A fresh look at metabolic bone diseases in reptiles and amphibians

Keeping reptiles as pets in Brazil: keepers' motivations and husbandry practices

BACKGROUND

Reptiles are considered one of the most popular pets in the world and are often associated with an incorrect belief that they are simple, highly adaptable, and easy to keep animals when compared with other pets, such as dogs and cats. However, keeping reptiles as pets can pose several challenges in meeting their needs in a domestic setting, requiring specific conditions and effort to maintain their health, well-being, and survival.

METHODS

During 2015, using online semi-structured questionnaires applied to 719 Brazilian pet reptile keepers who participated in online groups of reptile breeders on the social network Facebook, this study aimed to identify Brazilian keepers' motivations for maintaining reptiles as pets, investigate their monthly expenses, and the husbandry practices for the maintenance, such as housing and feeding conditions, handling of the animal, health issues, and treatment provided.

RESULTS

We found multiple motivations for keeping reptiles as pets (mostly snakes, lizards, and chelonians), the main motivation being emotional reasons, followed by entertainment and convenience reasons. The great majority of keepers (69%) declared to spend less than or up to US$30 per month in maintaining their reptiles. Most reptiles were kept alone in terrarium/aquarium enclosures, with basic environmental complexity in terms of physical elements. Lizards and chelonians were fed with a few insect species, cultivated fruits and vegetables, while snakes were fed mainly with domestic rodents, rabbits, or birds. Keepers declared frequent cleaning of the enclosure, but inappropriately handled their animals directly with their hands, which might result in potential threats to human and reptile health and safety. Several diseases or injuries were mentioned and 55.6% of the keepers declared taking the reptile to the vet for treatment.

CONCLUSIONS

Overall, our findings revealed several challenges that reptiles face when kept in domestic environments, including issues related to housing, nutrition, and healthcare. Even though keepers demonstrated positive feelings toward their pets, suggesting a positive relationship and a willingness to provide them with proper care, it seems that without the proper knowledge and awareness, reptiles may unintentionally be kept with poor husbandry. Addressing these challenges on husbandry practices is essential for improving reptiles' welfare and promoting a responsible pet ownership.

Metastasizing squamous cell carcinoma in a 50-year-old Eastern Hermann's tortoise (Testudo hermannii boettgeri)

A 50-year-old female Hermann's tortoise (Testudo hermannii boettgeri) was presented with anorexia and lethargy. Clinical examination revealed multiple, visually inconspicuous but indentable areas in the shell corresponding to osteolysis radiographically. Soft tissue nodules and osteolytic lesions were also noted in the limbs. Laboratory results revealed elevated aspartate aminotransferase activity and uric acid concentrations, hypoglycemia, and hyperphosphatemia. Klebsiella oxytoca was isolated from a biopsied scutal area, and the biopsy suggested neoplasia. After a short period of clinical improvement, the animal's condition deteriorated, and it died. Post mortem computed tomography revealed polyostotic lytic lesions of multiple bones and the shell with associated soft tissue nodules protruding into the coelom, and nodular lung lesions. Necropsy, histopathology, and immunohistochemistry secured a diagnosis of a poorly differentiated, pan-cytokeratin-positive squamous cell carcinoma with widespread soft tissue and bone metastases, osteolysis and desmoplasia.

Health condition of Chelonia mydas from a foraging area affected by the tailings of a collapsed dam in southeast Brazil

In 2015, the failure of the Fundão dam caused the release of 43 million m³ of tailings into the Doce River Basin, in southeast Brazil. It was considered the largest environmental disaster of the world mining industry. The tailings, composed mostly of heavy metals, caused massive destruction of the Doce River ecosystem endangering the organisms that live in the coastal zone where the mud reached the ocean. Among the exposed species are the sea turtles that use the region for food. The aim of this study was to evaluate the effect of contaminants on the health status of juvenile green sea turtles that feed in a coastal area exposed to ore mud (Santa Cruz) and to compare them with animals from an area not directly affected (Coroa Vermelha). A physical examination was performed to determine the health status. Blood samples were analyzed for hematological and biochemical parameters, and metal concentrations (As, Cd, Cr, Cu, Fe, Hg, Mn, Pb, and Zn). Santa Cruz sea turtles had more ectoparasites and a higher incidence of fibropapillomatosis. Statistically significant differences between sites were found for levels of calcium, phosphorus, glucose, protein, albumin, globulin, cholesterol, triglycerides, urea, CPK, ALT, and AST. The count of leukocytes, thrombocytes, and heterophils, as well as the concentrations of As and Cu were higher in Santa Cruz turtles. Together the results show a worse nutritional status and a greater degree of liver and kidney damage in animals affected by the tailings. The health status may indicate a physiological deficit that can affect their immune system and behavior, which is supported by the higher fibropapillomatosis tumor score and ectoparasite load in these animals. These results support the need for long-term monitoring of the exposed area to quantify the direct and indirect influence of the heavy metals levels on sea turtles and how this reflects the environmental health.

