P . Bas, P. Morand-Fehr Livestock Production Science 64 2000 61 –79
63 Table 1
Main animal characteristics of the data base
a b
Sex n
ADG Weaning age WA
Slaughter LW SLW Slaughter age SA
g day n
weeks n
kg n
weeks n
M 425
,ADG,100 20
,WA,5 190
SLW ,10
26 ,SA,5
38 F
136 10
,ADG,150 69
5 ,WA,10
340 10
,SLW,20 35
5 ,SA,10
73 C
174 150
,ADG,200 73
10 ,WA,15
35 20
,SLW,30 69
10 ,SA,15
141 Mixed sexes
152 200
,ADG,250 122
15 ,WA,20
25 30
,SLW,40 192
15 ,SA,20
188 250
,ADG,300 157
20 ,WA,30
10 40
,SLW,50 256
20 ,SA,50
161 ADG
.300 74
SLW .50
81 SA
.50 106
a
Sex: M, entire males; F, females; C, castrated males; mixed sexes, entire males 1castrated males or entire males1females or castrated
males 1females
b
ADG, average daily gain; LW, live weight; n, number of observations.
dock tail basis, costal, leg, inguinal and sternal bibliographic data base thus formed contained 979
regions, the Semimembranosus and Triceps Brachii, observations from 108 papers.
and around the fat tail. The information on the fatty Data were analysed by the Factor, GLM, REG and
acid composition of MU came most frequently from Nlin procedures of SAS SAS, 1987. The GLM
Longissimus dorsi, then from Semimembranosus procedure was used with the factors most frequently
Table 3 and lastly from Triceps Brachii. represented.
The variables concerning diet components were the type of forage and the main energy, protein, and
fat sources in concentrates or in complete diets.
3. Results
Other variables, when not provided in the articles, were calculated from available information such as
3.1. General characteristics of adipose tissues and the proportion of roughage and concentrate in diets,
muscles metabolisable energy, total protein, crude fibre, and
fat contents of the complete diets and concentrates, The fatty acid composition of three adipose tissues
while missing nutritive values were assessed using frequently mentioned in the data base, namely sub-
the INRA tables of feedstuff values Andrieu et al., cutaneous, omental, perirenal, and that of one intra-
1989. muscular tissue are reported in Table 2. In these
During milk- and post-weaning periods, ten types tissues three main fatty acids C
, C , and C
16:0 18:0
18:1
of diets were distinguished: ewes’ milk, milk re- represented the major part of total FA from 78 in
placer, ewes’ milk and concentrate, ewes’ milk and MU to 87 in OM. The coefficients of variation of
pasture, roughage alone, pasture alone, roughage and C
and C proportions by weight were lower
16:0 18:1
concentrate, pasture and concentrate, concentrate CV
5 18.5 and 14.2, respectively than that of alone, complete diet. The two latter diets were
C CV
5 40. The intra-tissue variability for
18:0
defined by using thresholds for the proportions of C
and C was approximately 10, but was far
16:0 18:1
main feedstuffs. For example, diets were classified in greater for C
reaching 20 in PR and 37 in
18:0
complete diets when the mixed diets contained more SC.
than 25 of chopped or ground roughage, but in Principal component analyses were performed on
concentrate alone diet if they contained less than overall adipose tissues Fig. 1A, SC Fig. 1B, PR
25 of roughage. In the same way, the diet was Fig. 1C, MU Fig. 1D to study the relationship
classified as roughage and concentrate when the between main fatty acid percentages. The first two
authors had mentioned a supply of raw straw un- factor axes expressed about 45 of the total variance
ground or unchopped, and was classified as concen- in overall adipose tissues, SC and MU, but about
trate alone when no straw supply was reported. The 60 in PR. Fig. 1A showed, on the first factor, an
64 P
. Bas, P. Morand-Fehr Livestock Production Science 64 2000 61 –79 Table 2
Mean fatty acid composition of the main fat deposits in lambs
b
Fat Fatty acids
a
deposits C
C C
C C
C C
C
14:0 16:0
18:0 16:1
18:1 18:2
18:3 17:0
a a
a a
a a
a a
SC 4.8
23.4 15.4
3.5 40.8
4.0 1.4
2.4
b b
b b
b b
a b
PR 4.0
20.6 26.1
2.7 36.7
4.9 1.5
1.9
a,b a,c
c a,b,c
c a,b
b a,b
OM 4.6
23.7 29.9
2.9 33.6
4.3 0.8
2.1
b c
a c
a c
b c
MU 3.8
22.5 15.6
3.2 40.4
6.3 1.1
1.4
a
SC, subcutaneous adipose tissue 250 ,x,411; PR, perirenal adipose tissue 111,x,219; OM, omental adipose tissue 7,x,17;
MU, intramuscular fat 86 ,x,143; x, number of observations for each fatty acid.
