Retracted: Effect of Post‐Thaw Storage Time on Motility and Fertility of Cryopreserved Beluga Sturgeon (Huso huso) Sperm

The aim of this study was to test the influence of post ‐ thaw storage time on the duration of sperm motility, percentage of motile sperm, and fertilization and hatching rates of fresh sperm and sperm stored for 0, 30 and 60 min at 4°C post‐thawing. After being frozen in liquid nitrogen and then thawed, the percentage of motile sperm and duration of motility were not affected by 30 min of storage at 4°C, whereas a significant decline in these parameters was observed after 60 min of storage. Similarly, fertilization and hatching rates were significantly affected within 60 min of storage at 4°C, and the fertility of frozen‐thawed sperm was significantly lower than that of fresh sperm. We conclude that cryopreserved sperm of beluga sturgeon could be stored for 30 min without the loss of sperm quality. This described procedure for beluga sturgeon cryopreservation is reliable and efficient and therefore can be recommended for hatchery practice after scaling up this technique.     

Response of Thawed Epidi dymal Red Deer Spermatozoa to Increasing Concentrations of Hydrogen Peroxide,and Importance of Individual Male Variability

Oxidative stress represents a challenge during sperm manipulation. We have tested the effect of increasing hydrogen peroxide (H₂O₂) levels on red deer spermatozoa after cryopreservation, and the role of male‐to‐male variation in that response. In a first experiment, eight thawed samples were submitted to 0, 25, 50, 100 and 200 μm H₂O₂ for 2 h at 37°C. Intracellular reactive oxygen species (H₂DCFDA‐CM) increased with H₂O₂ concentration, but we only detected a decrease in sperm function (motility by CASA and chromatin damage by sperm chromatin structure assay) with 200 μm . Lipoperoxidation assessed by the thiobarbituric acid reactive substance (TBARS) method increased slightly with 50 μm H₂O₂ and above. In a second experiment, samples from seven males were submitted to 0 and 200 μm H₂O₂ for 2 h, triplicating the experiment within each male. Males differed at thawing and regarding their response to incubation and H₂O₂ presence. We found that the kinematic parameters reflected male‐to‐male variability, whereas the response of the different males was similar for lipid peroxidation and viability. A multiparametric analysis showed that males grouped differently if samples were assessed after thawing, after incubation without H₂O₂ or after incubation with H₂O₂. Red deer spermatozoa are relatively resilient to H₂O₂ after thawing, but it seems to be a great male‐to‐male variability regarding the response to oxidative stress. The acknowledgement of this individual variability might improve the development of optimized sperm work protocols.     

Phenytoin as a novel anti-vitiligo weapon

Vitiligo is a psychologically devastating clinical conundrum which affects approximately 1% of the general population. The exact cause of the illness is an enigma, but several hypotheses about its pathogenesis are advanced.The autoimmune hypothesis proposes an autoimmune attack against melanocytes. Although anti-melanocyte autoantibodies have been demonstrated in vitiligo, recent research casts doubt on their pathogenic role and instead supports the involvement of cell-mediated autoimmune response in the pathobiology of this disorder, which is characterized by increase of suppressor T-cells and decrease of the helper/suppressor ratio in association with the presence of type-1 cytokine secreting cytotoxic T cells in the vicinity of disappearing melanocytes.The neural hypothesis proposes that increased release of norepinephrine, a melanocytotoxin, from the autonomic nerve endings in the microenvironment of melanocytes injures these cells. Moreover, norepinephrine induces the catecholamine degrading enzyme monoamine oxidase (MAO), which favors the formation of toxic levels of hydrogen peroxide in the vicinity of melanocytes.Another theory suggests that abnormal permeability of melanosome membrane, which normally prevents the diffusion of toxic melanin precursors into the cytoplasm, may cause melanocyte damage.Phenytoin, the widely-used anticonvulsant, has been employed both topically and systemically in the treatment of some dermatological disorders. The drug has been shown to significantly suppress mitogen-induced activation of lymphocytes and cytotoxic T lymphocyte activity and to polarize the immune response toward the type-2 pathway. It also significantly decreases suppressor T cells and increases the helper/suppressor ratio.At high concentrations, the drug inhibits the release of norepinephrine and the activity of MAO. Moreover, phenytoin is suggested to interact with membrane lipids, which may promote stabilization of the membranes.The hydantoin moiety of phenytoin exerts a direct stimulatory action on melanocytes; facial hyperpigmentation is a recognized side effect of orally administered phenytoin.Altogether, the above evidence suggests that phenytoin could be therapeutically effective against vitiligo. As phenytoin stimulates collagen production and inhibits its breakdown, its concomitant use with topical steroids could prevent steroid-induced skin atrophy while potentiating the anti-vitiligo effect of these agents.     

Rhodococcus equi-associated osteomyelitis in foals

Two cases of Rhodococcus equl infection in foals are described, in which osteomyelitis was a feature. Because rhodococcal infection is usually low grade and chronic, and because the signs of early metaphysitis can be subtle, any articular or periarticular swelling in a foal from a farm with a history of rhodococcosis should be strongly suspected to be associated with R equl until proven otherwise.     

Wildlife diseases in New Zealand: recent findings and future challenges

Our knowledge of diseases in New Zealand wildlife has expanded rapidly in the last two decades. Much of this is due to a greater awareness of disease as a cause of mortality in some of our highly threatened species or as a limiting factor to the successful captive rearing of intensely managed species such as hihi (Notiomystis cincta), kiwi (Apteryx spp.) and kakapo (Strigops habroptilus). An important factor contributing to the increase of our knowledge has been the development of new diagnostic techniques in the fields of molecular biology and immunohistochemistry, particularly for the diagnosis and epidemiology of viral and protozoan diseases. Although New Zealand remains free of serious exotic viruses there has been much work on understanding the taxonomy and epidemiology of local strains of avipox virus and circoviruses. Bacterial diseases such as salmonellosis, erysipelas and tuberculosis have also been closely investigated in wildlife and opportunist mycotic infections such as aspergillosis remain a major problem in many species. Nutritional diseases such as hyperplastic goitre due to iodine deficiency and metabolic bone disease due to Ca:P imbalance have made significant impacts on some captive reared birds, while lead poisoning is a problem in some localities. The increasing use of wildlife translocations to avoid the extinction of threatened species has highlighted the need for improved methods to assess the disease risks inherent in these operations and other intensive conservation management strategies such as creching young animals. We have also become more aware of the likelihood of inbreeding suppression as populations of many species decrease or pass through a genetic bottleneck. Climate change and habitat loss, however, remain the greatest threats to biodiversity and wildlife health worldwide. Temperature changes will affect our wildlife habitats, alter the distribution of disease vectors and wildlife predators, or directly harm threatened species in vulnerable localities.