Investigating factors of metabolic bone disease in baboons (Papio spp.) using museum collections

OBJECTIVES

To assess manifestations of metabolic bone disease (MBD) and their potential environmental and phenotypic factors in captive and non-captive baboon (Papio spp.) specimens.

MATERIALS AND METHODS

Our sample consisted of 160 baboon specimens at the Smithsonian's National Museum of Natural History accessioned from 1890 to 1971. Combining cranial indicators of MBD and the museum's historical data, we examined factors contributing to likely instances of MBD. We used binomial-family generalized linear models to assess differences in MBD frequency by environment (captive, non-captive), specimen accession year, and skin color (light, medium, dark).

RESULTS

Indicators of MBD were most frequently observed in captive baboons, with a decrease in MBD frequency over time. Fifteen non-captive individuals showed indicators of MBD, which are the first published cases of MBD in non-captive nonhuman primates (NHPs) to our knowledge. The most common MBD indicators were bone porosity (n = 35) and bone thickening/enlargement (n = 35). Fibrous osteodystrophy was observed frequently in our sample, likely relating to nutritional deficiencies. We found no association between exposed facial skin color variation and MBD.

CONCLUSIONS

Our findings are consistent with historical accounts of MBD prevalence in captive facilities, especially earlier in the 20th century. A decrease in MBD prevalence later in the 20th century likely reflects improvements in housing, diet, and veterinary care in captive settings. Causes of MBD development in non-captive baboons should be further explored, as understanding the potential health impacts that anthropogenic environments impose on NHPs is imperative as humans increasingly alter the natural world in the 21st century.

Degenerative Osteoarthropathy in Laboratory Housed Xenopus (Silurana) tropicalis

In this case study, 15 adult laboratory Xenopus (Silurana) tropicalis (7 adult males and 8 adult females) were examined for nodular enlargements of the clawed digits (digits 0, I, II, and III) on the hind feet. Radiographs showed smoothly margined, rounded, peripherally mineralized lesions arising from the distal phalanges of digits 0-III with osteoproductive and osteolytic components in all frogs. Micro computed tomography (microCT) scans further revealed interphalangeal (IP), metacarpophalangeal (MCP), and metatarsophalangeal (MTP) joint osteoarthritis characterized by periarticular new bone formation, rounded mineral foci both peripherally and centrally within the joints, and more rarely, linear mineralization palmar/plantar to the joints in the flexor tendons. In the nonclawed digits, the shape of the distal phalanx was variably distorted and both subluxation and malangulation of IP joints were identified. Histologically, nodules corresponded to a peripheral rim of mature cortical bone surrounding central adipose tissue, scattered hematopoietic elements, and residual bone of the distal phalanx. Occasionally, the peripheral rim of cortical bone extended proximally to encompass the distal aspect of adjacent phalanx. MCP, MTP and IP joint spaces of most digits exhibited widespread osteoarthritis characterized by periarticular cartilaginous or osseous metaplasia, bony remodeling, and less frequently, granulomatous osteomyelitis. Nutritional analyses of the feed did not indicate imbalances nor were the lesions consistent with metabolic bone disease. The exact etiopathogenesis of these lesions is unknown; however, we hypothesize that the osteoarthritic changes are due to a combination of the frogs' mature age, the unique structure of the Xenopus spp. claw, genetics and biomechanical forces on the digits and distal phalanges of the hind feet.

