Change of Plasma Chemistry Values in Captive Breeding Loggerhead Turtles (Caretta caretta)

Loggerhead turtles, Caretta caretta, have been laying eggs in an indoor artificial beach since 1995, at the Port of Nagoya Public Aquarium (PNPA). Two males and four females were mated and those four landed and laid eggs several times during the breeding period in 1996. In 1998 egg laying was observed from April to July and mating was one or two months prior to the nesting season. Blood samples from these individuals were collected monthly in the previously mentioned years in order to investigate the changes in sex steroid hormones (testosterone, estradiol, and progesterone). Moreover, blood chemistry values (total protein, albumin, triglyceride, total cholesterol, total calcium, and inorganic phosphorus) were investigated. In 1998, for the two males, changes in testosterone levels were additionally examined. Blood chemistry values of each turtle changed periodically as sex steroids did based on the breeding period and laying cycle. Data from a completely artificial environment such as the one at the PNPA provide elucidation of the reproductive physiology in these endangered species. 1. Introduction Designated as an endangered species and listed in the CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora) Appendices I, conservation of sea turtles has been actively conducted. However, wild population has been decreased due to the loss of egg-laying sites, fisheries bycatch, and the demand for their eggs as food. Sea turtles are common animals for exhibition in aquariums; however, their successful breeding in an artificial environment is only observed in Port of Nagoya Public Aquarium (PNPA) [1]. For the recovery of the stock of sea turtles, captive breeding should be stepped up as well as habitat conservation, and the returning of captive bred individuals to wild environment should be implemented actively. For the successive breeding of sea turtles in an artificial environment, the understanding of reproductive physiology and the establishment of blood characteristics for their health management are absolutely imperative. Since 1995, mainly the loggerhead turtles, C. caretta, have been landing and laying eggs every year, resulting in the first successful breeding in this species in an artificial environment. In PNPA, the studies for understanding reproductive physiology and ecology and the establishment of blood standard values have been continued by using those reproductive individuals. This study reports the transition of blood chemistry values (total protein (TP), albumin (ALB), triglyceride (TG), total cholesterol