Characterization and longitudinal monitoring of serum androgens and glucocorticoids during normal pregnancy in the killer whale (Orcinus orca)

Robeck, Todd R.; Steinman, Karen J.; O’Brien, Justine K.

doi:10.1016/j.ygcen.2017.01.023

Cited by 48 publications

(63 citation statements)

References 75 publications

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“…Fecal progesterone metabolites spiked around mid-pregnancy in our study, consistent with the time when 5α -DHP predominated in serum [15]. It is also noteworthy that our testosterone antibody [37,40] followed a similar temporal pattern in SRKW to that described for captive whales by [16]. That also supports the reliability of our projected conception dates and occurrences of spontaneous abortion.…”

Section: Discussionsupporting

confidence: 88%

Population growth is limited by nutritional impacts on pregnancy success in endangered Southern Resident killer whales (Orcinus orca)

Wasser¹,

Lundin²,

Ayres³

et al. 2017

PLoS ONE

125

107

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The Southern Resident killer whale population (Orcinus orca) was listed as endangered in 2005 and shows little sign of recovery. These fish eating whales feed primarily on endangered Chinook salmon. Population growth is constrained by low offspring production for the number of reproductive females in the population. Lack of prey, increased toxins and vessel disturbance have been listed as potential causes of the whale’s decline, but partitioning these pressures has been difficult. We validated and applied temporal measures of progesterone and testosterone metabolites to assess occurrence, stage and health of pregnancy from genotyped killer whale feces collected using detection dogs. Thyroid and glucocorticoid hormone metabolites were measured from these same samples to assess physiological stress. These methods enabled us to assess pregnancy occurrence and failure as well as how pregnancy success was temporally impacted by nutritional and other stressors, between 2008 and 2014. Up to 69% of all detectable pregnancies were unsuccessful; of these, up to 33% failed relatively late in gestation or immediately post-partum, when the cost is especially high. Low availability of Chinook salmon appears to be an important stressor among these fish-eating whales as well as a significant cause of late pregnancy failure, including unobserved perinatal loss. However, release of lipophilic toxicants during fat metabolism in the nutritionally deprived animals may also provide a contributor to these cumulative effects. Results point to the importance of promoting Chinook salmon recovery to enhance population growth of Southern Resident killer whales. The physiological measures used in this study can also be used to monitor the success of actions aimed at promoting adaptive management of this important apex predator to the Pacific Northwest.

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Section: Discussionsupporting

confidence: 88%

Population growth is limited by nutritional impacts on pregnancy success in endangered Southern Resident killer whales (Orcinus orca)

Wasser¹,

Lundin²,

Ayres³

et al. 2017

PLoS ONE

125

107

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“…Estrogen levels during gestation tended to being higher for pregnancies with female calves, although we cannot conclusively state if there is a sex specific difference, as has been reported in other species such as orcas (Orcinus orca) [31] and red-fronted lemurs (Eulemur fulvus rufus) [32]. In contrast to the trend in pygmy hippos, estrogen levels during gestation were higher in mother's carrying male calves for both of these species.…”

Section: Discussioncontrasting

confidence: 72%

Characterizing the reproductive biology of the female pygmy hippopotamus (Choeropsis liberiensis) through non-invasive endocrine monitoring