Comparative nutrient analysis of four species of cockroaches used as food for insectivores by life stage, species, and sex

A variety of insects are fed to insectivorous animals; however, nutritional analyses are often limited to adult life stages. Four species of nymph and adult female and male cockroaches (Blaberus giganteus, Blaptica dubia, Blatta lateralis, and Gromphadorhina portentosa) were analyzed for moisture, crude protein (CP), acid detergent fiber (ADF), fat, ash, and mineral content. The small sample size of this study precluded statistical analyses, however comparatively, CP in adult B. lateralis and B. dubia was greater than the CP in nymphs of the same species. Adult and nymph B. dubia had the greatest CP (96.6% and 65.3%, respectively) compared to the other three species. Inversely, fat content in adult B. lateralis and B. dubia was lower than that of nymphs of the same species. All adults contained similar levels of ADF, yet adult B. giganteus had greater ADF than nymphs; conversely, B. lateralis and B. dubia adults had less ADF than nymphs. There were differences noted in mineral parameters among the four species and life stages. Adult B. giganteus had less Ca than G. portentosa, and the lowest Ca content of the four species of nymphs and adults analyzed. This study underscores the differences in nutrient content with respect to life stage and species in previously understudied cockroaches to improve nutrient intake in captive insectivores.

Comparison of Dilution on Eastern Box Turtle (Terrapene carolina carolina) and Marine Toad (Rhinella marinus) Blood Parameters as Measured on a Portable Chemistry Analyzer

Biochemical testing is an important clinical tool in evaluating the physiology of reptiles and amphibians. Suitable point of care analyzers can allow for rapid delivery of results, but small patient size can inhibit sufficient sample collection. This study evaluated the utility of sample dilution with sterile distilled water as a means of biochemical evaluation when sample volume is limited. Blood was collected from 12 eastern box turtles (Terrapene carolina carolina) and 12 marine toads (Rhinella marinus) and analyzed via i-STAT CHEM8+ cartridges. Two undiluted samples and two samples diluted 1 : 1 with sterile water were evaluated immediately following collection for each animal in the study. Analytes reported in the diluted samples were limited to glucose, ionized calcium, and total carbon dioxide. The expected dilution ratio value of diluted to undiluted samples was 0.5, of which glucose in both turtles and toads was nearest. Dilution ratio values for ionized calcium, however, were higher than expected in both turtles and toads. Sample dilution is not recommended for most analytes included on the CHEM8+ cartridge due to values occurring outside the limits of detection for the analyzer. Glucose and ionized calcium values obtained on diluted samples should be interpreted with caution but may provide clinical utility in reptile and amphibian patients where sample volume is limited.

Spindly leg syndrome in Atelopus varius is linked to environmental calcium and phosphate availability

Spindly leg syndrome (SLS) is a relatively common musculoskeletal abnormality associated with captive-rearing of amphibians with aquatic larvae. We conducted an experiment to investigate the role of environmental calcium and phosphate in causing SLS in tadpoles. Our 600-tadpole experiment used a fully-factorial design, rearing Atelopus varius tadpoles in water with either high (80mg/l CaCO3), medium (50mg/l CaCO3), or low calcium hardness (20mg/l CaCO3), each was combined with high (1.74 mg/l PO4) or low (0.36 mg/l PO4) phosphate levels. We found that calcium supplementation significantly improved tadpole survival from 19% to 49% and that low calcium treatments had 60% SLS that was reduced to about 15% at the medium and high calcium treatments. Phosphate supplementation significantly reduced SLS prevalence in low calcium treatments. This experimental research clearly links SLS to the calcium: phosphate homeostatic system, but we were unable to completely eliminate the issue, suggesting an interactive role of other unidentified factors.

Digestibility of black soldier fly larvae (Hermetia illucens) fed to leopard geckos (Eublepharis macularius)

