Perspectives on SARS-CoV-2 Cases in Zoological Institutions

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections in a zoological institution were initially reported in March 2020. Since then, at least 94 peer-reviewed cases have been reported in zoos worldwide. Among the affected animals, nonhuman primates, carnivores, and artiodactyls appear to be most susceptible to infection, with the Felidae family accounting for the largest number of reported cases. Clinical symptoms tend to be mild across taxa; although, certain species exhibit increased susceptibility to disease. A variety of diagnostic tools are available, allowing for initial diagnostics and for the monitoring of infectious risk. Whilst supportive therapy proves sufficient in most cases, monoclonal antibody therapy has emerged as a promising additional treatment option. Effective transmission of SARS-CoV-2 in some species raises concerns over potential spillover and the formation of reservoirs. The occurrence of SARS-CoV-2 in a variety of animal species may contribute to the emergence of variants of concern due to altered viral evolutionary constraints. Consequently, this review emphasizes the need for effective biosecurity measures and surveillance strategies to prevent and control SARS-CoV-2 infections in zoological institutions.

Trabecular bone morphology in big cats reflects the complex diversity of limb use but not home range size or daily travel distance

A relationship exists between mechanical loading and bone morphology. Although studies show a relationship between trabecular bone morphology and locomotor strategy in mammals, none of them have studied trabecular bone morphology in felid species occupying disparate and overlapping habitats. We investigate trabecular bone volume fraction (BVF) in the femoral and humeral heads, and distal tibia of four felid species (mountain lions, jaguars, cheetahs, and leopards) to identify whether there is a relationship between BVF and locomotor behavior. This study's goals are to identify whether felid species with high daily travel distance or large home range size have greater BVF compared with those with small daily travel distance or home range size, and whether BVF is correlated among the three elements of the fore and hindlimb studied. We quantified BVF in micro- and peripheral computed tomography images and found no significant differences across species in the femoral and humeral head (p > 0.05). However, in the distal tibia, results showed that leopards, mountain lions, and cheetahs have significantly greater (p < 0.05) BVF than jaguars. Despite differences in home range size and daily travel distance, the proximal elements did not reflect differences in BVF; however, the distal-most element did, suggesting decreased loading among jaguars. These findings suggest that the observed pattern of trabecular bone morphology is potentially due to the diversity in locomotor strategy of the forelimb. Additionally, these results imply that neither home range size nor daily travel distance are clear indicators of activity levels. A cautious approach is warranted in studying how loading influences trabecular morphology.

Draft genomes of 16 Bartonella henselae strains from cats in Valdivia, Chile

Bartonella henselae is a primary zoonotic agent, having cats as asymptomatic reservoirs. In humans, it causes cat scratch disease. Here, we report the whole genome sequences of 16 strains isolated from cats in Valdivia city, Southern Chile. Strains showed little variability in the multilocus sequence typing profiles.

The perception of felid welfare by zookeepers in North America and the implications for zoo managers

Zookeepers working with felids were asked to complete an online survey to examine their perceptions of animal welfare. A total of 121 zookeepers in an AZA-accredited zoo completed the survey. Results from this study suggest that institutional offerings of professional development programming in animal welfare have the greatest potential to influence zookeeper perceptions of animal welfare. Participants also identified four areas of improvement for felid welfare, including 1) larger and more dynamic spaces, 2) increased attention to behavioral husbandry, 3) more unique diet presentations, and 4) the ability for the animal to remain out of the view of the public. In addition, there appear to be differences in perception between traditionally described "small cat" and "large cat" keepers in terms of the ability to deliver the Five Freedoms.

Comparative genomics of the Leukocyte Receptor Complex in carnivores

Background

The mammalian Leukocyte Receptor Complex (LRC) chromosomal region may contain gene families for the killer cell immunoglobulin-like receptor (KIR) and/or leukocyte immunoglobulin-like receptor (LILR) collections as well as various framing genes. This complex region is well described in humans, mice, and some domestic animals. Although single KIR genes are known in some Carnivora, their complements of LILR genes remain largely unknown due to obstacles in the assembly of regions of high homology in short-read based genomes.

Methods

As part of the analysis of felid immunogenomes, this study focuses on the search for LRC genes in reference genomes and the annotation of LILR genes in Felidae. Chromosome-level genomes based on single-molecule long-read sequencing were preferentially sought and compared to representatives of the Carnivora.

Results

Seven putatively functional LILR genes were found across the Felidae and in the Californian sea lion, four to five genes in Canidae, and four to nine genes in Mustelidae. They form two lineages, as seen in the Bovidae. The ratio of functional genes for activating LILRs to inhibitory LILRs is slightly in favor of inhibitory genes in the Felidae and the Canidae; the reverse is seen in the Californian sea lion. This ratio is even in all of the Mustelidae except the Eurasian otter, which has a predominance of activating LILRs. Various numbers of LILR pseudogenes were identified.

Conclusions

The structure of the LRC is rather conservative in felids and the other Carnivora studied. The LILR sub-region is conserved within the Felidae and has slight differences in the Canidae, but it has taken various evolutionary paths in the Mustelidae. Overall, the process of pseudogenization of LILR genes seems to be more frequent for activating receptors. Phylogenetic analysis found no direct orthologues across the Carnivora which corroborate the rapid evolution of LILRs seen in mammals.

Full confluency, serum starvation, and roscovitine for inducing arrest in the G0/G1 phase of the cell cycle in puma skin-derived fibroblast lines

The puma population is constantly decreasing, and cloning by somatic cell nuclear transfer can be used to conserve the species. One of the factors determining the success of the development of cloned embryos is the cell cycle stage of the donor cells. We evaluated the effects of full confluency (~100%), serum starvation (0.5% serum), and roscovitine (15 µM) treatments on the cell cycle synchronization in G₀/G₁ of puma skin-derived fibroblasts by flow cytometric analysis. Also, we assessed the effects of these synchronization methods on morphology, viability, and apoptosis levels using microscopy tools. The results showed that culturing the cells to confluence for 24 h (84.0%), 48 h (84.6%), and 72 h (84.2%) and serum starvation for 96 h (85.4%) yielded a significantly higher percentage of cells arrested in the G₀/G₁ (P 0.05) phase than cells not subjected to any cell cycle synchronization method (73.9%). Nevertheless, while serum starvation reduced the percentage of viable cells, no difference was observed for the full confluence and roscovitine treatments (P 0.05). Moreover, roscovitine for 12 h (78.6%) and 24 h (82.1%) was unable to synchronize cells in G₀/G₁ (P 0.05). In summary, full confluency induces puma fibroblast cell cycle synchronization at the G₀/G₁ stage without affecting cell viability. These outcomes may be valuable for planning donor cells for somatic cell nuclear transfer in pumas.

The Use of Commercial Microvolume Techniques for Feline Oocyte Vitrification

This project aimed to compare the three most popular commercial oocyte vitrification techniques to determine their suitability for the vitrification of felid germlines in rescue and conservation programs. The present study aimed to determine the viability and developmental competence of feline oocytes after IVM and vitrification using a commercial vitrification method. In the first experiment, oocytes were vitrified after in vitro maturation (IVM) using the Kitazato, Cryotech, and Vitrolife methods. The oocytes were stained with fluorescein diacetate and ethidium bromide to evaluate their viability. The differences between Vitrolife and the control, Cryotech and Kitazato were statistically significant (p < 0.05), and between the control and Kitazato, were highly significant (p < 0.01). There were no significant differences between the control and Cryotech, Vitrolife and Cryotech, or Kitazato and Vitrolife. In the second part of the experiment, oocytes, after IVM and vitrification using three commercial methods, were subjected to fertilization. After vitrification, IVF was performed. We observed 35% of embryonic divisions in the group where Vitrolife and Kitazato media were used and 45% in the control group. In the presented experiment, vitrification with Vitrolife media gave slightly better results for survival and fertilization, while in the case of emergency protocol vitrification, all of the above methods may be useful to protect material derived from valuable wild felids.

