RESOLUTION OF CALVARIAL HYPEROSTOSIS IN AFRICAN LION CUBS (PANTHERA LEO LEO) AFTER VITAMIN A SUPPLEMENTATION.

Two female (FL 1, FL 2) and one male (ML) 11-wk-old, intact, captive African lion cubs (Panthera leo leo) were presented with a history of mild vestibular signs. Initial serum vitamin A concentrations were low (140 nmol/L) for ML. Calvarial hyperostosis was confirmed using computed tomography (CT) of the head and cervical vertebrae in each cub. CT measurements were adapted in relation to the skull width. ML showed the most pronounced thickening of the tentorium cerebelli and occipital bone, represented by a tentorium cerebelli to skull width ratio (TCR) of 0.08 (FL 1: 0.06, FL 2: 0.05) and a basisphenoid to skull width ratio (BBR) of 0.07 (FL 1: 0.06, FL 2: 0.04). Magnetic resonance imaging (MRI) revealed cerebellar herniation and cervical intramedullary T2-weighted hyperintensity from C1, extending caudally for at least two cervical vertebrae in all cubs. Treatment was initiated with subcutaneous vitamin A supplementation and feeding of whole carcasses. Improvement in ataxia was noticed 3 wk later. Follow-up CT and MRI examinations were performed in ML after 3 and 8 mon. The affected bones appeared slightly less thickened and TCR and BBR had decreased to 0.05 after 3 mon. The cerebellum remained mildly herniated, accompanied by amelioration of cervical T2w hyperintensities. After 8 mon, evaluation and diagnostic imaging revealed further improvement regarding the neurologic status and measurements (TCR 0.05, BBR 0.04) despite persistence of a subtle cerebellar herniation. In conclusion, bone remodeling and improvement in clinical signs may be achievable in young lion cubs presented with calvarial hyperostosis and may be attributable to high-dose vitamin A supplementation.

Melting corneal ulcers (keratomalacia) in dogs: A 5-year clinical and microbiological study (2014-2018).

OBJECTIVES: To identify bacterial microorganisms associated with canine keratomalacia, review their antimicrobial sensitivity, and evaluate clinical outcomes compared to results of microbial culture. METHODS: Retrospective analysis of clinical records of dogs diagnosed with a melting corneal ulcer presented to a referral hospital in Hertfordshire, UK between 2014 and 2018. RESULTS: One hundred and ten melting corneal ulcers were sampled in 106 dogs. The most common pure bacterial isolate was Pseudomonas aeruginosa (n = 26) followed by ß-hemolytic Streptococcus (n = 12). Melting corneal ulcers that cultured coagulase-positive Staphylococcus, coliform bacteria, Pasteurella multocida, Enterococcus, and Streptococcus viridans presented in smaller numbers and were analyzed together (n = 16). Multiple cultures were identified in nine cases (n = 9). Forty-seven cultures yielded no bacterial growth (n = 47). The susceptibility to fluoroquinolones remained high with the exception of ß-hemolytic Streptococci. There was no significant difference in the ulcer severity at presentation in regard to the cultured bacteria. Overall, 63 eyes (57%) received surgical grafting in addition to medical treatment. In 14 cases (13%), the progression of corneal melting despite medical ± surgical treatment resulted in enucleation. Fifty-seven percent (8/14) of the enucleated eyes cultured pure Pseudomonas aeruginosa isolates. In contrast, all ß-hemolytic Streptococcus-associated ulcers healed. CONCLUSIONS: The most common bacterial species associated with canine keratomalacia were Pseudomonas aeruginosa and ß-hemolytic Streptococcus. Because of the variation in antibacterial sensitivity between these two species, bacterial culture and sensitivity testing should be performed in all dogs presenting with keratomalacia. Melting corneal ulcers associated with pure Pseudomonas infection were significantly more likely to result in globe loss than melting corneal ulcers associated with other cultures.

Amniotic membrane grafting for traumatic complete spectaculectomy and keratomalacia in a Boelen's python (Simalia boeleni).