b
Superscripts a, b and c, means in a column with different superscripts were significantly different P ,0.05.
antagonism between the percentages of C and
were negatively correlated r 5 2 0.33, P , 0.05
14:0
C and that of C
and, on the second factor, an and in SC, MP was significantly in opposition to
16:0 18:2
antagonism between the percentages of C , C
odd-numbered and branched-chain fatty acid per-
14:0 18:0
and C and those of C
and C . But these
centages. For these two tissues, the MP was best
18:3 17:0
18:1
relationships showed noticeable differences between explained from the C
percentage, with a coeffi-
18:0
the tissues. In PR Fig. 1C, the percentages of cient of determination over 75 Fig. 2. The two
saturated acids C , C
, and C were op-
prediction equations became not significantly differ-
16:0 17:0
18:0
posed to those of polyunsaturated fatty acids C ent when the C
and the C percentages were
18:2 18:0
18:2
and C on the first factor axis. In SC Fig. 1B,
used simultaneously as explicit variables.
18:3
there was an opposition between the percentages of MP
8C 5 0.51 ? C 2 0.28 ? C
1 29.0;
18:0 18:2
C and C
and those of C C
, C and
17:0 18:1
14:0 16:0
18:0 2
C on the first factor, and in MU Fig. 1D, C
, R
5 0.86, RSD 5 1.7, n 5 101
18:3 18:0
C , and C
percentages were opposed to those
18:1 18:3
For one group of animals, the mean difference in MP of C
and C on the first factor axis also. The
17:0 18:2
between the PR and SC from caudal region, which second factor axis revealed an opposition between
approximatively represented 75 of the SC samples, C
and C in PR Fig. 1C, and between C
18:1 14:0
18:2
analysed for MP, was about 6.4 8C.
and C in SC Fig. 1B.
18:1
The SI was less closely linked to fatty acid The relationship between the melting point MP
proportion than was the MP probably because of its and the percentage of the main fatty acids were
more subjective estimation and the important vari- studied in SC and PR. The softness index SI was
ability of SC composition according to sampling studied in SC only, and most particularly in samples
sites. In SC, the C percentage was the variable
from the dorsal region. The SI values were stan-
16:0
which predicted SI best. Taking into account a dardised on a scale varying from 1 very firm to 5
second fatty acid percentage in the equation im- very soft and oily. On the whole, the MP was
proved slightly but not significantly the prediction of linked to the same acids in PR and in SC. The
the SI. coefficients of correlation between the MP and the
percentages of C and C
were significant and
16:0 18:0
SI 5 2 0.22 ? C
1 7.3;
16:0
positive r 5 0.32, P , 0.05 and 0.87, P , 0.001, in
2
R 5 0.40, RSD 5 0.75, n 5 67
PR, 40 , n , 49, and r 5 0.38, P , 0.01, r 5 0.88,
P , 0.001, in SC, 49 , n , 58, respectively. They
were significant and negative between the MP and 3.2. Variation of fatty acid composition due to
the percentages of C , C
, and C 20.60,
sampling site
16:1 18:1
18:2
P , 0.001; 2 0.54, P , 0.001; 2 0.62, P , 0.001, in
PR, and 2 0.63, P , 0.001; 2 0.42, P , 0.01;
Although there were change in lipid content and in 2 0.40, P , 0.01, in SC, respectively. Moreover, in
fatty acid composition in omental adipose tissue PR the variations of the MP and C
percentage according to tissue site Bas et al., 1992, the precise
14:0
P . Bas, P. Morand-Fehr Livestock Production Science 64 2000 61 –79
65
Fig. 1. Principal component analyses showing relationship between main fatty acid content in all fat deposits A or in subcutaneous adipose tissue B, or in perirenal adipose tissue C, or in intramuscular fat D.