Changes in Serum Amyloid A Level in Domestic Cats during Pregnancy

Reproduction of endangered species in captivity is an urgent problem for the conservation and restoration of biodiversity. For mammals, including felids, assessing and monitoring of pregnancy progression is fundamental for successful breeding. For the first time, changes in the concentrations of serum amyloid A (SAA), the main protein of the acute phase of inflammation in felines, were assessed during pregnancy in a domestic cat. It was found that changes in SAA concentrations in pregnant females are consistent: an increase to the middle of pregnancy (day 30) and a decrease to day 60. After parturition, the SAA concentrations in the blood of domestic cats increase. The litter size significantly affected the dynamic of SAA concentrations during the experiment, in particular, after parturition, the increase in its level was significantly higher in the females that gave birth to larger litters (from four to seven kittens).

Rapid evolution of SARS-CoV-2 in domestic cats

SARS-CoV-2 (SARS2) infection of a novel permissive host species can result in rapid viral evolution. Data suggest that felids are highly susceptible to SARS2 infection, and species-specific adaptation following human-to-felid transmission may occur. We employed experimental infection and analysis of publicly available SARS2 sequences to observe variant emergence and selection in domestic cats. Three cohorts of cats (N = 23) were inoculated with SARS-CoV-2 USA-WA1/2020 or infected via cat-to-cat contact transmission. Full viral genomes were recovered from RNA obtained from nasal washes 1-3 days post-infection and analyzed for within-host viral variants. We detected 118 unique variants at ≥3 per cent allele frequency in two technical replicates. Seventy of these (59 per cent) were nonsynonymous single nucleotide variants (SNVs); the remainder were synonymous SNVs or structural variants. On average, we observed twelve variants per cat, nearly 10-fold higher than what is commonly reported in human patients. We observed signatures of positive selection in the spike protein and the emergence of eleven within-host variants located at the same genomic positions as mutations in SARS2 variant lineages that have emerged during the pandemic. Fewer variants were noted in cats infected from contact with other cats and in cats exposed to lower doses of cultured inoculum. An analysis of ninety-three publicly available SARS2 consensus genomes recovered from naturally infected domestic cats reflected variant lineages circulating in the local human population at the time of sampling, illustrating that cats are susceptible to SARS2 variants that have emerged in humans, and suggesting human-to-felid transmission occurring in domestic settings is typically unidirectional. These experimental results underscore the rapidity of SARS2 adaptation in felid hosts, representing a theoretical potential origin for variant lineages in human populations. Further, cats should be considered susceptible hosts capable of shedding virus during infections occurring within households.

Differential susceptibility of SARS-CoV-2 in animals: Evidence of ACE2 host receptor distribution in companion animals, livestock and wildlife by immunohistochemical characterisation

Angiotensin converting enzyme 2 (ACE2) is a host cell membrane protein (receptor) that mediates the binding of coronavirus, most notably SARS coronaviruses in the respiratory and gastrointestinal tracts. Although SARS-CoV-2 infection is mainly confined to humans, there have been numerous incidents of spillback (reverse zoonoses) to domestic and captive animals. An absence of information on the spatial distribution of ACE2 in animal tissues limits our understanding of host species susceptibility. Here, we describe the distribution of ACE2 using immunohistochemistry (IHC) on histological sections derived from carnivores, ungulates, primates and chiroptera. Comparison of mink (Neovison vison) and ferret (Mustela putorius furo) respiratory tracts showed substantial differences, demonstrating that ACE2 is present in the lower respiratory tract of mink but not ferrets. The presence of ACE2 in the respiratory tract in some species was much more restricted as indicated by limited immunolabelling in the nasal turbinate, trachea and lungs of cats (Felis catus) and only the nasal turbinate in the golden Syrian hamster (Mesocricetus auratus). In the lungs of other species, ACE2 could be detected on the bronchiolar epithelium of the sheep (Ovis aries), cattle (Bos taurus), European badger (Meles meles), cheetah (Acinonyx jubatus), tiger and lion (Panthera spp.). In addition, ACE2 was present in the nasal mucosa epithelium of the serotine bat (Eptesicus serotinus) but not in pig (Sus scrofa domestica), cattle or sheep. In the intestine, ACE2 immunolabelling was seen on the microvillus of enterocytes (surface of intestine) across various taxa. These results provide anatomical evidence of ACE2 expression in a number of species which will enable further understanding of host susceptibility and tissue tropism of ACE2 receptor-mediated viral infection.

Effects of reduced mobility on trabecular bone density in captive big cats

Bone responds to elevated mechanical loading by increasing in mass and density. Therefore, wild animals should exhibit greater skeletal mass and density than captive conspecifics. This expectation is pertinent to testing bone functional adaptation theories and to comparative studies, which commonly use skeletal remains that combine zoo and wild-caught specimens. Conservationists are also interested in the effects of captivity on bone morphology as it may influence rewilding success. We compared trabecular bone volume fraction (BVF) between wild and captive mountain lions, cheetahs, leopards and jaguars. We found significantly greater BVF in wild than in captive felids. Effects of captivity were more marked in the humerus than in the femur. A ratio of humeral/femoral BVF was also lower in captive animals and showed a positive relationship to home range size in wild animals. Results are consistent with greater forelimb than hindlimb loading during terrestrial travel, and possibly reduced loading of the forelimb associated with lack of predatory behaviour in captive animals. Thus, captivity among felids has general effects on BVF in the postcranial skeleton and location-specific effects related to limb use. Caution should be exercised when identifying skeletal specimens for use in comparative studies and when rearing animals for conservation purposes.

Morphological, Ultrastructural, and Immunocytochemical Characterization and Assessment of Puma (Puma concolor Linnaeus, 1771) Cell Lines After Extended Culture and Cryopreservation

Cell lines are valuable tools to safeguard genetic material from species threatened with extinction that is mainly due to human action. In this scenario, the puma constitutes a species whose population is being rapidly reduced in the ecosystems it inhabits. For the first time, we characterized puma skin-derived cell lines and assessed these cells after extended culture (experiment 1) and cryopreservation (experiment 2). Initially, we identified and characterized four dermal fibroblast lines using morphology, ultrastructure, and immunofluorescence assays. Moreover, we evaluated the effects of culture time (1st, 3rd, and 10th passages) and cryopreservation on their morphology, ultrastructure, viability, metabolism, proliferative activity, reactive oxygen species (ROS) levels, mitochondrial membrane potential (ΔΨm), and apoptosis. The cells showed a typical spindle-shaped morphology with centrally located oval nuclei. The cells were identified as fibroblasts by staining for vimentin. In vitro culture after the 1st, 3rd, and 10th passages did not alter most of the evaluated parameters. Cells in the 3rd and 10th passages showed a reduction in ROS levels (p < 0.05). The ultrastructure revealed morphological damage in the prolongments, and nuclei of cells derived from the 3rd and 10th passages. Moreover, cryopreservation resulted in a reduction in ΔΨm compared with that of noncryopreserved cells, suggesting that the optimization of cryopreservation methods for puma fibroblasts is essential. In conclusion, we found that viable fibroblasts could be obtained from puma skin, with slight changes after the 10th passage in in vitro culture and cryopreservation. This is the first report on the development of cell lines derived from pumas.

The influence of welfare and bonds with animals on the job satisfaction of felid keepers in North America

The current study set out to examine the perceptions of felid welfare in zoos and elucidate the factors that influence an individual animal care professional's acceptance and recognition of welfare. A total of 121 felid keepers employed in an Association of Zoos & Aquariums facility were included in analysis. Results demonstrate job satisfaction is directly linked to access to training on welfare topics. The relationship between job satisfaction and the fulfillment of the Five Freedoms is positively correlated. Additionally, overall job satisfaction does not appear to influence the bond with felids, but it does with other zoo animals. Those with lower reported job satisfaction demonstrate an overall lower bond with nonfelids, where this not observed in felids. Participants in this study demonstrate the direct connection between job satisfaction and perceived fulfillment of the Five Freedoms. Participants who were provided access to training and information on animal welfare often demonstrated a higher job satisfaction, more positive perception of their employer, and overall view of zoos meeting the Five Freedoms with captive felids.