Black soldier fly (BSF) larvae have been marketed as an excellent choice for providing calcium to reptiles without the need of dusting or gut loading. However, previous studies have indicated that they have limited calcium digestibility and are deficient in fat soluble vitamins (A, D3, and E). In this feeding and digestibility trial, 24 adult male leopard geckos were fed one of three diets for 4 months: 1) whole, vitamin A gut loaded larvae; 2) needle pierced, vitamin A gut loaded larvae; or 3) whole, non-gut loaded larvae. Fecal output from the geckos was collected daily and apparent digestibility was calculated for dry matter, protein, fat, and minerals. There were no differences in digestibility coefficients among groups. Most nutrients were well digested by the leopard geckos when compared to previous studies, with the exception of calcium (digestibility co-efficient 43%), as the calcium-rich exoskeleton usually remained intact after passage through the GI tract. Biochemistry profiles revealed possible deficits occurring over time for calcium, sodium, and total protein. In regards to vitamin A digestibility, plasma and liver vitamin A concentrations were significantly higher in the supplemented groups (plasma- gut loaded groups: 33.38 ± 7.11 ng/ml, control group: 25.8 ± 6.72 ng/ml, t = 1.906, p = 0.04; liver- gut loaded groups: 28.67 ± 18.90 μg/g, control group: 14.13 ± 7.41 μg/g, t = 1.951, p = 0.03). While leopard geckos are able to digest most of the nutrients provided by BSF larvae, including those that have been gut loaded, more research needs to be performed to assess whether or not they provide adequate calcium in their non-supplemented form.

Diseases of the Reptile Renal System

Renal disease accounts for a considerable amount of morbidity and mortality in reptiles, in part owing to inadequate husbandry practices, such as inappropriate temperature, humidity, and access to water. Inappropriate husbandry practices may lead to subclinical dehydration that can specifically impact the renal system, which relies on vascular perfusion to function. This article aims to highlight urinary pathophysiology and summarize infectious and noninfectious causes of renal disease in reptiles as a guide for differential diagnoses to consider during clinical evaluation.

Effect of Dietary Replacement of Fishmeal by Insect Meal on Growth Performance, Blood Profiles and Economics of Growing Pigs in Kenya

Simple Summary

Pig keeping is an important source of income but the high cost of fishmeal (FM), which is the main protein source in animal feeds, has hindered the sector from realizing its full potential. As an alternative, we investigated the suitability of a meal derived from black soldier fly larvae (BSFLM) as a protein source. Pigs were fed different diet types: Control (no BSFLM: 0% (T0)), 25% (T25), 50% (T50), 75% (T75) and 100% (T100) replacement of FM by BSFLM. Average daily feed intake, body weight gain and feed conversion ratio were not affected by the replacement of FM by BSFLM. Red or white blood cell parameters did not differ among diets, except for neutrophil counts, which were higher at T75 and T100 compared to T0. At T25, T75 and T100, pigs had lower platelet counts compared to pigs fed T0 and T50. Dietary BSFLM inclusion did not influence blood cholesterol levels. The cost–benefit ratio and return on investment were similar across diets. Our study shows that BSFLM is a suitable and cost-effective alternative to FM in pig feeds.

Abstract

Pig production is one of the fastest growing livestock sectors. Development of this sector is hampered by rapidly increasing costs of fishmeal (FM), which is a common protein source in animal feeds. Here, we explored the potential of substituting FM with black soldier fly larval meal (BSFLM) on growth and blood parameters of pigs as well as economic aspects. At weaning, 40 hybrid pigs, i.e., crossbreeds of purebred Large White and Landrace were randomly assigned to five iso-nitrogenous and iso-energetic dietary treatments: Control (0% BSFLM and 100% FM (T0)), and FM replaced at 25% (T25), 50% (T50), 75% (T75) and 100% (T100) with BSFLM. Average daily feed intake (ADFI), average daily gain (ADG), body weight gain (BWG) and feed conversion ratio (FCR) were calculated for the whole trial. Hematological and serum biochemical parameters, the cost–benefit ratio (CBR) and return on investment (RoI) were evaluated. No significant effect of diet type was observed on feed intake and daily weight gain. Red or white blood cell indices did not differ among diets. Pigs fed T25, T75 and T100, had lower platelet counts compared to T0 and T50. Dietary inclusion of BSFLM did not affect blood total cholesterol, triglycerides, low-density lipoprotein and high-density lipoprotein. CBR and RoI were similar for the various diets. In conclusion, BSFLM is a suitable and cost-effective alternative to fishmeal in feed for growing pigs.

