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Roudebush, William E.; Wetzel, Dana L.; Breuel, Kevin F.; Reynolds, John E., III
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2009 |
Validation of an Anti-Mullerian Hormone (AMH) ELISA for use in an endangered marine mammal, the West Indian Manatee (Trichechus manatus).
Biology of Reproduction 81.
–ABSTRACT: Environmental and human-caused stressors can affect wildlife populations in a number of ways, some more critical than others. One of the more serious effects can involve fertility and reproductive success. Especially for endangered taxa, it is important to understand whether reproduction is being impaired and, if possible,to mitigate the stressors that may be the cause of the impairment. For marine mammals such as the West Indian manatee (Trichechus manatus), certain stressors or conservation risk factors have been identified, but their effects have been very difficult to assess using traditional methods. The inability to demonstrate clearly the magnitude and extent of effects of environmental stressors such as climate change, red tides and contaminants on manatees and other marine mammals represents a significant impediment to their conservation. Without such information to inform decision makers, the motivation to make changes has been lacking. The development of "biomarkers" allows us to correlate effects, such as impaired reproduction, with possible causes(e.g., chemical contaminants, and biotoxins). A recently-developed biomarker (anti-Mullerian hormone; AMH) provides an ELISA*-based analysis of gonadal function plus reproductive potential. AMH is a glycoprotein dimer composed of two 72kDa monomers linked by disulfide bridges and belongs to the transforming growth factor-beta superfamily. AMH is secreted by the Sertoli cells in males and by ovarian granulosa cells in females and is age and maturity dependent. The study objective was to validate the AMH ELISA for use in the manatee. A total of 21 male and 9 female manatee serum samples were obtained and assayed for AMH by a commercially available ELISA kit from Diagnostic Systems Laboratory (Webster, TX; a Beckman-Coulter, Inc. company). Animal demographics included collection date, body weight (kg) and length (cm). AMH levels were assessed according to the manufacturer's instructions. AMH levels ranged from 160-1,010 ng/mL (mean 491.48ng/mL) in the male and 0.0-0.2 ng/mL (mean 0.08 ng/mL) in the female. Linear regression analysis (AMH = (0.649*kg) - 97.5);R2=0.46) found a significant relationship (P<0.01) between male AMH levels and body weight. Linear regression analysis(AMH = (4.970*cm) - 887.9; R2=0.29) found a significant relationship(P<0.05) between male AMH levels and body length. Due to the low sample size, regression analysis for female AMH andbody weight and length only approached significance. Body length is an excellent indicator of animal maturity. This represents the first report of AMH detection in the West Indian manatee.AMH levels in the male are the highest in any mammalian species reported on to date. By comparison, AMH levels in the femaleare within reported ranges for other mammalian species. Following this assay, validation will allow us soon to assess the fertility potential of manatees as a function of various parameters including,but not limited to geographic location, nutritional status,exposures to biotoxins or contaminants, or disease.
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Wilson, Rhian C.; Reynolds, John E., III; Wetzel, Dana L.; Schwierzke-Wade, Leslie; Bonde, Robert K.; Breuel, Kevin F.; Roudebush, William E.
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2011 |
Secretion of anti-Müllerian hormone in the Florida manatee Trichechus manatus latirostris, with implications for assessing conservation status.
Endangered Species Research 14: 107-112. 2 tabs. 2 figs. DOI: 10.3354/esr00346. Publ. online June 22, 2011.
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Wetzel, Dana L.; Pulster, Erin; Reynolds, John E., III
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2012 |
Organic contaminants and sirenians. Chap. 22 in: E. M. Hines et al. (eds.), Sirenian conservation: issues and strategies in developing countries (q.v.).
Gainesville, University Press of Florida (xiv + 326): 196-203. 1 fig.
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Wetzel, Dana L.; Reynolds, John E., III; Bonde, Robert K.; Schloesser, Ryan W.; Schwierzke-Wade, Leslie; Roudebush, William E.
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2019 |
Enhancing reproductive assessments of the Florida manatee (Trichechus manatus latirostris) by establishing optimal time period and inhibin B baseline concentrations.
Endangered Species Research 39: 283-292. https://doi.org/10.3354/esr00972 Aug. 2019.
–ABSTRACT: The Florida manatee (Trichechus manatus latirostris) occupies coastal and riverine habitats that may influence endogenous biological rhythms, including reproductive potential. Inhibin b provides a biomarker of gonadal function and reproductive potential in humans and other eutherian mammals. This study examined the influence of size, sex, and time of year on inhibin B levels in manatees sampled among three habitats with varying degrees of environmental stress in Florida. Inhibin B levels in 38 males averaged (±SE) 4.90 ±0.23 pg/mL; the average level in 31 females was 5.63 ± 0.46 pg/mL. Elevated patterns in inhibin B were exhibited between mid-March and mid-August corresponding to increased mating activity and testicular function, with significant differences in inhibin B levels between male and female manatees (P=0.03) throughout the year. No significant differences in inhibin B were detected between low impacted and higher impacted sampling locations during winter, suggesting the potential influence of environmental stress on manatee reproduction may be best examined between mid-March and mid-August, the midpoint of the reproductively active, non-winter time period. Establishing temporal baselines for inhibin B values may be useful in assessing manatee reproductive status and potential conservation threats, shedding light on fertility potential and enabling future assessment of the effects of stressors on reproduction in Florida manatees.
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Bibliography and Index of the Sirenia and Desmostylia 