PROTEIN ELECTROPHORESIS AND REFERENCE INTERVALS OF SERUM PROTEINS OF A CAPTIVE POPULATION OF ROTI ISLAND SNAKE-NECKED TURTLES (CHELODINA MCCORDI).

Protein electrophoresis (PEP) is an important tool in mammals to characterize specific dysproteinemias and detect acute and chronic inflammatory responses. In reptiles, PEP is the gold standard method for globulin fraction determination and albumin measurement. In this study, preliminary reference intervals were established for serum PEP in 22 clinically healthy adult Roti Island snake-necked turtles (Chelodina mccordi), a critically endangered species, kept in captivity and sampled over two monsoon seasons. The species has a prominent prealbumin fraction and ß-globulins were the dominant globulin fraction. Significant differences between females and males were found in prealbumin (P < 0.01), albumin (P = 0.02), α1-globulin (P = 0.05) and γ-globulin (P = 0.01). Gravid females had significantly lower total protein (P < 0.01), prealbumin (P < 0.01), albumin (P < 0.01) and albumin:globulin ratio (P = 0.01). These preliminary reference intervals should aid in clinical investigation in this species as well as further research studies seeking to understand the application of PEP in reptilian species.

HEMATOLOGIC AND PLASMA BIOCHEMICAL REFERENCE VALUES FOR CAPTIVE LEOPARD SHARKS (TRIAKIS SEMIFASCIATA).

Leopard sharks (Triakis semifasciata) are temperate, Eastern Pacific elasmobranchs popular in public aquariums. Blood analysis is commonly used for assessing animal health, yet reference values have not been established for this species. This study analyzed T. semifasciata population data to characterize blood reference values for a collection of T. semifasciata housed at a public aquarium. Twenty-one captive leopard sharks were sampled. Blood was collected during annual health examinations from sedated animals. After collection, blood samples were anticoagulated with lithium heparin, and hematocrit and plasma biochemistry values were analyzed. The minimum-maximum ranges were hematocrit 11-31%, buffy coat 1-2%, glucose 4.94-9.38 mM/L, sodium 244-272 mM/L, potassium 3.7-5.5 mM/L, chloride 214-246 mM/L, aspartate aminotransferase 5-31 U/L, creatine kinase 36-1,136 U/L, calcium 3.65-3.95 mM/L, phosphorus 1.13-2.23 mM/L, total protein 21-38 g/L, and total CO2 12-18 mM/L. The values identified will contribute to a better understanding of captive leopard shark physiology and to improved veterinary care for captive leopard sharks. Further research can examine the validity of machines like the Vetscan VS2, which will expand the resources available to care professionals.

ASSESSMENT OF ACUTE PHASE PROTEINS AND PROTEIN ELECTROPHORESIS IN HEALTHY GIBBONS (HYLOBATIDAE) IN MANAGED SETTINGS.

Acute phase proteins (APP) and protein electrophoresis (EPH) offer crucial insights into inflammation and overall health in various species. In this study, we validated serum amyloid A (SAA) and C-reactive protein (CRP) reagents for use with serum samples from gibbons (Hylobatidae, n = 50), spanning five species across four gibbon genera: eastern hoolock (Hoolock leuconedys), Javan (Hylobates moloch), pileated (Hylobates pileatus), siamang (Symphalangus syndactylus), and white-cheeked (Nomascus leucogenys). Preliminary reference intervals (n = 50) were calculated for SAA (1.8-48.1 mg/L), CRP (0.1-11.1 mg/L), and EPH via capillary zone electrophoresis, in healthy gibbons. Comparing clinically normal (n = 38) and abnormal (n = 12) individuals, significant differences were observed in the albumin/globulin ratio (P = 0.0003), prealbumin (P = 0.0345), and albumin (P = 0.0094), with abnormal individuals exhibiting statistically significantly higher γ-globulins (P = 0.0224), SAA (P = 0.0001), and CRP (P = 0.0003). Despite significant chromosomal rearrangements among different gibbon species, we found no statistically significant differences of SAA and CRP levels across species. However, some differences between species were observed in EPH fractions. This study presents the first report of the evaluation of APP and EPH in gibbons, underscoring the potential use of these biomarkers in gibbon health monitoring. Further research with larger sample sizes of both normal and abnormal gibbons is recommended to solidify the clinical utility of these biomarkers in these species.

Biochemistry, Doppler echocardiography, and electrocardiography evaluation in captive owl monkeys (Aotus sp).