66 P
. Bas, P. Morand-Fehr Livestock Production Science 64 2000 61 –79
even-numbered saturated fatty acids. But the C
18:1
percentage was clearly higher in leg than in back samples.
In spite of the low representivity of the Semimem- branosus, one may say it was characterised by higher
percentages of unsaturated fatty acids C , C
,
16:1 18:1
C , and C
and by a lower percentage of C
18:2 18:3
18:0
than Longissimus dorsi. As variability in compositions was related to
sampling sites, and as the number of samples avail- able varied from one site to another, because of the
higher number of samples indicated in Table 3, the back site of SC and the Longissimus dorsi site of
MU were favourably considered to study the effects of diets on the fatty acid composition of tissues.
3.3. Effect of milk feeding on the adipose tissue composition
As shown in Table 4 ewes’ milk fed lambs and in comparison with Tables 5 and 6 weaned lambs,
the fatty acid composition of tissues from lambs fed
Fig. 2. Relation between the melting point and the C content
18:0
ewe milk was characterised by lower percentages of
of adipose tissues.
C , C
, and C and higher percentages of
18:0 18:2
18:3
C , C
, and C than that of tissues from
14:0 16:0
18:1
anatomic site of sampling of OM was not precisely lambs slaughtered after weaning. In the most cases,
known as for PR. Whereas SC and MU were the composition of adipose tissues reflected the fatty
analysed in accurately defined locations in about acid composition of ewe milk which is rich in C
14:0
90 of the cases. and C
in comparison to post-weaning diets. The
16:0
In Table 3, SC samples from the inguinal region percentages of total saturated fatty acids did not
were characterised by the highest contents of satu- differ between SC and PR, but SC had a lower C
18:0
rated fatty acids C and C
. On the opposite, percentage and higher C
and C percentages
16:0 18:0
14:0 16:0
back and leg samples were the poorest in total than PR. During the milk feeding period, the C
18:1
Table 3
1
Changes in fatty acid composition of fat deposits according to sample location AD
Sample location Fatty acids
C C
C C
C C
C C
14:0 16:0
18:0 16:1
18:1 18:2
18:3 17:0
a a
a a
a a
a a
SC Back
4.2 22.2
16.7 3.6
39.5 4.5
1.5 2.4
a b
a a
b a
a a
Dock 4.1
24.4 16.1
3.3 41.2
3.9 1.6
2.5
a b
a a
b a
a
Costal 4.0
24.4 15.6
3.2 42.5
3.4 2
2.7
a a,b
a a
b a
a a
Leg 5.0
23.9 14.4
3.0 43.8
3.6 1.6
1.6
a b
b a
b a
Inguinal 4.0
25.2 20.2
4.5 42.9
3.5 2
2
a a
a a
a a
a a
MU Longissimus dorsi
3.0 22.7
15.7 3.8
41.4 7.3
1.0 1.5
a a
b a
a b
b a
Semimembranous 3.2
22.3 13.7
4.1 43.8
10.3 1.9
1.4
1
AD, adipose tissues; SC, subcutaneous adipose tissue; MU, intramuscular fat. Sample location, back 131 ,n,181; dock 42,n,
118, costal 8 ,n,15, leg 6,n,9, inguinal 6,n,8; Longissimus dorsi 72,n,105, Semimembranous 4,n,13; n, number of
observations for each fatty acid. Superscripts a and b, means in a column with different superscripts were significantly different P ,0.05.
P . Bas, P. Morand-Fehr Livestock Production Science 64 2000 61 –79
67 Table 4
1
Fatty acid composition from three fat deposits in lambs fed ewe milk Fat
Fatty acids deposits
C C
C C
C C
C C
14:0 16:0
18:0 16:1
18:1 18:2
18:3 17:0
a a
a a
a a
a a
SC 9.4
24.8 11.7
4.0 40.0
3.1 0.8
1.5
b b
b a
a a
b a
PR 6.8
22.2 17.1
2.9 40.2
3.8 1.2
1.5
b b
a b
a b
b b
MU 6.6
21.7 13.0
2.3 40.4
5.9 1.4
1.0
1
SC, subcutaneous adipose tissue 12 ,n,18; PR, perirenal adipose tissue 4,n,8; MU, intramuscular fat n56; n, number of
observations for each fatty acid. Superscripts a and b, means in a column with different superscripts were significantly different P ,0.05.
