Transcript Diapositive 1

Within and Across Breeds Differences in Fatty
Acids Profiles of Milk and Milk Fat in Dairy Cows
H. Soyeurt1,2, P. Dardenne3, P. Mayeres1,4, C. Croquet1,5, S. Vanderick1, C. Bertozzi4
1,5
and N. Gengler
1 Gembloux
Agricultural University, Passage des Déportés 2, B-5030 Gembloux, Belgium,
E-mail: [email protected]
2 F.R.I.A.,
Agricultural Research Centre, Quality Department, B-5030 Gembloux, Belgium
Walloon Breeders Association, B-5530 Ciney, Belgium
5National
3
Results
Improving the nutritional
quality of milk fat by animal
selection ?
RED
2.00
MON
JER
1.50
1.00
0.50
18
:2
C
18
:1
C
18
:0
C
16
:1
C
16
:0
C
14
:0
C
12
:0
C
N
O
-0.50
O
0.00
M
standard deviation units
The variability within and across
breeds in fatty acid (FA) profile of
cow milk was studied with the
predicted concentrations of FA by
Mid-Infrared (MIR) Spectrometry
for each milk sample and with
mixed model theory.
DPB
Fatty acids concentrations in milk
SA
T
Objective
1
Fund for Scientific Research, B-1000 Brussels, Belgium
G
4
M
3 Walloon
B-1000 Brussels, Belgium
-1.00
Figure 1 : Differences in fatty acids composition in milk
(standardized units) compared to Holsteins.
Methods
• From April to June 2005, 600 milk
samples were analysed from 275
cows derived to 6 breeds (Dual
Purpose Belgian Blue (DPB),
Holstein-Friesian (HOL), Jersey
(JER), Montbeliarde (MON) and
Red and White (RED).
• Single trait mixed model :Fixed
effect: herd*test date, number of
lactation, stage of lactation and
regressions on breed composition
effects as a lot of animals were
crossbred, when FA contents in
fat were analyzed a regression on
% of milk fat was added
• The variation within and across
breeds in the activity of delta-9
desaturase was also studied with
the same mixed model.
4
0.40
1.20
1.00
standard deviation units
• After calibration, the FA contents
of cow milk was predicted by MIR
Spectrometry.
Activity of delta-9 desaturase
Fatty acids concentrations in milk fat
standard deviation units
2
0.80
0.60
0.40
0.20
0.00
-0.20
SAT
C12:0
C14:0
-0.40
0.20
0.00
C18:1/C18:0
C16:1/C16:0
C14:1/C14:0
-0.20
-0.40
-0.60
-0.80
Figure 2: Differences in fatty acids
Figure 3: Differences in activity of delta-9
profiles in milk fat (standardized units)
compared to Holsteins.
desaturase (standardized units) compared to
Holsteins.
DPB : lowest fat (MG) but C18:1 and C18:2 9-cis, 12-cis not the lowest
concentrations (Figure 1)  unsaturated FA proportion in fat might be
high  In fact, the fat of DPB contained the lowest proportion in
saturated FA (SAT) (Figure 2)  These observations might be explained
by the higher activity of delta-9 desaturase for this breed (Figure 3).
JER : very high difference in monounsaturated fatty acids (MONO)  not
lowest delta-9 desaturase activity.
RED and MON : high proportion of SAT  low delta-9 activity.
To estimate the differences within breed, the repeatability for each
studied traits were estimated and the obtained results were high with
values between 43 and 61 %. Future studies should show if this is also
an indication for reasonable high heritabilities.
Conclusions
• High variability across breeds  choice of breed modified the FA profile
• High repeatability  potentially high heritability for each FA
Suggest the possibility of
genetic improvement