No abstract

Information regarding the physiology of African lions is scarce, mainly due to challenges associated with essential routine research procedures. The aim of this experiment was to test the possibility of training six captive lionesses by positive reinforcement conditioning (PRC) to voluntarily allow the collection of vaginal swabs and blood samples. This was done with the final goal of avoiding frequent anesthesia, and potential stressful management during research. All lionesses mastered basic clicker and targeting principles within two weeks. Routine sampling was possible after 20 weeks of training, enabling collection of about 750 vaginal swabs and 650 blood samples over the course of the study (18 months). These samples served to describe in detail the African lioness' ovarian cycle by combination of behavioral observations, longitudinal steroid hormone monitoring, and vaginal cytology. They also helped establish the ideal time for ovulation induction and artificial insemination of lionesses presenting natural estrus. The animals remained calm and cooperative during all sessions, and demonstrated curiosity in the training. PRC training of captive lionesses proved to be a suitable, minimally 1 invasive method for repeated collection of vaginal swabs and blood. Additionally, PRC may serve as behavioral enrichment for African lions in captive settings. Compared to chemical or physical restraining methods, this non-invasive management approach may reduce distress and physiological negative side effects, thus opening up new avenues for feline research.

On their way to the oocyte, sperm cells are subjected to oxidative stress, which may trigger the oxidation of phospholipids (PL). Applying MALDI-TOF MS, HPTLC and ESI-IT MS, we comparatively analyzed the PL compositions of semen and blood of species differing in their reproductive systems and types of nutrition (bull, boar, stallion, lion and man) with regard to the sensitivity to oxidation as well as the accumulation of harmful lyso-PL (LPL), transient products of lipid oxidation. In addition, the protective capacity of seminal fluid (SF) was also examined. The PL composition of erythrocytes and blood plasma is similar across the species, while pronounced differences exist for sperm and SF. Since the blood function is largely conserved across mammalian species, but the reproductive systems may vary in many aspects, the obtained results suggest that the PL composition is not determined by the type of nutrition, but by the relatedness of species and by functional requirements of cell membranes such as fluidity. Sperm motion and fertilization of oocytes require a rather flexible membrane, which is accomplished by significant moieties of unsaturated fatty acyl residues in sperm lipids of most species, but implies a higher risk of oxidation. Due to a high content of plasmalogens (alkenyl ether lipids), bull sperm are most susceptible to oxidation. Our data indicate that bull sperm possess the most effective protective power in SF. Obviously, a co-evolution of PL composition and protective mechanisms has occurred in semen and is related to the reproductive characteristics. Although the protective capacity in human SF seems well developed, we recorded the most pronounced individual contaminations with LPL in human semen. Probably, massive oxidative challenges related to lifestyle factors interfere with natural conditions.

Reports of the vaginal flora of wild cats such as lions or leopards are scarce. The micro-organisms most commonly found in the vagina of clinically healthy cats are aerobic bacteria such as coagulase-negative Staphylococcus, Streptococcus canis, and Escherichia coli. Simonsiella spp are large Gram-negative bacteria belonging to the Neisseriaceae family, typically found in the oral cavity and upper respiratory tract of many species. To date, there are no reports of the detection of Simonsiella spp in the vaginal flora of any felid. For a period of six months, daily behaviour monitoring was performed on six captive lionesses at a South African conservation centre, in parallel with the collection of vaginal swabs and interpretation of the resultant vaginal cytologies every other day. Oestrus was identified by typical female reproductive behaviours, as well as by enlarged and separated vulvar lips, and a predominant proportion of superficial cornified cells, clearing of the background, and high bacterial presence in the vaginal smear. Simonsiella spp were identified by their characteristic morphology in 58% (60 of 103) of the vaginal samples collected during oestrus. They were also found in oral swabs of three out of three lions tested. Additionally, Simonsiella spp were opportunistically found in a vaginal smear from a zoo housed female Sri Lankan leopard in oestrus, during a routine reproduction assessment. The finding of Simonsiella spp may be more common than previously suspected, transitory, and without detectable clinical relevance. A connection between occurrence of these bacteria and oestrus was apparent.