Radiographic and histological evidence of metabolic bone disease in gliding leaf frogs (Agalychnis spurrelli)

Bone alterations due to metabolic bone disease in captive animal populations can have a negative impact on repopulation and research initiatives. This investigation has the purpose of describing the principal radiographic and anatomopathological findings present in nine gliding leaf frogs (Agalychnis spurrelli) kept in captivity with alterations in their spines and long bones. The observed histopathological findings were in the canalis vertebralis, paraspinal muscle and long bones, and included deformed bones with alteration of the adjacent tissues, alterations in the ossification process, bone degeneration and resorption, decreased number of osteocytes and deposition of osteoid and fibrous material in the compact bone tissue. Additionally, the spinal cord showed compressed white matter, chronic meningitis in the duramater, alteration in the number of glial cells and loss of delimitation between the gray and white matter. Radiographical changes were found mainly in the long bones and included moth-eaten osteolysis, solid periosteal reaction, bone deformities, cortical tunneling and inflammation of adjacent soft tissues. Also, pathological fractures of the femur and urostyle were observed together with spinal column deviations with increased bone density.

The relationship between spindly leg syndrome incidence and water composition, overfeeding, and diet in newly metamorphosed harlequin frogs (Atelopus spp.)

Spindly Leg Syndrome (SLS) is a persistent animal welfare issue associated with the rearing of amphibians in captivity. We conducted two experiments to investigate the effects of diet, water composition and overfeeding on prevalence of SLS in newly metamorphosed harlequin frogs (Atelopus spp.). In our first experiment, we offered 400 full-sibling tadpoles of Atelopus certus isocaloric diets in treatments of 31%, 37%, 42% and 48% crude protein respectively. Tadpoles fed higher protein diets metamorphosed faster, but the incidence of SLS exceeded 80% in all treatments leading to the conclusion that variation in dietary protein was not responsible for causing SLS. We used 720 full-sibling Atelopus glyphus tadpoles in a second experiment to examine the effects of diet type, water composition and diet ration on SLS. We found that an overall incidence of 58% spindly leg in tadpoles reared in tap water, but reduced to about 10% in water treated by reverse osmosis and then reconstituted. It is possible that the reverse osmosis treatment removed some factor that caused the SLS, or that the reconstitution may have added a mineral lacking in the original tap water. Within tap water treatments, overfeeding tadpoles in tanks increased the incidence of SLS. We recommend further experimental research into this condition to identify the causative factors in the water. Additional research into the nutritional composition of food available to wild tadpoles would be useful in formulating captive diets, that have to date been solely based on surrogate species.

VEGF, FGF-2 and TGFβ expression in the normal and regenerating epidermis of geckos: implications for epidermal homeostasis and wound healing in reptiles

The skin is a bilayered organ that serves as a key barrier between an organism and its environment. In addition to protecting against microbial invasion, physical trauma and environmental damage, skin participates in maintaining homeostasis. Skin is also capable of spontaneous self-repair following injury. These functions are mediated by numerous pleiotrophic growth factors, including members of the vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF), and transforming growth factor β (TGFβ) families. Although growth factor expression has been well documented in mammals, particularly during wound healing, for groups such as reptiles less is known. Here, we investigate the spatio-temporal pattern of expression of multiple growth factors in normal skin and following a full-thickness cutaneous injury in the representative lizard Eublepharis macularius, the leopard gecko. Unlike mammals, leopard geckos can heal cutaneous wounds without scarring. We demonstrate that before, during and after injury, keratinocytes of the epidermis express a diverse panel of growth factor ligands and receptors, including: VEGF, VEGFR1, VEGFR2, and phosphorylated VEGFR2; FGF-2 and FGFR1; and phosphorylated SMAD2, TGFβ1, and activin βA. Unexpectedly, only the tyrosine kinase receptors VEGFR1 and FGFR1 were dynamically expressed, and only during the earliest phases of re-epithelization; otherwise all the proteins of interest were constitutively present. We propose that the ubiquitous pattern of growth factor expression by keratinocytes is associated with various roles during tissue homeostasis, including protection against ultraviolet photodamage and coordinated body-wide skin shedding.

