Temporal stability of fecal cortisol metabolites in mountain-dwelling ungulates

Fecal cortisol metabolites (FCMs) are widely used to track stress responses in wildlife and captive species. Rules of thumb suggest that samples should be collected as soon as possible after defecation, to avoid decay of FCMs. To date, however, only a few studies investigated the stability of defecated FCMs over time, and most of them were conducted in controlled laboratory conditions. Here, we investigated the stability of FCMs over seven consecutive days, in two mountain-dwelling ungulates, under natural environmental conditions using a semi-experimental approach. Fecal samples from Northern chamois Rupicapra rupicapra (n = 24) and red deer Cervus elaphus (n = 22) were collected in summer of 2020 within the Stelvio National Park, Italy, and placed in an open area above 2000 m a.s.l. For the next 7 days, we collected a portion of each sample, and all sub-samples were analyzed with an 11-oxoetiocholanolone enzyme immunoassay. Exposure, temperature, and precipitation were fitted as covariates in non-linear generalized mixed models to assess FCM variation over time, and competing models were selected using AICc. For chamois, the best model included only time as a predictor, while for red deer, it included time, precipitation, and exposure. For both species, FCM values decreased rapidly from the first days after deposition until the fourth day. For red deer, in northern-exposed samples, FCM values decreased slower than in south-exposed ones; furthermore, FCM values increased with increasing precipitation. Our results offer a solid methodological basis to wildlife researchers and practitioners interested in the investigation of the ecological factors affecting stress variation in wildlife and support the recommendation to collect samples as fresh as possible, to avoid misleading inference. Further studies are necessary to evaluate the stability of FCMs when other enzyme immunoassays are used.

Perfluoroalkyl Acid Concentrations in Livers of Fox (Vulpes vulpes) and Chamois (Rupicapra rupicapra) from Germany and Austria

The concentrations of 11 perfluorinated alkyl acids (PFAAs) were measured in the livers of foxes (Vulpes vulpes) from Germany, a primarily carnivorous species, and chamois (Rupicapra rupicapra) from Austria, an herbivorous species. Perfluorooctanesulfonate (PFOS) at concentrations [all results refer to wet weight (ww)] of 3.2-320 µg/kg were detected in all 40 fox livers tested, yielding an arithmetic mean of 46.6 µg/kg and a median of 29.8 µg/kg. Long-chain PFAAs were detected at concentrations of 1.7 µg/kg perfluorononanoic acid (PFNA) to 2.4 µg/kg perfluorodecanoic acid (PFDA) and perfluorododecanoic acid (PFDoDA). Of the short-chain PFAAs tested, only perfluorohexanoic acid (PFHxA) was found in 1 fox liver at a concentration of 1.4 µg/kg, and perfluorohexane sulfonate (PFHxS) was found in 2 fox livers at a concentration of 1 µg/kg each. PFOS and PFNA concentrations higher than limit of quantification (LOQ) were detected in 90.9 and 81.8 % of chamois livers, respectively. The arithmetic mean for PFOS concentrations was 2.2 µg/kg (median 2.4 µg/kg), a factor of 21 (median factor of 12) lower than in fox livers. The arithmetic mean for PFNA concentrations was 2.0 µg/kg (median 1.9 µg/kg). Perfluorobutanoic acid, PFHxA, perfluorooctanoic acid, perfluorobutanesulfonate, and PFHxS were not detected at concentrations higher than the LOQ in any of the samples. The various results are compared with one another and with the results of other studies of herbivorous, carnivorous, and omnivorous wild animals. The highest concentrations of PFAA, in particular PFOS, were found in omnivorous animals followed by carnivores. The lowest levels were present in herbivores.

Mineral levels in Pyrenean chamois (Rupicapra pyrenaica)

The effects of mineral deficiencies are often sub-clinical, and the importance of mineral status is often underestimated in wildlife populations. To our knowledge, this is the first study that gives reference intervals of hepatic minerals for Pyrenean chamois (Rupicapra pyrenaica). We determined macro and trace mineral concentrations in liver samples from 100 animals (44 healthy and 56 sick) collected in the Catalan Pyrenees (NE Spain) from 1995 to 2008. After wet digestion, we determined Na, K, Ca, P, Mg, S, and Fe concentrations by inductively coupled plasma optical emission spectrometry (ICP-OES) and Cu, Zn, and Mo concentrations by inductively coupled plasma mass spectrometry (ICP-MS). We observed low hepatic concentrations of Cu in a considerable percentage of chamois, without evidences that these low concentrations increased their susceptibility to infectious diseases. The group of sick chamois had very similar percentage of animals (10/56) with low concentration of Cu (<20 ppm DW) than the group of healthy chamois (9/44). On the other hand, we observed that infectious diseases increased significantly the hepatic concentrations of Na, Ca, Mg, Fe and Zn, very likely, as a consequence of processes associated with the acute phase inflammatory response. The obtained values of liver mineral levels and their sources of variation, such as sex, age and disease, mostly fall within the range of those described for other ruminants, but possible deficiencies and differences between individuals and populations require further study.