Zoo Biology最新文献

Captive cheetahs are prone to unusual diseases which may be attributed to their high muscle meat, collagen deficient captive diet. Glycine is a simple amino acid that is abundant in collagen rich tissues and has many physiological functions, specifically in collagen synthesis and in the conjugation of detrimental by-products produced during gut bacterial fermentation. Therefore, the aim of this study was to investigate the effect of a 4 week glycine supplementation on the body measurements, haematology and serum blood parameters of 10 captive cheetahs using a randomised controlled cross-over design. This approach has not yet been used to investigate the effect of diet in captive cheetahs. Cheetahs were randomly assigned to a control diet (horse meat only) or a glycine diet (30 g glycine per 1 kg meat) for 4 weeks before being crossed over. Blood was collected at baseline and after each intervention. The glycine diet resulted in a decreased serum albumin, alkaline phosphatase and total calcium concentration and increases in eosinophils and basophils counts compared to the control diet. Body weight also decreased on the glycine diet which may be due to increased β-oxidation and fat loss. This was the first study to investigate the effect of glycine supplementation, which resulted in slight body and blood changes, in captive cheetahs using a cross-over design and this approach should be utilised for future dietary studies.

Leatherback sea turtle (Dermochelys coriacea) hatchlings have previously been kept alive for over a year in captive conditions but these were the few survivors of initially larger groups. In this report, newly hatched leatherback sea turtles were randomly harvested from two nests in Thailand and successfully reared before release back to the wild. In captivity, the survival of the turtles decreased sharply during the first 4 or 5 months, and then steadied until the end of the 12-month trial. The survival of yearlings from one nest was 13.3% and from the other nest 46.7%. Their growth was exponential, reaching 1.36-3.35 kg (n = 9) at the end of program. The causes of death of the reared turtles were accidents (25.0-38.5%) and infections from water and live food (61.5-75.0%). The dietary requirements of the turtles were investigated by determining the digestibility of protein and carbohydrate in vitro, using enzymes from the digestive tracts of hatchlings that had died in an accident (70.1-92.9 g body weight). The results indicated that the most suitable source of protein was wheat gluten, followed by soybean meal, nonruminant meat and bone meal, fish meal, nonruminant meat meal, pork meal, and skimmed milk, while suitable carbohydrate sources were mashed cassava, corn, wheat flour, and alpha starch, followed by cereal meal and rice flour. Findings from the current report provide a practical protocol for head-starting leatherback sea turtles, and indicate the possible basis of an effective artificial diet for this species.

As part of a comparative research agenda that promises insights that help extend the human lifespan and combat cancer, cancer prevalence in zoo animals has received recent attention. Here, we want to draw attention to a principle of cancer research that was introduced into the zoo world as early on as 1933, but that seems to have gone somewhat forgotten: Cancer is mainly a disease of old age, and therefore studies aiming at identifying taxa that are particularly susceptible or resistant to cancer must control for whether the respective zoo populations are 'old.' In a comparative context, 'old age' cannot be measured in absolute terms (e.g., years), but only in relation to a species' maximum lifespan: Species that achieve, across zoos, a higher mean lifespan as a percent of their maximum lifespan are 'older.' When applying this metric to former as well as more recently published data on cancer prevalence, it appears that those species that become relatively old in zoos-in particular, the carnivores-have a relatively high cancer prevalence. Any improvement in animal husbandry-which reduces premature deaths-should, by default, lead to more cancer. Cancer in zoo animals, like any other old-age condition, might therefore be embraced as a proxy for good husbandry. Rather than following a sensationalist approach that dramatizes disease and death per se, zoos should be clear about what their husbandry goals are, what relative longevities they want to achieve for which species, and what old-age diseases they should therefore expect: in the end, one has to die of something.