OBJECTIVE: To describe the surgical repair of traumatic complete spectaculectomy and keratomalacia in a snake. ANIMALS: A 10.5-year-old, female, Boelen's python (Simalia boeleni) was presented with iatrogenic, near-complete spectaculectomy associated with bacterial keratitis, keratomalacia, and hypopyon. PROCEDURES: Corneal samples for cytological evaluation and bacterial culture were collected. Following medical stabilization of the bacterial keratitis, a double-layered dry amniotic membrane graft was placed. The first amniotic membrane layer was placed over the cornea with the edges tucked under the peripheral remnants of the spectacle and secured in place with fibrin glue. The second amniotic membrane layer was placed over the entirety of the spectacle remnant and secured in place with a combination of fibrin glue and sutures. Topical and systemic antimicrobials, topical ophthalmic lubricants, and systemic non-steroidal anti-inflammatory therapy were administered postoperatively. RESULTS: Heterophilic keratitis was identified by cytology and Enterobacter cloacae, Pseudomonas aeruginosa, and Staphylococcus sciuri were cultured from the corneal samples. The amniotic membrane grafts remained in place for several weeks. At 4 months postoperatively, the spectacle was completely regenerated, the subspectacular space restored, and the cornea was transparent. Spectacular vascularization and fibrosis then slowly cleared over the following 6 months. CONCLUSIONS AND CLINICAL RELEVANCE: Amniotic membrane grafting with fibrin glue is a relatively simple and effective surgical method to reconstruct extensive defects in the reptilian spectacle and to assist in the management of bacterial keratitis associated with spectacle avulsion.

Vitamin A deficiency and its treatment in captive Sunda pangolins.

The high incidence of disease in captive pangolins is a major obstacle in pangolin-conservation breeding programs. Therefore, elucidating pangolins' susceptibility to disease is the key to conservation progress. At the Pangolin Research Base for Artificial Rescue and Conservation Breeding of South China Normal University (PRB-SCNU), vitamin A deficiency was diagnosed in 14 captive Sunda pangolins. Typical eye signs included lacrimal eyes, keratopathy and a blank, milky orb. The afflicted pangolins were treated with vitamins A and D for 15-30 days; all individuals recovered. We report the detection and treatment of vitamin A deficiency in captive Sunda pangolins at the PRB-SCNU. Our results could provide guidance for the future prevention and treatment of vitamin A deficiency and associated diseases in pangolin species, both to reduce the incidence of these diseases in captive pangolins and to aid conservation efforts.

Dietary vitamin A deficiency reduces growth performance, immune function of intestine, and alters tight junction proteins of intestine for juvenile hybrid grouper (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂).

This study was carried out to investigate the effects of dietary vitamin A (VA) on growth performance, antioxidant capacity, digestion, intestinal immune response, and mRNA expression of intestinal tight junction proteins for juvenile hybrid grouper (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂). Six isonitrogenous and isolipidic experimental diets were formulated to obtain VA levels (317, 1136, 2038, 4142, 7715, 15204 IU/kg diet, respectively). The triplicate groups of fish (average weight of 9.01 ± 0.27 g) were fed twice daily (8:00 and 16:00) for 7 weeks. Based on the broken-line analysis model of WG and LYZ activity, the dietary VA requirement of hybrid grouper were estimated to be 2688.58 and 4096.36 IU/kg diet. The results showed that VA deficiency or excess could reduce Weight gain, specific growth rate, and protein efficiency ratio, and increase feed conversion ratio and hepatosomatic index (P < 0.05). In addition, VA deficiency could reduce the serum activities of acid phosphatase (ACP), superoxide dismutase, and total antioxidant capacity and increase the malondialdehyde content (P < 0.05). VA deficiency also could reduce intestinal activities of ACP, alkaline phosphatase, lysozyme, complement 3, complement 4 contents, and activities of alpha-amylase, lipase, and trypsin (P < 0.05). Meanwhile, VA deficiency could reduce villus height in proximal intestine (PI) and mid intestine (MI), as well as muscle thickness in PI and distal intestine (DI) (P < 0.05). Moreover, VA deficiency could down-regulated antimicrobial peptides (ß-defensin, Hepcidin [not in MI and DI], Epinecidin), anti-inflammatory cytokines (interleukin 10 and transforming growth factor ß1 [not in DI]), tight junction proteins (occluding and claudin3) mRNA levels in the PI, MI and DI, and up-regulated pro-inflammatory cytokines (tumor necrosis factor α [not in MI] and interleukin 1ß [not in MI]), signaling molecules c-Rel and p65 (P < 0.05). Collectively, VA deficiency could reduce growth performance because of a negative effect on intestinal health by depressing digestive abilities, intestinal morphology, immunity and tight junction function in the intestine.

Outcome of medical therapy for keratomalacia in dogs.

