Reproduction

Robeck, Todd R.; Atkinson, Shannon; Brook, Fiona

doi:10.1201/9781420041637.ch11

Cited by 50 publications

(74 citation statements)

References 93 publications

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“…The use of altrenogest in marine mammals for contraception or as a synchronization agent has been well documented in killer whales, bottlenose dolphins, and beluga (Young & Huff 1996, Robeck et al 2001, 2005b). However, unlike killer whales and bottlenose dolphins, at the time of study, the Pacific white-sided dolphin was the first seasonally estrus cetacean where altrenogest had been used.…”

Section: Dates Of Artificial Inseminationmentioning

confidence: 99%

Seasonality, estrous cycle characterization, estrus synchronization, semen cryopreservation, and artificial insemination in the Pacific white-sided dolphin (Lagenorhynchus obliquidens)

Robeck¹,

Steinman²,

Greenwell³

et al. 2009

Reproduction

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The reproductive physiology of the Pacific white-sided dolphin, Lagenorhynchus obliquidens, was characterized to facilitate the development of artificial insemination (AI) using cryopreserved spermatozoa. Specific objectives were to: 1) describe reproductive seasonality of the Pacific white sided dolphins; 2) describe urinary LH and ovarian steroid metabolites during the estrous cycle; 3) correlate LH and ovarian steroidal metabolite patterns to ultrasound-monitored follicular growth and ovulation; and 4) assess the efficacy of synchronizing estrus, sperm collection/cryopreservation, and intrauterine insemination. Ovulations (64%, nZ37) and conceptions (83%, nZ18) occurred from August to October. Peak mean serum testosterone (24 ng/ml), cross-sectional testicular area (41.6 cm 2 ), and sperm concentration (144.3!10 7 sperm/ml) occurred in July, August, and September respectively. Spermatozoa were only found in ejaculates from July to October. Estrous cycles (nZ22) were 31 d long and were comprised of a 10 d follicular and 21 d luteal phase. Ovulation occurred 31.2 h after the onset of the LH surge and 19.3 h after the LH peak. Follicular diameter and circumference within 12 h of ovulation were 1.52 and 4.66 cm respectively. Estrus synchronization attempts with altrenogest resulted in 17 (22%) ovulatory cycles with ovulation occurring 21 d post-altrenogest. Ten AI attempts using cryopreserved semen resulted in five pregnancies (50%). The mean gestation length was 356 days (range 348-367). These data provide new information on the Pacific whitesided dolphin's reproductive physiology and collectively enabled the first application of AI in this species.

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Section: Dates Of Artificial Inseminationmentioning

confidence: 99%

Seasonality, estrous cycle characterization, estrus synchronization, semen cryopreservation, and artificial insemination in the Pacific white-sided dolphin (Lagenorhynchus obliquidens)

Robeck¹,

Steinman²,

Greenwell³

et al. 2009

Reproduction

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“…Methods of cryopreservation of bottlenose dolphin sperm using pellets or straws on dry ice or in liquid nitrogen vapor have been reported previously (Seager et al 1981, Schroeder & Keller 1990, Durrant et al 2000, Robeck et al 2001, Robeck & O'Brien 2004. Despite these efforts, in vivo competence of frozen-thawed spermatozoa has never been demonstrated.…”

Section: Introductionmentioning

confidence: 99%

Estrous cycle characterisation and artificial insemination using frozen–thawed spermatozoa in the bottlenose dolphin (Tursiops truncatus)

