The effects of training, acute exercise and dietary fatty acid composition on muscle lipid oxidative capacity in European starlings.

Migratory birds undergo seasonal changes to muscle biochemistry. Nonetheless, it is unclear to what extent these changes are attributable to the exercise of flight itself versus endogenous changes. Using starlings (Sturnus vulgaris) flying in a wind tunnel, we tested the effects of exercise training, a single bout of flight and dietary lipid composition on pectoralis muscle oxidative enzymes and lipid transporters. Starlings were either unexercised or trained over 2 weeks to fly in a wind tunnel and sampled either immediately following a long flight at the end of this training or after 2 days recovery from this flight. Additionally, they were divided into dietary groups that differed in dietary fatty acid composition (high polyunsaturates versus high monounsaturates) and amount of dietary antioxidant. Trained starlings had elevated (19%) carnitine palmitoyl transferase and elevated (11%) hydroxyacyl-CoA dehydrogenase in pectoralis muscle compared with unexercised controls, but training alone had little effect on lipid transporters. Immediately following a long wind-tunnel flight, starling pectoralis had upregulated lipid transporter mRNA (heart-type fatty acid binding protein, H-FABP, 4.7-fold; fatty acid translocase, 1.9-fold; plasma membrane fatty acid binding protein, 1.6-fold), and upregulated H-FABP protein (68%). Dietary fatty acid composition and the amount of dietary antioxidants had no effect on muscle catabolic enzymes or lipid transporter expression. Our results demonstrate that birds undergo rapid upregulation of catabolic capacity that largely becomes available during flight itself, with minor effects due to training. These effects likely combine with endogenous seasonal changes to create the migratory phenotype observed in the wild.

Linear infrastructure drives habitat conversion and forest fragmentation associated with Marcellus shale gas development in a forested landscape.

Large, continuous forest provides critical habitat for some species of forest dependent wildlife. The rapid expansion of shale gas development within the northern Appalachians results in direct loss of such habitat at well sites, pipelines, and access roads; however the resulting habitat fragmentation surrounding such areas may be of greater importance. Previous research has suggested that infrastructure supporting gas development is the driver for habitat loss, but knowledge of what specific infrastructure affects habitat is limited by a lack of spatial tracking of infrastructure development in different land uses. We used high-resolution aerial imagery, land cover data, and well point data to quantify shale gas development across four time periods (2010, 2012, 2014, 2016), including: the number of wells permitted, drilled, and producing gas (a measure of pipeline development); land use change; and forest fragmentation on both private and public land. As of April 2016, the majority of shale gas development was located on private land (74% of constructed well pads); however, the number of wells drilled per pad was lower on private compared to public land (3.5 and 5.4, respectively). Loss of core forest was more than double on private than public land (4.3 and 2.0%, respectively), which likely results from better management practices implemented on public land. Pipelines were by far the largest contributor to the fragmentation of core forest due to shale gas development. Forecasting future land use change resulting from gas development suggests that the greatest loss of core forest will occur with pads constructed farthest from pre-existing pipelines (new pipelines must be built to connect pads) and in areas with greater amounts of core forest. To reduce future fragmentation, our results suggest new pads should be placed near pre-existing pipelines and methods to consolidate pipelines with other infrastructure should be used. Without these mitigation practices, we will continue to lose core forest as a result of new pipelines and infrastructure particularly on private land.

Site-specific regulation of adult neurogenesis by dietary fatty acid content, vitamin E and flight exercise in European starlings.

Exercise is known to have a strong effect on neuroproliferation in mammals ranging from rodents to humans. Recent studies have also shown that fatty acids and other dietary supplements can cause an upregulation of neurogenesis. It is not known, however, how exercise and diet interact in their effects on adult neurogenesis. We examined neuronal recruitment in multiple telencephalic sites in adult male European starlings (Sturnus vulgaris) exposed to a factorial combination of flight exercise, dietary fatty acids and antioxidants. Experimental birds were flown in a wind tunnel following a training regime that mimicked the bird's natural flight behaviour. In addition to flight exercise, we manipulated the composition of dietary fatty acids and the level of enrichment with vitamin E, an antioxidant reported to enhance neuronal recruitment. We found that all three factors - flight exercise, fatty acid composition and vitamin E enrichment - regulate neuronal recruitment in a site-specific manner. We also found a robust interaction between flight training and vitamin E enrichment at multiple sites of neuronal recruitment. Specifically, flight training was found to enhance neuronal recruitment across the telencephalon, but only in birds fed a diet with a low level of vitamin E. Conversely, dietary enrichment with vitamin E upregulated neuronal recruitment, but only in birds not flown in the wind tunnel. These findings indicate conserved modulation of adult neurogenesis by exercise and diet across vertebrate taxa and indicate possible therapeutic interventions in disorders characterized by reduced adult neurogenesis.

Constitutive immune function in European starlings, Sturnus vulgaris, is decreased immediately after an endurance flight in a wind tunnel.

Life-history theory predicts that animals face a trade-off in energy allocation between performing strenuous exercise, such as migratory flight, and mounting an immune response. We experimentally tested this prediction by studying immune function in European starlings, Sturnus vulgaris, flown in a wind tunnel. Specifically, we predicted that constitutive immune function decreases in response to training and, additionally, in response to immediate exercise. We compared constitutive immune function among three groups: (1) 'untrained' birds that were kept in cages and were not flown; (2) 'trained' birds that received flight training over a 15 day period and performed a 1-4 h continuous flight, after which they rested for 48 h before being sampled; and (3) 'post-flight' birds that differed from the 'trained' group only in being sampled immediately after the final flight. A bird in our trained group represents an individual during migration that has been resting between migratory flights for at least 2 days. A bird in our post-flight group represents an individual that has just completed a migratory flight and has not yet had time to recover. Three of our four indicators (haptoglobin, agglutination and lysis) showed the predicted decrease in immune function in the post-flight group, and two indicators (haptoglobin, agglutination) showed the predicted decreasing trend from the untrained to trained to post-flight group. Haptoglobin levels were negatively correlated with flight duration. No effect of training or flight was detected on leukocyte profiles. Our results suggest that in European starlings, constitutive immune function is decreased more as a result of immediate exercise than of exercise training. Because of the recent emergence of avian-borne diseases, understanding the trade-offs and challenges faced by long-distance migrants has gained a new level of relevance and urgency.