UVB lamps are used to provide reptiles housed indoors with the UV radiation necessary to synthesize vitamin D₃ in their skin. Since 2019, UVB-LED lamps have been on sale for use in reptile husbandry. We performed spectral analysis and mapped the UV irradiance for 18 of these lamps. The positive benefits of UVB-LED lamps over traditional products include greater energy efficiency, freedom from mercury and easy installation without external ballasts. However, the spectra of all the UVB-LED lamps tested had little similarity to the solar UV spectrum. Some lamps emitted short-wavelength, non-terrestrial, radiation known to cause acute photo-kerato-conjunctivitis; we report one case. All lamps were lacking significant output in the range 315-335 nm, essential for natural self-regulation of cutaneous vitamin D₃ synthesis, preventing overproduction. We describe a possible risk of serious hypervitaminosis D based on our spectral analysis. We call for long-term animal studies to assess this risk, in which the reptiles under these lamps are exposed to species-appropriate UV index levels according to their Ferguson Zone allocation and serum levels of vitamin D₃ and 25(OH)D₃ monitored. Spectral modifications of the lamps to make the spectrum more like sunlight may be an essential way of mitigating this risk.

The implementation of environmental enrichment (EE) can be effective in promoting zoo animal welfare by enhancing the performance of natural or species-typical behaviors. Research on the effects of EE is biased towards larger mammalian species, with less charismatic species being overlooked. Armadillos are one such overlooked example. A captive environment that results in inactivity, obesity, and associated poor health can negatively affect armadillo well-being. The aim of this study was to evaluate how the implementation of four physical object-based EEs could positively affect the behaviors of three armadillo species, housed in four similar exhibits. Behavioral data were collected both before (baseline) and during (treatment) EE periods, alongside of visitor number and environmental temperatures. The EE comprised of a plastic ball or a cardboard tube or a cardboard box, or a scatter-feed, and these were rotated each week of study until each exhibit had received them in turn. Despite the presence of different EE types, activity remained low throughout the study. However, results suggest that the plastic ball and cardboard box increased exploratory behaviors in the armadillos, but no overall increase in activity was noted during the scatter feed. Visitor presence had no effect on armadillo activity, and armadillos showed reduced activity with increasing environmental temperature. Overall, the use of physical object-based EE promoted beneficial natural behaviors in zoo-housed armadillos, but environmental conditions (i.e., temperature) also impacted armadillo activity, suggesting a complicated relationship between an enclosure's environmental variable and any behavioral husbandry measures.

Forty-seven free-ranging sea turtles (46- Chelonia mydas, 1- Eretmochelys imbricata) were examined via novel use of an endoscopy combined with a rectal enema to obtain large fecal sample volumes. The cloaca was insufflated using an endoscope, after which the bladder and rectum separated, allowing access to the colon. Environmental conditions and location influenced the performance of the procedure initially, but after several attempts the procedure was successfully initiated. In all cases, fecal samples were obtained, and the animals were released to their respective locations. Fecal sample collection using this approach enhances the ability to obtain diagnostic information and perform other scientific analyses of sea turtles.

The short-beaked echidna is sexually monomorphic such that gender identification without veterinary intervention is challenging. The aim of this study was to evaluate and compare the most optimal noninvasive genetic source by extracting echidna genomic DNA (gDNA) from fecal scats, plucked hair, and quills to perform genetic sex testing using a range of molecular markers. Sex determination of 14 captive short-beaked echidnas was determined by amplifying isolated DNA from noninvasive samples, targeting two Y chromosome (male-specific) genes (mediator complex subunit 26 Y-gametologue [CRSPY] and anti-Müllerian hormone Y-gametologue [AMHY]), in addition to four confirmed sex-specific RADseq markers. Results of noninvasive samples were compared with blood samples and clinical records. Receiver operating characteristic curves were used to assess accuracy of sex determination of markers for each sample type. The gender of the echidnas was successfully identified on 75% of occasions using fecal samples, 90.6% occasions using hair, and 84.6% occasions with quills. Overall, the male-specific RADseq markers accurately identified the sex of echidnas with all sample types for 90% of animals; compared with 81.5% using CRSPY, and 82.0% using AMHY to identify sex. Collection of hair, quills, and feces provides a useful alternative to invasively collected samples, however, the accuracy of results depends on sample type and genetic marker selected. We found gender determination in the short-beaked echidna was most accurate using four male-specific RADseq markers on gDNA isolated from blood and hair. The noninvasive genetic sexing techniques documented here will inform and facilitate husbandry and genetic management of captive echidna populations.