BACKGROUND: The cardiovascular system of owl monkeys has been studied due to frequent postmortem findings of heart disease in asymptomatic animals. The silent aspect and the difficulty of early diagnosis intensify the importance of studying the cardiovascular system in this species. METHODS: Echocardiogram evaluation was carried out on 60 animals, grouped into suspect or non-suspect of having heart diseases, and evaluated through electrocardiogram, hematology, and biochemical tests. RESULTS: Doppler echocardiography indicated two animals with suspicion of left ventricular hypertrophy and eight with dilated cardiomyopathy. Suspect animals had higher cardiac measurements and reduced shortening fraction. Troponin I was detectable in two animals (0.128 ng/mL and 0.584 ng/mL), and serum albumin concentration was significantly higher in non-suspect animals (P < .05). CONCLUSIONS: The importance of echocardiographic measurements of IVSd, IVSs, LVIDd, LVIDs, LVPWd, LVPWs, LA, EF, and FS in the cardiac evaluation of captive owl monkeys was evidenced.

Microsatellite characterization and development of unified STR panel for big cats in captivity: a case study from a Seoul Grand Park Zoo, Republic of Korea.

The zoos manage small populations of endangered big cat species like tiger, lion, and leopard for display, research, and conservation breeding. Genetic management of these populations is essential to ensure long term survival and conservation utility. Here we propose a simple and cost effective microsatellite based protocol for the genetic management of captive big cats. We sampled 36 big cat individuals from Seoul Grand Park Zoo (Republic of Korea) and amplified 33 published microsatellite loci. Overall, allelic richness and gene diversity was found highest for leopards, followed by lions and tigers. Twelve of the thirty-three markers showed a high degree of polymorphism across all target species. These microsatellites provide a high degree of discrimination for tiger (1.45 × 10-8), lion (1.54 × 10-10), and leopard (1.88 × 10-12) and thus can be adopted for the genetic characterization of big cats in accredited zoos globally. During captive breeding, zoo authorities rely on pedigree records maintained in studbooks to ensure mating of genetically fit unrelated individuals. Several studies have reported errors in studbook records of big cat species. Microsatellites are simple and cost effective tool for DNA fingerprinting, estimation of genetic diversity, and paternity assessment. Our unified microsatellite panel (12-plex) for big cats is efficient and can easily be adopted by zoo authorities for regular population management.

Hematology and Biochemistry Panel Reference Intervals for Captive Saddleback Clownfish Amphiprion polymnus and Tomato Clownfish A. frenatus.

Reference intervals of blood analytes are important diagnostic tools that clinicians use as a basis for making clinical decisions and that have been documented for many fish species. Although the effects of dietary supplementation on hematology and blood biochemistry variables in clownfish have been shown, there are no published reference intervals to date for routine hematology and blood biochemistry panels for these popular cultured marine fish (including Amphiprion spp.). The objective of this study was to establish de novo reference intervals for selected hemogram data and, using whole-blood analysis, commonly utilized chemistry analytes in two species of aquacultured clownfish: the Tomato Clownfish Amphiprion frenatus and Saddleback Clownfish A. polymnus. This study is based on blood samples from 25 clinically normal Tomato Clownfish and 38 clinically normal Saddleback Clownfish from two clownfish production facilities in Florida. Guidelines by the American Society for Veterinary Clinical Pathology were followed to generate robust reference intervals from the data collected. We report descriptive statistics and reference intervals for several hematology (n = 12) and biochemistry (n = 8) analytes using a small sample size and a small amount of blood per sample. The blood analyte data from this study are comparable with hematology and biochemistry data that have been reported in other teleost species. These results provide baseline health data for clownfish species that can be used in various clinical settings while also serving as a springboard for further research studies.

Ovarian cyclicity and prolactin status of African elephants (Loxodonta africana) in North American zoos may be influenced by life experience and individual temperament.

