Long-term effect of heavy-metal pollution on diversity of gastrointestinal microbial community of Bufo raddei.

Gastrointestinal (GI) microbiota plays a very important role in maintaining its host's health. However, the effects of environmental contamination on the GI microbiota homeostasis of amphibians have not yet been reported. The present study reveals the long-term effect of natural heavy-metal pollution on the GI microbial community diversity and structural changes of Bufo raddei (B. raddei). Basing on the 16S rRNA sequencing method, the GI microbiota of B. raddei from a heavily heavy-metal-polluted area (Baiyin, (BY)) and a relatively unpolluted area (Liujiaxia, (LJX)) were profiled. The results showed that heavy-metal pollution had caused significant shifts in the composition of the GI microbiota both at the phylum and genus levels. Specifically, Bacteroidetes dominated in the GI tract of B. raddei from BY, while Tenericutes was much more common in those from LJX. The ratio of Firmicutes/Bacteroidetes and the proportion of probiotics in the GI microbiota of B. raddei from BY were reduced compared to those from LJX, as well. Heavy-metal pollution also induced in a reduction of species diversity and decreased proportion of unique operational taxonomic units in the GI tract. In short, our results demonstrate that long-term heavy-metal exposure re-shaped the composition and decreased the species diversity of GI microbiota of B. raddei; our results also represent a novel approach to uncover the toxic effects of pollution on amphibians.

Experimentally increased temperature and hypoxia affect stability of social hierarchy and metabolism of the Amazonian cichlid Apistogramma agassizii.

The primary goal of this study was to understand how changes in temperature and oxygen could influence social behaviour and aerobic metabolism of the Amazonian dwarf cichlid Apistogramma agassizii. Social hierarchies were established over a period of 96h by observing the social interactions, feeding behaviour and shelter use in groups of four males. In the experimental environment, temperature was increased to 29°C in the high-temperature treatment, and oxygen lowered to 1.0mg·L(-1)O2 in the hypoxia treatment. Fish were maintained at this condition for 96h. The control was maintained at 26°C and 6.6mg·L(-1)O2. After the experimental exposure, metabolism was measured as routine metabolic rate (RMR) and electron transport system (ETS) activity. There was a reduction in hierarchy stability at high-temperature. Aggression changed after environmental changes. Dominant and subdominant fish at high temperatures increased their biting, compared with control-dominant. In contrast, hypoxia-dominant fish decreased their aggressive acts compared with all other fish. Shelter use decreased in control and hypoxic dominant fish. Dominant fish from undisturbed environments eat more than their subordinates. There was a decrease of RMR in fish exposed to the hypoxic environment when compared with control or high-temperature fish, independent of social position. Control-dominant fish had higher RMR than their subordinates. ETS activity increased in fish exposed to high temperatures; however, there was no effect on social rank. Our study reinforces the importance of environmental changes for the maintenance of hierarchies and their characteristics and highlights that most of the changes occur in the dominant position.

Reported health conditions in animals residing near natural gas wells in southwestern Pennsylvania.

Natural gas extraction activities, including the use of horizontal drilling and hydraulic fracturing, may pose potential health risks to both human and animal populations in close proximity to sites of extraction activity. Because animals may have increased exposure to contaminated water and air as well as increased susceptibility to contaminant exposures compared to nearby humans, animal disease events in communities living near natural gas extraction may provide "sentinel" information useful for human health risk assessment. Community health evaluations as well as health impact assessments (HIAs) of natural gas exploration should therefore consider the inclusion of animal health metrics in their assessment process. We report on a community environmental health survey conducted in an area of active natural gas drilling, which included the collection of health data on 2452 companion and backyard animals residing in 157 randomly-selected households of Washington County, Pennsylvania (USA). There were a total of 127 reported health conditions, most commonly among dogs. When reports from all animals were considered, there were no significant associations between reported health condition and household proximity to natural gas wells. When dogs were analyzed separately, we found an elevated risk of 'any' reported health condition in households less than 1km from the nearest gas well (OR = 3.2, 95% CI 1.07-9.7), with dermal conditions being the most common of canine disorders. While these results should be considered hypothesis generating and preliminary, they suggest value in ongoing assessments of pet dogs as well as other animals to better elucidate the health impacts of natural gas extraction on nearby communities.

Environmental control to maintain stabled COPD horses in clinical remission: effects on pulmonary function.

The objective of this study was to test the hypothesis that stabled COPD horses can be maintained in clinical remission by replacing hay by grass silage and bedding made of wood shavings (Period B) and of wheat straw (Period C) during 6 weeks, respectively. At the end of these different periods, the pulmonary function of the horses was assessed by mechanics of breathing and arterial blood analyses. These results were compared to those measured in clinical remission obtained after 2 months in pasture (Period A). No significant difference was observed between these 3 periods neither to values obtained for healthy horses placed during 6 weeks in a hay environment. For all that, COPD horses placed in contact with hay in the same barn developed within mean +/- s.d. 8+/-3 days clinical signs of heaves and significant alterations of pulmonary function parameters.