Table 5
1
Effects of types of diets on the mean fatty acid composition of three fat deposits in lambs Diets
Fatty acids C
C C
C C
C C
C
14:0 16:0
18:0 16:1
18:1 18:2
18:3 17:0
a a
a a,c
a a
a a
Pasture 4.2
21.5 23.6
2.8 36.9
4.2 2.4
1.2
a,b,c a,b
a a,b
a,b a,b,c
b
Past 1conc.
3.4 21.5
22.6 3.7
37.4 5.2
1.5 2
b,c a
b a,c
b b
c b
Rough 1conc.
3.6 21.9
17.6 3.0
39.5 5.1
0.5 2.6
c b
b b
c c
c c
Concentrate 2.9
20.4 17.7
3.7 41.5
6.1 0.7
2.3
b c
c c
a c
b c
Complete diet 3.6
23.4 19.9
2.7 38.2
6.4 2.0
2.1
1
SC, subcutaneous adipose tissue from the mid back area; PR, perirenal adipose tissue; MU, muscle Longissimus dorsi. Pasture, pasture alone 21
,n,45; Past1conc., pasture and concentrate 8,n,12; Rough1conc., roughage and concentrate 57,n,78; Concentrate, concentrate alone 161
,n,236; complete diet, mixed compound diet with roughage and concentrate 64,n,120; n, number of observations for each fatty acid. Superscripts a–d, LS means in a column with different superscripts were significantly different P
,0.05; the LS means of the five diets was calculated for three adipose tissues.
Table 6
1
Effects of three types of diets on fatty acid composition of three fat deposits in lambs AD
Diets Fatty acids
C C
C C
C C
C C
C C
14:0 16:0
18:0 16:1
18:1 18:2
18:3 15:0
17:0 17:1
a a
a a,b
a,b a
a a
a a
SC Rough
1conc. 3.2
21.6 11.7
3.7 40.8
3.7 0.4
1.3 3.4
3.1
a a
b a
a b
a b
b b
Concentrate 3.4
20.9 15.8
4.1 42.5
5.6 0.8
0.8 2.7
1.6
b b
b b
b b
b a
b b
Complete diet 4.7
24.9 16.2
3.2 39.0
6.0 2.2
1.1 2.6
1.5
a a
a a
a a
a a
a a
PR Rough
1conc. 3.6
20.6 26.2
2.5 36.2
4.7 0.4
0.5 2.4
0.9
b b
b b
b a
a a
a a
Concentrate 2.7
19.2 24.1
3.1 40.0
5.4 0.7
0.6 2.2
1.0
ab a
a a,b
a b
b a
b
Complete diet 3.1
21.3 27.5
2.7 35.6
6.6 2.6
2 2.4
0.6
a a
a a
a a
ab a
a a
MU Rough
1conc. 4.0
23.6 14.7
2.7 41.9
7.0 0.5
0.6 2.0
1.4
b b
b b
a a
a a
a a
Concentrate 2.9
20.8 13.3
4.2 41.0
7.2 0.5
0.6 1.9
1.5
c a
c c
a b
b b
Complete diet 2.0
23.1 17.0
2.0 40.5
5.5 0.8
2 1.1
2
1
AD, adipose tissues; SC, subcutaneous adipose tissue from the mid back area; PR, perirenal adipose tissue; MU, muscle Longissimus dorsi. Diets for SC: Rough
1conc. 15,n,24; concentrate 49,n,78; complete diet 14,n,55; diets for PR, rough1conc. 18
,n,30; concentrate 4 9,n,109; complete diet 8,n,40; diets for MU, rough1conc. 11,n,29; concentrate 38,n,49; complete diet 10
,n,18; n, number of observations for each fatty acid; Superscripts a,b,c, means in a column with different superscripts were significantly different P
,0.05.
68 P
. Bas, P. Morand-Fehr Livestock Production Science 64 2000 61 –79
Fig. 4. Relation between the FA content of all fat deposits in Fig. Fig. 3. Effect on age of the C
content of fat deposits in milk
18:1
3 and the corresponding FA content in the liquid milk fed lambs. fed lambs.
C 50.65?exp0.077?C
, RSD
51.5; C
50.24?
12:0 AD 12:0 D
14:0 AD
exp0.30 ?C
, RSD
52.1; C 536.6235.1?exp0.033?