Hyperprolactinemia is an endocrine disorder associated with infertility in many species, including elephants. In a recent survey of zoos accredited by the Association of Zoos and Aquariums (AZA), over half of African elephant females (N = 101) were not cycling normally, 30% of which exhibited hyperprolactinemia. We examined whether life experience and temperament predict ovarian cyclicity and circulating prolactin status in individual African elephant females. We hypothesized that, similar to humans, acyclicity and hyperprolactinemia in elephants will be associated with an apprehensive or fearful, anxious temperament, and an increased number of potentially challenging life events (transfers, deaths and births). Ninety-five adult African elephant females housed at 37 AZA institutions were included in this study. Blood samples were collected twice a month for 1 year to determine ovarian cycle (cycling, n = 44; irregular, n = 13; non-cycling, n = 38) and prolactin (normal, n = 44; low; n = 23; high; n = 28) status. Keeper ratings on a 6-point scale were obtained on 32 temperament traits in 85 of these elephants. We determined that giving birth and being exposed to herd mates entering the facility were positively associated with normal ovarian cycle and prolactin profiles. By contrast, age, serum cortisol, and an increased number of herd mates leaving a facility were negatively associated with both. Contrary to our hypothesis, hyperprolactinemia was associated with a popular and caring temperament rating, whereas consistently low prolactin was associated with a fearful, apprehensive temperament. These findings indicate that pituitary-ovarian function may be impacted by life history (cyclicity) and temperament (prolactin), which should be taken into consideration when making management decisions.

HEMATOLOGY AND SERUM BIOCHEMISTRY VALUES OF CAPTIVE SOUTHERN LECHWES (KOBUS LECHE).

Blood samples collected from captive Southern lechwes (Kobus leche) were used to develop reference intervals for complete blood count and serum biochemistry values. The study population consisted in 108 healthy individuals, including 62 females and 46 males and 38 neonates (<2 days old), 27 juveniles (2 mo to 2 yr old), and 43 adults (>2 yr old) from the Réserve Africaine de Sigean, Sigean, France, between 2014 and 2016. No significant effects of sex and season of sampling were found. No significant differences were found for all hematology and biochemistry parameters between juveniles and adults, and their results were then combined. Significant differences were found between animals >2 mo old and neonates for most tested parameters; in particular, neonates had lower hemoglobin, eosinophil count, alanine transaminase, and total protein values, but higher alkaline phosphatase values. The reference intervals obtained were similar to values previously reported for other Bovidae species.

BIOLOGICAL VARIATION OF HEMATOLOGY AND BIOCHEMISTRY PARAMETERS FOR THE ASIAN ELEPHANT (ELEPHAS MAXIMUS), AND APPLICABILITY OF POPULATION-DERIVED REFERENCE INTERVALS.

The aim of this study was to objectively evaluate the biological variation of healthy Asian elephant (Elephas maximus) hematology and biochemistry parameters, therefore enabling evidence-based clinical decision-making to improve patient management. Ten clinically healthy elephants had blood samples collected weekly for 5 wk under standardized conditions. The analytical, between- and within-individual variation, index of individuality, and reference change values were calculated using previously reported methods. Large between-individual variation and small within-individual variation for almost all parameters indicated that individual normal values should be used for interpreting blood results from Asian elephants.

TEMPORAL STABILITY OF IN VITRO VENOUS BLOOD GAS, pH, AND LACTATE VALUES OF COWNOSE RAYS (RHINOPTERA BONASUS) AND RED-EARED SLIDER TURTLES (PSEUDEMYS SCRIPTA ELEGANS).

This study assessed the in vitro temporal changes that occur in blood pH and lactate concentrations for an elasmobranch species and a chelonian species, as well as blood gases (partial pressures of carbon dioxide [pCO2] and oxygen [pO2]) for a chelonian species, with a portable clinical point-of-care analyzer. Blood samples were collected from 10 cownose rays (Rhinoptera bonasus) and 10 red-eared sliders (Pseudemys scripta elegans), stored on ice, and serially analyzed at six time points up to 90 min postcollection. Results indicate that analysis should be conducted as soon as possible after blood collection for these species, with immediate analysis being preferred. However, if analysis must be delayed, syringes may be capped, placed on ice, and analyzed at a later time. Analysis within 90 min provided clinically acceptable results for pH and lactate in both species and for pCO2 in red-eared sliders, whereas substantial artifactual increases of pO2 were seen in red-eared sliders.

ESTABLISHMENT OF ACUTE-PHASE PROTEIN AND SERUM PROTEIN ELECTROPHORESIS PRELIMINARY REFERENCE VALUES FOR PRONGHORN (ANTILOCAPRA AMERICANA).