OBJECTIVES: To evaluate the clinical and visual outcomes following intensive medical therapy for keratomalacia in dogs. MATERIALS AND METHODS: Medical records were screened to identify dogs with corneal ulcers and keratomalacia. All patients were given the same topical treatment protocol with frequent administrations of tobramycin in combination with equine serum. Surgical treatment during the first 15 days of follow-up was considered as medical treatment failure. RESULTS: We report on 57 ulcers with keratomalacia from 53 dogs. Medical treatment was successful in 31 of 57 ulcers with a median healing time of 5 days (range 2 to 15 days). At 60 days after epithelialisation, 14/15 medically-treated eyes were visual. In one case, corneal perforation was observed 1 month after healing and required surgical stabilisation. CLINICAL SIGNIFICANCE: Intensive medical therapy has the potential to achieve healing of some ulcers with keratomalacia. Surgical stabilisation in response to progression of stromal loss was required in less than half of the cases.

Vitamin A and its metabolic pathway play a determinant role in high-fructose-induced triglyceride accumulation of the visceral adipose depot of male Wistar rats.

Here, we tested a hypothesis that vitamin A and/or its metabolic pathways are involved in the high-fructose-mediated alteration in adipose tissue biology. For this purpose, weanling male Wistar rats were provided with one of the following diets: control (C), control with vitamin A deficiency (C-VAD), high fructose (HFr), and HFr with VAD (HFr-VAD) for 16 weeks, except that half of the C-VAD diet-fed rats were shifted to HFr diet (C-VAD(s)HFr), after 8-week period. Compared with control, feeding of HFr diet significantly increased the triglyceride content (P ≤ .01) and thus adipocyte size (hypertrophy) (P ≤ .001) in visceral adipose depot; retroperitoneal white adipose tissue (RPWAT) and these changes were corroborated with de novo lipogenesis, as evidenced by the increased glycerol-3-phosphate dehydrogenase activity (P ≤ .01) and up-regulation of lipogenic pathway transcripts, fructose transporter, and aldehyde dehydrogenase 1 A1. On the contrary, the absence of vitamin A in the HFr diet (HFr-VAD) failed to exert these changes; however, it induced adipocyte hyperplasia. Further, vitamin A deficiency-mediated changes were reversed by replenishment, as evident from the group that was shifted from C-VAD to HFr diet. In conclusion, vitamin A and its metabolic pathway play a key determinant role in the high-fructose-induced triglyceride accumulation and adipocyte hypertrophy of visceral white adipose depot. SIGNIFICANCE OF THE STUDY: Here, we report the metabolic impact of high-fructose feeding under vitamin A-sufficient and vitamin A-deficient conditions. Feeding of high-fructose diet induced triglyceride accumulation and adipocyte hypertrophy of the visceral white adipose depots. These changes corroborated with augmented expression of vitamin A and lipid metabolic pathway genes. Contrarily, absence of vitamin A in the high-fructose diet did not elicit such responses, while vitamin A replenishment reversed the changes exerted by vitamin A deficiency. To our knowledge, this is the first study to report the role of vitamin A and its metabolic pathway in the high-fructose-induced triglyceride synthesis and its accumulation in visceral adipose depot and thus provide a new insight and scope to understand these nutrients interaction in clinical conditions.

Retinol isotope dilution accurately predicts liver reserves in piglets but overestimates reserves in lactating sows.

IMPACT STATEMENT: Vitamin A (VA) deficiency and hypervitaminosis A have been reported in groups of people worldwide. Conventional biomarkers of VA deficiency (e.g. serum retinol concentration, dose response tests) are not able to distinguish between sufficiency and hypervitaminosis A. Retinol isotope dilution (RID) predictions of VA status have been validated in humans and animal models from deficiency through toxicity; however, RID during life stages with unique issues related to isotopic tracing, such as infancy and lactation, requires further evaluation. This study investigated RID in piglets and lactating sows as models for human infants and women. In piglets, RID successfully determined VA deficiency (confirmed with liver analysis), and that the tracer mixes quickly. Conversely, in lactating sows, although serum and milk enrichments were similar, traditional RID equations overestimated VA stores, likely due to losses of tracer and higher extrahepatic VA storage than predictions. These data inform researchers about the challenges of using RID during lactation.

Vitamin A deficiency impairs intestinal physical barrier function of fish.

