DOI: 10.5061/dryad.zkh18939b
title: Plasma metabolite indices are robust to extrinsic variation and useful indicators of foraging habitat quality in Lesser Scaup (Aythya affinis)

description: 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.   
description: <strong>Captive Methods:</strong>
 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).  <strong>Laboratory
 Methods:</strong> 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.
description: 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.