Pronghorn (Antilocapra americana) are native to western North America and are found in 24 Association of Zoos and Aquariums (AZA)-accredited institutions. Acute-phase proteins (APP) are a broad class of proteins that are stimulated in response to inflammation and have been shown to be a sensitive measure of inflammation in equids and ruminants. In this study, blood samples from clinically normal free-ranging and captive populations of pronghorn were analyzed using assays for protein electrophoresis (EPH) and APP, including serum amyloid A (SAA) and haptoglobin (HP), to develop preliminary ranges to gauge potential differences between these populations. Additional samples were taken from clinically abnormal captive pronghorn with facial abscesses. By EPH measurements, albumin: globulin ratio mean and SE were significantly different (P <0.05) with 1.02 (0.08) for captive populations and 1.91 (0.05) for free-ranging populations. Total protein mean and SE were significantly different (P <0.05) for captive and free-ranging populations, respectively 5.6 (0.3) g/dl and 6.9 (0.1) g/dl. Mean and SD of SAA for captive pronghorn were 1.4 (3.2) mg/L, and were significantly different from the free-ranging population, which was below the limits of detection for (P <0.05). There was no difference in HP levels between these groups. In a case study of a pronghorn with facial abscesses, elevated levels of HP, but not SAA, suggested that HP maybe useful in certain disease states. Future studies should explore the use of these biomarkers as tools to monitor general health, prognosis, and subclinical disease.

SEX DIFFERENCES IN THE REFERENCE INTERVALS OF HEALTH PARAMETERS IN SEMICAPTIVE ASIAN ELEPHANTS (ELEPHAS MAXIMUS) FROM MYANMAR.

The reference intervals of health parameters are valuable tools for veterinarians and conservationists to monitor the health status and viability of endangered species. Natural variation in the health of the long-lived Asian elephant (Elephas maximus) is poorly understood, particularly in relation to differences between males and females. Longitudinal health data were collected from clinical examination, hematology, and serum chemistry analyses over 3 yr from 227 healthy individually marked Asian elephants varying in age and sex. The study population was semicaptive and used in Myanmar's timber industry, but maintained natural feeding and breeding behavior. Body condition score (BCS) and blood pressure were investigated in clinical examinations. Hematological parameters included hematocrit, hemoglobin, total white blood cell count, and differential blood cell counts. Serum chemistry parameters included blood urea nitrogen, creatinine, total protein, albumin, globulins, aspartate aminotransferase, alkaline phosphatase, triglycerides, creatine kinase, glucose, calcium, potassium, sodium, and chloride. To the knowledge of the authors, this is the first description of BCS in an elephant population outside of zoos, and of blood pressure in this species using a novel adaptation of the Intelli Wrap Cuff pressure monitor. Several differences between the sexes were observed, with females generally having higher BCS and triglycerides, and males displaying higher alkaline phosphatase and glucose levels. This study provides important clinical tools that can be used to assess the health status and improve management in this endangered species.

Serum prolactin and testosterone levels in captive and wild brown kiwi (Apteryx mantelli) during the prebreeding, breeding, and incubation periods.

In brown kiwi (Apteryx mantelli), the male is the primary incubator, a trait that is relatively rare among birds. The maintenance of avian incubation behavior is controlled by the protein hormone prolactin (PRL). Although steroid hormone concentrations in both wild and captive kiwi have previously been reported, this study is the first to report levels of PRL in captive and wild male and female kiwi through the prebreeding and breeding seasons, and to directly compare testosterone (T) concentrations between captive and wild males during the breeding and incubation periods. Female PRL concentrations increased at the time of oviposition, whereas male PRL concentrations rose gradually between the prebreeding and incubation periods. Although males are considered the main incubator, an increase in PRL levels could help females maintain behaviors such as nest guarding, or to take over incubation the event of mate loss. A gradual increase in PRL allows the male to be ready for incubation during the long breeding season. Interestingly, T concentrations in captive males did not decrease during incubation and was significantly higher than in wild males. Continual elevated T could have an impact on sperm production through negative feedback, thereby contributing to the low egg fertility seen in captive kiwi. Therefore, determining the underlying reason for the differences in hormone levels could be significant, if not vital, for improving the success of captive kiwi breeding programs.

Partial replacement of dietary buffalo meat on the bone with chicken carcass improves serum antioxidant profile of zoo-housed Indian leopards (Panthera pardus fusca).

