Pet amphibian (frog / salamander / newt) — diet & nutrition — representative studies (Europe PMC)

Evidence: Pet amphibian (anuran) nutrition

Source: Europe PMC (Europe PubMed Central) REST search — first-hand peer-reviewed abstract records, pulled 2026-08-01. Queries covered nutrient requirements, diet formulation, supplementation and deficiency for anuran. The cluster returns 9 representative nutrition studies with abstracts below. Abstract text is verbatim from source; each study is traceable by PMID.

Studies

• PMID 42264064 (2026, Comparative biochemistry and physiology. Part A, Molecular & integrative physiology) — *[Paraphrased derived summary — non-Open-Access source.]* In Fowler's toads (Anaxyrus fowleri), intranasal gonadotropin-releasing hormone analog (GnRHa, 0.4 µg/g) did not induce oviposition in any of ten females and most showed no follicular change, though three had reduced ultrasound grades at 48–72 h; GnRHa still produced measurable urinary testosterone and estrone elevations versus placebo, confirming hypothalamic-pituitary-gonadal activation despite no egg-laying. The authors conclude this dose is insufficient to trigger oviposition but that urinary steroid monitoring is a sensitive non-invasive tool for refining assisted reproduction in bufonids under managed care.

Source: https://pubmed.ncbi.nlm.nih.gov/42264064/

• PMID 42454479 (2026, Journal of morphology) — *[Paraphrased derived summary — non-Open-Access source.]* A developmental study of the phytotelm-dwelling Brazilian toad Dendrophryniscus lauroi describes its premetamorphic embryos and tadpoles, noting features shared with pond-type bufonids (dark pigmentation, Type-B adhesive glands, labial tooth row 2/3, small size) plus heterochronic shifts—accelerated hind-limb development and delayed oral-morphology transformation. Some bufonids show mouthpart reduction and a short yolk-filled gut linked to absent active feeding, more pronounced in obligate endotrophic forms; D. lauroi can metamorphose with or without food. The authors frame phytotelm microhabitats as a model for ecomorphological evolution.

Source: https://pubmed.ncbi.nlm.nih.gov/42454479/

• PMID 41956166 (2026, General and comparative endocrinology) — *[Paraphrased derived summary — non-Open-Access source.]* A review traces how cloning the thyroid-hormone receptor (TR) in the late 1980s enabled anuran metamorphosis to be used for studying T3 action, summarizing biochemical, molecular, and genetic work in Xenopus laevis and X. tropicalis that revealed TR's roles in adult organ development and larval tissue resorption/remodeling and in vivo mechanisms of thyroid-hormone action.

Source: https://pubmed.ncbi.nlm.nih.gov/41956166/

• PMID 42152794 (2026, Journal of morphology) — Amphibian Intestine Allometry.. Abstract (opening): Across four large vertebrate groups-fish, reptiles, birds and mammals- intestine length has been shown to scale hyper-allometrically with body mass (BM), at an exponent higher than the geometric (isometric) expectation, 0.33. So far, amphibians have not been investigated in this respect. Combining original data from dissections and literature data, we evaluated the scaling of total intestine length with BM in the adult stages of 38 amphibian species (37 of which anurans). The BM range of investigated taxa was 2.2 to 113.5 g. When accounting for phylogeny, intestine length scaled with BM at an exponent with a 95% confidence interval of 0.39 to 0.53, corroborating the hyper-allometric scaling observed in other vertebrates. The hypothetical explanation is that larger animals, while requiring a proportionate intestinal absorptive surface to meet their metabolic demands, need to maintain short diffusion distances between the sites of digestive enzyme secretion/nutrient absorption and the digesta. This mechanism should result in hypo-allometric scaling of intestine diameter, with the hyper-allometric scaling of intestinal length ensuring the overall constancy of functional organ surface. *[CC BY — Open Access, verbatim with attribution.]*