Metastatic mineralisation caused by vitamin D intoxication in hand-raised short-beaked echidnas (Tachyglossus aculeatus)

CASE REPORT

Two cases of metastatic mineralisation caused by dietary excess of vitamin D are reported in hand-raised short-beaked echidna (Tachyglossus aculeatus) puggles at the Australian Wildlife Health Centre. Oversupplementation was attributed to excessive levels of vitamin D in Wombaroo Echidna Milk Replacer fed to the puggles. No information exists regarding the naturally occurring vitamin D levels in echidna milk, but, given the low serum levels that have been observed in free-ranging animals, it is likely to be low.

CONCLUSION

The vitamin D concentration in Wombaroo Echidna Milk Replacer has been reduced.

Record-Breaking Pain: The Largest Number and Variety of Forelimb Bone Maladies in a Theropod Dinosaur

Bone abnormalities are common in theropod dinosaur skeletons, but before now no specimen was known with more than four afflicted bones of the pectoral girdle and/or forelimb. Here we describe the pathology of a specimen of the theropod dinosaur Dilophosaurus wetherilli with eight afflicted bones of the pectoral girdle and forelimb. On its left side the animal has a fractured scapula and radius and large fibriscesses in the ulna and the proximal thumb phalanx. On its right side the animal has abnormal torsion of the humeral shaft, bony tumors on the radius, a truncated distal articular surface of metacarpal III, and angular deformities of the first phalanx of the third finger. Healing and remodeling indicates that the animal survived for months and possibly years after its ailments began, but its right third finger was permanently deformed and lacked the capability of flexion. The deformities of the humerus and the right third finger may be due to developmental osteodysplasia, a condition known in extant birds but unreported in non-avian dinosaurs before now.

Clinical pathology reference intervals for an in-water population of juvenile loggerhead sea turtles (Caretta caretta) in Core Sound, North Carolina, USA

The loggerhead sea turtle (Caretta caretta) is found throughout the waters of the Atlantic, Pacific, and Indian Oceans. It is a protected species throughout much of its range due to threats such as habitat loss, fisheries interactions, hatchling predation, and marine debris. Loggerheads that occur in the southeastern U.S. are listed as “threatened” on the U.S. Endangered Species List, and receive state and federal protection. As part of an on-going population assessment conducted by the National Marine Fisheries Service, samples were collected from juvenile loggerhead sea turtles in Core Sound, North Carolina, between 2004 and 2007 to gain insight on the baseline health of the threatened Northwest Atlantic Ocean population. The aims of the current study were to establish hematologic and biochemical reference intervals for this population, and to assess variation of the hematologic and plasma biochemical analytes by season, water temperature, and sex and size of the turtles. Reference intervals for the clinical pathology parameters were estimated following Clinical Laboratory Standards Institute guidelines. Season, water temperature, sex, and size of the turtles were found to be significant factors of variation for parameter values. Seasonal variation could be attributed to physiological effects of decreasing photoperiod, cooler water temperature, and migration during the fall months. Packed cell volume, total protein, and albumin increased with increasing size of the turtles. The size-related differences in analytes documented in the present study are consistent with other reports of variation in clinical pathology parameters by size and age in sea turtles. As a component of a health assessment of juvenile loggerhead sea turtles in North Carolina, this study will serve as a baseline aiding in evaluation of trends for this population and as a diagnostic tool for assessing the health and prognosis for loggerhead sea turtles undergoing rehabilitation.

Updates on amphibian nutrition and nutritive value of common feeder insects

The study of amphibian nutrition requires a detailed review of species-specific natural prey analysis. Invertebrate nutrient composition has been formally studied for more than 60 years and presents the following conclusions: (1) in general, insects are poor in overall calcium content; (2) larval insects have high fat and protein components; and (3) altering the gut contents of some insects can improve their overall nutritive quality. The fat-soluble vitamin profile for most inverts is lacking. There are new guidelines for calcium and vitamin A supplementation that can help augment invertebrate nutrient profiles to match the minimum NRC requirements established for rats.

Update on common nutritional disorders of captive reptiles

Nutritional disorders of captive reptiles remain very common despite the increasing knowledge about reptile husbandry and nutrition. Many nutritional disorders are diagnosed late in the disease process; often secondary complications, such as pathologic fractures in reptiles suffering from nutritional secondary hyperparathyroidism have occurred. Therefore, every attempt should be made to educate reptile owners and keepers about the proper care and dietary needs of reptiles under their care because all nutritional disorders seen in captive reptiles are preventable.