This experiment was conducted to study the effect of gradual replacement of dietary buffalo meat on the bone (BMB) with chicken carcass (CC) on nutrient utilization, serum cortisol, and total serum antioxidant profile of zoo-housed Indian leopard. Twelve adult leopards were randomly distributed into a replicated Latin square design comprising three treatments, three periods, four animals, and three sequences. Leopards in group T1 were fed normal zoo diet of BMB. On the basis of dry matter, 10% and 20% of BMB was replaced with CC in groups T2 and T3 , respectively. Each experimental period comprised 21 days. During each period, a digestion trial of 4-day collection period was conducted after an adaptation period of 17 days. On Day 21 of each experimental period, blood was collected from all the animals by puncturing the ventral coccygial vein. Intake and apparent digestibility of major nutrients were similar among the groups. Replacement of 20% BMB with addition of CC increased (p < 0.001) the calculated supply of I, niacin, and vitamin A. Carotenoid intake increased (p < 0.01) with increased level of CC in the diet. Serum concentration of cortisol decreased (p < 0.01) whereas serum concentration of total carotenoids increased (p < 0.001) with increased level of CC in the diet. Serum concentration of antioxidant enzymes increased (p < 0.001) with increased level of CC in the diet. It was concluded that replacement of 20% of BMB with CC increased antioxidant profile. This may reduce oxidative stress in zoo-housed Indian leopards without any adverse effect on nutrient utilization.

HEMATOLOGICAL REFERENCE INTERVALS OF ENDANGERED CAPTIVE BLACK-FRONTED PIPING-GUANS (ABURRIA JACUTINGA) IN THE STATE OF PARANÁ, BRAZIL.

The black-fronted piping-guan (Aburria jacutinga) is and an endangered cracid species and little is known about its health. Hematology allows researchers to assess the health and physiological status of a population, but, to our knowledge, reference intervals are not available in the literature for A. jacutinga. Thus, the present study aimed to determine the hematological reference intervals of 31 captive black-fronted pipingguan adults in the state of Paraná, Brazil. Blood samples were collected from brachial vein and stored in heparinized tubes to be processed. The red blood cell (RBC) and white blood cell (WBC) counts were performed in a hemocytometer, and hemoglobin (HGB) concentration was obtained by the spectrophotometric cyanmethemoglobin method; packed cell volume (PCV) was determined by microhematocrit technique, and the mean corpuscular volume (MCV) and mean corpuscular hemoglobin concentration (MCHC) were calculated according to a previously established formula. The heterophil : lymphocyte ratio was calculated by dividing the number of heterophils by the number of lymphocytes. Determination of the 95% reference intervals and 90% confidence intervals were performed in accordance with American Society for Veterinary Clinical Pathology guidelines using Reference Value Advisor (version 2.0). The results obtained were as follows: RBC, 1.4-2.8 × 106/µl; PCV, 34.3-51.2%; HGB, 8.0-12.6 g/dl; MCV, 157.3-261.4 fl; MCHC, 22.0-26.7 g/dl; WBC, 2.3-33.1 × 103/µl; heterophils, 12.1-16.3%, 0.5-14.4 × 103/µl; lymphocytes, 19.8-69.0%, 1.4-16.4 × 103/µl; monocytes, 0.7-17.3%, 0.1-2.8×103/µl; eosinophils, 0.4-12.8%, 0.0-3.9 × 103/µl; basophils, 0.8-12.0%, 0.0-1.9 × 103/µl; and the heterophil : lymphocyte ratio, 0.2-3.0. The present study fills gaps in the literature on hematological values for A. jacutinga, which can be used to assess the health of the species populations. In addition, it contributed to establishing the health status of captive black-fronted piping-guans, indicating the possible welfare of the birds.

EFFECT OF A NUTRIENT ENEMA ON SERUM NUTRIENT CONCENTRATIONS IN WHITE-SPOTTED BAMBOO SHARKS (CHILOSCYLLIUM PLAGIOSUM).

Ill and anorectic captive sharks present a unique challenge for husbandry and veterinary staff. Providing adequate fluid and nutritional support to sharks while minimizing handling remains difficult. This study aimed to evaluate the ability of a nutrient enema to alter blood analyte concentrations. Thirty-six healthy, fasted white-spotted bamboo sharks (Chiloscyllium plagiosum) were enrolled in the study with 18 sharks receiving a nutrient enema and 18 sharks receiving a non-nutrient saline enema. The metabolic state of sharks was evaluated via measurement of blood glucose, blood urea nitrogen, and ß-hydroxybutyrate as well as other serum biochemistry parameters. Changes in sodium, chloride, calcium, ß-hydroxybutyrate, glucose, total protein, and triglyceride concentrations were seen across time in both groups. Blood glucose absolute concentrations and changes over time differed between the nutrient and nonnutrient groups. This pilot study indicates that it is possible to influence the glucose metabolism of healthy sharks via nutrient enema. Further study is needed to better understand potential therapeutics for ill and anorectic sharks.

SERUM TRACE NUTRIENT VALUES IN FOUR CAPTIVE GIANT PANDAS (AILUROPODA MELANOLEUCA).

