Compromised survivorship in zoo elephants

Keeping elephants in zoos is extremely costly, yet does not yield self-sustaining 16 populations. In Europe, which holds c. half the global zoo elephant population, a long17 term decline of c.10% per year is expected in both species, if reliant on zoo-bred animals 18 under historically prevailing conditions. Fitness in zoos is compromised in several ways. 19 Compared with protected in situ populations (Burmese working Asians; Kenyan free20 living Africans), zoo elephants show premature reproductive senescence and -- despite 21 improving adult survivorship for Africans -- die earlier in adulthood than expected. In 22 Asian elephants, infant survivorship in zoos is also greatly reduced relative to Burmese 23 elephants, and furthermore, zoo-born animals die earlier in adulthood than wild-caught 24 conspecifics kept in zoos, via effects ‘programmed’ peri-natally. In this species, being 25 transferred between zoos also increases mortality rates. Both survival and fecundity 26 would need to improve to attain self-sustaining zoo populations. Our findings 27 demonstrate deficits in zoo elephant management, particularly for Asians, and implicate 28 stress and obesity as likely problems

Solid-Phase Microextraction and the Human Fecal VOC Metabolome

The diagnostic potential and health implications of volatile organic compounds (VOCs) present in human feces has begun to receive considerable attention. Headspace solid-phase microextraction (SPME) has greatly facilitated the isolation and analysis of VOCs from human feces. Pioneering human fecal VOC metabolomic investigations have utilized a single SPME fiber type for analyte extraction and analysis. However, we hypothesized that the multifarious nature of metabolites present in human feces dictates the use of several diverse SPME fiber coatings for more comprehensive metabolomic coverage. We report here an evaluation of eight different commercially available SPME fibers, in combination with both GC-MS and GC-FID, and identify the 50/30 µm CAR-DVB-PDMS, 85 µm CAR-PDMS, 65 µm DVB-PDMS, 7 µm PDMS, and 60 µm PEG SPME fibers as a minimal set of fibers appropriate for human fecal VOC metabolomics, collectively isolating approximately 90% of the total metabolites obtained when using all eight fibers. We also evaluate the effect of extraction duration on metabolite isolation and illustrate that ex vivo enteric microbial fermentation has no effect on metabolite composition during prolonged extractions if the SPME is performed as described herein

Fecundity and population viability in female zoo elephants: problems and possible solutions

We previously reported that African (Loxodonta africana) and Asian (Elephas maximus) female elephants in European zoos have shorter adult lifespans than protected conspecifics in range countries. This effect was the cause of greatest concern in Asian elephants, and risk factors within this species included being zoo-born, transferred between zoos, and possibly removed early from the mother. Here, we investigate these risk factors further; assess fecundity and sustainability in European zoos; and propose testable hypotheses as to the causes of these animals’ problems. Although imported wild-born Asian elephants live longer than zoo-born conspecifics, being imported when juvenile or adult appears no more protective than being imported in infancy, suggesting that the benefits of being wild- rather than zoo-born are conferred early in life. Zoo-born Asian neonates are significantly heavier than those born to working animals in range countries, with a possible tendency to be fatter. In zoos, African elephants have tended to be removed from their mothers at older ages than young Asians, and were also transferred between zoos significantly less often: factors that could possibly underlie this species’ lower calf losses and improving adult survivorship in Europe. Both species have low fecundity in European zoos compared to in situ populations, and are not self-sustaining, declining at approximately 10% per annum if reliant on captive-bred females under historically prevailing conditions. Data from other species suggest that stress and/or obesity are parsimonious explanations for the suite of problems seen. We recommend specific screens for testing these hypotheses, and for potentially identifying vulnerable individuals within the extant zoo populations

Extraction duration and headspace SPME of human feces.

<p>A) A plot of identified analytes as a function of extraction time. Nonlinear regression fitting the hyperbolic extraction curve yields a Y_max of 114+/−3 for the CAR-DVB-PDMS fiber (R² = 0.9937) and 94+/−4 for the PA fiber (R² = 0.9791). The PEG plot could not be extended beyond 20 min due to an unknown analyte overwhelming the MS detector. Also shown in this plot is the number of identified analytes obtained from a sample that was pretreated by boiling for 5 min before extraction. Essentially no difference in analyte number or composition is observed with the pretreated sample (CAR-DVB-PDMS+boiled sample) relative to an untreated sample (CAR-DVB-PDMS). All samples were analyzed in duplicate. See text for further discussion. B) A plot of area under the chromatographic curve as a function of time for the indicated analytes obtained using the CAR-DVB-PDMS fiber. Differences in extraction rates for the indicated metabolites are apparent.</p

GC Inlet temperatures per fiber type.

<p>GC Inlet temperatures per fiber type.</p

Fiber-dependent GC-MS identification and analysis of metabolites present in the human fecal VOC metabolome.

<p>A heat map presents the identified metabolites extracted by each SPME fiber and their relative chromatographic peak areas. Each of the eight columns in the heat map represents a different fiber. Metabolites are indicated on each row and are organized by functional group. Each extraction was performed in duplicate and replicates combined by averaging peak area values. Fiber legend: A - 75 µm CAR-PDMS, B - 85 µm CAR-PDMS, C - 50/30 µm CAR-DVB-PDMS, D - 85 µm PA, E - 65 µm DVB-PDMS, F - 7 µm PDMS, G - 100 µm PDMS, H - 60 µm PEG.</p

Heat sterilization of human feces.

<p>A) Human fecal aliquots, dispensed in vials, were either autoclaved or placed in a boiling water bath then used as inoculum for liquid cultures incubated aerobically or anaerobically, as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0018471#s2" target="_blank">Materials and Methods</a>. While untreated (not autoclaved or boiled) fecal samples display growth in all three media compositions (LB – Luria Bertani media, TSB-cys – tryptic soy broth +0.1% cysteine media, Chamberlain – Chamberlain media) and culturing conditions, autoclaving or boiling the samples abolishes growth. Reported values are average of duplicates. B) Aliquots of a human fecal sample were incubated at 60°C for the indicated duration then used as inoculum for LB-agar plates, as detailed in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0018471#s2" target="_blank">Materials and Methods</a>. A plot of colony forming units (cfu) as a function of incubation duration illustrates the loss of enteric microbial viability over the first hour of 60°C incubation, with no growth observed after 2 hours and beyond. The experiment was performed in duplicate.</p

Binary plot illustrating the GC-MS chromatographic peaks (metabolites) associated with each SPME fiber.

<p>Columns represent the fibers while rows indicate peak retention times. Each extraction was performed in duplicate and replicates combined. Fiber legend: A - 75 µm CAR-PDMS, B - 85 µm CAR-PDMS, C - 50/30 µm CAR-DVB-PDMS, D - 85 µm PA, E - 65 µm DVB-PDMS, F - 7 µm PDMS, G - 100 µm PDMS, H - 60 µm PEG.</p

Top fiber combinations.

a<p>based on maximal coverage of the total metabolites identified.</p>b<p>bracketed values are the percentage of total metabolites obtained using all eight fibers.</p

Recommended fiber combinations.

a<p>percentage of total metabolites obtained using all eight fibers.</p>b<p>substitution with the 85 µm PA fiber results in 92, 92, and 97% coverage, respectively.</p