Isolation and Genetic Characterization of Canine Parvovirus in a Malayan Tiger

Naïve Felidae in the wild may harbor infectious viruses of importance due to cross-species transmission between the domesticated animals or human–wildlife contact. However, limited information is available on virus shedding or viremia in the captive wild felids, especially in Malaysia. Four infectious viruses of cat, feline herpesvirus (FHV), feline calicivirus (FCV), canine distemper virus (CDV), and canine parvovirus (CPV), were screened in leopards, feral cats, and tigers in Malaysia based on virus isolation in Crandell-Rees feline kidney (CRFK) cells, PCR/RT-PCR, and whole-genome sequencing analysis of the positive isolate. From a total of 36 sera collected, 11 samples showed three consecutive cytopathic effects in the cell culture and were subjected to PCR using specific primers for FHV, FCV, CDV, and CPV. Only one sample from a Malayan tiger was detected positive for CPV. The entire viral genome of CPV (UPM-CPV15/P. tigris jacksoni; GenBank Accession number MW380384) was amplified using the Sanger sequencing approach. Genome sequencing of the isolate revealed 99.13, 98.65, and 98.40% close similarity to CPV-31, CPV-d Cornell #320, and CPV-15 strains, respectively, and classified as CPV-2a. Time-scaled Bayesian Maximum Clade Credibility tree for the non-structural (NS) genes of CPV showed a close relationship to the isolates CPV-CN SD6_2014 and KSU7-SD_2004 from China and USA, respectively, while the capsid gene showed the same ancestor as the FPV-BJ04 strain from China. The higher evolution rate of the capsid protein (CP) (VP 1 and VP2) [1.649 × 10⁻⁵ (95% HPD: 7.626 × 10⁻³ to 7.440 × 10⁻³)] as compared to the NS gene [1.203 × 10⁻⁴ (95% HPD: 6.663 × 10⁻³ to 6.593 × 10⁻³)] was observed in the CPV from this study, and fairly higher than other parvovirus species from the Protoparvovirus genus. Genome sequencing of the isolated CPV from a Malayan tiger in the present study provides valuable information about the genomic characteristics of captive wild felids, which may add information on the presence of CPV in species other than dogs.

Plant-eating carnivores: Multispecies analysis on factors influencing the frequency of plant occurrence in obligate carnivores

Plant-eating behavior is one of the greatest mysteries in obligate carnivores. Despite unsuitable morphological and physiological traits for plant consumption, the presence of plants in scat or stomach contents has been reported in various carnivorous species. However, researchers' interpretations of this subject are varied, and knowledge about it is scarce, without any multispecies studies. This study assessed the extent of variation in the frequency of plant occurrence in scat and stomach contents, as well as its relationship with various factors in 24 felid species using data from 213 published articles. Since the frequency of plant occurrence has not always been reported, we created two-part models and estimated parameters in a Bayesian framework. We found a significant negative relationship between the frequency of plant occurrence and body mass. This may be because plant-eating behavior reduces the energy loss caused by parasites and increases the efficiency of energy intake, which has a greater importance in smaller animals that have relatively high metabolic rates. This exploratory study highlights the importance of considering plant consumption in dietary studies on carnivorous species to understand the adaptive significance of this behavior and the relationship between obligate carnivores and plants.

Can detomidine replace medetomidine for pharmacological semen collection in domestic cats?

Among the different methods used for semen collection from domestic cats, the pharmacological collection by urethral catheterization becomes disruptive. Medetomidine is the elected α²-adrenoceptor agonist for that, but in several countries, it is not commercially available. This study aimed to evaluate the efficacy of detomidine compared to medetomidine in collecting semen by urethral catheterization in domestic cats. Urethral catheterization was performed on 13 mongrel cats using a disposable semi-rigid tomcat urinary catheter. Of the 19 semen collections performed with medetomidine induction, 94.7% were successful, while with detomidine induction, only 56.3% of 16 were successful. The values semen samples variables were as follows for volume - 10.56 ± 0.4 vs 8.88 ± 0.5 mL, motility - 171.67 ± 0.79 vs 49.77 ± 3.45%, vigor - 4.1 ± 0.03 vs 3.10 ± 0.1 and concentration - 3.24 ± 0.19 vs 2.15 ± 0.13 ×10⁹ sperm/mL respectively for medetomidine and detomidine group. The failure in semen collections with detomidine was mainly due to azoospermic samples, poor urethral relaxation, insufficient volume, or contamination of urine. The sperm concentration was also lower in the detomidine group (P <0.05) when compared to medetomidine. However, when the volume of semen collected was compared, we found no statistical differences. Despite its low performance in collecting semen from cats, detomidine may be an alternative when medetomidine is not accessible.

SARS-CoV-2 Clinical Outcome in Domestic and Wild Cats: A Systematic Review

Recently, it has been proved that SARS-CoV-2 has the ability to infect multiple species. This work was aimed at identifying the clinical signs of SARS-CoV-2 infection in domestic and wild felids. A PRISMA-based systematic review was performed on case reports on domestic and wild cats, reports on experimental infections, case reports in databases, preprints and published press releases. Descriptive statistical analysis of the data was performed. A total of 256 articles, 63 detailed official reports and 2 press articles on SARS-CoV-2 infection in domestic and wild cats were analyzed, of which 19 articles and 65 reports were finally included. In domestic cats, most cats' infections are likely to be asymptomatic, and 46% of the reported infected animals were symptomatic and predominantly presented respiratory signs such as sneezing and coughing. In wild felines, respiratory clinical signs were most frequent, and up to 96.5% of the reported affected animals presented coughing. It is noteworthy that, to date, symptomatic animals with SARS-CoV-2 infection have been reported to belong to two different subfamilies (Phanterinae and Felinae), with up to five different felid species affected within the Felidae family. Reported results evince that the signs developed in felids show similar progression to those occurring in humans, suggesting a relationship between the viral cycle and target tissues of the virus in different species. While viral transmission to humans in contact with animal populations has not been reported, spill-back could result in the emergence of immune-escape mutants that might pose a risk to public health. Despite the clear results in the identification of the typical clinical picture of SARS-CoV-2 infection in felines, the number of detailed academic reports and papers on the subject is scarce. Therefore, further description of these cases will allow for more accurate and statistically robust clinical approaches in the future.

IGF-I Medium Supplementation Improves Singly Cultured Cat Oocyte Maturation and Embryo Development In Vitro

Embryo production is a routine procedure in several species. However, in felids, the effectiveness of this approach is far behind that in the majority of laboratory species. The development of a suitable environment starts with the proper composition of culture media. Therefore, for the improvement of assisted reproduction techniques and their outcome in cats, this is an urgent task. As the addition of insulin-like growth factors (IGF-I, IGF-II) or granulocyte-macrophage colony-stimulating factor (GM-CSF) was beneficial in other mammalian species, this study aims to check whether these components, combined with other factors (such as type of fertilisation or type of culture) can provide a benefit in the felid culture system in current use. Thus, these supplements, in different concentrations and combinations, were merged with the use of two fertilisation techniques and randomly assigned to single or group culturing. The results showed that the addition of IGF-I and/or GM-CSF produced an increase in morula and blastocyst rate in a single culture system. In particular, the supplementation with 20 ng/mL of IGF-I incremented the maturation rate by 10% and significantly increased the morula and blastocyst rates in single culturing. This result is especially remarkable for wild felids, where only a few oocytes and/or embryos are available.

Evaluation of Fecal Glucocorticoid Metabolite Levels in Response to a Change in Social and Handling Conditions in African Lions (Panthera leo bleyenberghi)

Simple Summary

Non-invasive determination of cortisol metabolite concentrations in feces is widely used to evaluate the influence of housing and handling conditions on the stress physiology of wildlife in captivity. The present study aimed to assess the physiological response of a lion pride to a change in management and social conditions after the death of the dominant male of the pride. Before the dominant male died, weekly management routines between the indoor and outdoor enclosures were conducted to avoid cohabitation problems between the two males of the pride. After the death of the dominant male, these weekly management dynamics ceased, leading to a decrease in the daily management routine of the lion pride. An individualized sampling of the animals through the utilization of indigestive markers was conducted, and fecal samples were collected before and after the death of the dominant male. Significant lower cortisol metabolite concentrations in feces were detected after the death of the dominant male, suggesting a positive impact of a decrease in daily management routines, together with a more stable social environment. In addition, assessment of individualized hormone concentrations throughout the study revealed variable physiological responses among lions, providing evidence of the importance of monitoring hormonal profiles individually.