Trace nutrients have been shown to play important health roles in both domestic and wild animals, but there has been little investigation into their values and effects in giant pandas (Ailuropoda melanoleuca). The goal of this study was to obtain serum vitamin and mineral values in a group of healthy, captive giant pandas (n = 4). Twenty-seven samples were obtained from the group from 2008 to 2012. Serum analytes measured included retinol, α-tocopherol, hydroxyvitamin D, cobalt (Co), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), selenium (Se), and zinc (Zn). The diet was evaluated for protein, fat, fiber, Ca, P, magnesium (Mg), potassium (K), sodium (Na), Fe, Zn, Cu, Mn, and Mo. Comparison with other giant panda nutrient values were made. Further research with increased sample sizes and different populations are warranted.

Seasonal changes in circulating gonadal steroid levels and physiological evidence for the presence of intrinsic circannual reproductive cycles in captive finless porpoises Neophocaena asiaeorientalis from the western Inland Sea, Japan.

We monitored annual fluctuations of gonadal steroid levels in three sexually mature captive finless porpoises (Neophocaena asiaeorientalis; two males and one female) from two different facilities over 56-91 months. Two animals (one male and one female) were held in an indoor tank with a sunroof (facility A) and the other male was held in an indoor tank without a sunroof (facility B). Water temperatures in both facilities reflected seasonal changes during the study period with a minor difference in the fluctuation pattern. Testosterone levels of the male in facility A were higher from spring to summer every year and exhibited a 12-month cycle. The female showed estrus cycles in 1-month intervals from summer to winter, excluding 2 anestrus years. In contrast, the period of higher testosterone levels of the male in facility B gradually initiated earlier over the years under a constant photoperiod (11.5L:12.5D) and exhibited a 9-month cycle during the first 52 months. After changing the light conditions to a natural photoperiod, its testosterone levels were high from early spring to summer for 3 consecutive years and exhibited a 12-month cycle. Our results showed that under a constant artificial photoperiod, the male in facility B failed to recognize the seasonal changes of a natural external environment, resulting in a 9-month, free-running hormone cycle.

Blood Lead Levels in Captive Giant Pandas.

Fifteen giant pandas (Ailuropoda melanoleuca) from the Chinese Conservation and Research Center for the Giant Panda (CCRCGP) in Bifengxia, Sichuan, China were analyzed for blood lead concentrations (Pb-B) during the 2017 breeding season. Thirteen of the 15 bears showed Pb-B below the method detection limit (MDL) of 3.3 µg/dL. The two remaining bears, although above the MDL, contained very low concentrations of lead of 3.9 and 4.5 µg/dL. All 15 giant pandas in this analysis had Pb-B concentrations that were within normal background concentrations for mammals in uncontaminated environments. For a threatened species, whose native country is plagued by reports of extremely high air pollution, our findings suggest that giant pandas at the CCRCGP are not absorbing lead at concentrations that would adversely affect their health.

SEASONAL VARIATION OF SERUM 25-HYDROXY-VITAMIN D IN TWO CAPTIVE EASTERN BLACK RHINOCEROS ( DICEROS BICORNIS MICHAELI) HOUSED IN A NORTH AMERICAN ZOO.

Black rhinoceros ( Diceros bicornis spp.) are critically endangered species, with less than 65 individual animals housed in captivity within Association of Zoos and Aquariums-accredited zoos within the United States, and an estimated 5,500 individual animals of all subspecies surviving in the wild. Previously published reference values for circulating vitamin D3 (25OHD3; 55.7 ± 34.2 ng/ml) were based upon samples from free-ranging black rhinoceros in Africa. Recent research in human medicine has highlighted the importance of subclinical vitamin D deficiency, with links to increased risks for developing various health conditions. Serum samples collected opportunistically from two captive Eastern black rhinoceros ( Diceros bicornis michaeli) housed with seasonal access outdoors in a North American zoo were tested for 25-hydroxy-vitamin D (25OHD) levels over a 3-yr period. A commercially prepared pelleted diet containing vitamin D3 was fed to both rhinos. This study correlates environmental ultraviolet (UV) index, dietary supplementation, and seasonal serum 25OHD levels to compare with known 25OHD3 levels in free-ranging African black rhinoceros. Results in these two individuals suggest that D. bicornis spp. are dependent upon sunlight or UVB for measurable circulating 25OHD, and that current vitamin D3 supplementation levels may have little effect for Diceros spp. in human care housed in northern latitudes.