Directory UMM :Data Elmu:jurnal:A:Animal Feed Science and Technology:Vol81.Issue3-4.Oct1999:
Animal Feed Science and Technology
81 (1999) 309±318
Effect of fat coating on rumen degradation and
intestinal digestibility of soybean meal
F. Rossi*, L. Fiorentini, F. Masoero, G. Piva
Istituto di Scienze degli Alimenti e della Nutrizione, UniversitaÁ Cattolica del Sacro Cuore,
FacoltaÁ di Agraria,Via Emilia Parmense 84, 29100 Piacenza, Italy
Received 2 December 1998; received in revised form 23 April 1999; accepted 19 May 1999
Abstract
Three rumen and duodenum fistulated dairy cows were used to determine the effects of fat and
methionine addition to soybean meal on rumen degradation of crude protein, the amino acid pattern
and the intestinal digestibility of undegraded residues. The addition of 10% and 25% fat resulted in
lower DM degradation after 8 and 24 h of incubation. Protein degradation was reduced by 10% fat
addition at 8 and 24 h, while 25% fat addition considerably lowered crude protein disappearance
after only 8 h of incubation. A 10% fat addition increases the content of essential amino acids in the
undegraded residue vs. the control, while 25% fat addition only increases the concentration of
lysine, histidine and arginine. Standard soybean meal has higher intestinal dry-matter digestibility
than fat-coated soybean, probably due to interference between the lipid matrix and the enteric
enzyme attack which, most likely, does not affect the proteolytic enzymes, given the small
differences in intestinal nitrogen disappearance found among the different soybean types. # 1999
Elsevier Science B.V. All rights reserved.
Keywords: Protective treatment; Ruminal degradability; Amino acids; By-pass protein
1. Introduction
The recent European limitations concerning the use of animal meals in the formulation
of ruminant feeds (94/381/EC; 95/60/EC) have made it more difficult to meet the by-pass
protein requirements in high-yielding cows. This has increased the interest in plantprotein sources of low rumen degradability and good supply of essential amino acids like
*
Corresponding author. Tel.: ++39-523-599-286; fax:++39-523-599-259
E-mail address: rossi@pc.unicatt.it (F. Rossi)
0377-8401/99/$ ± see front matter # 1999 Elsevier Science B.V. All rights reserved.
PII: S 0 3 7 7 - 8 4 0 1 ( 9 9 ) 0 0 0 7 4 - 7
310
F. Rossi et al. / Animal Feed Science and Technology 81 (1999) 309±318
lysine and methionine. Corn gluten, is the only vegetable feed with high protein content
of low rumen degradability, but with low content of lysine (Masoero et al., 1994) and high
cost. Coconut meal has also a low degradability but its protein content is only slightly
higher than 20% (NRC, 1988). Soybean meal is the main source of plant proteins, but its
rumen degradability is >60% (I.N.R.A., 1988; NRC, 1988). Higher values (75%) are
found for sunflower meal. Both these meals are characterized by lower methionine and
lysine supply when compared to fish meal (Erasmus et al., 1994; Masoero et al., 1994); in
particular, soybean meal lacks methionine and sunflower has a low content of lysine. A
reduction in the rumen degradation of oil-free soybean can be obtained by treatment with
heat (Faldet et al., 1991; Schroeder et al., 1995), formaldehyde (Subuh et al., 1994 et al.,
1996), lignosulfonate (Waltz and Stern, 1989; Standford et al., 1995), xylose (Nakamura
et al., 1992) or protein coatings (Mahadevan, 1990; Atwal et al., 1995; Matsumoto et al.,
1995). The efficacy of some treatments is poor (e.g. xylose); others reduce lysine
availability (e.g. heat) or generate problems of toxicity (e.g. formaldehyde). Furthermore
the high cost of the protective treatment is the major disadvantage that occurs when
protein coatings are used. Recently, Kowalski et al. (1997) suggested that Ca-salts of
highly unsaturated oil (from rapeseed) could be used for coating soybean meal and
reducing protein rumen degradation. However, they did not evaluate the effect of this
treatment on the amino acid pattern of undegraded residue.
This study was carried out to evaluate the effectiveness of using saturated fat-coating
and methionine addition as a means of protecting soybean meal protein against
degradation in the rumen and increasing the amount of essential amino acids available for
the animal.