Abstract

Monitoring the hypothalamic–pituitary–adrenal (HPA) axis through determination of fecal cortisol metabolite (FCM) levels is a non-invasive method useful for understanding how handling and social conditions may affect the physiological status of zoo animals. The present study used FCM analysis to evaluate whether the HPA axis activity of a lion pride was modified by a change in social and handling conditions after the death of the dominant male. Five African lions (Panthera leo bleyenberghi), two males and three females, were included in the study. Fecal samples were collected before and after the death of the dominant male. To avoid cohabitation conflicts between males before the dominant male died, subgroups were established and subjected to weekly changes between indoor and outdoor facilities. After the death of the dominant male, these management dynamics ceased, and the remaining four lions were kept together outdoors. Significant lower group FCM concentrations (p < 0.001) were detected after the decease of the dominant male, probably associated with a decrease in daily handling, together with a more stable social environment. Overall, the present study indicates the effect of different management scenarios on the HPA axis activity and differentiated physiological responses to the same situation between individuals.

Characteristics of Plant Eating in Domestic Cats

Simple Summary

Plant eating by domestic cats is of interest to veterinarians and cat owners. Two surveys of cat owners were launched testing important questions regarding whether plant eating: (1) is a response to the cat feeling ill; (2) induces vomiting; (3) is a means of expelling hair balls from consumed hair. Based on observations of wild felids, it was also considered that plant eating may reflect an innate predisposition acquired from the ancestral cat. This study found that very few cats showed signs of illness before eating plants. However, 27 to 37 percent of cats, respectively in the two surveys, frequently vomited after eating plants; this indicates that gastrointestinal disturbance may be related to vomiting in some cats. Young cats consumed plants more frequently than older cats and young cats also appeared ill and vomited less frequently than older cats in association with plant eating. Short-haired cats ate plants as frequently as long-haired cats, suggesting that plant eating is not for expelling hairballs. Some guidelines for cat owners with indoor cats are provided.

Abstract

Plant eating by domestic cats is of interest to veterinarians and cat owners, especially with the current trend to keep cats totally indoors. Feline grass gardens are commonly provided to such cats as a reflection of cat owners believing in the need or desire of cats for eating plants. Two surveys with 1000 to 2000 returns from cat owners were launched over 10 years to test different hypotheses regarding plant eating. These hypotheses are that plant eating: (1) is a response to the cat feeling ill; (2) induces vomiting; (3) is a means of expelling hair balls from consumed hair. Additionally, a perspective acquired from observations of wild felids is that plant eating reflects an innate predisposition acquired from the ancestral cat. In this study, very few cats showed signs of illness before eating plants. However, 27 to 37 percent of cats, respectively in the two surveys, frequently vomited after eating plants, indicating that gastrointestinal disturbance may be related to vomiting in some cats. Young cats consumed plants more frequently than older cats and appeared ill and vomited less frequently in association with plant eating. Short-haired cats ate plants as frequently as long-haired cats, arguing against the hairball expelling hypothesis. Some guidelines for cat owners with indoor cats are provided.

Dynamics and epidemiology of Toxoplasma gondii oocyst shedding in domestic and wild felids

Oocyst shedding in domestic and wild felids is a critical yet understudied topic in Toxoplasma gondii ecology and epidemiology that shapes human and animal disease burden. We synthesized published literature dating from the discovery of felids as the definitive hosts of T. gondii in the 1960s through March 2021 to examine shedding prevalence, oocyst genotypes, and risk factors for shedding. Oocyst shedding prevalence in many geographic regions exceeded the commonly accepted 1% reported for domestic cats; crude prevalence from cross-sectional field studies of domestic cat shedding ranged from 0% in Australia to 18.8% in Africa, with greater variation in reports of oocyst shedding in free-ranging, wild felids. Shedding in wild felid species has primarily been described in captive animals, with attempted detection of oocyst shedding reported in at least 31 species. Differences in lifestyle and diet play an important role in explaining shedding variation between free-ranging unowned domestic cats, owned domestic cats and wild felids. Additional risk factors for shedding include the route of infection, diet, age and immune status of the host. It is widely reported that cats only shed oocysts after initial infection with T. gondii, but experimental studies have shown that repeat oocyst shedding can occur. Factors associated with repeat shedding are common amongst free-ranging felids (domestic and wild), which are more likely to eat infected prey, be exposed to diverse T. gondii genotypes, and have coinfections with other parasites. Repeat shedding events could play a significant yet currently ignored role in shaping environmental oocyst loading with implications for human and animal exposure. Oocyst presence in the environment is closely linked to climate variables such as temperature and precipitation, so in quantifying risk of exposure, it is important to consider the burden of T. gondii oocysts that can accumulate over time in diverse environmental matrices and sites, as well as the spatial heterogeneity of free-ranging cat populations. Key directions for future research include investigating oocyst shedding in under-sampled regions, genotyping of oocysts detected in faeces and longitudinal studies of oocyst shedding in free-ranging felids.

Comparison of Different Materials for Self-Pressurized Vitrification of Feline Oocytes-First Results

Cryobanking is a crucial part on species conservation. Nowadays, there is no suitable protocol for vitrification of feline oocytes. Self-pressurized rapid freezing of different cell types proved to mimic the advantages of high pressure freezing. As this method could also be applied for gamete rescue under field conditions, the aim here was to analyse the impact of self-pressurized vitrification on feline cumulus-oocyte-complexes (COCs) and to determine the appropriate material. Therefore, COCs of domestic cat were randomly vitrified (n = 189) in metal tubes of different materials: Aluminium, silver, and titanium. No significant differences were found on oocytes' competence after thawing. On average, 44% of the COCs presented normal morphology and 48.2% of them showed a polar body after in vitro maturation (IVM) and were subsequently fertilised. Aluminium tubes were positive on toxicity tests, producing the lowest cleavage rates. Silver tubes showed no toxic effect, but the cleavage rate was lower than with titanium tubes, and a previous association with embryotoxicity and biological alterations makes us aware of its indiscriminate use. Titanium seems to be the only inert material of them, presenting a slightly higher maturation (55.6%) and cleavage (20%) rates. Nevertheless, more studies should follow to increase embryo competence after warming.

Cloprostenol, a synthetic analog of prostaglandin F2α induces functional regression in cultured luteal cells of felids†

In the present study, we investigated the effect of the synthetic analog of prostaglandin F2α (PGF2α)-cloprostenol-on cultured steroidogenic luteal cells of selected felid species over a 2-day culture period. The changes induced by cloprostenol were measured based on progesterone concentration and mRNA expression analysis of selected genes. Cloprostenol significantly reduced concentration of progesterone in cell culture medium of small luteal cells isolated from domestic cat corpora lutea (CL) at the development/maintenance stage (P < 0.05), but did not influence progesterone production in cultured cells from the regression stage. A decrease or complete silencing of progesterone production was also measured in cultured luteal cells of African lion (formation stage) and Javan leopard (development/maintenance stage). Gene-expression analysis by real-time PCR revealed that treatment with cloprostenol did not have an influence on expression of selected genes coding for enzymes of steroidogenesis (StAR, HSD3B, CYP11A1) or prostaglandin synthesis (PTGS2, PGES), nor did it effect hormone receptors (AR, ESR1, PGR, PTGER2), an anti-oxidative enzyme (SOD1) or factors of cell apoptosis (FAS, CASP3, TNFRSF1B, BCL2) over the studied period. Significant changes were measured only for expressions of luteinizing hormone (P < 0.05), prolactin (P < 0.05) and PGF2α receptors (P < 0.005) (LHCGR, PRLR, and PTGFR). The obtained results confirm that PGF2α/cloprostenol is a luteolytic agent in CL of felids and its impact on progesterone production depends on the developmental stage of the CL. Cloprostenol short-term treatment on luteal cells was associated only with functional but not structural changes related to luteal regression.

