Biology

Effects of experimental manipulation of hematocrit on avian flight performance in high and low altitude conditions [RESEARCH ARTICLE]

Kang Nian Yap, Morag F. Dick, Christopher G. Guglielmo, and Tony D. Williams

Despite widely held assumptions that hematocrit (Hct) is a key determinant of aerobic capacity and exercise performance, this relationship has not often been tested rigorously in birds and results to date are mixed. Migration in birds involves high intensity exercise for long durations at various altitudes. Therefore, it provides a good model system to examine the effect of Hct on flight performance and physiological responses of exercise at high altitude. We treated yellow-rumped warblers (Setophaga coronata) with avian erythropoietin (EPO) and anti-EPO to experimentally manipulate Hct and assessed flight performance at low and high altitudes using a hypobaric wind tunnel. We showed that anti-EPO treated birds had lower Hct than vehicle and EPO treated birds post-treatment. Anti-EPO treated birds also had marginally lower exercise performance at low altitude, committing a higher number of strikes (mistakes) in the first 30 min of flight. However, anti-EPO treated birds performed significantly better at high altitude, attaining a higher altitude in a ramped altitude challenge to 3000 m equivalent altitude, and with longer duration of flight at high altitude. Birds exercising at high altitude condition, decreased Hct, increased glucose mobilization, and decreased antioxidant capacity, regardless of treatment. In summary, we provided experimental evidence that the relationship between Hct and exercise performance is dependent on altitude. Future studies should investigate whether free-living birds adaptively modulate their Hct, potentially through a combination of erythropoiesis and plasma volume regulation (i.e. hemodilution), based on the altitude they fly at during migratory flight.

Source link

Related posts

Some Things Never Change: Conserved MYC-Family bHLH Transcription Factors Mediate Dinor-OPDA Signaling in Liverworts

Newsemia

Werner Syndrome versus Natural Aging

Newsemia

Pivotal Roles of Cryptochromes 1a and 2 in Tomato Development and Physiology

Newsemia

This website uses cookies to improve your experience. We'll assume you're ok with this, but you can opt-out if you wish. Accept Read More

Privacy & Cookies Policy

COVID-19

COVID-19 (Coronavirus) is a new illness that is having a major effect on all businesses globally LIVE COVID-19 STATISTICS FOR World