Endocrine correlates of musth and the impact of ecological and social factors in free-ranging African elephants (Loxodonta africana)

Ganswindt, André; Muenscher, Stefanie B.; Henley, Michelle; Henley, Stephen; Heistermann, Michael; Palme, Rupert; Thompson, Peter N.; Bertschinger, H.J.

doi:10.1016/j.yhbeh.2010.02.009

Cited by 48 publications

(70 citation statements)

References 34 publications

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“…GCMs, although a corticosterone RIA was (Goymann et al 1999). However, the tested 11-oxoetiocholanolone EIA has successfully been used to detect hormonal changes in other mammal species (Ganswindt et al 2010a(Ganswindt et al , 2010bKleinsasser et al 2010;Hulsman et al 2011). These results highlight the necessity for species-specific validation of every assay used to detect GCM in feces (Palme 2005;Touma and Palme 2005).…”

Section: Discussionmentioning

confidence: 99%

Validation of Noninvasive Monitoring of Adrenocortical Endocrine Activity in Ground-Feeding Aardwolves (Proteles cristata): Exemplifying the Influence of Consumption of Inorganic Material for Fecal Steroid Analysis

Ganswindt

Muilwijk²,

Engelkes³

et al. 2012

Physiological and Biochemical Zoology

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JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.The University of Chicago Press is collaborating with JSTOR to digitize, preserve and extend access to Physiological and Biochemical Zoology.http://www.jstor.org ABSTRACTBiologically inert material in feces may confound interpretations of noninvasive fecal endocrine data, because it may induce variance related to differences in foraging behavior rather than to differences in endocrine activity. We evaluated two different enzyme immunoassays (EIAs) for the noninvasive evaluation of adrenocortical activity in ground-feeding aardwolves (Proteles cristata) and tested the influence of soil content in aardwolf feces on the interpretation of fecal glucocorticoid metabolite data. Using adrenocorticotropic hormone (ACTH) challenges for validation, we successfully identified a cortisol EIA suitable for assessing adrenocortical activity in aardwolves. An alternatively tested 11-oxoetiocholanolone EIA failed to detect a biologically relevant signal after ACTH administration. Although the proportion of inorganic content in aardwolf feces did not alter qualitative conclusions from the endocrine data, the data related to mass of organic content had a larger amount of variance attributed to relevant biological contrasts and a lower amount of variance attributed to individual variation, compared with data related to total dry mass of extracted material. Compared with data expressed as dry mass of extracted material, data expressed as mass of organic content may provide a more refined and statistically powerful measure of endocrine activity in species that ingest large amounts of indigestible material.

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Section: Discussionmentioning

confidence: 99%

Validation of Noninvasive Monitoring of Adrenocortical Endocrine Activity in Ground-Feeding Aardwolves (Proteles cristata): Exemplifying the Influence of Consumption of Inorganic Material for Fecal Steroid Analysis

Ganswindt

Muilwijk²,

Engelkes³

et al. 2012

Physiological and Biochemical Zoology

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“…To account for the serial autocorrelation of measurements, we included a first-order autoregressive disturbance term with the autocorrelation parameter (q) estimated based on a single-lag regression of residuals. Due to the fact that season and reproductive state also affect glucocorticoid levels in African elephants (Foley et al 2001, Ganswindt et al 2005a, Viljoen et al 2008b, Ganswindt et al 2010, both factors were additionally entered as binary independent variables. We categorised sam- ples by season into two groups (i.e.…”

Section: Discussionmentioning

confidence: 99%

“…We then extracted approximately 0.05 g of the faecal powder with 3 ml 80% ethanol in water. After vortexing for 15 minutes, we centrifuged the mixture for 10 minutes at 3,300 g, and transferred the supernatant to a microcentrifuge tube for hormone analysis (Ganswindt et al 2010). We analysed immunoreactive GCM in diluted extracts (1:50 or 1:100 in aqueous buffer) with an 11-oxoaetiocholanolone enzyme immunoassay (EIA) first described by .…”

Section: Extraction and Analysis Of Faecal Glucocorticoid Metabolitesmentioning

confidence: 99%

Concentrations of faecal glucocorticoid metabolites in physically injured free‐ranging African elephants Loxodonta africana

et al. 2010

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Free-ranging African elephants Loxodonta africana use their front feet frequently during the process of foraging and this could be the reason for the high prevalence of physical injuries to these parts of the body. Although the occurrence of severe lameness caused by foot lesions in adult elephants has already been investigated and the clinical and pathological findings have been reported, the effect of foot injuries on glucocorticoid levels as a potential physiological stress response has not been examined. Given the practical difficulties involved in monitoring unpredictable events in free-ranging animals, like the occurrence of foot injuries in elephants, it is not surprising that information regarding the endocrine correlates of physical injury is still limited for elephants. In our study we investigated the effects of foot injuries on concentrations of faecal glucocorticoid metabolites (GCM), body condition score (BCS) and reproductive behaviour in two GPS/radio-collared elephant bulls in the Kruger National Park, South Africa. We monitored the bulls aged 40+ (Bull 1) and 30+ (Bull 2) 2-3 times per week for 13 months starting in June 2007 and frequently collected faecal samples for non-invasive hormone monitoring. Faecal samples were lyophilised, extracted and assayed with an enzyme immunoassay which detects GCM with a 3a-hydroxy-11-oxo-structure. Both bulls acquired foot injuries (right-front), which caused temporary lameness, but the effect of injury on GCM concentration differed between bulls (P , 0.001). In Bull 1 the injury lasted 6 250 days and was associated with an up to four-fold increase in GCM concentrations (P , 0.001) and his BCS reduced from 'good' to 'very thin' by the end of the injury period. In Bull 2 the injury lasted 65 days and was associated with a smaller increase in GCM concentrations (P ¼ 0.03) together with a reduced loss in condition when compared to Bull 1. Following recovery, the condition of both bulls improved progressively and faecal GCM returned to baseline concentrations. Collectively, the data clearly underlined the value of non-invasive hormone measurements as a tool to provide information on the level of stress experienced by elephants. Thus, monitoring GCM levels could help improve the assessment of an elephant's state of health.