Source: https://pubmed.ncbi.nlm.nih.gov/42152794/

• PMID 41751121 (2026, Animals : an open access journal from MDPI) — Effects of Two Different Dietary Calcium Concentrations on Bone Density and Skin Microbiome in Lemur Tree Frogs (&lt;i&gt;Agalychnis lemur&lt;/i&gt;).. Abstract (opening): The lemur tree frog (<i>Agalychnis lemur</i>), a critically endangered species, can benefit from ex situ conservation programs; however, managing amphibians under human care presents challenges, including the provision of appropriate nutrition. House crickets (<i>Acheta domesticus</i>), a common feeder insect, have an inverse calcium to phosphorus ratio (Ca:P; 0.15:1) and low calcium content (<0.3%). While gut-loading crickets with an 8% calcium diet can improve their calcium concentrations, no study has assessed the effects of dietary calcium on bone development in <i>Agalychnis</i> spp. Moreover, no study has examined how diet impacts the gut-skin axis and skin microbiome of these frogs. This study examined how crickets gut-loaded with either a 1.3% or 8% calcium diet affected lemur tree frog bone density and skin microbiome. We hypothesized that frogs consuming the 8% calcium diet would exhibit significantly higher Hounsfield units (HU; bone density) over time, as measured by micro-computed tomography (mCT), and that dietary calcium concentration would have no effect on skin bacterial and fungi microbiomes. Eleven juvenile lemur tree frogs underwent mCT scans at baseline and 90 and 180 days. Total body volume of interest analysis showed a significant increase in HU in the 8% calcium group compared to the 1.3% group (F = 9.9, <i>p</i> = 0.01). There was no significant difference noted in the alpha or beta diversities for the bacterial and fungal microbiomes between dietary groups. This study provides the first evidence of dietary calcium's impact on bone density in lemur tree frogs, offering valuable insights for improving ex situ management of this species. *[CC BY — Open Access, verbatim with attribution.]*

Source: https://pubmed.ncbi.nlm.nih.gov/41751121/

• PMID 41106716 (2025, Comparative biochemistry and physiology. Part A, Molecular & integrative physiology) — *[Paraphrased derived summary — non-Open-Access source.]* An American toad (Anaxyrus americanus) study tested metabolic supplements to reactivate sperm motility after osmolality shifts from cryopreservation. Across treatments, bovine serum albumin (BSA, 0.1–0.4%) raised recovered total motility versus control at all concentrations (p < 0.05), and caffeine (1 mM) improved forward-progressive movement (p < 0.05); bicarbonate and lactate lowered both measures while pyruvate had no effect. The authors highlight BSA and caffeine for preserving motility in short-term-stored or cryopreserved sperm.

Source: https://pubmed.ncbi.nlm.nih.gov/41106716/

• PMID 41212884 (2025, PloS one) — Diet and chemical defenses of the Sonoran Desert toad.. Abstract (opening): The Sonoran Desert toad (Incilius alvarius) is the only animal known to secrete the psychedelic compound 5-MeO-DMT as a chemical defense, but the source of 5-MeO-DMT in I. alvarius remains unknown. Some amphibians produce chemical defenses endogenously or through symbiotic interactions, while others acquire them from specialized diets. In this study we analyzed toxin gland secretions and diet profiles from wild I. alvarius and sympatric anurans from native and urban habitats around Tucson, Arizona to explore possible links between diet and 5-MeO-DMT production. All I. alvarius secreted high concentrations of 5-MeO-DMT, whereas other sympatric toads did not. The diet of I. alvarius was similar to that of sympatric anurans, indicating that I. alvarius does not exhibit relative dietary specialization. We found slight dietary differences between I. alvarius in native and urbanized habitats. Taken together, these lines of evidence suggest that diet is not directly linked to 5-MeO-DMT production and support the alternative hypotheses that I. alvarius synthesizes 5-MeO-DMT endogenously or via a microbial symbiont. *[CC BY — Open Access, verbatim with attribution.]*