14:0 D 16:0 AD
C ,
RSD 53.5;
C 515.3214.3?exp0.20?C
,
16:0 D 18:0 AD
18:0 D
content in SC, PR, and MU Fig. 3 regularly
RSD 53.0; C
5105.4286.7?exp0.012?C , RSD
55.7;
18:1 AD 18:1 D
decreased with the age of lambs by about 1 per
C 5138.22136.9?exp0.008?C
, RSD
52.2; Cn:0
18:2 AD 18:2 D
AD
and Cn:0 5FA content in tissues and in milk replacer, respective-
week, whereas C and C
contents increased.
D
16:1 18:2
ly.
As with ewe milk, the fatty acid percentages of adipose tissues from milk-replacer fed lambs varied
with the lipid composition of milk replacers Fig. 4. Increasing the C
supply in milk increased the high percentage of total C
acids in post-weaning
12:0 18
tissular content in C but also in C
and C .
diets and the hydrogenation potential of the unsatu-
12:0 14:0
16:0
Likewise, an increase in the C content in milk
rated C acids in the rumen. The fatty acid profile of
16:0 18
replacers increased the C , C
and C per-
tissues, which reflects the milk feeding period,
16:0 18:0
18:1
centages in tissues. Moreover, an increase in C in
gradually disappeared after weaning.
18:3
milk replacers had favourable repercussions on the C
and in C percentages in tissues. Thus,
3.4. Influence of post weaning feeding
18:3 18:2
knowledge of fatty acid percentages in milk replacers made predictions of the fatty acid composition in
3.4.1. Effects of the type of diets tissues possible with a confidence interval of be-
Table 5 reports the mean fatty acid composition of tween 70 and 99, for C
and C , respectively.
three tissues SC, PR, and MU in lambs fed with
18:0 18:2
After weaning, with the diets normally offered to five types of diets: two diets based on grazing on
lambs, the percentage of C gradually decreased in
Pasture, with or without Concentrate, and three diets
14:0
all tissues whereas the percentages of long-chain distributed indoors roughage and concentrate, com-
saturated fatty acids, particularly C , increased
plete diet and concentrate alone. The roughage alone
18:0
Fig. 5. This probably resulted from the low short- diet was not mentioned because the number of
and medium-chain fatty acid percentages and the observations was too low n
56. The differences in
P . Bas, P. Morand-Fehr Livestock Production Science 64 2000 61 –79
69
anatomical location of the fat deposit. For example SC, PR and MU from lambs receiving the complete
diet were all characterised by a lower C per-
18:1
centage and a higher percentage of C and total
18:3
saturated fatty acids than with other diets. In SC, the variability of the C
percentage reached nearly
18:0
twice that of other tissues CV 533, 19, and 15,
respectively for SC, PR, and MU. In SC again, the percentage of C
was relatively low whereas those
18:0
of odd-numbered and branched-chain fatty acids were high. The concentrate alone diet presented the
highest C percentage and lowest percentage of
18:1
total saturated fatty acids. On the whole, the pasture alone and pasture and concentrate diets on the one
hand and concentrate alone and roughage and con- centrate diets on the other hand resulted in very
similar compositions in each tissue.
When crude protein CP, crude fibre CF ether extract EE and energy values of diets were together
taken into account, the coefficients of determination of most fatty acid percentages, except C
, were
14:0
strongly increased. With these variables and when
Fig. 5. Variation of the C and of the C
content of fat
14:0 18:0
deposits with time t after weaning. C SC
50.12t112.6;
considering the tissue and diet effects, the coeffi-
18:0
P 50.06, RSD52.4; C
PR 50.25t119.1; P,0.01; RSD52.5;
18:0
cients of determination of the percentages of the
C MU
512.8, SD51.3; C SC
58.4?exp20.097t, RSD5
18:0 14:0
main fatty acids were increased from 27, 57, and
2.8; C PR
54.8?exp20.092t, RSD51.5; C MU
55.8?