Robeck¹,

Steinman²,

Yoshioka³

et al. 2005

Reproduction

105

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The reproductive endocrinology of the bottlenose dolphin, Tursiops truncatus, was characterized to facilitate the development of artificial insemination using cryopreserved spermatozoa. Specific objectives were: (i) to determine the excretory dynamics of urinary luteinizing hormone (LH) and ovarian steroid metabolites during the estrous cycle; (ii) to evaluate the effect of an exogenously administered synthetic progesterone analog (altrenogest) on reproductive hormone excretion; (iii) to correlate follicular growth and ovulation (as determined by transabdominal ultrasound) to urinary LH and ovarian steroid metabolites; (iv) examine the in vivo fertilisation capacity of cryopreserved semen, and (v) to develop an intrauterine insemination technique. Based on urinary endocrine monitoring of natural estrous cycles (2 consecutive cycles) and nine post altrenogest cycles in ten females, estrous cycles were found to be 36 days long and comprised of an 8 day and 19 day follicular and luteal phase, respectively. Peak estrogen conjugates (EC; 5.4 6 3.8 ng/mg creatinine (Cr)) occurred 8 h prior to the LH surge (70.9 6 115.7 ng/mg Cr). The time of ovulation, as determined by ultrasonography, occurred 32.1 6 8.9 h and 24.3 6 7.0 h after the onset of the LH surge and LH peak, respectively. Mean preovulatory follicular diameter and circumference were 2.1 6 0.5 cm and 6.5 6 1.5 cm, respectively. Of the 27 estrous synchronisation attempts, 13 resulted in an ovulatory cycle, with ovulation occurring 21 days post-altrenogest treatment. Intrauterine (4 of 5) and intracornual (1 of 3) inseminations conducted across eight estrous cycles resulted in five pregnancies (63%), one pregnancy resulted from the use of liquid stored semen, whereas four were achieved using cryopreserved semen. These data provide new information on female bottlenose dolphin reproductive physiology, and demonstrate that the combination of endocrine monitoring and serial ultrasonography contributed to successful AI using liquid-stored and cryopreserved semen.

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“…The secretory activities in syncytiotrophoblasts of placentae in the seal species described by Harrison and Young [10] are therefore presumably derived from the secretion of estrogen and/or chorionic gonadotropin. The presence of estrogen synthesized in luteal cells and the placenta during pregnancy may contribute to the synthesis or availability of intracellular progesterone receptors [5], whereas placental chorionic gonadotropin is believed to be essential for the maintenance of pregnant corpus luteum [25]. The placental chorionic gonadotropin of the grey seal (Halichoerus grypus) possesses biological activity similar to that of human chorionic gonadotropin (hCG), which has LH-like activity [11,12].…”

Section: Discussionmentioning

confidence: 99%

Immunohistochemical Localization of Steroidogenic Enzymes and Prolactin Receptors in the Corpus Luteum and Placenta of Spotted Seals (<i>Phoca largha</i>) during Late Pregnancy

Ishinazaka

Suzuki

Mizuno

et al. 2002

The Journal of Veterinary Medical Science

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ABSTRACT. To study luteal function in the late gestational period of Phocidae (seals), we analyzed the localization of steroidogenic enzymes (P450scc, 3βHSD and P450arom) and prolactin receptors in the corpora lutea of pregnant spotted seals (Larga seal; Phoca largha) immunohistochemically. P450scc, 3βHSD and prolactin receptors were present in all luteal cells of each corpus luteum, and most luteal cells were immunostained for P450arom. Although we analyzed only two specimens, P450scc, 3βHSD and prolactin receptors were negatively immunostained in the placentae. P450arom was present in the syncytiotrophoblast of placentae. These findings suggest that 1) the corpus luteum of the spotted seal synthesizes pregnenolone, progesterone and estrogen during late gestational period, 2) the placenta of this species do not possess the capacity to synthesize progesterone, and 3) like other terrestrial carnivores, this species requires prolactin to maintain the corpus luteum during pregnancy. These characteristics support the recent classification of family Phocidae in the order Carnivora, and suggest a relationship between prolactin and reproductive failure during the post-implantation period in pinnipeds. KEY WORDS: corpus luteum, late pregnancy, prolactin receptor, spotted seal, steroidogenic enzyme.

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Reproduction

Cited by 50 publications

References 93 publications

Seasonality, estrous cycle characterization, estrus synchronization, semen cryopreservation, and artificial insemination in the Pacific white-sided dolphin (Lagenorhynchus obliquidens)

Seasonality, estrous cycle characterization, estrus synchronization, semen cryopreservation, and artificial insemination in the Pacific white-sided dolphin (Lagenorhynchus obliquidens)

Estrous cycle characterisation and artificial insemination using frozen–thawed spermatozoa in the bottlenose dolphin (Tursiops truncatus)

Immunohistochemical Localization of Steroidogenic Enzymes and Prolactin Receptors in the Corpus Luteum and Placenta of Spotted Seals (<i>Phoca largha</i>) during Late Pregnancy

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