2. Materials and methods
Soybean was protected against rumen degradation by adding two different levels (10%
and 25%) of long-chain triglycerides (palmitic and stearic acids) salified with Ca++ and
mixed with tristearate and tripalmitate. Methionine was also added in amounts of 2 and
6 g/kg for profiles 10 and 25, respectively, the efficiency of methionine addition
technology was ca. 30%. A patent for this technique was requested (application number
FI96A29). Two samples, taken from the same lot of feed, underwent treatment and the
untreated residue was used as control. The products obtained were marked as Profile 10
and Profile 25, depending on the amount of added fat. Normal and fatted soybean meal
were analyzed for their content in fibrous fractions (Goering and Van Soest, 1970) ether
extract (Commission of the European Communities, 1998), ash (AOAC, 1980), the
analytical composition of these feeds is shown in Table 1.
Dry-matter and nitrogen solubilities were assessed by incubating 0.5 g of feed in a
borate-phosphate buffer (Krishnamoorty et al., 1983) at 398C for 8 and 24 h; the insoluble
amount was collected on an ash-free filter paper (S&S No. 589, Germany), washed with
bidistilled water and analyzed for nitrogen content using the Kjeldhal method.
Rumen degradability was determined in situ in three Friesian cows (576 kg liveweight), with rumen fistulae, and fed with grass hay (24.9% of DM), corn silage (32.2%
of DM) and concentrate (42.9% of DM); the protein level of the ration was 14.6% while
311
F. Rossi et al. / Animal Feed Science and Technology 81 (1999) 309±318
Table 1
Chemical analysis (% on DM basis) of the tested soybean meal
Feedstuffs
Dry
matter
Crude
protein
Methionine
content (% N)
NDF
ADF
Ether
extracta
Ash
Soybean meal
Profile 10
Profile 25
89.90
91.74
93.70
52.34
42.85
32.71
1.33
1.49
1.90
12.25
11.99
12.60
6.02
7.15
7.08
1.88
12.87
20.13
6.40
6.68
6.81
a
After hydrolysis with HCl 3 N.
energy concentration was 0.86 forage unit lactation (FUL) (Jarrige, 1998) /kg DM. This
diet, administered in the morning (8:00 a.m.) and in the evening (5:00 p.m.), was started
15 days before the beginning of the experiment. Using nylon bags (12.5 cm 7.5 cm;
pore size 46 mm) (Michalet-Doreau et al., 1987), filled with 5 g of feed, three kinetic
studies were performed for each animal with two replicates for feed and incubation time
(8 and 24 h), thus 18 replicates for feed and incubation time were obtained. To assure
enough residue after rumen incubation, particularly for the 24-h incubation time, the
amount weighted in each nylon-bags was higher than that suggested by Michalet-Doreau
et al. (1987). Once extracted, the bags were machine-washed for 15 min with cold water,
dried in an oven at 658C for 48 h and analyzed for their nitrogen content; the amino acid
content was determined by means of ion exchange chromatography using Amino
Analyzer 3A30 (Carlo Erba, Milan, Italy) on the original feeds and the undegraded
residues of all the bags incubated for 24 h. The effect of fat-coating on amino acids rumen
degradation was assessed considering the following ratio:
AAn =SEAA before rumen incubation
AAn =SEAA post rumen incubation
where: AAn is the content (g/100 g CP) of a single essential amino acid, and EAA the
total essential amino acids (g/100 g of CP).
Using the data of rumen degradability for crude proteins and the amino acid
composition of the undegraded residue, the amount of by-pass essential amino acids after
24 h of rumen incubation was calculated as follows:
100 g of feed CP g=100 g CP rumen byÿpass
AAn content of undegraded residue %
where AAn is referred to each single essential amino acids.
In order to evaluate the effect of fat-coating on intestinal digestibility, nitrogen
disappearance from the intestinal mobile bags was evaluated using the method proposed
by Peyraud et al. (1988).
3. Results
Addition of fat reduces nitrogen solubility in proportion to the lipid content.
Particularly marked was the drop observed with Profile 25 (Table 2). The addition of a
312
F. Rossi et al. / Animal Feed Science and Technology 81 (1999) 309±318
Table 2
Nitrogen solubility in a borate±phosphate buffer of normal and two types of fat-coated soybean meal
Feedstuffs
N solubility (% on total N)
Soybean meal
Profile 10
Profile 25
8 h of incubation
24 h of incubation
4.41
3.26
1.26
16.83
13.38
3.18
Table 3
Dry matter (DM) and crude protein (CP) in situ rumen degradation of normal and fat coated soybean meal
(profiles 10 and 25)a
Soybean meal
Profile 10
Profile 25
SE
8-h Rumen degradation (%)
24-h Rumen degradation (%)
D.M.