14:0 14:0
17 to 55, 65, and 35, for C , C
, and C ,
16:0 18:0
18:1
exp 20.090t, RSD51.8.
respectively. The richest diets in terms of metabolis- able energy were generally associated with the
lowest C , C
and C percentages and the
18:0 18:1
18:2
fatty acid composition of tissues between the types highest C
, C , C
and C percentages in
16:0 16:1
15:0 17:0
of diets was relatively limited although significant. SC, PR, and MU. With higher crude protein content
Extreme concentrations were observed with the in diets lamb tissues were poorer in C
and in
16:0
pasture alone and concentrate alone diets. C
and richer in C , C
and C . The
18:0 16:1
18:1 18:3
With the pasture alone diet, tissues were richer in increasing crude fibre content in diets were associ-
C , C
and C and poorer in C
, C and
ated with increase in C percentage and with
14:0 18:0
18:3 18:1
18:2 18:0
C . In lambs reared on pasture alone, the C
decrease in C percentage in tissues. The ether
17:0 18:3
18:2
percentage in all three tissues was relatively high extract contents of diets were negatively correlated
2.7, 2.6, and 1.7, in SC, PR, and MU, respective- with the percentages of C
, C , C
and C
16:0 18:3
15:0 17:0
ly. The percentage of polyunsaturated fatty acids and positively correlated with C
percentages in
18:0
PUFA of the n-3 series in MU was also high and at tissues. Moreover, in SC the metabolisable energy
least twice that from lambs fed the roughage and density of the diets was significantly P
,0.001 concentrate diet. This high n-3 PUFA percentage had
opposed to the percentage of C , but positively
18:0
repercussions on the n-3 PUFA n-6 PUFA ratio in correlated with that of odd-numbered and branched-
MU. chain fatty acids. An increase in dietary fat content
Table 6 presents the fatty acid compositions of slightly reduced the C
, C , and C
per-
18:3 16:1
17:0
tissues obtained with the most commonly used diets. centages in SC, PR and MU, but more markedly the
Generally, the type of diet tended to have similar sum of odd-numbered and that of the branched-chain
effects on the fatty acid composition, regardless of fatty acid percentages in SC.
70 P
. Bas, P. Morand-Fehr Livestock Production Science 64 2000 61 –79 Table 7
1
Effects of the main sources of energy of the concentrate on the fatty acid composition of lamb fat deposits Energy source
Fatty acids C
C C
C C
C C
C C
C
14:0 16:0
18:0 16:1
18:1 18:2
18:3 15:0
17:0 17:1
a a
a a,b
a a
a,b a
a,b
Beet pulp 3.1
21.1 15.0
2.2 41.8
3.8 0.7
0.8 1.9
2
a b
a,b a
a a
a a
a a
Barley 3.1
23.0 18.1
2.1 39.6
4.3 0.9
0.9 1.9
1.7
a a
b b
a b
b a
b a
Maize 3.1
21.4 18.9
2.7 38.8
6.5 1.2
1.1 2.4
1.3
a c
c a,b
b a
a,b a
a,b
Wheat 3.5
24.7 21.6
2.8 36.0
4.6 0.8
0.7 2.0
2
1
Beet pulp n 58; Barley 31,n,92; Maize 33,n,131; Wheat 5,n,18; n, number of observations for each fatty acid.
Superscripts a,b,c, LS means in a column with different superscripts were significantly different P ,0.05; The LS means of the four
sources of energy was calculated for three adipose tissues, SC: subcutaneous adipose tissue from the mid-back area, PR: perirenal adipose tissue, MU: muscle Longissimus dorsi.
3.4.2. Energy sources ton, 1971. The similarity between the compositions
The energy sources of the concentrates or the of all tissues from lambs receiving semi-synthetic
complete diets significantly influenced the percent- diets or beet pulp based diets could be the result of
ages of most fatty acids. The C and C
the low fat contents of these two diets. Thus, in both
18:2 18:3
percentages in tissues were higher when maize was cases the fatty acids in the tissues do not originate
the main energy supply Table 7 probably because from the diets but from a de novo synthesis. The
it has a higher fat content than the other energy tissues of lambs fed diets rich in wheat had a low
sources and because of its high C content. As
percentage of C and high percentages of saturated
18:2 18:1
shown in Fig. 6, the C percentage in SC, PR, and
fatty acids. A rise in the level of incorporation of
18:2
MU increased as the proportion of maize increased barley or maize in the diets led to significant
in the diet, whereas the C percentage decreased.
increases in C percentages in SC, PR, and MU,
16:0 17:0
Beet pulp decreased the percentages of saturated and a significant decrease in the C
in SC.