Environmental enrichment (EE) is commonly provided to animals managed under human care, being beneficial to behavioral diversity and improving animal welfare. Use of EE appears to be particularly beneficial to individual wild animals spending a short period of time in captivity, for example, as part of conservation or rehabilitation programs. This paper documents a case study on the application and relevance of EE for a group of captive mute swans housed in a rescue center. Observational data were analyzed for two groups of juvenile swans that were provided with a physical EE device to increase time spent foraging. Periods of no EE were observed and compared to data from when birds were provided with EE. Results show that EE promoted foraging time and helped to reduce long periods of inactivity in captive birds. EE helped to reduce occurrence of captive-focused (i.e., abnormal behaviors) although these was already seen at very low rates. Inactivity as a measure of welfare in captive swans specifically (and waterbirds generally) should be further investigated to understand potential impacts on bird health. Our research shows the benefits of simple and easy-to-use EE devices on captive animal behavior and how use of EE for individuals spending a short amount of time in captivity (e.g., within a rescue center) could ensure diversity of behavior patterns and promote the performance of adaptive behaviors upon release to the wild.

Numerous facilities around the world offer tourists interactive experiences with captive tigers. Yet, the animal welfare implications of this practice have not been widely studied. This study aimed to investigate whether qualitative behavioral assessment (QBA) could: (i) provide a valid indicator of tiger's emotional state and (ii) be applied to assess whether unfamiliar human presence with hand-raised captive tigers had an impact on the emotional state of those tigers. To investigate this, QBA was applied to video clips of hand-raised captive tigers from three sites (two offering unfamiliar human interaction, Sites A and C, and one retirement site with no direct interactions, Site B) in Thailand. QBA allows inferences to be made about animal emotion on the basis of descriptions of behavioral expression. Analysis, using a free choice profiling methodology, was provided by observers (N = 38) split between three groups; tiger keepers and vets from the Thai venues (n = 12), UK-based animal behavior MSc and vet students (n = 16), and international tiger keepers (n = 10). Tigers (N = 35) were split between Sites A (n = 7), B (n = 18), and C (n = 10) and filmed at three time points; morning (0800-0930 h); midday, (1130-1230 h); and evening, (1630-1830h) totaling 105 clips. Using generalized procrustes analysis, a consensus profile was calculated for each observer group. Two meaningful dimensions of behavioral expression, explaining 75.0% of the variation, were observed across these groups: Dimension 1 (D1: "active"/"interested"/"agitated" to "relaxed"/"calm"/"chilled-out") and Dimension 2 (D2: "bored"/"stressed"/"frustrated" to "relaxed"/"curious"/"interested"). There was clear agreement between the three observer groups in terms of tiger emotional expression along D1. However, agreement was more variable on D2. The behavioral expression on D1 was not significantly affected by site but was significantly affected by an interaction between age and time of day. Time of day also affected scores on D2, with the Thai observer group also showing an effect of site. During the midday period, when unfamiliar humans were present, all tiger age groups showed more positive behavioral expressions on D1 (lower scores: "relaxed"/"calm"/"chilled-out") and more negative behavioral expressions on D2 (higher scores: "bored"/"stressed"/"frustrated"), which could indicate that the presence of unfamiliar humans was a stressor. However, tigers in the retirement Site C also displayed similar behavioral expressions, which could indicate a deeper welfare issue. With further development, QBA could be used as part of a valid tool for long-term measurement of behavioral expression in captive tigers.

Egg weight loss during incubation is a key indicator used to monitor successful egg development and is closely related to hatchability and chick survival. Artificial incubation is one of the most important captive breeding techniques used in conservation efforts to bolster avian populations. To repair damage to the eggshell and ensure embryonic viability during incubation, a variety of repair coverings can be applied. This study tested the impact of four repair materials (nail polish, synthetic glue, medical dressing, and molten wax film) on egg weight loss during incubation. We found no impact on weight loss for coverings smaller than 35% of the eggshell surface, nor did we find any differences between covering types. The average egg weight loss decreased as the coverage area increased, and the weight loss did not differ when blunt versus sharp-end coverings were compared. Given the relative insensitivity of egg weight loss and survival to the type of patch material used, we concluded that the selection of material for the purpose of weight loss management could be based on practical considerations, such as ease of application and availability.