The present study was the first to investigate the effects of dietary vitamin A (VA) on the intestinal physical barrier function associated with oxidation, antioxidant system, apoptosis and cell-cellular tight junction (TJ) in the proximal (PI), mid (MI) and distal (DI) intestines of young grass carp (Ctenopharyngodon idella). Fish were fed graded levels of dietary VA for 10 weeks, and then a challenge test using an injection of Aeromonas hydrophila was conducted for 14 days. Results indicated that dietary VA deficiency caused oxidative damage to fish intestine partly by the reduced non-enzymatic antioxidant components glutathione (GSH) and VA contents as well as reduced antioxidant enzyme activities [not including manganese superoxide dismutase (MnSOD)]. Further results observed that the decreased antioxidant enzyme activities by VA deficiency were partly related to the down-regulation of their corresponding mRNA levels which were regulated by the down-regulation of NF-E2-related factor 2 (Nrf2) mRNA levels and up-regulation of kelch-like-ECH-associated protein (Keap1a) (rather than Keap1b) mRNA levels in three intestinal segments of fish. Meanwhile, VA deficiency up-regulated the mRNA levels of the apoptosis signalling [caspase-3, caspase-8, caspase-9 (rather than caspase-7)] associated with the inhibition of the target of rapamycin (TOR) signalling pathway in three intestinal segments of fish. Additionally, VA deficiency decreased the mRNA levels of TJ complexes [claudin-b, claudin-c, claudin-3, claudin-12, claudin-15a, occludin and zonula occludens-1 (ZO-1) in the PI, MI and DI, as well as claudin-7 and claudin-11a in the MI and DI] linked to the up-regulation of myosin light chain kinase (MLCK) signalling. These results suggested that VA deficiency impaired structural integrity in three intestinal segments of fish. Meanwhile, excessive VA also showed similar negative effects on these indexes. Taken together, the current study firstly demonstrated that VA deficiency impaired physical barrier functions associated with impaired antioxidant capacity, aggravated cell apoptosis and disrupted TJ complexes in the PI, MI and DI, but different segments performed different actions in fish. Based on protecting fish against protein oxidation, the optimal VA levels for grass carp were estimated to be 2622 IU/kg diet.

SUSPECTED HYPOVITAMINOSIS A-ASSOCIATED SALT GLAND ADENITIS IN NORTHERN ROCKHOPPER PENGUINS ( EUDYPTES MOSELEYI).

Supraorbital salt-excreting glands are present in at least 10 avian orders and are largest in marine species, including penguins. Diseases of the avian salt gland have been described infrequently. From September 2015, five captive northern rockhopper penguins ( Eudyptes moseleyi) were presented over a 6-wk period for unilateral or bilateral supraorbital swellings. In September 2016, two cases recurred and two additional cases were identified. Histopathology demonstrated salt gland adenitis with extensive squamous metaplasia. Blood plasma testing demonstrated marked vitamin A and E deficiencies within the colony. Prolonged frozen storage of feed-fish was implicated as a cause of vitamin depletion; reducing storage times and addition of dietary supplementation prevented recurrence.

Evaluation of ß-carotene assimilation in leopard geckos (Eublepharis macularius).

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 ß-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 ß-carotene. Insects were gut-loaded continuously with a supplement containing vitamin A or ß-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 ß-carotene allows sufficient vitamin A hepatic storage.

Developing a Model of Vitamin A Deficiency in a Hibernating Mammal, the 13-Lined Ground Squirrel (Ictidomys tridecemlineatus).

Retinoic acid, a bioactive metabolite of vitamin A, plays key roles in immune function and vision and adipose tissue development. Our goal was to study the effect of vitamin A deficiency in physiologic changes seen in hibernating 13-lined ground squirrels (Ictidomys tridecemlineatus). In this study, we first developed a model of vitamin A deficiency that was based on published mouse models; we then examined the role of RA in the circannual cycle of and adipose accumulation in this hibernating species. Gravid female ground squirrels began consuming a deficient diet during the last 2 wk of their 4-wk gestation; pups received the diet until they were 8 wk old, when severe symptoms of hypovitaminosis were observed, requiring the animals' removal from the protocol. Body size and adipose mass were significantly lower in vitamin-deficient pups than controls. To avoid these complications, we developed a second model, in which pups started on the deficient diet after weaning. The revised model produced few symptoms of deficiency, and squirrels were able to remain on the diet through spring emergence. Liver retinol analysis showed that deficient squirrels essentially had no vitamin A stores. Our data suggest that 13-lined ground squirrels maintain higher concentrations of stored retinol than other rodent species, such that their dietary needs may differ from those of traditional laboratory rodent models. Our results indicate that ground squirrels are especially susceptible to vitamin A deficiency, and ground squirrels should not be fed a deficient diet until after weaning, to avoid severe symptoms. Interestingly, vitamin A deficiency does not seem to affect this species' ability to hibernate successfully.

