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Plasma metabolite indices are robust to extrinsic variation and useful indicators of foraging habitat quality in Lesser Scaup (Aythya affinis)

Citation

Smith, Eric; Anteau, Michael; Hagy, Heath; Jacques, Christopher (2021), Plasma metabolite indices are robust to extrinsic variation and useful indicators of foraging habitat quality in Lesser Scaup (Aythya affinis), Dryad, Dataset, https://doi.org/10.5061/dryad.zkh18939b

Abstract

This dataset contains plasma lipid metabolite values collected from Lesser Scaup (Aythya affinis) during spring migration (March 2016 and 2017) as described in the paper "Smith, E.J., M.J. Anteau, H. M. Hagy and C.N. Jacques (2021). Plasma metabolite indices are robust to extrinsic variation and useful indicators of foraging habitat quality in Lesser Scaup (Aythya affinis). Ornithology. In press."

The experiment investigates the use of plasma metabolites beta-hydroxybutyrate (BOHB) and triglyceride (TRIG) as predictors of mass change in Lesser Scaup. Previously, linear relationships have been examined between these two metabolites, where beta-hydroxybutyrate has a negative relationship with mass change and triglycerides have a positive relationship with mass change.   

Our results using short-term captive scaup indicate that the relationship between these metabolites and daily mass change is robust to extrinisic factors and could be used by waterfowl/wetland managers to index habitat quality during migration.   

Methods

Captive Methods:

Approximately 24 hr after recording initial weight and 4-hr post experimental treatment, we recorded final mass measurements and extracted 0.5 mL of blood from the tibiotarsal vein  anterior the intertarsal joint using a heparinized 1-cc syringe affixed with a 25-ga needle. We transferred blood to 1.5-mL heparinized micro-centrifuge tubes and centrifuged at 6,000 rpm (2,000 × G) for 7 min within 30 min of collection. We extracted plasma using a micropipette, transferred to a sterile vial, and froze within 20 min at 20º C until analysis (Guglielmo et al. 2002, Anteau and Afton 2008b, Janke 2016). The U.S. Geological Survey Bird Banding Laboratory approved markers, blood drawings, and handling methods (#23923). 

Laboratory Methods:

We followed established protocols that utilize endpoint assay for measuring total triglycerides (TRIG + glycerol) and glycerol. Free TRIG was calculated by subtracting glycerol from total TRIG (Guglielmo et al. 2002, Anteau 2006, Janke 2016). We measured BOHB by kinetic assay using standard protocols (Guglielmo et al. 2005, Anteau 2006, Janke 2016). Plasma-lipid Plasma-lipid metabolites as mass change indicators in birds metabolite assays, both endpoint and kinetic, were completed at Northern Prairie Wildlife Research Center using a microplate spectrophotometer (BioTek, Inc., model EON, Winooski, Vermont, USA). Upon completion of metabolite assays, we censored two males and one female due to irregular sample quality, thus our analysis included 28 males and 30 females.

Usage Notes

Samples were collected from 30 females and 27 females.  

Plasma metabolites value units are mmol/L-1.

BOHB value have been transformed (natural log).

TRIG is free triglycerides meaning that we subtracted glycerol values from output of metabolite assays. 

xvalidation.csv file contains z-score standardization values for TRIG, and predicted mass change values. 

 

Funding

Mississippi Flyway Council

Western Illinois University

Mississippi Flyway Council