C.P.
D.M.
C.P.
34.83Bb
30.53ABa
26.25Aa
1.409
23.57C
17.53B
9.08A
1.013
70.20B
57.87A
56.74A
2.421
61.14b
44.72a
50.82AB
4.772
a
Means in the same column with different letters are significantly different: A,B,C Ð.(P
81 (1999) 309±318
Effect of fat coating on rumen degradation and
intestinal digestibility of soybean meal
F. Rossi*, L. Fiorentini, F. Masoero, G. Piva
Istituto di Scienze degli Alimenti e della Nutrizione, UniversitaÁ Cattolica del Sacro Cuore,
FacoltaÁ di Agraria,Via Emilia Parmense 84, 29100 Piacenza, Italy
Received 2 December 1998; received in revised form 23 April 1999; accepted 19 May 1999
Abstract
Three rumen and duodenum fistulated dairy cows were used to determine the effects of fat and
methionine addition to soybean meal on rumen degradation of crude protein, the amino acid pattern
and the intestinal digestibility of undegraded residues. The addition of 10% and 25% fat resulted in
lower DM degradation after 8 and 24 h of incubation. Protein degradation was reduced by 10% fat
addition at 8 and 24 h, while 25% fat addition considerably lowered crude protein disappearance
after only 8 h of incubation. A 10% fat addition increases the content of essential amino acids in the
undegraded residue vs. the control, while 25% fat addition only increases the concentration of
lysine, histidine and arginine. Standard soybean meal has higher intestinal dry-matter digestibility
than fat-coated soybean, probably due to interference between the lipid matrix and the enteric
enzyme attack which, most likely, does not affect the proteolytic enzymes, given the small
differences in intestinal nitrogen disappearance found among the different soybean types. # 1999
Elsevier Science B.V. All rights reserved.
Keywords: Protective treatment; Ruminal degradability; Amino acids; By-pass protein
1. Introduction
The recent European limitations concerning the use of animal meals in the formulation
of ruminant feeds (94/381/EC; 95/60/EC) have made it more difficult to meet the by-pass
protein requirements in high-yielding cows. This has increased the interest in plantprotein sources of low rumen degradability and good supply of essential amino acids like
*
Corresponding author. Tel.: ++39-523-599-286; fax:++39-523-599-259
E-mail address: rossi@pc.unicatt.it (F. Rossi)
0377-8401/99/$ ± see front matter # 1999 Elsevier Science B.V. All rights reserved.
PII: S 0 3 7 7 - 8 4 0 1 ( 9 9 ) 0 0 0 7 4 - 7
310
F. Rossi et al. / Animal Feed Science and Technology 81 (1999) 309±318
lysine and methionine. Corn gluten, is the only vegetable feed with high protein content
of low rumen degradability, but with low content of lysine (Masoero et al., 1994) and high
cost. Coconut meal has also a low degradability but its protein content is only slightly
higher than 20% (NRC, 1988). Soybean meal is the main source of plant proteins, but its
rumen degradability is >60% (I.N.R.A., 1988; NRC, 1988). Higher values (75%) are
found for sunflower meal. Both these meals are characterized by lower methionine and
lysine supply when compared to fish meal (Erasmus et al., 1994; Masoero et al., 1994); in
particular, soybean meal lacks methionine and sunflower has a low content of lysine. A
reduction in the rumen degradation of oil-free soybean can be obtained by treatment with
heat (Faldet et al., 1991; Schroeder et al., 1995), formaldehyde (Subuh et al., 1994 et al.,
1996), lignosulfonate (Waltz and Stern, 1989; Standford et al., 1995), xylose (Nakamura
et al., 1992) or protein coatings (Mahadevan, 1990; Atwal et al., 1995; Matsumoto et al.,
1995). The efficacy of some treatments is poor (e.g. xylose); others reduce lysine
availability (e.g. heat) or generate problems of toxicity (e.g. formaldehyde). Furthermore
the high cost of the protective treatment is the major disadvantage that occurs when
protein coatings are used. Recently, Kowalski et al. (1997) suggested that Ca-salts of
highly unsaturated oil (from rapeseed) could be used for coating soybean meal and
reducing protein rumen degradation. However, they did not evaluate the effect of this
treatment on the amino acid pattern of undegraded residue.
This study was carried out to evaluate the effectiveness of using saturated fat-coating
and methionine addition as a means of protecting soybean meal protein against
degradation in the rumen and increasing the amount of essential amino acids available for
the animal.