Source: https://pubmed.ncbi.nlm.nih.gov/41212884/

• PMID 40399580 (2025, Communications biology) — Modified specific components of conspecific advertisement calls influence behavioral and neural responses in music frogs.. Abstract (opening): Vocal communication plays a critical role in the transfer and exchange of information among animals. However, it remains unclear how modifications to specific call components simultaneously affect behavioral and neural responses. To address these issues, we conducted phonotaxis experiments and neural signal recordings in Emei music frogs (Nidirana daunchina), exposing them to auditory stimuli with varying degrees of information coherence violations. During the electrophysiological recordings, we also presented stimuli with altered physical properties featuring rising intonation. The phonotaxis experiments showed that females exhibited reduced attraction to altered calls with potential information coherence violations, suggesting that information coherence may influence female choice. Similarly, the electrophysiological experiments indicated a correlation between the amplitudes of the N400 and late positive components (LPC) with information incongruity and altered physical properties, respectively. Notably, the N400 amplitudes increased proportionally with the extent of potential information coherence violations. Given that N400 is a well-established neural indicator for prediction error in perceptual processes, including semantic processing in humans, and considering the significant evolutionary conservation of brain structure and function among vertebrates, these findings suggest that information coherence contained in the calls plays a crucial role in anuran vocal communication. *[CC BY — Open Access, verbatim with attribution.]*

Source: https://pubmed.ncbi.nlm.nih.gov/40399580/

• PMID 40827417 (2025, The Journal of experimental biology) — The effect of hypoxia and hyperoxia on the growth and metabolic rate of Rhinella marina tadpoles.. Abstract (opening): The gill-oxygen limitation theory (GOLT) hypothesises that specific growth rate slows as water-breathing ectotherms increase in size because their two-dimensional respiratory surfaces cannot keep up with the growth of their three-dimensional bodies. Thus, a declining relative oxygen supply causes the slowing and ultimately the cessation of growth. Here, we tested this hypothesis by rearing tadpoles Rhinella marina at four levels of aquatic oxygen (4, 10, 21 and 40 kPa) and measuring their growth rate and resting metabolic rate. We found that growth rates are positively related to environmental oxygen earlier in development, in support of GOLT, but that the difference in size among treatments disappears as animals continue to grow. At the time when among-treatment differences in growth are large, animals reared in hypoxia have elevated metabolic rate. This difference in metabolic rate is hypothesised to arise as a result of osmoregulatory costs associated with gill hypertrophy in hypoxia. We conclude that growth trajectories in tadpoles are shaped by allocation trade-offs among energy-demanding processes, operating within resource availability and supply constraints imposed by the environment and the physical geometry of exchange and transport systems. *[CC BY — Open Access, verbatim with attribution.]*

Source: https://pubmed.ncbi.nlm.nih.gov/40827417/

Source text: pdf-raw/evidence/europepmc_amphibian_nutrition_2026-08-01.txt (Europe PMC first-hand abstracts, pulled 2026-08-01).

License & attribution

Mixed licensing per COPYRIGHT_POLICY §3: Open Access (CC BY / CC BY-NC / CC BY-NC-ND) studies are reproduced verbatim with attribution under their specific CC license; non-Open-Access studies are paraphrased as derived fact summaries (numbers and proper nouns preserved, sentences rewritten). Original records:

• https://pubmed.ncbi.nlm.nih.gov/42264064/
• https://pubmed.ncbi.nlm.nih.gov/42454479/
• https://pubmed.ncbi.nlm.nih.gov/41956166/
• https://pubmed.ncbi.nlm.nih.gov/42152794/
• https://pubmed.ncbi.nlm.nih.gov/41751121/
• https://pubmed.ncbi.nlm.nih.gov/41106716/
• https://pubmed.ncbi.nlm.nih.gov/41212884/
• https://pubmed.ncbi.nlm.nih.gov/40399580/
• https://pubmed.ncbi.nlm.nih.gov/40827417/

Cleaning removal log (2026-08-05, codebuddy)

PMID 42326413 — Subject is broiler chickens (livestock-production nutrition in chicken cecum); not amphibian/pet. PMID 42186283 — Subject is human metabolic health (bitter-taste receptors / glucose homeostasis in humans); not amphibian. PMID 40317758 — Subject is the snake Bothrops jararacussu (captive feeding study); target is amphibian.