No abstract

Diet quality may have an important effect on the regulation of oxidative status and the immune system during an infectious disease. However, the relationship among intake of specific dietary molecules, an individual’s oxidative status and the occurrence and progress of a viral disease remains almost unexplored in free‐living organisms. Here, we study a wild, long‐lived animal, the Magnificent frigatebird Fregata magnificens to investigate: (a) the differences in a number of physiological traits (biomarkers of blood oxidative status, corticosterone (CORT), immunity and inflammation) between sick and healthy nestlings; and (b) whether experimentally increased intake of resveratrol (a polyphenol with antioxidant and antiviral properties) affects these physiological markers during the progress of a severe viral disease. Birds with visible clinical signs showed higher oxidative damage, haemolysis and haemagglutination scores and lower antioxidant defences in comparison with birds without clinical signs. At the end of the experiment, supplemented birds showed the following: (a) increased plasma haptoglobin levels and circulating antioxidant defences; (b) reduced generation of lipid oxidative damage; and (c) negligible to no influence on immune markers, baseline CORT levels and activity of antioxidant enzymes. Our work illustrates how the availability of specific organic molecules in the diet may constrain the individuals’ capacity to cope with viral infections in free‐living animals. http://onlinelibrary.wiley.com/doi/10.1111/1365-2435.13195/suppinfo is available for this article.

No abstract

Status epilepticus (SE) affects approximately 41 of every 100 000 adults and is difficult to treat. For this reason, up to 20% of cases are reported to involve mortality. 1 Various neurological disorders are associated with SE, including cerebrovascular diseases, trauma, intoxication, and also others, but it is unclear why SE develops only in some patients affected by the previously mentioned central nervous system (CNS) disorders. In addition, SE also develops without a clear reason in some cases. Finally, patients with epilepsy may experience one or more episodes of SE, whereas others

Selective logging is a major driver of environmental changes in the tropics. Recently, there has been increasing interest in understanding which traits make bird species resilient or vulnerable to such changes. Physiological stress mediated by the steroid hormone corticosterone (CORT) might underlie changes in local abundance of species because it regulates a range of body functions and behaviours to maintain homeostasis in changing environments. We conducted a 3‐year study to assess (a) the variation in CORT levels in feathers (where CORT is deposited during the moult) of 10 understorey bird species across both unlogged old‐growth forest and selectively logged forest in Borneo, (b) how this variation is associated with within‐year variation in population abundance between forest types and (c) whether the difference in feather CORT (fCORT) between co‐specific populations living in unlogged and logged forests in 1 year is related with their difference in population abundance the following year. We used effect size estimates to measure standardized magnitude and direction of fCORT changes between unlogged and selectively logged forest. We found small to large effect sizes, indicating large among‐species variation in physiological acclimatization to changes in forest conditions. In 2016 and 2018, species with relatively higher fCORT in unlogged forest were relatively more abundant in logged forest in the same year; in 2017, species with relatively higher fCORT in logged forest were relatively more abundant in logged forest. Importantly, we found that for a given species, the difference in fCORT at year (x) between unlogged and logged forests was negatively related with a difference in its local abundance between the two forest types in the following year (x + 1). Our results point to glucocorticoid hormones as potential mediators of carry‐over effects on population abundance due to direct and indirect effects of silvicultural practices in tropical forests of Borneo, suggesting fCORT as a potential marker of population changes. A free Plain Language Summary can be found within the Supporting Information of this article.