Ovulation Induction with Follicle-Stimulating Hormone Administration in Hawksbill Turtles<i>Eretmochelys imbricata</i>

Kawazu, Isao; Suzuki, Miwa; Maeda, Konomi; Kino, Masakatsu; Koyago, Masanori; Moriyoshi, Masaharu; Nakada, Ken; Sawamukai, Yutaka

doi:10.5358/hsj.33.88

Cited by 10 publications

(12 citation statements)

References 14 publications

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“…The nine turtles were subjected to FSH (porcine anterior pituitary gonadotropic hormone preparations, Antorin R-10; Kyoritsu Seiyaku Corporation, Japan) administration at a dosage of 0.25 armor units/kg (approximately 15-20 armor units per turtle), as described previously (Kawazu et al, 2014). As a result, they exhibited follicular development, leading to the formation of infertile eggs.…”

Section: Methodsmentioning

confidence: 99%

“…The retention of turtles was mandatorily terminated at 2 h after oxytocin administration, and the turtles were returned to the holding tanks. At 24 h after oxytocin administration, the eggs in oviduct of the turtles were observed by ultrasonography with a 5-MHz probe (Mini-dock P04341-04; Sonosite Inc., US) at a depth of 200 mm under the water, as described previously (Kawazu et al, 2014). As a control experiment, two of the turtles (Turtle nos.…”

Section: Methodsmentioning

confidence: 99%

“…Hence, ovulation and eggshell formation, which cannot be induced directly by non-mating stimuli, such as artificial insemination, must be induced artificially prior to insemination. Kawazu et al (2014) successfully addressed this issue in the artificial insemination of sea turtles by inducing ovulation and eggshell formation through administering follicle-stimulating hormone (FSH) to hawksbill turtles. However, in this previous study, the turtles did not oviposit their eggs (Kawazu et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

“…Kawazu et al (2014) successfully addressed this issue in the artificial insemination of sea turtles by inducing ovulation and eggshell formation through administering follicle-stimulating hormone (FSH) to hawksbill turtles. However, in this previous study, the turtles did not oviposit their eggs (Kawazu et al, 2014). Consequently, it was not possible to evaluate the condition of the eggs (egg shape, egg size, clutch size) that were induced to form by FSH administration.…”

Section: Introductionmentioning

confidence: 99%

“…In addition, the ovulation induction technique by FSH administration (Kawazu et al, 2014) was re-evaluated based on the measurements of egg shape, egg diameter, and clutch size of the oviposited eggs.…”

Section: Introductionmentioning

confidence: 99%

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Induction of Oviposition by the Administration of Oxytocin in Hawksbill Turtles

et al. 2014

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We set out to develop an oviposition induction technique for captive female hawksbill turtles Eretmochelys imbricata. The infertile eggs of nine females were induced to develop by the administration of follicle-stimulating hormone, after which we investigated the effects of administering oxytocin on oviposition. Seven of the turtles were held in a stationary horizontal position on a retention stand, and then oxytocin was administrated (0.6-0.8 units/kg of body weight; 5 mL). The seven turtles were retained for a mandatory 2 h period after oxytocin administration, and were then returned to the holding tanks. As the control, normal saline (5 mL) was administered to the other two turtles, followed by the administration of oxytocin after 24 h. The eggs in oviducts of all nine turtles were observed by ultrasonography at 24 h after oxytocin administration. The control experiment validated that stationary retention and normal saline administration had no effect on egg oviposition. Eight of the turtles began ovipositing eggs at 17-43 min after oxytocin administration, while one began ovipositing in the holding tank immediately after retention. All turtles finished ovipositing eggs within 24 h of oxytocin administration. This report is the first to demonstrate successful induced oviposition in sea turtles. We suggest that the muscles in the oviducts of hawksbill turtles may respond to relatively lower doses of oxytocin (inducing contractions) compared to land and freshwater turtles (4-40 units/kg) based on existing studies.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Induction of Oviposition by the Administration of Oxytocin in Hawksbill Turtles

et al. 2014

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Age and body size of captive hawksbill turtles at the onset of follicular development

et al. 2014

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The aim of this study was to record the age and body size of 23 captive female hawksbill turtles at the onset of follicular development. The age, straight carapace length (SCL), and body mass (BM) of the turtles were recorded between 2006 and 2014 at follicular development (determined via ultrasonography) these parameters were 17.7 ± 1.7 years (range: 13-20 years), 77.7 ± 3.3 cm (73.3-83.5 cm), and 61.1 ± 8.0 kg (48.2-76.1 kg), respectively. When the year of the onset of follicular development was designated year 0, the increase in SCL in years -7-0 and 0-3 averaged 2.2 cm and 1.0 cm, respectively. Correspondingly, the increase in BM in years -7-0 and 0-3 averaged 5.0 kg and 2.2 kg, respectively. This is the first study to report the age and body size of captive female hawksbill turtles at the onset of follicular development, which indicates the beginning of sexual maturation. The reduction in growth after follicular development suggests that at the onset of sexual maturation, female hawksbills may utilize energy for follicular development rather than growth.

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Physiological determinants of the internesting interval in sea turtles: a novel ‘water-limitation’ hypothesis

et al. 2019

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The internesting interval separates successive clutches of sea turtle eggs, and its duration varies both among and within species. Here, we review the potential physiological limits to this interval, and develop the hypothesis that desalination capacity limits the internesting interval owing to the requirement for water deposition in eggs. Sea turtles deposit 1–4 kg of water per clutch in egg albumen; for most species, this represents about 2% of adult body mass. We calculate how quickly turtles can recover this water by estimating maximal salt excretion rates, metabolic water production and urinary losses. From this water balance perspective, the ‘water-limitation’ hypothesis is plausible for green turtles but not for leatherbacks. Some plasma biochemistry studies indicate dehydration in sea turtles during the nesting season, although this is not a universal finding and these data have rarely been collected during the internesting interval itself. There is mixed support for a trade-off between clutch size and the length of the interval. We conclude that the ‘water-limitation’ hypothesis is plausible for most sea turtle species, but requires direct experimentation.

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Ovulation Induction with Follicle-Stimulating Hormone Administration in Hawksbill TurtlesEretmochelys imbricata

Cited by 10 publications

References 14 publications

Induction of Oviposition by the Administration of Oxytocin in Hawksbill Turtles

Induction of Oviposition by the Administration of Oxytocin in Hawksbill Turtles

Age and body size of captive hawksbill turtles at the onset of follicular development

Physiological determinants of the internesting interval in sea turtles: a novel ‘water-limitation’ hypothesis

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