fish

1. EFFECTS OF PARTIAL SUBSTITUTION OF
FISHMEAL WITH SOYBEAN MEAL BEFORE AND
AFTER ITS EXTRUSION ON DIGESTIBILITY AND
TRYPSIN ACTIVITY IN THE DIGESTIVE TRACK OF
GILTHEAD SEA BREAM (SPARUS AURATA L.).
Venou, B., Alexis, Μ., Fountoulaki, E., Nengas, I Apostolopoulou,
M., Cathariou-Castritsi, I.
Hellenic Centre for Marine Research, Ag. Kosmas Helliniko 16604
Athens, Greece

2. Protein supply
Substitution of fish meal by soybean meal
 high protein content
good AA composition
 reasonable price
 steady supply
selective substitution
 Meth-Cys deficiencies
 phytate-P low availability
 inhibitors
 several products
 different processing methods
restricted
supplementation
different properties
and effects
Aim of the study
 digestibility of nutrients
 enzyme activity
need for knowledge

3. Nutrient Composition of the ingredients
as fed
Moist ure %
Prot ein %
Lipid %
ASH %
FI BRE %
NFE % ( by difference )
TI A( m g / g m eal )
Trypsin inhibit or act ivit y
Fishm eal
( LT )
Soybean m eal
( SBM )
Ex t ruded SBM
( EX ) *
8.5
67.6
10.8
11.0
2.0
9.6
40.9
3.6
6.0
6.2
33.6
8.8
39.0
3.9
5.9
5.9
36.4
5.3
4.6
* Extrusion conditions for soybean meal (Instapro ex-1500)
temperature (110 - 125 0C), pressure (25-30 bars)
time conditioning (185-240min).

4. Formulation and Composition of the test diets
I ngredient s ( % in diet )
Fish m eal LT
Diet 1
Cont rol
Diet 2
S20
Diet 3
S40
Diet 4
EX20
Diet 5
EX30
Diet 6
EX40
62,9
50,5
21,0
37,6
43,0
50,6
43,8
37,7
22,0
34,0
45,0
soybean m eal ( SBM)
ex t ruded soybean m eal ( EX)
st arch m ix t yre ( 2:1)
( raw :progelat inized)
Cod liver oil
cellulose
Vit am in/ Mineral prem ix
Dicalcium phosphat e
DL-Met h
Chem ical com posit ion ( % DM)
Prot ein
Lipid
Ash
NFE ( by difference)
St arch
-1
Gross energy ( KJ g ) DM
20,7
12,7
4,1
11,8
6,8
2,2
8,2
2,5
1,5
4,0
0,1
8,8
1,2
1,5
4,1
0,2
9,4
8,9
0,5
1,5
4,2
0,2
9,2
1,5
4,3
0,3
8,7
1,2
1,5
4,1
0,2
47,9
15,2
12,4
24,5
20,6
21,6
46,9
14,7
12,5
25,9
16,1
21,4
46,8
15,8
12,2
25,1
12,4
21,1
46,2
15,4
12,4
25,9
16,6
21,5
46,3
15,4
12,3
25,9
14,4
21,5
46,1
16,0
12,3
25,6
13,9
21,6
1,5
4,2
0,2

5. Experimental conditions and Evaluations
Experiment I (Digestibility trial):
6 duplicate groups / 120-l tanks
20 fish, 100 g initial weight,
fed 1.8% of bw / 22 ±20C / 18 days
*indirect method/ Cr2O3 (1% diet):
(settling of faecal samples)
Experiment II (Trypsin activities):
9 fish / 100g, initial weight,
fed one single meal/ 1.5% of bw
4 hours after feeding/ 22 ±20C
3 intestine parts:
U (upper) M (Mid) L (Lower)
Statistical treatment of the data
Two way ANOVA
Evaluations:
ADCs of:
protein, lipid,
starch, energy,
dry matter
 gut fluids
 trypsin activity
Factors:
*extrusion * inclusion level
* interactions

