ABSTRACT Dietary fiber is a central driver of gut function in camelids, yet empirical data on how specific fiber sources shape hind‐gut ecology remain scarce. This longitudinal pilot study assessed the impact of two sequential high‐fiber dietary transitions on fecal consistency and microbiota in five captive dromedary camels ( Camelus dromedarius ). Over 63 days, straw was offered ad libitum alongside hay; this was followed by a 25‐day phased replacement of a lower‐fiber concentrate with a high‐fiber pellet. Daily fecal scores were recorded, and 98 samples (74 fecal and 24 environmental swab samples) were analyzed using 16S rRNA amplicon sequencing, with PICRUSt2 used to predict functional profiles from fecal microbiota data. Straw supplementation did not noticeably change group‐level fecal consistency, although individual responses were pronounced, with some camels showing increases of up to +2.5 score units. In contrast, high‐fiber pellets softened feces at the group level, with a median increase in score of +1.2 and the largest effects observed in two animals. Fecal scores were positively correlated with ambient temperature (Pearson's r up to 0.67). Alpha diversity remained stable or rose slightly during the straw phase but declined transiently during pellet transition, returning to baseline by Day 25. Core hind‐gut families (Oscillospiraceae, Rikenellaceae, and Christensenellaceae) persisted throughout; pellet feeding prompted short‐lived blooms of Monoglobaceae and Methanocorpusculaceae. Despite taxonomic shifts, functional profiles were dominated by amino‐acid, nucleotide, and vitamin biosynthesis, with only modest, reversible increases in polysaccharide‐degradation pathways during pellet feeding. Follow‐up sampling approximately one year later revealed a relatively stable microbial community during the control period. Collectively, these findings suggest that incremental fiber enrichment may elicit distinct, animal‐specific gastrointestinal and microbial adjustments in dromedaries, but metabolic functions remain apparently resilient. These findings suggest individualized dietary management when deploying fiber‐based strategies to mitigate diarrhea in captive camelids.
ABSTRACT Diet is a crucial factor in modulating the gut microbiome, and understanding these interactions in captive primates is essential for their health and welfare. This study assessed the impact of the transition to a high‐fiber, low‐sugar diet on the gut microbiome, behavior, and physical health of five captive Bornean orangutans ( Pongo pygmaeus ). We hypothesized that altering dietary patterns would significantly influence gut microbiome diversity and composition, as well as behavioral and physiological indicators. Over 12 weeks, the orangutans were gradually transitioned from a fruit‐rich diet to a high‐fiber, fruitless diet, with progressive dietary changes implemented every 2 weeks. Fecal samples were collected throughout the study, and the microbial diversity and composition were analyzed using 16S rRNA amplicon sequencing. Statistical analyses using linear mixed‐effects models evaluated changes in microbial diversity and composition over time. In parallel, fecal consistency, behavior, and body condition scores were monitored regularly. The results showed significant changes in microbial richness and diversity associated with the dietary transition, with specific taxa, such as the genus Prevotella and the family Ruminococcaceae, increasing in abundance. The microbiome shifts were accompanied by changes in body condition and fecal scores, as well as reduced stress‐related behaviors ( p < 0.05), increased feeding duration ( p < 0.001), and increased social behaviors, including intraspecific interactions ( p < 0.05). This study provides preliminary evidence that a high‐fiber, low‐sugar dietary approach may influence gut microbiome composition and selected behavioral indicators in zoo‐housed orangutans.