Analysis of Morphokinetic Parameters of Feline Embryos Using a Time-Lapse System

Simple Summary

This study was conducted with the aim of analyzing the morphokinetic parameters that determine the proper development of feline embryos in vitro. Our research was carried out using a time-lapse monitoring system shows that the timing of the first and second cleavage divisions, the timing of blastocyst cavity formation and morphological anomalies can all be used as early and non-invasive indicators of cat embryo development in vitro.

Abstract

The aim of this study was to analyze the morphokinetic parameters of feline embryos using a time lapse system. Oocytes matured in vitro were fertilized (IVF) and in vitro cultured in a time lapse-system (Primo Vision^®, Gothenburg, Sweden). The first cell division of embryos occurred between 17 h post insemination (hpi) and 38 hpi, with the highest proportion of embryos (46%) cleaving between 21 and 24 hpi. The timing of the first cleavage significantly affected further embryo development, with the highest development occurring in embryos that cleaved at 21–22 hpi. Embryos that cleaved very early (17–18 hpi) developed poorly to the blastocyst stage (2%) and none of the embryos that cleaved later than 27 hpi were able to reach the blastocyst stage. Morphological defects were observed in 48% of the embryos. There were no statistically significant differences between the timing intervals of the first cleavage division and the frequency of morphological defects in embryos. Multiple (MUL) morphological defects were detected in more than half (56%) of the abnormal embryos. The most frequent single morphological defects were cytoplasmic fragmentation (FR) (8%) and blastomere asymmetry (AS) (6%). Direct cleavage (DC) from 1–3 or 3–5 blastomeres, reverse cleavage (RC) and vacuoles were rarely observed (2–3%). The timing of blastocyst cavity formation is a very good indicator of embryo quality. In our study, blastocyst cavity formation occurred between 127–167 hpi, with the highest frequency of hatching observed in blastocysts that cavitated between 142–150 hpi. Blastocysts in which cavitation began after 161 h did not hatch. In conclusion, the timing of the first and second cleavage divisions, the timing of blastocyst cavity formation and morphological anomalies can all be used as early and non-invasive indicators of cat embryo development in vitro.

Not a cakewalk: Insights into movement of large carnivores in human-dominated landscapes in India

Large carnivores play an important role in the functioning of ecosystems, yet their conservation remains a massive challenge across the world. Owing to wide-ranging habits, they encounter various anthropogenic pressures, affecting their movement in different landscape. Therefore, studying how large carnivores adapt their movement to dynamic landscape conditions is vital for management and conservation policy. A total of 26 individuals across 4 species of large carnivores of different sex and age classes (14 Panthera tigris, 3 Panthera pardus, 5 Cuon alpinus, and 4 Canis lupus pallipes) were GPS collared and monitored from 2014-19. We quantified movement parameters (step length and net squared displacement) of four large carnivores in and outside protected areas in India. We tested the effects of human pressures such as human density, road network, and landuse types on the movement of the species. We also examined the configuration of core areas as a strategy to subsist in a human-dominated landscape using BBMM. Mean displacement of large carnivores varied from 99.35 m/hr for leopards to 637.7 m/hr for wolves. Tigers outside PAs exhibited higher displacement than tigers inside PAs. Moreover, displacement during day-night was significantly different for tigers inside and outside PAs. Similarly, wolf also showed significant difference between day-night movement. However, no difference in day-night movement was found for leopard and dholes. Anthropogenic factors such as road length and proportion of agriculture within the home range of tigers outside PAs were found to be significantly different. All the habitat variables in the home range showed significant difference between the social canids. The core area size for tiger outside PA and wolf was found greater than PAs. The study on movement of large carnivore species across landscapes is crucial for conservation planning. Our findings can be a starting point for interlinking animal movement and landscape management of large carnivore conservation in the current Anthropocene.

Luteinizing Hormone Effect on Luteal Cells Is Dependent on the Corpus Luteum Stage in Felids

Simple Summary

The corpus luteum is a transient endocrine gland on the mammalian ovary, and its main function is to produce progesterone. Knowledge about the corpus luteum in felids is very limited and luteolytic and luteotrophic factors which regulate its maintenance and regression are not extensively studied. Information about corpus luteum function is needed to understand breeding strategies and to successfully implement assisted reproductive techniques for felids, of which most of the species are threatened. The aim of this study was to reveal the effect of luteinizing hormone on cultured luteal cells from corpora lutea obtained from selected felids and to investigate the protein expression of steroidogenic enzyme 3β-hydroxysteroid dehydrogenase by immunohistology.

Abstract

The objective of this study was to investigate the effect of luteinizing hormone (LH) on steroidogenic luteal cells obtained from corpora lutea (CL) of the domestic cat and selected wild felids. Luteal cells were isolated enzymatically from CL at different developmental stages and cultured for two days in the presence and absence of 100 ng/mL LH, respectively. Functionality was assessed by progesterone (P4) accumulation in cell culture media determined by ELISA. In addition, steroidogenic function was confirmed using immunohistochemistry for 3β-hydroxysteroid dehydrogenase (HSD3B). The enzymatic method allowed for the isolation of mostly small luteal cells in all investigated felids. Treatment with LH resulted in an increase in P4 secretion of cultured luteal cells obtained from CL in the formation stage (African lion) and development/maintenance stage (domestic cat (p < 0.05), Javan leopard), whereas luteal cells from more advanced stages of luteal development (regression) responded moderately or not at all to LH stimulation (domestic cat, Asiatic golden cat, Asiatic lion). The protein signal for HSD3B on CL was visible until development/maintenance. In conclusion, this study shows that LH promotes P4 production in luteal cells only until the onset of regression, when morphological signs are visible on the CL of felids and HSD3B is no longer detectable.

Comparison of the Morphology and Developmental Potential of Oocytes Obtained from Prepubertal and Adult Domestic and Wild Cats

Simple Summary

This study was conducted with the aim of determining the morphological similarities and developmental potential of oocytes obtained from adult and prepubertal domestic cats (Felis catus) and wild cats. The results of our research showed that ovaries obtained from prepubertal felids may be a rich source of good quality oocytes that are competent for in vitro maturation and able to reach blastocyst stage after in vitro fertilization. The results are important in the context of the possibility of using oocytes from prepubertal felids threatened with extinction in conservation programs based on assisted reproductive techniques (ART).

Abstract

The aim of the study was to compare the morphology and developmental potential of oocytes obtained from adult and prepubertal domestic cats (Felis catus) and wild cats (Lynx lynx, Leptailurus serval, Felis manul, Panthera tigris altaica). The average number of oocytes obtained from an adult domestic cat was 23 ± 11, which was significantly lower than from kittens (43 ± 29). A similar number of oocytes was derived from adult Pallas’s cats (28 ± 8), and serval (30). The lowest number of oocytes was collected from the lynx (5 ± 3). No oocytes were obtained from newborn Amur tiger while in the case of older domestic and Pallas’s cat and lynx kittens (1–3 months) 43, 48 and 41 oocytes were collected, respectively. Significant differences (p < 0.001) were observed between the number of oocytes with dark cytoplasm from adult and prepubertal animals of all analyzed species. The diameter of oocytes from adult and prepubertal animals was similar in all species, and was on average 161 ± 4 µm for oocytes with dark cytoplasm and 150 ± 18 µm for oocytes with light cytoplasm. In all species, oocytes with light cytoplasm were significantly smaller (p < 0.05) than dark ones, and their population was more diverse. Results of in vitro maturation of the domestic and wild cat′s oocytes obtained from adult and prepubertal females were similar (47–52%). The cleavage rate after in vitro fertilization (IVF) was lower for prepubertal than adult domestic cats (42 vs. 51%; p < 0.05%). Moreover, we observed differences in the quantity (28 vs. 39%; p < 0.05) and quality of blastocysts and even greater problems with hatching blastocysts from prepubertal kittens (8 vs. 19%; p < 0.001). More blastomeres were detected in blastocysts of adult cats. They also demonstrated significantly higher number of inner cell mass (ICM) (p < 0.001) and higher number of trophoblast cells (TE) (p < 0.05).