Vitamin A and marbling attributes: Intramuscular fat hyperplasia effects in cattle.

Twenty Angus steers were fed a diet low in ß-carotene and vitamin A for 10months. Ten steers were supplemented with vitamin A weekly, while the other ten steers did not receive any additional vitamin A. The results demonstrated that the restriction of vitamin A intake increased intramuscular fat (IMF) by 46%. This was a function of the total number of marbling flecks increasing by 22% and the average marbling fleck size increasing by 14%. Vitamin A restriction resulted in marbling flecks that were less branched (22%) and slightly more round (4%) with an increased minor axis length (7%). However, restricting vitamin A did not affect the size of the intramuscular or subcutaneous adipocyte cells or the subcutaneous fat depth. The results suggest that vitamin A affects the amount of marbling and other attributes of the marbling flecks due to hyperplasia rather than hypertrophy. This may explain why vitamin A restriction specifically affects IMF rather than subcutaneous fat deposition.

[Unusual case of struvite urolithiasis in a dog. A case report]. / Ungewöhnlicher Fall von Struvit-Urolithiasis bei einem Hund. Ein Fallbericht.

A dog was referred for nutrition consultation after surgical removal of struvite uroliths from the bladder. Inspection of the dog's current ration revealed a pronounced vitamin-A deficiency together with a marked deficiency of protein, phosphorus and magnesium. Therefore, a supersaturation of the urine with ammonium, magnesium and phosphate, the three constituents of struvite, as a cause of struvite calculi formation appears rather unlikely. Vitamin-A deficiency can promote urinary infections and consequently struvite stone formation because of the lack of the protective effect of vitamin A on the epithelia of the urinary tract. Not only common causes for struvite urolith formation, including urinary supersaturation with stone-forming constituents and urinary tract infection, but also less common causes, including vitamin-A deficiency, which was the presumed trigger in the present case study, have to be taken into consideration. Dietetic measures appear to be a useful tool in such cases to prevent uroliths from reoccurring.

Ocular abnormalities associated with hypovitaminosis A in Hanwoo calves: a report of two cases.

This study reports on two Hanwoo (a native Korean breed of cattle) calves, a 3- and 6-month-old presenting with diarrhea, anorexia and blindness. Ophthalmoscopic examination revealed bilateral papilledema in both calves. Reverse-transcription polymerase chain reaction tests for bovine viral diarrhea virus, rotavirus and coronavirus were all negative. The levels of serum vitamin A in the two affected calves were 0.317 µg/dl and 0.481 µg/dl, respectively. These values are much lower than the normal vitamin A levels; therefore, the calves were diagnosed with hypovitaminosis A.

Hypovitaminosis A in extensively grazed beef cattle.

CASE REPORT: Vitamin A deficiency was diagnosed in a herd of 97 19-month-old Braford heifers in the Mitchell Grass Downs (Astrebla spp.) bioregion of Hughenden in north-western Queensland during November 2015. Two heifers died after a 48-h history of sternal recumbency and of the 19 that had neurological signs, 7 were blind. Histological changes in the optic nerves of the two necropsied cattle were consistent with vitamin A deficiency. This diagnosis was supported by vitamin A concentrations in fresh liver samples of 5 and 6 mg/kg wet tissue (reference range, 100-175 mg/kg) despite treatment of the cattle with twice the recommended dose of parenteral vitamin A 3 weeks prior to sampling. Rainfall on the property during the 2 years before the outbreak was less than the annual rainfall average of 464 mm, with a total of 281 mm in 2014 and 117 mm from January to November in 2015, most of this falling in January. CONCLUSION: Plant assays for both ß-carotene and crude protein concentrations in dry matter (DM) were less than the recommended dietary requirements for beef cattle (0.30 mg/kg DM and 56 g/kg, respectively).

Serum selenium and liposoluble vitamins in Japanese Black cows that had stillborn calves.

Stillbirth and dystocia are major factors that negatively affect beef production. We sought to clarify serum selenium and liposoluble vitamin levels in Japanese Black cows that gave birth to stillborn calves (stillbirth cows). Blood samples were collected from 103 stillbirth cows and 95 cows that gave birth to healthy calves (control cows). Serum levels of selenium (45.8 ± 16.0 ng/ml) and vitamin A (73.0 ± 24.8 IU/dl) in stillbirth cows were lower (P<0.05) than those in control cows (52.2 ± 8.9 ng/ml and 93.3 ± 14.8 IU/dl, respectively). Our findings suggest that appropriate serum selenium and vitamin A levels are important for calving cows.

