![]() ELISA demonstrated significantly higher serum IgM titers to salivary gland extract in exposed zebra sharks compared to the non-exposed population. Antibody response was examined by ELISA and Western blot assays in 20 serum samples from six zebra sharks, with a 5 year history of leech infection, and 18 serum samples from 8 captive bred zebra sharks, with no history of leech exposure. This retrospective study examined antigen-specific serum IgM responses in captive zebra sharks Stegostoma fasciatum to leech salivary gland extract. Preliminary characterization of the salivary gland transcriptome of B. torpedinis has identified anticoagulants, proteases, and immunomodulators that may be secreted into host tissues to aid leech feeding. Parasitism by the marine leech Branchellion torpedinis is known to cause disease and mortality in captive elasmobranchs and is difficult to control when inadvertently introduced into public aquaria. Marancik, David P Leary, John H Fast, Mark M Flajnik, Martin F Camus, Alvin C Humoral response of captive zebra sharks Stegostoma fasciatum to salivary gland proteins of the leech Branchellion torpedinis. ![]() These results strongly suggest that E2 is an indicator for ovarian follicle development, and that T is a useful indicator for both the onset and end of the egg-laying period in captive zebra sharks. Moreover, high levels of testosterone (T) correlated well with the laying period. Interestingly, E2 levels were inversely correlated with water temperature (R = -0.901). Plasma estradiol-17ß (E2) concentrations increased two months before ovarian follicle development and decreased along with follicle regression. Additionally, we showed that the variations in sex steroid hormone levels correlated with reproductive status in mature female zebra sharks. We confirmed that mature female zebra sharks undergo an annual reproductive cycle. We investigated the relationships among changes in the sex steroid hormone levels, follicle size, and egg-laying period to develop indicators for the female reproductive status. Here, we used zebra sharks, Stegostoma fasciatum, as a model for elasmobranch reproduction in captivity. However, information regarding reproductive status in female elasmobranchs is limited. To promote captive breeding, it is important to determine the female reproductive status. Nozu, Ryo Murakumo, Kiyomi Yano, Nagisa Furuyama, Rina Matsumoto, Rui Yanagisawa, Makio Sato, KeiichiĬaptive breeding in aquaria is a useful means for ex situ preservation of threatened elasmobranch species. Journal of Fish Biology © 2011 The Fisheries Society of the British Isles.Ĭhanges in sex steroid hormone levels reflect the reproductive status of captive female zebra sharks ( Stegostoma fasciatum). Parthenogenesis was confirmed through DNA analysis for three pups sampled during the first two consecutive egg cycles and is presumed to be the method of reproduction responsible thereafter. A total of 15 pups were produced from eggs laid within the aquarium over a period of four consecutive years commencing 2007. Robinson, D P Baverstock, W Al-Jaru, A Hyland, K Khazanehdari, K AĪ zebra shark, Stegostoma fasciatum, held in captivity at the Burj Al Arab aquarium, produced embryos and pups in the absence of a male. The training accomplished has allowed for easier maintenance of the zebra sharks by the aquarium staff and an improvement in the care of the sharks.Īnnually recurring parthenogenesis in a zebra shark Stegostoma fasciatum. All of these procedures are common in veterinary examinations, and it is hoped that desensitization to these stimuli will reduce the stress associated with examinations. One of the 4 zebra sharks was also successfully desensitized to the presence of a stretcher being brought into the holding tank. As a result of PRT, all 4 zebra sharks were desensitized to staying within a closed holding tank off of the main exhibit, the presence of multiple trainers in the closed holding tank, and tactile stimulation. One male and 3 female sharks were trained for 12 weeks. Positive reinforcement training (PRT) was used on 4 adult zebra sharks, Stegostoma fasciatum, housed at the Downtown Aquarium, Denver, to determine the ability of zebra sharks to become desensitized to various stimuli associated with veterinary procedures. ![]() ![]() The use of positive reinforcement in training zebra sharks ( Stegostoma fasciatum).
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