Distribution of uterine histological changes in aged captive cheetahs (Acinonyx jubatus)

The histological effect on the felid uterus of sterilization, via ovariectomy or salpingectomy, is currently unknown. To investigate the association of ovariectomy or salpingectomy with uterine health, it is first necessary to establish if changes are distributed evenly throughout the uterus. Both laparoscopic ovariectomy and salpingectomy with concurrent sampling of the tip of the uterine horn are possible in the cheetah. Currently accepted practice for histopathological screening of the uterus utilizes four biopsy samples. It is not known whether this method accurately reflects the status of the entire uterus. In this study we histologically examined the uteri of six older cheetahs (one 7-year-old and five 10-10.5-year-old animals) via 21 tissue samples (three samples from seven different anatomical regions) per cheetah to determine overall uterine health. Although no defined lesions were detected, mild endometrial gland dilation, assumed to be of no functional consequence, was observed in multiple samples. The odds of observing this dilation was lowest in the uterine body and progressively increased in a cranial direction, being significantly higher at the tip of the uterine horns (OR = 11.5; 95% CI, 2.0-65.1; p = 0.006). This supported the reliability of sampling the tip of the uterine horn to screen for endometrial gland dilation.

Analysis of metabolic flux in felid spermatozoa using metabolomics and 13C-based fluxomics†

Spermatozoa from three feline species-the domestic cat (Felis catus), the cheetah (Acinonyx jubatus), and the clouded leopard (Neofelis nebulosa)-were analyzed using metabolomic profiling and 13C-based fluxomics to address questions raised regarding their energy metabolism. Metabolic profiles and utilization of 13C-labeled energy substrates were detected and quantified using gas chromatography-mass spectrometry (GC-MS). Spermatozoa were collected by electroejaculation and incubated in media supplemented with 1.0 mM [U13C]-glucose, [U13C]-fructose, or [U13C]-pyruvate. Evaluation of intracellular metabolites following GC-MS analysis revealed the uptake and utilization of labeled glucose and fructose in sperm, as indicated by the presence of heavy ions in glycolytic products lactate and pyruvate. Despite evidence of substrate utilization, neither glucose nor fructose had an effect on the sperm motility index of ejaculated spermatozoa from any of the three felid species, and limited entry of pyruvate derived from these hexose substrates into mitochondria and the tricarboxylic acid cycle was detected. However, pathway utilization was species-specific for the limited number of individuals (four to seven males per species) assessed in these studies. An inhibitor of fatty acid beta-oxidation (FAO), etomoxir, altered metabolic profiles of all three felid species but decreased motility only in the cheetah. While fluxomic analysis provided direct evidence that glucose and fructose undergo catabolic metabolism, other endogenous substrates such as endogenous lipids may provide energy to fuel motility.

Size Matters: Zoo Data Analysis Shows that the White Blood Cell Ratio Differs between Large and Small Felids

The total number of white blood cells (WBCs) is related the immune system. In mammals, it is affected by the body mass, but it is unclear how the numbers of different WBC types correlate with this parameter. We analyzed the effect of body mass on WBC number and ratio in felids, where species are similar in diet (warm-blood vertebrates) and reproductive strategy (promiscuity). Based on zoo veterinary data (ZIMS database) we analyzed the effect of body mass on WBC number and neutrophils/lymphocytes ratio in 26 species of felids. The number of WBCs correlated with the body masses of animals: large cats had more WBC, which may be due to greater risks of infection associated with larger body surface, lifespan and home range size. For the first time we found obvious differences in the number of WBC types. Large cats also had more neutrophils and monocytes but fewer lymphocytes than smaller cats. The ratio of neutrophils to lymphocytes is greater in large felids. This phenomenon may be related to diet (relative prey size and kill utilization time), which suggests regular contact of large cats with bacterial and protozoal pathogens in contrast to the small cats.

Anatomical description of the origin and distribution of the lumbosacral plexus in one puma (Puma concolor)

Wild felids often suffer spinal and limb disorders; however, their nervous system anatomy is poorly studied. Herein, the lumbosacral plexus (Plexus lumbosacralis) of an adult puma and the motor and sensitive innervation of the pelvic limb is described. We found anatomical similarities to other felids, but also some differences. Branches L4-S3 form the lumbosacral plexus (Plexus lumbosacralis) in the puma. The femoral nerve (N. femoris) arises from the union of L4-L5, while in other felids, it is formed by L5-L6. Unlike in the cat, the sartorius muscle receives branches from the saphenous (N. saphenous) and femoral nerves (N. femoris), and the lateral head of the gastrocnemius and superficial digital flexor muscles are innervated by a branch of the soleus muscle.

Assisted reproduction for felid species conservation-Sperm competences at risk

Cryobanking of gametes in combination with artificial insemination is an essential option to support conservation programmes for endangered and threatened species. About two-thirds of the felid species are classified as 'near threatened', 'vulnerable' or 'endangered' (www.cites.org), and mostly, epididymal sperm are collected from euthanized or castrated male felids and cryopreserved. However, epididymal compared with ejaculated and cryopreserved compared with fresh sperm have a limited potential to fertilize if vaginal non-surgical insemination is applied in feline species. Missing or highly diluted seminal fluid in epididymal and cryopreserved sperm, as well as a potential interference of extender ingredients with the natural interactive properties of sperm in the female genital tract is discussed as potential drawback which hampers a proper sperm transit and fertilization besides the limited longevity of cryopreserved feline sperm. Individual components in seminal fluid as well as cryoextenders may adversely alter sperm properties and have a different impact on fertility and preservation success. The identification and investigation of beneficial as well as detrimental components is a precondition to deduce options for improving the process of cryopreservation in felids, particularly, if only epididymal sperm are available.

Function of Cryopreserved Cat Ovarian Tissue after Autotransplantation

Simple Summary

Assisted reproduction techniques are potentially important tools for the creation of gene banks largely focused on preserving female germ cells and tissues, cryopreservation being one of the most important. Since there is not yet a protocol established for the preservation of cat ovarian tissue, we decided to assess our cryopreservation protocol with autotransplantation of the ovary. Our study showed that even though follicular survival was low, follicles were able to survive up to 28 days of transplantation and develop up to the antral stage, which helps elucidate the path for preservation of felid ovaries. Once this technique is improved, it may contribute to the preservation of wild feline species.

Abstract

The aim of this study was to assess a slow-freezing protocol of cat ovarian tissue cryopreservation using autotransplantation. Four adult queens were ovariohysterectomized and the ovaries were fragmented and cryopreserved. After one week, the grafts were thawed and autografted to the subcutaneous tissue of the dorsal neck of each queen, then randomly removed after 7, 14, 28, 49, and 63 days after transplantation. Percentages of morphologically normal primordial and growing follicles (MNFs) were 88% and 97%, respectively, in fresh tissue samples (fresh controls), and 74% and 100%, respectively, immediately after thawing (cryo D0). No MNFs were found after 49 days of transplantation. In both fresh control and cryo D0 fragments, granulosa cells were frequently in proliferation. Two morphologically normal antral follicles were detected in one queen on Day 28 post-transplantation. Connective tissue fibers increased, suggesting replacement of active ovarian cortex by fibrous tissue. Tissue vascularization was observed at 7 days after grafting, and wide blood vessels were clearly visible on Days 49 and 63. In conclusion, although follicular survival was low after cryopreservation and grafting of cat ovarian tissue, follicles were able to develop up to the antral stage, which is an encouraging outcome.

Type X strains of Toxoplasma gondii are virulent for southern sea otters (Enhydra lutris nereis) and present in felids from nearby watersheds

Why some Toxoplasma gondii-infected southern sea otters (Enhydra lutris nereis) develop fatal toxoplasmosis while others have incidental or mild chronic infections has long puzzled the scientific community. We assessed robust datasets on T. gondii molecular characterization in relation to detailed necropsy and histopathology results to evaluate whether parasite genotype influences pathological outcomes in sea otters that stranded along the central California coast. Genotypes isolated from sea otters were also compared with T. gondii strains circulating in felids from nearby coastal regions to assess land-to-sea parasite transmission. The predominant T. gondii genotypes isolated from 135 necropsied sea otters were atypical Type X and Type X variants (79%), with the remainder (21%) belonging to Type II or Type II/X recombinants. All sea otters that died due to T. gondii as a primary cause of death were infected with Type X or X-variant T. gondii strains. The same atypical T. gondii strains were detected in sea otters with fatal toxoplasmosis and terrestrial felids from watersheds bordering the sea otter range. Our results confirm a land–sea connection for virulent T. gondii genotypes and highlight how faecal contamination can deliver lethal pathogens to coastal waters, leading to detrimental impacts on marine wildlife.