Flacke

Schwarzenberger

Penfold³

et al. 2017

Theriogenology

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The pygmy hippopotamus (Choeropsis liberiensis) is endangered in the wild and very little is known about its reproductive biology. In zoological facilities, this species experiences a number of reproductive issues that complicate breeding management, including a high rate of stillbirths and failure of many pairs to reproduce. We conducted a comprehensive study to evaluate reproductive cycles and pregnancy in this species using enzyme immunoassays (EIAs) for fecal hormone metabolite analysis. Fresh fecal samples were collected twice weekly for a one to three year period from 36 female pygmy hippos housed at 24 zoological institutions. Samples were analyzed in three separate laboratories. Three progestogen metabolite EIAs (Pg-diol: 5β-pregnane-3α,20α-diol 3HS:BSA; PdG: pregnanediol-3-glucuronide R13904; mono-P4: Quidel clone 425) and three estrogen metabolite EIAs (E2a: estradiol-17β-OH 17-HS:BSA; E2b: estradiol 17β R0008; E2c: estradiol 17β R4972) accurately reflected reproductive events. Average estrous cycle length was 31.8 ± 7.4 days based on estrogen metabolite peaks and 30.9 ± 7.3 days based on nadir to nadir progestogen metabolite concentrations. Cyclical patterns in both estrogen and progestogen metabolites were detected throughout the year, indicating a lack of seasonality. Estrogen metabolite peaks were also observed during pregnancy and lactation, suggesting that follicular development occurs during both reproductive states. Pregnancy was most reliably demonstrated by elevation in progestogen metabolites (Pg-diol or PdG) in the second half of gestation. Average gestation length based on breeding to calving date was 203 ± 4 days for 15 pregnancies. This comprehensive overview of the reproductive biology of the female pygmy hippo provides valuable data for guiding long-term breeding management for this endangered species and serves as a baseline for future studies addressing the potential influence of social structure, diet, body condition, and other husbandry factors on estrous cycling and reproduction.

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“…Statistical analyses were performed using Stata statistical software (version 14; StataCorp LP, College Station, TX, USA). A two‐stage mixed effects maximum likelihood (ML) regression model (West et al.,2015, Robeck et al., 2017) quantifying the relationship between the dependent variable (analyte), the fixed effects variable (stage 1, animal age or age category, sex, and season) and the random effects variable, animal ID (stage 2, n = 11, coded 1‐32), was used to control for the variance associated with an unequal number of repeated measures per animal. The mixed effects model was used because it can incorporate the effect of the variance associated with the unbalanced design between and the correlated repeated measures from within each animal with the effects of any independent or fixed variables to predict their collective effect on the sample means (marginal means).…”

Section: Methodsmentioning

confidence: 99%

Effect of age, sex, and season on the variation in blood analytes of a clinically normal ex situ population of killer whales (Orcinus orca)

Nollens

Robeck

Schmitt

et al. 2019

Veterinary Clinical Pathol

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BackgroundThe effects of sex, age, and season on blood analyte concentrations have not been investigated for the killer whale (Orcinus orca). Defining these changes provides background data for improving the care of managed populations and defines normal changes that could occur in wild counterparts.ObjectivesWe aimed to define hematologic and serum biochemical variation by age, sex, and season for an ex situ killer whale population.MethodsBlood samples collected from killer whales during normal wellness exams were retrospectively identified. Killer whales were categorized by age; calf (0‐2.9 years), juvenile (3‐10.9 years), early adult (11‐20.9 years), adult (21‐30.9 years), and aged (>30.9 years); sex; and season. Standard CBC and biochemistry were collated, and only samples without evidence of disease were used. A mixed effects maximum likelihood regression with animal identification (ID) as the random effects variable was used to compare groups with a significance set at P ≤ 0.01.ResultsAll analytes differed by age, while only four differed by sex. Red blood cell parameters and associated renal analytes increased with age, while liver‐associated analytes and glucose decreased. Season affected 59% of the blood analytes.ConclusionsAged killer whales showed strong evidence of altered physiology as compared with younger animals. Anemia did not develop with age as was observed in one bottlenose dolphin population. Observed decreases in renal function could be caused by chronic disease or dehydration. Decreases in immune function parameters suggest immune senescence. These results provide background data for evaluating the health of managed and free‐ranging killer whales.

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Characterization and longitudinal monitoring of serum androgens and glucocorticoids during normal pregnancy in the killer whale (Orcinus orca)

Cited by 48 publications

References 75 publications

Population growth is limited by nutritional impacts on pregnancy success in endangered Southern Resident killer whales (Orcinus orca)

Population growth is limited by nutritional impacts on pregnancy success in endangered Southern Resident killer whales (Orcinus orca)

Characterizing the reproductive biology of the female pygmy hippopotamus (Choeropsis liberiensis) through non-invasive endocrine monitoring

Effect of age, sex, and season on the variation in blood analytes of a clinically normal ex situ population of killer whales (Orcinus orca)

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