Stable carbon isotope composition of perirenal adipose tissue fatty acids from Engadine sheep grazing either mountain or lowland pasture

Details

Serval ID
serval:BIB_43ECBE04861A
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Stable carbon isotope composition of perirenal adipose tissue fatty acids from Engadine sheep grazing either mountain or lowland pasture
Journal
Journal of Animal Science
Author(s)
Richter E.K., Spangenberg J.E., Willems H., Kreuzer M., Leiber F.
ISSN-L
0021-8812
Publication state
Published
Issued date
2012
Peer-reviewed
Oui
Volume
90
Pages
905-913
Language
english
Notes
ISI:000300610500023
Abstract
To provide further insights into ruminant lipid digestion and
metabolism, and into cis9, trans-11 18:2 synthesis, 12 growing Engadine
lambs grazing either mountain pasture (2,250 m above sea level; n = 6)
or lowland pasture (400 m above sea level; n = 6) were studied. Both
pastures consisted exclusively of C-3 plants. Before the experiment, all
animals grazed a common pasture for 6 wk. Grasses and perirenal adipose
tissues of the sheep were analyzed for fatty acids by gas
chromatography. Stable C-isotope ratios (delta C-13 values in % vs. the
Vienna Pee Dee Belemnite standard) were determined in the composite
samples by elemental analysis-isotope ratio mass spectrometry. The delta
C-13 of the individual fatty acids were measured by gas
chromatography-combustion-isotope ratio mass spectrometry. The delta
C-13 value of the entire mountain pasture grass was -27.5% (SD 0.31),
whereas that of the lowland pasture grass was -30.0% (SD 0.07). This
difference was reflected in the perirenal adipose tissues of the
corresponding sheep (P < 0.05), even though the delta C-13 values were
less in the animals than in the grass. The delta C-13 values for cis-9
16:1 and cis-9 18:1 in perirenal fat differed between mountain and
lowland lambs (P < 0.05). The 16:0 in the adipose tissue was enriched in
C-13 by 5% compared with the dietary 16:0, likely as a result of partly
endogenous synthesis. The d13C values of cis-9, trans-11 18:2 (cis-9,
trans-11 CLA) in the adipose tissue were smaller than those of its
dietary precursors, cis-9, cis-12 18:2 and cis-9, cis-12, cis-15 18:3;
conversely, the delta C-13 values of trans-11 18:1 were not, suggesting
that large proportions of perirenal cis-9, trans-11 18:2 were of
endogenous origin and discrimination against C-13 occurred during
Delta(9)-desaturation. The same discrimination was indicated by the
isotopic shift between 16:0 and cis-9 16:1 in the mountain grazing
group. Furthermore, the delta C-13 values of cis-9, trans-11 18:2 were
smaller relative to the precursor fatty acids in the mountain lambs
compared with the lowland group. This result suggests a reduced extent
of biohydrogenation in lambs grazing on mountain grass in comparison
with those grazing on lowland grass. This was supported by the smaller
cis-9, trans-11 18:2 concentrations in total fatty acids found in the
adipose tissues of the lowland lambs (P < 0.001). The results of this
study demonstrate that natural differences between delta C-13 values of
swards from different pastures and the adipose tissue fatty acids could
be used as tracers in studies of lipid metabolism in ruminants.
Create date
26/09/2012 14:11
Last modification date
20/08/2019 13:48
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