Copper isotopes as possible neoplasia biomarkers in captive wild felids

The longevity of zoo animals is increasing due to continuous improvement in husbandry and veterinary medicine. However, increasing age is correlated to a higher prevalence of neoplasia. Despite tremendous improvement in diagnoses and monitoring capacities, cancers are still a challenge for veterinarians within the global zoo community. The recent use of copper isotopes as biomarkers for neoplasia in both human and veterinary medicine is a promising and cost-effective diagnostic tool. Two hundred and twenty-nine serum samples from 10 different species of wild felids under human care were processed through mass spectrometry to determine the ratio of heavy and light copper isotopes (⁶⁵ Cu/⁶³ Cu). The results of this preliminary study exhibit an important variability between felid species, with a ratio ranging between -1.71 and 0.63. Additionally, copper isotopes seem to be a promising diagnostic tool in monitoring cancer in wild animals, as in human medicine, where the isotopic ratio decreases significantly with time in the presence of a tumor.

Evaluation of management in North American zoos to enhance breeding success of the fishing cat (Prionailurus viverrinus) ex situ population

The ex situ population of fishing cats (Prionailurus viverrinus) face many challenges to its sustainability such as mate incompatibility, low founder numbers and disease prevalence. The North American population was monitored for a three-year period during institutional transfers and breeding introductions. In total, 26 fishing cats, including 15 different breeding pairs were monitored during 20 transfers. Most institutional transfers occurred in the fall months (September, October and November; 62%; n = 13) and males were transferred more often (62%; n = 13). Breeding success (observed copulations) was recorded in 33% (n = 5) of pairs but only 13% (n = 2 pairs) produced offspring during the study period. Institutions with successful breeding pairs had a greater number of indoor, off-exhibit enclosures (2.67 ± 0.29 enclosures; n = 5) compared to facilities with unsuccessful pairs (1.69 ± 0.25 exhibits; n = 6; p = 0.035). In addition, facilities housing successful pairs performed positive reinforcement training more frequently (14.77 ± 3.27 training days/month) than facilities with unsuccessful pairs (4.00 ± 2.73 days/month; p = 0.035). A binomial generalized linear model showed that friendly vocalizations (p = 0.000) during physical introductions of intended breeding pairs predicted copulation success. Introductions performed when a female was exhibiting estrous behavior (p = 0.020), was also predictive of copulation success. Results from this study are the first comprehensive analyses of captive management in the fishing cat. Environmental factors and management approaches are highlighted that could advance animal welfare and improve reproductive success in this species.

Forest structure provides the income for reproductive success in a southern population of Canada lynx

Understanding intrinsic and extrinsic drivers of reproductive success is central to advancing animal ecology and characterizing critical habitat. Unfortunately, much of the work examining drivers of reproductive success is biased toward particular groups of organisms (e.g., colonial birds, large herbivores, capital breeders). Long-lived mammalian carnivores that are of conservation concern, solitary, and territorial present an excellent situation to examine intrinsic and extrinsic drivers of reproductive success, yet they have received little attention. Here, we used a Canada lynx (Lynx canadensis) data set, from the southern periphery of their range, to determine if reproductive success in a solitary carnivore was consistent with capital or income breeding. We radio-marked and monitored 36 female Canada lynx for 98 lynx years. We evaluated how maternal characteristics and indices of food supply (via forest structure) in core areas influenced variation in body condition and reproductive success. We characterized body condition as mass/length and reproductive success as whether a female produced a litter of kittens for a given breeding season. Consistent with life-history theory, we documented a positive effect of maternal age on body condition and reproductive success. In contrast to predictions of capital breeding, we observed no effect of pre-pregnancy body condition on reproductive success in Canada lynx. However, we demonstrated statistical effects of forest structure on reproductive success in Canada lynx, consistent with predictions of income breeding. The forest characteristics that defined high success included (1) abundant and connected mature forest and (2) intermediate amounts of small-diameter regenerating forest. These attributes are consistent with providing abundant, temporally stable, and accessible prey resources (i.e., snowshoe hares; Lepus americanus) for lynx and reinforce the bottom-up mechanisms influencing Canada lynx populations. Collectively, our results suggest that lynx on the southern range periphery exhibit an income breeding strategy and that forest structure supplies the income important for successful reproduction. More broadly, our insights advance the understanding of carnivore ecology and serve as an important example on integrating long-term field studies with ecological theory to improve landscape management.

A naturally occurring feline APOBEC3 variant that loses anti-lentiviral activity by lacking two amino acid residues

Apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3 (APOBEC3) is a mammalian protein that restricts lentiviral replication. Various polymorphisms of mammalian APOBEC3 genes have been observed in humans, Old World monkeys and domestic cats; however, the genetic diversity of APOBEC3 genes in other mammals remains unaddressed. Here we identify a novel haplotype of the feline APOBEC3Z3 gene, an APOBEC3 gene that restricts feline immunodeficiency virus (FIV) replication, in a Eurasian lynx (Lynx lynx). Compared to the previously identified lynx APOBEC3Z3 (haplotype I), the new sequence (haplotype II) harbours two amino acid deletions (Q16 and H17) and a nonsynonymous substitution (R68Q). Interestingly, lynx APOBEC3Z3 haplotype II does not suppress FIV infectivity, whereas haplotype I does. Mutagenesis experiments further revealed that deleting two amino acids (Q16 and H17) causes anti-FIV activity loss. This report demonstrates that a naturally occurring APOBEC3 variant loses anti-lentiviral activity through the deletion of two amino acid residues.

The effects of intrinsic enrichment on captive felids

Environmental enrichment is a well-known technique, which has been used to enhance the welfare of captive animals. The aim of this study is to investigate how three different forms of intrinsic enrichment, namely, a hay ball without scent, a hay ball with catnip, and a hay ball with cinnamon, influenced the behavior of six cheetah and two Sumatran tigers at Fota Wildlife Park, Ireland. Enrichment-directed behaviors, as well as pacing, locomotion, inactive, and exploratory behaviors were investigated. The results indicated that the three forms of enrichment had similar effects, in terms of enrichment-directed behavior, with cinnamon resulting in the highest levels of enrichment-directed behaviors. The cinnamon treatment resulted in a significant decrease in pacing behavior when compared with baseline observations. No evidence of habituation (i.e., a significant reduction in enrichment-directed behaviors) was observed for any of the three enrichments. This means that these low cost, easy to apply, practical forms of enrichment could be frequently applied for these species as part of an enrichment regime.

Spontaneous proliferative and neoplastic lesions in thyroid and parathyroid glands of nondomestic felids

Based on microscopic and immunohistochemical characterization, we documented spontaneous proliferative and neoplastic lesions in the thyroid and parathyroid glands of nondomestic felids. Ten animals (4 leopards, 3 tigers, and 3 cougars), all with a previous diagnosis of thyroid neoplasia were identified from the University of Tennessee College of Veterinary Medicine database. The mean age of affected animals was 15.9 y. Twelve neoplasms were identified; 2 animals had 2 concurrent neoplasms. After immunohistochemical characterization using a panel of chromogranin A, thyroglobulin, and calcitonin, 7 of the former thyroid neoplasms were diagnosed as thyroid adenomas, 1 was diagnosed as a thyroid carcinoma, and 4 were diagnosed as parathyroid adenomas. No thyroid medullary neoplasms (C-cell tumors) were diagnosed in the current study. Most of the diagnosed neoplasms were benign (11 of 12), and metastasis was not documented in the single carcinoma. Only 2 animals were suspected to have functional neoplasms (1 thyroid adenoma and 1 parathyroid adenoma), based on associated tissue lesions or serum biochemistry. Other documented lesions in the thyroid and parathyroid glands included thyroid nodular hyperplasia ( n = 7), parathyroid hyperplasia associated with chronic renal disease ( n = 2), a thyroid abscess, and a branchial cyst. Parathyroid adenomas were more commonly diagnosed than expected in comparison with domestic cats. We demonstrated that an immunohistochemistry panel for thyroglobulin, calcitonin, and chromogranin A can be used to differentiate neoplasms of thyroid from parathyroid origin in nondomestic felids.