ABSTRACT Animal personality impacts how animals experience and perceive their surroundings. Understanding how to reliably assess and incorporate animal personality is important for species management. This study aimed to investigate three personality assessment methods in zoo‐housed white rhinoceros (response to a novel object, response to a novel sound, and trait ratings by knowledgeable informants), compare the personality profiles generated by these methods and then investigate their relationship to activity budgets to determine instrument validity. This study was undertaken on 12 unrelated Southern white rhinoceros ( Ceratotherium simum simum ) (6 male, 6 female) from 4 collections in the United Kingdom (2 zoos and 2 safari parks). Activity budgets were calculated from a total 80 h of behavioral observations (mean ± SD 20 h ± 1 h per collection). Nine of the 12 rhinos interacted with the novel object, whilst only 4 rhinos exhibited a behavioral response (e.g., startle) to the familiar and 5 to the unfamiliar playbacks, respectively. Fourteen keepers across all collections reliably rated 9 of 21 personality adjectives. There were a number of significant correlations between trait ratings and rhino behavior ( p < 0.05), although the correlations did not always make clear biological sense. There were no significant correlations between response to novel objects or novel sounds and rhino behavior ( p > 0.05). These results suggest the personality tools are capturing different aspects of rhino personality and thus cannot be used interchangeably. Understanding the relationship between rhino personality as assessed using each instrument and observed behavior is important in reliably and efficiently assessing behavior profiles for routine integration into rhino management.
ABSTRACT Captive honey badgers ( Mellivora capensis ) are routinely exposed to environmental and husbandry‐related stressors that differ markedly from their natural conditions; however, physiological welfare assessments in this species remain limited. This study aimed to validate a non‐invasive approach to evaluate stress‐related fecal glucocorticoid metabolite (fGCM) concentrations and individual responses to visitors and other environmental stressors in two zoo‐housed individuals. Five enzyme immunoassays (EIAs) were assessed for suitability using routine veterinary examinations as a presumed biological stressor. The 5α‐pregnane‐3β,11β,21‐triol‐20‐one EIA proved most suitable, detecting increases in fGCM concentrations of 251% and 127% in the male and female, respectively. This EIA also demonstrated immunoreactive fGCM stability for up to 16 days post‐defecation under ambient conditions, supporting application to field surveys where immediate sample collection is not always feasible. While visitor numbers showed no correlation with changes in fGCM concentrations, both individuals displayed persistent stereotypic behaviors, suggesting that they had habituated to human presence but remained responsive to other environmental disturbances. Longitudinal profiles revealed substantial individual variation in fGCM responses, with baseline concentrations being higher in the male. Elevations in fGCM concentrations (up to 945%) were associated with construction noise, neighboring animal introductions, and high visitor presence during special events. This validated method provides a reliable tool for monitoring stress physiology in captive honey badgers, with an application for evidence‐based improvements in zoo husbandry and future application in free‐ranging individuals.
ABSTRACT Blue catfish ( Ictalurus furcatus ) remain a prevalent invasive species in the Chesapeake Bay, with juveniles a common bycatch during commercial fishing operations. Rather than returning them to the water as is the current practice, these smaller‐bodied fish can be harvested for niche markets, including as forage fish consumed by piscivorous species in zoos and aquariums. Baseline compositional data are useful for balanced diet formulation, determination of necessary supplementation regimens, and contributions to animal health. The nutritional value of whole juvenile blue catfish ( ~ 100 mm–300 mm total length) was determined in 9 samples collected during June from 3 separate locations in three different tributary rivers. Composition of fish varied among rivers [water content (ranging from 71% to 78%, as‐fed basis), protein (50%–69%), crude fat (16%–36%), and ash (12%–20%, all dry matter basis]. Ranges approximated that of fish species commonly used in managed feeding programs, as did amino acid balance. While polyunsaturated fatty acids comprised only 22%–27% of total fatty acids measured, total omega‐3 to omega‐6 fatty acid ratios averaged ~1:1. Both macro‐ and trace mineral levels were within expected ranges for whole prey, with no indication of elevated heavy metal contaminants. Fish contained fat‐soluble vitamin D and E levels averaging 4722 and 26 IU/kg dry matter, respectively, and unexpected levels of particular water‐soluble vitamins such as biotin (193 mg/kg) and folic acid (648 mg/kg). Locally sourced juvenile blue catfish from Chesapeake Bay may be an alternative diet ingredient for piscivores and other carnivores, while removal simultaneously benefits local aquatic ecosystems and native species habitats.