Porcine urinary bladder extracellular matrix grafts (ACell Vet® Corneal Discs) for keratomalacia in 17 equids (2012-2013).

OBJECTIVE: To describe the clinical course, outcomes, and complications associated with use of commercially available porcine urinary bladder extracellular matrix (ECM) grafts (ACell Vet(®) Corneal Discs) in equid patients with keratomalacia, and to evaluate the efficacy of ECM grafts as a viable alternative to other biomaterials for corneal grafting in equid patients. ANIMALS: Sixteen horses and one donkey (17 eyes) with unilateral keratomalacia severe enough to warrant surgical repair between August 2012 and September 2013. PROCEDURE: Retrospective medical record review to identify equid patients meeting inclusion criteria of (i) diagnosis with keratomalacia severe enough to warrant surgical repair and (ii) surgical repair with an extracellular matrix graft. RESULTS: Eleven geldings, four mares, and two colts met inclusion criteria. Patients averaged 9 years of age. Twelve of 17 eyes (71%) were considered infected based on either corneal cytology (10/17, or 59%) or corneal culture (12/17, or 71%) positive for bacteria (8/17, or 47%) or fungi (9/17, or 53%). At the time topical medications were discontinued, 16 eyes (94%) were visual. One operated eye ruptured 5 days postoperatively and was enucleated. Keratouveitis developed in 14/14 eyes that underwent regular examinations approximately 2 weeks postoperatively which responded to systemic nonsteroidal anti-inflammatory drug therapy. CONCLUSIONS: Extracellular matrix grafts may be a viable alternative to other biomaterials for corneal grafting in equids. Advantages include commercial availability and shelf storage.

Nutrition and health in amphibian husbandry.

Amphibian biology is intricate, and there are many inter-related factors that need to be understood before establishing successful Conservation Breeding Programs (CBPs). Nutritional needs of amphibians are highly integrated with disease and their husbandry needs, and the diversity of developmental stages, natural habitats, and feeding strategies result in many different recommendations for proper care and feeding. This review identifies several areas where there is substantial room for improvement in maintaining healthy ex situ amphibian populations specifically in the areas of obtaining and utilizing natural history data for both amphibians and their dietary items, achieving more appropriate environmental parameters, understanding stress and hormone production, and promoting better physical and population health. Using a scientific or research framework to answer questions about disease, nutrition, husbandry, genetics, and endocrinology of ex situ amphibians will improve specialists' understanding of the needs of these species. In general, there is a lack of baseline data and comparative information for most basic aspects of amphibian biology as well as standardized laboratory approaches. Instituting a formalized research approach in multiple scientific disciplines will be beneficial not only to the management of current ex situ populations, but also in moving forward with future conservation and reintroduction projects. This overview of gaps in knowledge concerning ex situ amphibian care should serve as a foundation for much needed future research in these areas.

Serum and hepatic vitamin A levels in captive and wild marine toads (Bufo marinus).

The captive breeding program for the endangered Puerto Rican crested toad (Peltophryne [Bufo] lemur) has been hampered by an undiagnosed condition called "Brown Skin Disease" (BSD). Toads develop widespread skin darkening, skin thickening and abnormal shedding and eventually succumb to a chronic loss of viability. This project evaluated the marine toad (Bufo marinus) as a model for the PRCT, examining vitamin A deficiency as a potential cause of BSD. Wild caught marine toads had significantly higher liver vitamin A concentrations (61.89 ± 63.49 µg/g) than captive born marine toads (0.58 ± 0.59 µg/g); P<0.001). A significant difference in serum vitamin A concentration was found between the captive and wild caught toads (P=0.013) and between the low vitamin A-fed and wild caught toads (P=0.004), when controlling for liver vitamin A concentrations. After captive toads were treated with topical and/or oral vitamin A, their hepatic vitamin A concentrations were similar to those of the wild toads, averaging 48.41 ± 37.03 µg/g. However, plasma vitamin A concentrations pre- and post-vitamin A supplementation did not differ statistically. We concluded that plasma vitamin A concentrations do not provide a linear indication of liver/body vitamin A status, and that both topical and oral supplementation with an oil-based vitamin A formulation can increase liver stores in amphibians. No evidence of BSD or other signs of deficiency were noted in the marine toads, although this feeding trial was relatively short (127 days). To date, clinical, pathological and research findings do not support vitamin A deficiency as a primary factor underlying BSD.