Comparison of Subjective Well-Being and Personality Assessments in the Clouded Leopard (Neofelis nebulosa), Snow Leopard (Panthera uncia), and African Lion (Panthera leo)

The study of subjective well-being in nonhuman animals is growing in the field of psychology, but there are still only a few published studies and the focus is on primates. To consider whether the construct of subjective well-being could be found in another mammal, this study aimed to assess subjective well-being in felids and to examine its association with personality. Personality is one of the strongest and most consistent predictors of well-being in humans. This relationship could have important implications for other species, because personality has also been shown to affect health outcomes including stress, morbidity, and mortality. As in previous studies in nonhuman animals, the study results revealed that subjective well-being was related to agreeableness/openness and neuroticism in clouded leopards, neuroticism in snow leopards, and impulsiveness and neuroticism in African lions. The implications of these results for health outcomes and the welfare of animals in captivity are discussed. More research on any direct links among personality, subjective well-being, and these outcomes is important to advancing this field and adding another tool for improving captive animals' lives.

Using detection dogs and genetic analyses of scat to expand knowledge and assist felid conservation in Misiones, Argentina

Many carnivores require large ranges to meet their ecological and energetic needs; however, anthropogenic changes threaten species and their habitats. Camera traps have been used to effectively collect data on carnivores in a variety of habitat types; however, a single survey effort is typically limited to species that have similar body size, habitat use and movement patterns, and individual identification of animals is not always possible. We evaluated whether scat detection dogs could effectively survey for 4 wide-ranging felids that vary in these characteristics: jaguars (Panthera onca), pumas (Puma concolor), ocelots (Leopardus pardalis) and oncillas (Leopardus tigrinus). From June to October 2009 and May to August 2011, a detection dog-handler team detected 588 scats, from which 176 unique genotypes were detected. We assigned sex to 84.7% of the genotyped scats and identified 55 individuals multiple times. The effectiveness of these noninvasive techniques (detection dogs and genetic analyses of scat) not only opens the door for additional studies in areas that were previously difficult or impossible with standard survey techniques, but also provides conservationists with a set of tools that overcome some of the limitations associated with the use of camera traps alone.

A comparative study of trabecular bone mass distribution in cursorial and non-cursorial limb joints

Skeletal design among cursorial animals is a compromise between a stable body that can withstand locomotor stress and a light design that is energetically inexpensive to grow, maintain, and move. Cursors have been hypothesized to reduce distal musculoskeletal mass to maintain a balance between safety and energetic cost due to an exponential increase in energetic demand observed during the oscillation of the distal limb. Additionally, experimental research shows that the cortical bone in distal limbs experiences higher strains and remodeling rates, apparently maintaining lower mass at the expense of a smaller safety factor. This study tests the hypothesis that the trabecular bone mass in the distal limb epiphyses of cursors is relatively lower than that in the proximal limb epiphyses to minimize the energetic cost of moving the limb. This study utilized peripheral quantitative computed tomography scanning to measure the trabecular mass in the lower and upper limb epiphyses of hominids, cercopithecines, and felids that are considered cursorial and non-cursorial. One-way ANOVA with Tukey post hoc corrections was used to test for significant differences in trabecular mass across limb epiphyses. The results indicate that overall, both cursors and non-cursors exhibit varied trabecular mass in limb epiphyses and, in certain instances, conform to a proximal-distal decrease in mass irrespective of cursoriality. Specifically, hominid and cercopithecine hind limb epiphyses exhibit a proximal-distal decrease in mass irrespective of cursorial adaptations. These results suggest that cursorial mammals employ other energy saving mechanisms to minimize energy costs during running.

Behavioral and physiological responses in felids to exhibit construction

Despite the growing body of literature examining the welfare of zoo-housed animals, little standardized work has been published on the effect of construction and environmental disruption on the physiology and behavior of affected animals. When Lincoln Park Zoo (Chicago, IL), embarked on a renovation project for its Kovler Lion House, the opportunity was taken to perform a scientific study of behavioral and physiological markers in the resident felids to determine the effect of construction and environmental disruption. Fecal samples and behavioral observations were collected on four felid species (five individuals) before, during, and after the period of construction. As a group, the average z-score for fecal glucocorticoid metabolite concentration increased during construction relative to baseline. Levels remained elevated after construction, but trended toward baseline. All individuals demonstrated a significant decrease in the frequency of pacing and time spent visible during construction. Overall activity levels also showed a significant decrease relative to baseline measures. As zoological institutions continue to recognize the importance of habitat design, construction and renovation become inevitable. It is important to be aware of the potential consequences this can have on animals in the vicinity and to work toward minimizing negative effects. One recommendation is the availability of ample retreat and hiding space for felids during disruption to their environment.

Recent host range expansion of canine distemper virus and variation in its receptor, the signaling lymphocyte activation molecule, in carnivores

The signaling lymphocyte activation molecule (SLAM) is a receptor for morbilliviruses. To understand the recent host range expansion of canine distemper virus (CDV) in carnivores, we determined the nucleotide sequences of SLAMs of various carnivores and generated three-dimensional homology SLAM models. Thirty-four amino acid residues were found for the candidates binding to CDV on the interface of the carnivore SLAMs. SLAM of the domestic dog (Canis lupus familiaris) were similar to those of other members of the suborder Caniformia, indicating that the animals in this group have similar sensitivity to dog CDV. However, they were different at nine positions from those of felids. Among the nine residues, four of domestic cat (Felis catus) SLAM (72, 76, 82, and 129) and three of lion (Panthera leo persica) SLAM (72, 82, and 129) were associated with charge alterations, suggesting that the felid interfaces have lower affinities to dog CDV. Only the residue at 76 was different between domestic cat and lion SLAM interfaces. The domestic cat SLAM had threonine at 76, whereas the lion SLAM had arginine, a positively charged residue like that of the dog SLAM. The cat SLAM with threonine is likely to have lower affinity to CDV-H and to confer higher resistance against dog CDV. Thus, the four residues (72, 76, 82, and 129) on carnivore SLAMs are important for the determination of affinity and sensitivity with CDV. Additionally, the CDV-H protein of felid strains had a substitution of histidine for tyrosine at 549 of dog CDV-H and may have higher affinity to lion SLAM. Three-dimensional model construction is a new risk assessment method of morbillivirus infectivity. Because the method is applicable to animals that have no information about virus infection, it is especially useful for morbillivirus risk assessment and wildlife conservation.

Values, animal symbolism, and human-animal relationships associated to two threatened felids in Mapuche and Chilean local narratives

BACKGROUND

The Chilean temperate rainforest has been subjected to dramatic fragmentation for agriculture and forestry exploitation. Carnivore species are particularly affected by fragmentation and the resulting resource use conflicts with humans. This study aimed at understanding values and human-animal relationships with negatively perceived threatened carnivores through the disclosure of local stories and Mapuche traditional folktales.

METHODS

Our mixed approach comprised the qualitative analysis of 112 stories on the kodkod cat (Leopardus guigna) and the puma (Puma concolor) collected by students (9-14 years) from 28 schools in the Araucania region within their family contexts, 10 qualitative in-depth interviews with indigenous Mapuche people, 35 traditional Mapuche legends, and the significance of naming found in ethnographic collections.

RESULTS

We revealed a quasi-extinction of traditional tales in the current knowledge pool about pumas and kodkods, local anecdotes, however, were present in significant numbers. Values associated to both felids were manifold, ranging from negativistic to positive values. While pumas played an important role in people's spirituality, negative mythological connotations persisted in kodkod stories. Four prominent relationships were derived: (1) Both felids represent threats to livestock, pumas even to life, (2) both felids are symbols for upcoming negative events, (3) pumas are spiritual creatures, and (4) kodkods are threatened by humans. Recommendations are provided for stimulating new ways of perceiving unpopular and threatened carnivores among those who live in vicinity to them.