The Wilson Journal of Ornithology 123( 1): 116-120, 2011 
MUSCLE MEMBRANE PHOSPHOLIPID CLASS COMPOSITION IN 
WHITE-THROATED SPARROWS IN RELATION TO MIGRATION 
JEREMY SPRINGER, 1 EDWIN R. PRICE, 1 ’ 2 
RAYMOND THOMAS, 1 AND CHRISTOPHER G. GUGLIELMO 1 
ABSTRACT.—We document seasonal changes in the ratio of phosphatidylcholine (PC) to phosphatidylethanolamine 
(PE) in pectorahs muscles of captive and wild White-throated Sparrows (Zonotrichia albicollis). We manipulated day 
length in captive sparrows to induce ‘winter’ or ‘migratory’ condition. The PC/PE ratio in these sparrows was 1.87 ± 0.11 
(mean ± SE), and did not vary significantly between treatments. However, the PC/PE ratio was higher in wild adult 
sparrows in winter (1.90 ± 0.19) than those caught in migration (1.20 ± 0.13 in spring; 1.37 ± 0.14 in fall). No effect of 
migratory state on PC/PE ratio was found among wild juveniles (1.32 ± 0.09 in fall, 1.18 ± 0.14 in winter). Seasonal 
™ a >n ge f t0 PC/ , PE rat ' 0S may be 3 reSUlt ° f migratoI T exercise > ra ther than migratory condition per se. Received 30 April 
2010. Accepted 23 September 2010. 
Findings of several recent studies have gener¬ 
ated increased interest in muscle membrane 
alterations during exercise and how changes in 
membranes affect exercise performance (Ayre 
and Hulbert 1997, Infante et al. 2001, Guglielmo 
et al. 2002, Valencak et al. 2003, Nagahuedi et al. 
2009) . Ornithologists, in particular, have been 
interested in how membrane composition could 
a^ect migration, a period of high-intensity 
endurance exercise (Guglielmo et al. 2002, Pierce 
et al. H)05. Maillet and Weber 2006. Price et al 
2010) . Biological membranes are composed 
primarily of phospholipids which consist of a 
polar head group, a glycerol phosphate backbone, 
and two fatty acid tails. Exercise is known to 
affect both the fatty acid and head group moieties 
(class composition) of phospholipids in mammals 
and birds (Morgan et al. 1969, Ayre et al. 1998, 
Gorski et al. 1999, Mitchell et al. 2004, Turner et 
al. 2004, Price et al. 2010). Changes to membrane 
fatty acid composition brought about by dietary 
manipulation have been associated with exercise 
performance alterations in mammals, fish, and 
birds (Ayre and Hulbert 1997, McKenzie et al. 
1998, Pierce et al. 2005), although the role of 
membranes in these studies has been questioned 
(Price and Guglielmo 2009). In addition, a 
comparative study of mammalian maximal run¬ 
ning speed demonstrated a correlation with 
membrane fatty acid composition (Ruf et al. 
The mechanism by which muscle membranes 
might affect migratory exercise is poorly under¬ 
1 Department of Biology, University of Western Ontario 
London, ON N6A 5B7, Canada. 
2 Corresponding author; e-mail: eprice3@uwo.ca or 
rrlemur@hotmail.com 
stood. It has often been ascribed to changes in 
membrane fluidity, permeability, or the local 
membrane-bound protein environment, which 
can in turn affect the activity of membrane-bound 
proteins, and could thereby impact key metabolic 
processes that affect exercise (Murphy 1990, 
Power and Newsholme 1997, Infante et al. 2001, 
Valencak et al. 2003, Guo et al. 2005, Nagahuedi 
et al. 2009). Both the fatty acid and class 
composition of phospholipids have the potential 
to affect these membrane properties (Pan et al. 
1994, Hazel 1995, Hulbert and Else 1999, Li etal. 
2006, Gerson et al. 2008. Guderley et al. 2008). 
Variation in the fatty acid composition of muscle 
membranes has been investigated in relation to 
migration (Guglielmo et al. 2002, Maillet and 
Weber 2006, Klaiman et al. 2009), but phospho¬ 
lipid class composition has not been studied in a 
migratory context. Our objective is to provide a 
first description of phospholipid class composition 
in migratory birds and how it changes seasonally, 
using photoperiod-manipulated captive birds as 
well as wild-caught migrating and wintering birds. 
METHODS 
Photoperiod-manipulated Captive Sparrows.— 
White-throated Sparrows (Zonotrichia albicollis ) 
are short-hop, long-distance migrants common to 
eastern North America. Twelve White-throated 
Sparrows were captured near Long Point, Ontario 
by mist-netting in October. All birds were housed 
singly in 40 (height) X 45 X 45-cm cages, and 
were initially exposed to short day (8L.16D) 
photoperiod for 8 weeks to break photorefractori¬ 
ness (Agatsuma and Ramenofsky 2006). Small 
night lights were used during the dark periods to 
avoid complete darkness. Birds were initially fed 
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