6. Digestibility trial (Experiment I)
Diet1
Diet2
Diet3
Diet4
Control
S20
S40
EX20
Diet
5
Diet6
EX40
EX3
0
ADCs
Protein
92,6
93,3
92,3
93,2
93,0
92,1
Lipid
90,8
92,2
88,0
92,1
89,1
88,2
Starch
82,0
82,2
80,6
87,7
87,6
84,7
Energy
87,5
84,2
80,5
85,2
82,7
81,5
Dry matter
77,7
74,1
70,7
76,8
73,3
72,8
Protein
Lipid
Starch
Energy
Dry matter
4,4
21,4***
Two-way
ANOVA
extrusion
inclusion level
interactions
0,2
0,4
32,7
33,5
7,9*
44,8***
0,4
0,2
1,2
0,0
79,4***
38,0***
0,5

7. EXPERIMENT II (Digestive fluids)
Upper
Mid
Low er
Volu m e ( m l)
0,3
0,2
0,2
0,1
0,1
0,0
C
S20
EX20
S40
EX40
Two-Way ANOVA
Upper
Mid
extrusion
14.3 **
14.9*
inclusion
0.5
6.9
34.4 ***
15.9 *
23.0 **
34.0 ***
0.4
interactions
63.9 ***
Lower
5.3
Whole Intestine
37.1 ***

8. TRYPSIN ACTIVITIES IN INTESTINE SEGMENTS (Upper, Mid,
Lower)
S2 0
EX4 0
2
1
0
Upper
C
EX2 0
16
14
12
10
8
6
4
2
0
S20
EX20
S40
EX40
TA ( U/ ml )
Tot al TA ( U )
3
C
S4 0
Mid
Low er
Upper
Mid
Low er
Two-way ANOVA
Activity
(U/ml)
Mid
extrusion
17.5 **
36.6 ***
7.6 ***
inclusion level
0.05
29.2 ***
51.6 ***
interaction
Total
activity
(U)
Upper
44.3 ***
inclusion level
0.2
3.1
21.6*
Lower
35.3 ***
6.8

9. EXPERIMENT II (TRYPSIN ACTIVITIES)
TAt ot al (U )
F.
1
C
5
4
3
S2 0
EX20
4,4
2
1,8
1
2,4
TA (U/ ml)
S20
C S20
20
10
0
Figure 1 and 2
1,9
1,4
EX20
EX20
TA total
S40
S40
EX40
27 ***
23 *
Two-Way ANOVA
interactions
36
20
C
(U)
45 ***
(U/ml)
extrusion
EX40
TA
inclusion level
C
40
30
EX40
WHOLE INTESTINE
(upper+mid+lower)
0
F.
2
S4 0
22
S20
EX20
17
19
S40
EX40
1.5
15 *
0.2

10. Correlations of TA and PER / PPV
1,6
PER
1,8
0,3
PPV
0,35
0,25
1,2
0,2
0,15
1,4
1
0
1
2
3
TA total ( U )
4
5
0
1
2
3
TA t ot al ( U )
4
PER and PPV values : related to the Trypsin activity in the intestine.
The change of the values is stronger the lower the trypsin activity is.
5

11. Conclusions
1.
2.
3.
4.
5.
Digestibility of starch increased when diets contained extruded
soybean meal, indicating a beneficial effect of extrusion on the
carbohydrate content of soybean meal.
Trypsin activity in the supernatant of the digestive fluid was
negatively affected by soybean meal inclusion in the diets for
gilthead sea bream.
Extrusion increases values of Trypsin activity at both inclusion
levels of soybean meal.
Trypsin activity does not appear to be related to protein
digestibility values obtained but is related to the retention of
protein indicating that affects its availability.
The reduction of trypsin activity in the supernatant could be due
to remaining trypsin inhibitor activity on soybean meal, however
other factors could contribute and this needs further examination.

12. GILTHEAD SEA BREAM
Thank you!