Advances in Reproductive Science for Wild Carnivore Conservation

Knowledge about reproduction is critical for predicting the viability of wildlife populations in nature and for managing breeding programmes in captivity. Intensive species-based studies are the priority, because reproductive mechanisms are extraordinarily diverse, even within the same taxonomic family. Carnivores deserve more attention as such species are highly vulnerable to environmental change and human persecution. The present review provides contemporary illustrations of how reproductive science is contributing to understand unique reproductive mechanisms that are both of fundamental and applied interest. In the case of the endangered African wild dog ( Lycaon pictus ) free-living in South Africa, non-invasive faecal corticosteroid assessments have yielded new insights about the impact of animal relocation and reintroduction on adaptive responses, reproductive fitness and survival. For the maned wolf ( Chrysocyon brachyurus ), advances have been made in characterizing and comparing reproductive traits in free-ranging vs captive individuals. For the cheetah ( Acinonyx jubatus ), recent studies have focused on the cryosensitivity of sperm and the ability to develop a field-friendly sperm cryo-method. The by-product has been a large-scale frozen repository of sperm from wild-caught cheetahs useful for infusing new genes into ex situ populations. Finally, rigorous, multi-disciplinary and cross-institutional reproductive studies of the black-footed ferret ( Mustela nigripes ), including the use of artificial insemination, have contributed to the remarkable recovery and restoration of this species, once on the brink of extinction. In summary, advances in reproductive science are not necessarily related to 'assisted breeding'. However, understanding the unique ways of carnivore reproduction greatly contributes to species management and conservation.     

Confirmation that PCR can be used to identify NAD-dependent and NAD-independent Haemophilus paragallinarum isolates.

Seventy five bacteria tentatively identified as Haemophilus paragallinarum (the causative agent of infectious coryza), eight identified as Ornithobacterium rhinotracheale and 13 identified as NAD-independent Pasteurella species were isolated from chickens with respiratory infection in various provinces in South Africa. The isolates were characterized by conventional biochemical and serological methods. A polymerase chain reaction (PCR) assay specific for H. paragallinarum was used to identify the cultures directly from colonies. The PCR assay gave positive results for all isolates that were identified by conventional methods as H. paragallinarum, irrespective of whether they were nicotinamide adenine dinucleotide (NAD)-dependent (43 isolates) or NAD-independent (32 isolates). The eight isolates that were identified by conventional methods as O. rhinotracheale and the 13 isolates identified as various Pasteurella species gave negative results in the PCR assay. This study has demonstrated that colony PCR is a rapid method for uniquely identifying both NAD-dependent and NAD-independent strains of H. paragallinarum and distinguishing them from other bacteria, such as O. rhinotracheale and Pasteurella species.     

New perspective to control of tenacibaculosis in sea bass Dicentrarchus labrax L

This work was carried out to investigate the effects of injection of Tenacibaculum maritimum formalin‐killed cells (FKC), extracellular products (ECPs) and crude lipopolysaccharide (LPS) as well as 1% feed supplements of oil extracts of Echinacea purpurea and Origanum vulgare on sea bass immunity improvement to the favour of T. maritimum experimental infection control after 4 weeks of the experiment. Tenacibaculum maritimum isolated from naturally infected sea bass showed brown to yellowish‐brown lesions (sores) on gills, skin and/or fins and identified by different biochemical methods and polymerase chain reaction technique. Immune parameters namely, total protein, globulin and lysozyme activity, as well as the relative level of protection were improved by T. maritimum (FKC), (LPS), (ECPs), O. vulgare and E. purpurea, respectively compared with control. Histopathological examination of T. maritimum naturally infected sea bass indicated many pathological changes in gill, skin and musculatures. Present study could be concluded that application of T. maritimum (FKC), (LPS), (ECPs), O. vulgare or E. purpurea improved sea bass immunity to the favour of disease resistance against T. maritimum. Further investigations on the combination between the previous control methods and the vaccine application methods will be needed.     

Pb isotopic variability in melt inclusions from oceanic island basalts, polynesia

Previous studies have suggested that melting processes are responsible for the trace element variability observed in olivine-hosted basaltic melt inclusions. Melt inclusions from three individual lava samples (two from Mangaia, Cook Islands, and one from Tahaa, Society Islands) have heterogeneous Pb isotopic compositions, even though the erupted lavas are isotopically homogeneous. The range of Pb isotopic compositions from individual melt inclusions spans 50 percent of the worldwide range observed for ocean island basalts. The melt inclusion data can be explained by two-component mixing for each island. Our data imply that magmas with different isotopic compositions existed in the volcanic plumbing system before or during melt aggregation.     

Suppression of testicular function using two dose rates of a reversible water soluble gonadotrophin releasing hormone (GnRH) vaccine in colts

Objective: To investigate the effect of two dose rates (200 and 400 ng) of a gonadotrophin releasing hormone (GnRH) vaccine on testicular function. Design: A vaccination dose rate experiment. Procedure: Two injections were administered 4 weeks apart to six colts in each treatment group. To maintain immunosuppression until the end of the breeding season, a third injection was given if antibody titres fell below 1000. Results: Effective antibody titres were present for 12 to 27 weeks. Testosterone concentrations decreased from 2.22 to 0.31 nmol/L 6 weeks after primary vaccination. Androstenedione concentrations decreased from 1.78 to 0.28 nmol/L 5 weeks after vaccination. Testosterone and androstenedione concentrations above 0.69 and 0.87 nmol/L were attained 31 to 43 weeks after vaccination. Mean scrotal widths and lengths decreased over 29 weeks from 9.2 cm and 9.7 cm to 6.7 cm and 7.6 cm. At surgical castration these dimensions were 10.1 cm and 11.0 cm. Mean semen characteristics before vaccination and after recovery were: gel-free volume 16.5 and 13.5 mL, sperm concentration 295.5 times 10⁶ 315.6 times 10⁶/mL, total sperm per ejaculate 4041 times 10⁶ 4657 times 10⁶ live normal spermatozoa 32% and 60%. Histologically, the testes showed active spermatogenesis. The mean testicular parenchyma weights for the 200 and 400 mg groups were 129.0 g and 109.8 g. Daily sperm production per testis and per gram of testis for the 200 and 400 mg groups were 3.7 times 10⁸ 2.8 times 10⁶ 2.3 times 10⁸ 2.0 times 10⁶. Conclusions: Both dose rates suppressed testicular function. Data showed that the vaccine effects were reversible. Individual immune response was less varied in the 200 mg group. Further work is necessary to achieve a less variable response in the immunosuppression of testicular function.