used in social interactions and used for vitamin D synthesis. With respect to housing, most reptilians are best kept pairwise or individually. Environmental enrichment can be effective but depends on the form and the species to which it is applied. Temperature gradients around preferred body temperatures allow accurate thermoregulation, which is essential for reptiles. Natural distributions indicate suitable ambient temperatures, but microclimatic conditions are at least as important. Because the nutrient requirements of reptiles are largely unknown, facilitating self-selection from various dietary items is preferable.