18:0
fatty acids C and C
in tissues, in the same
16:0 18:0
way as with semi-synthetic diets based on glucose or 3.4.3. Protein sources
starch Tove and Matrone, 1962; Duncan and Gar- Ingredients included in diets to increase their
protein contents may also influence the fatty acid composition of adipose tissues and muscles of lambs
Table 8. Addition of cotton meal as the main protein source brought about a significant raise in
C
and C percentages in tissues, probably
18:0 18:2
because of the high content of total unsaturated C
18
acids in cotton lipids. But when lambs received complete, concentrate alone or roughage and concen-
trate diets rich in cotton meal, the tissues had low C
, C and C
contents. These effects per-
18:3 18:1
16:0
sisted when crude protein, crude fibre, and ether extract content were at even levels in the diets. When
incorporating fish meal in lamb diets, C and C
18:0 18:2
percentages in the tissues were reduced, whereas C
percentage was increased. Alfalfa meal, rich in
18:1
linolenic acid, induced a higher percentage of C
18:3
in tissues than the three other protein sources shown in Table 8. When the proportion of alfalfa meal was
increased in a diet, C , C
and C percentages
16:1 18:1
18:2
were generally lower in tissues. But, as shown by
Fig. 6. Relation between the C content of adipose tissues and
18:2
muscles and the maize content of the solid diets.
Fig. 7, the decrease in the C percentage seemed
18:1
P . Bas, P. Morand-Fehr Livestock Production Science 64 2000 61 –79
71 Table 8
1
Effects of the main sources of nitrogen of the concentrate on the fatty acid composition of lamb fat deposits Energy source
Fatty acids C
C C
C C
C C
C C
C
14:0 16:0
18:0 16:1
18:1 18:2
18:3 15:0
17:0 17:1
a a
a a,b
a a
b b
b a
Alfalfa meal 3.1
21.8 19.5
2.8 38.1
5.7 1.4
1.0 2.4
0.9
a a,b
a a
a,c a,b
a a
a
Soybean meal 3.2
22.5 19.3
2.3 39.3
5.1 0.8
1.3 1.7
2
a c
b b
b c
a b
c a
Cotton meal 3.3
19.3 29.2
1.4 32.0
8.3 0.4
0.6 1.1
1.4
a a,b
c a,b
c b
a,b
Fish meal 2.9
22.4 15.8
2.7 41.2
3.9 0.6
2 2
2
1
Soybean meal 18 ,n,66; alfalfa meal 20,n,115; fish meal 6,n,18; cotton meal 12,n,16; n, number of observations for
each fatty acid. Superscripts a, b and c, LS means in a column with different superscripts were significantly different P ,0.05. The LS
means of the four sources of nitrogen was calculated for three adipose tissues, SC: subcutaneous adipose tissue from the mid back area, PR: perirenal adipose tissue, MU: muscle Longissimus dorsi.
presented some difficulties because the number of records differed widely between fatty acids, tissues
and diets. The number of missing data for the main fatty acids varied from 52 for C
to 338 for C
18:0 18:3
and reached 423, 528, and 331 for the odd-numbered fatty acids: C
, C , and C
, respectively.
15:0 17:0
17:1
The type of diet could be defined for nearly 95 of the observations but the type of roughage and the
main sources of energy and nitrogen could not be defined for 40–50 of the observations. The chemi-
cal compositions of the concentrate alone and com- plete diets were determined in more than 80 of the
cases but the chemical composition of post-weaning diets could be estimated in only 70 of the cases
because
information about
the unprocessed
roughage concentrate ratio in diets was often miss- ing.
In addition, information was often incomplete or
Fig. 7. Relation between the C content of adipose tissues and
inaccurate on other aspects of the experiments,
18:1
muscles and the alfalfa content of the solid diets. C SC
5
18:1
including details of the method of feeding, the
2
38.6 10.24x20.0035x , RSD52.4; n557; C
PR 531.01
18:0
number of times feed was offered each day, and of
2
0.37x 20.0048x , RSD52.9; n542; C
MU 551.220.22x2
18:0 2
genotype, sex and stage of growth of the lambs. In
0.0013x , RSD 51.74; n512.
some cases the imprecision about weight and age at weaning or slaughter of the lambs also raised
difficulties. to take place only when incorporation rate in the diet
was above 40–50. 4.2. Validity of the data base contents
4. Discussion When available or reliable information was lack-
