Isolation of Clostridium Perfringens type C from a Neonatal Yangtze Finless Porpoise (Neophocaena Asiaeorientalis Asiaeorientalis)

The aim of this study was to culture pathogenic bacteria from the blowhole, lung, stomach and fecal samples of a neonatal crucially endangered Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis) that died 27 days after birth. Bacteria were inoculated and representative isolates were identified through 16S rRNA gene sequence analysis. A total of three Clostridium perfringens type C strains from the fecal samples were isolated. Toxin genes, including cpa, cpb and cpb2, were detected by PCR amplification, while the etx, iap and cpe genes were absent. Biofilm formation of the three strains was examined. Only one strain was able to form a biofilm. In addition, isolates showed strong resistance against the antibiotics amikacin (3/3), erythromycin (1/3), gentamicin (3/3), streptomycin (3/3), and trimethoprim (3/3), while sensitivity to ampicillin (3/3), bacitracin (3/3), erythromycin (2/3), penicillin G (3/3), and tetracycline (3/3). The results suggested C. perfringens type C could have contributed to the death of this neonatal porpoise.

Social, Reproductive and Contextual Influences on Fecal Glucocorticoid Metabolites in Captive Yangtze Finless Porpoises (Neophocaena asiaeorientalis asiaeorientalis) and Bottlenose Dolphins (Tursiops truncatus)

Although the use of fecal glucocorticoid metabolite (FGCM) measurements as non-invasive biomarkers for the stress response in mammals has increased, few studies have been conducted in odontocetes. We investigated if animal sex, age, pregnancy or contextual variations (season, sampling time, enrichment, social separation and presence of visitors) influenced the FGCM concentrations in presumably healthy, captive and endangered Yangtze finless porpoises (YFPs, N = 4) and bottlenose dolphins (BDs, N = 3). For YFPs, the FGCM concentrations were influenced by season (p = 0.01), diurnal variation (p = 0.01) and pregnancy (p = 0.005). Contextual variables that were associated with increases in FGCM concentrations included social separations (p = 0.003) and numbers of visitors (p = 0.0002). Concentrations of FGCMs were lower (p = 0.001) after exposure to environmental enrichment. For BDs, enrichment was associated with reduced concentrations of FGCMs (p < 0.0001). The presence of visitors also influenced this species’ FGCM concentrations (p = 0.006). These results demonstrate that changes in the FGCM concentrations in YFPs and BDs may occur in response to contextual and social changes. In combination with other behavioral and physiological assessments, measurements of FGCMs may be a useful tool for monitoring cetacean welfare. Such monitoring may help researchers identify and better understand situations that may be stressful for animals and, therefore, improve management and husbandry. Furthermore, results from our study and inferences of the FGCM concentrations in cetaceans, and their potential relationship to stress, may be extrapolated to studies of free-ranging animals, which may help detect possible environmental or anthropogenic stressors that could be affecting these populations.

Body Contacts and Social Interactions in Captive Odontocetes Are Influenced by the Context: An Implication for Welfare Assessment

Research on the welfare of captive odontocetes has increased in recent years, but has been mostly focused on bottlenose dolphins (Tursiops truncatus). Few studies investigated potential welfare indicators using quantitative data linked to a range of conditions or stimuli that are thought to impact the animals’ emotional state. Since odontocetes are social animals that engage in various social interactions, these interactions might inform us on their welfare state. We investigated pectoral contact laterality and the effect of the context on several social behaviors in three groups of captive odontocetes (Yangtze finless porpoises, YFPs: Neophocaena asiaeorientalis asiaeorientalis; East-Asian finless porpoises, EAFPs: N. a. sunameri, and bottlenose dolphins, BDs). Animals exhibited patterns depending on the time of the day for most of the social behaviors we analyzed; social separation was associated with lower rates of social behaviors for the two analyzed groups (YFPs and BDs), the accessibility to several pools was associated with higher rates of social behaviors for BDs. The effect of enrichment, disturbances and public presence was less clear and strongly depended on the group, the type of enrichment and disturbance. Our results confirm that captive odontocetes’ social behaviors are influenced by the context, and that, depending on the group, some of them, such as pectoral contacts, other body contacts, agonistic interactions or social play exhibit consistent patterns across contexts. Monitoring these behaviors might be useful to adapt the captive management to each species and group. The different responses among the three studied groups confirm that species and groups react differently to a stimulus and therefore, management decisions should be species/group specific. We recommend that more studies should be conducted to validate our findings in other groups of odontocetes under human care.