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“…Furthermore, the revealed fecal glucocorticoid metabolite (FGM) levels for elephants at EFAF indicate that these animals are not differently affected by potential stress-related environmental and ecophysiological factors than their free-ranging counterparts. Elephants at EFAF had FGM levels comparable with those from elephants sampled in zoological institutions located in Europe and the United States (Ganswindt et al 2005a), as well as from animals monitored in East and South Africa (Ganswindt et al 2005b(Ganswindt et al , 2010a. Actually, the low ␦ 15 N values of elephants at EFAF may indicate relatively low levels of nutritional stress because when nutrients are limiting, animals rely more heavily on catabolically derived proteins, effectively synthesizing body proteins at higher trophic levels and resulting in higher ␦ 15 N values (Hobson et al 1993).…”

Section: Discussionmentioning

confidence: 88%

“…The assessment of FGM concentrations in elephants housed at EFAF facilities revealed hormone levels comparable with those from elephants in the wild (Student's t test, t [12,58] = 396, p = 0.646; data from Ganswindt et al 2005bGanswindt et al , 2010aGanswindt et al , 2010b. The five animals (25-39 samples/animal) monitored in 2006 had individual mean FGM baseline values between 0.38 and 0.80 g/g dry mass (DM) (mean 0.58 g/g DM), and the seven elephants (9 samples/animal) monitored in 2007 showed individual mean FGM levels between 0.48 and 0.69 g/g DM (mean 0.59 g/g DM).…”

Section: Captive Elephantsmentioning

confidence: 99%

Stable isotope turnover and variability in tail hairs of captive and free-ranging African elephants (Loxodonta africana) reveal dietary niche differences within populations

et al. 2013

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Many herbivore species expand their dietary niche breadths by switching from browse-rich diets in dry seasons to grass-rich diets in rainy seasons, in response to phenological changes in plant availability and quality.Weanalyzed stable isotope series along tail hairs of captive and free-ranging African elephant (Loxodonta africana (Blumenbach, 1797)) to compare patterns of seasonal dietary variability across individuals. Results from elephants translocated from the wild into captivity, where their diets are semicontrolled, revealed tail hair growth rates of 0.34 mm/day, on average, and relatively rapid isotope turnover through the transition from wild into captivity. Sampling hairs at 10 mm increments thus archives dietary chronologies at a resolution suitable for tracking diet switches at seasonal, and even subseasonal, scales. Hairs of free-ranging elephants showed extensive carbon isotopic variability within individuals, consistent with seasonal switches between C3-browsing and C4-grazing. Similarly extensive, but asynchronous, shifts in nitrogen isotope ratios were also observed, suggesting an influence of factors other than seasonality. Across individuals, switching patterns differed across habitats, and across age classes, with older, larger animals including increasing amounts of C3 browse into their diets. These results demonstrate how stable isotope approaches characterize complex patterns of resource use in wildlife populations. ARTICLEStable isotope turnover and variability in tail hairs of captive and free-ranging African elephants (Loxodonta africana) reveal dietary niche differences within populations Jacqueline Codron, Kevin Kirkman, Kevin J. Duffy, Matt Sponheimer, Julia A. Lee-Thorp, Andre Ganswindt, Marcus Clauss, and Daryl Codron Abstract: Many herbivore species expand their dietary niche breadths by switching from browse-rich diets in dry seasons to grass-rich diets in rainy seasons, in response to phenological changes in plant availability and quality. We analyzed stable isotope series along tail hairs of captive and free-ranging African elephant (Loxodonta africana (Blumenbach, 1797)) to compare patterns of seasonal dietary variability across individuals. Results from elephants translocated from the wild into captivity, where their diets are semicontrolled, revealed tail hair growth rates of ϳ0.34 mm/day, on average, and relatively rapid isotope turnover through the transition from wild into captivity. Sampling hairs at 10 mm increments thus archives dietary chronologies at a resolution suitable for tracking diet switches at seasonal, and even subseasonal, scales. Hairs of free-ranging elephants showed extensive carbon isotopic variability within individuals, consistent with seasonal switches between C 3 -browsing and C 4 -grazing. Similarly extensive, but asynchronous, shifts in nitrogen isotope ratios were also observed, suggesting an influence of factors other than seasonality. Across individuals, switching patterns differed across habitats, and across age classes, with older,...

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Endocrine correlates of musth and the impact of ecological and social factors in free-ranging African elephants (Loxodonta africana)

Cited by 48 publications

References 34 publications

Validation of Noninvasive Monitoring of Adrenocortical Endocrine Activity in Ground-Feeding Aardwolves (Proteles cristata): Exemplifying the Influence of Consumption of Inorganic Material for Fecal Steroid Analysis

Validation of Noninvasive Monitoring of Adrenocortical Endocrine Activity in Ground-Feeding Aardwolves (Proteles cristata): Exemplifying the Influence of Consumption of Inorganic Material for Fecal Steroid Analysis

Concentrations of faecal glucocorticoid metabolites in physically injured free‐ranging African elephants Loxodonta africana

Stable isotope turnover and variability in tail hairs of captive and free-ranging African elephants (Loxodonta africana) reveal dietary niche differences within populations

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