2. Materials and methods
Soybean was protected against rumen degradation by adding two different levels (10%
and 25%) of long-chain triglycerides (palmitic and stearic acids) salified with Ca++ and
mixed with tristearate and tripalmitate. Methionine was also added in amounts of 2 and
6 g/kg for profiles 10 and 25, respectively, the efficiency of methionine addition
technology was ca. 30%. A patent for this technique was requested (application number
FI96A29). Two samples, taken from the same lot of feed, underwent treatment and the
untreated residue was used as control. The products obtained were marked as Profile 10
and Profile 25, depending on the amount of added fat. Normal and fatted soybean meal
were analyzed for their content in fibrous fractions (Goering and Van Soest, 1970) ether
extract (Commission of the European Communities, 1998), ash (AOAC, 1980), the
analytical composition of these feeds is shown in Table 1.
Dry-matter and nitrogen solubilities were assessed by incubating 0.5 g of feed in a
borate-phosphate buffer (Krishnamoorty et al., 1983) at 398C for 8 and 24 h; the insoluble
amount was collected on an ash-free filter paper (S&S No. 589, Germany), washed with
bidistilled water and analyzed for nitrogen content using the Kjeldhal method.
Rumen degradability was determined in situ in three Friesian cows (576 kg liveweight), with rumen fistulae, and fed with grass hay (24.9% of DM), corn silage (32.2%
of DM) and concentrate (42.9% of DM); the protein level of the ration was 14.6% while
311
F. Rossi et al. / Animal Feed Science and Technology 81 (1999) 309±318
Table 1
Chemical analysis (% on DM basis) of the tested soybean meal
Feedstuffs
Dry
matter
Crude
protein
Methionine
content (% N)
NDF
ADF
Ether
extracta
Ash
Soybean meal
Profile 10
Profile 25
89.90
91.74
93.70
52.34
42.85
32.71
1.33
1.49
1.90
12.25
11.99
12.60
6.02
7.15
7.08
1.88
12.87
20.13
6.40
6.68
6.81
a
After hydrolysis with HCl 3 N.
energy concentration was 0.86 forage unit lactation (FUL) (Jarrige, 1998) /kg DM. This
diet, administered in the morning (8:00 a.m.) and in the evening (5:00 p.m.), was started
15 days before the beginning of the experiment. Using nylon bags (12.5 cm 7.5 cm;
pore size 46 mm) (Michalet-Doreau et al., 1987), filled with 5 g of feed, three kinetic
studies were performed for each animal with two replicates for feed and incubation time
(8 and 24 h), thus 18 replicates for feed and incubation time were obtained. To assure
enough residue after rumen incubation, particularly for the 24-h incubation time, the
amount weighted in each nylon-bags was higher than that suggested by Michalet-Doreau
et al. (1987). Once extracted, the bags were machine-washed for 15 min with cold water,
dried in an oven at 658C for 48 h and analyzed for their nitrogen content; the amino acid
content was determined by means of ion exchange chromatography using Amino
Analyzer 3A30 (Carlo Erba, Milan, Italy) on the original feeds and the undegraded
residues of all the bags incubated for 24 h. The effect of fat-coating on amino acids rumen
degradation was assessed considering the following ratio:
AAn =SEAA before rumen incubation
AAn =SEAA post rumen incubation
where: AAn is the content (g/100 g CP) of a single essential amino acid, and EAA the
total essential amino acids (g/100 g of CP).
Using the data of rumen degradability for crude proteins and the amino acid
composition of the undegraded residue, the amount of by-pass essential amino acids after
24 h of rumen incubation was calculated as follows:
100 g of feed CP g=100 g CP rumen byÿpass
AAn content of undegraded residue %
where AAn is referred to each single essential amino acids.
In order to evaluate the effect of fat-coating on intestinal digestibility, nitrogen
disappearance from the intestinal mobile bags was evaluated using the method proposed
by Peyraud et al. (1988).
3. Results
Addition of fat reduces nitrogen solubility in proportion to the lipid content.
Particularly marked was the drop observed with Profile 25 (Table 2). The addition of a
312
F. Rossi et al. / Animal Feed Science and Technology 81 (1999) 309±318
Table 2
Nitrogen solubility in a borate±phosphate buffer of normal and two types of fat-coated soybean meal
Feedstuffs
N solubility (% on total N)
Soybean meal
Profile 10
Profile 25
8 h of incubation
24 h of incubation
4.41
3.26
1.26
16.83
13.38
3.18
Table 3
Dry matter (DM) and crude protein (CP) in situ rumen degradation of normal and fat coated soybean meal
(profiles 10 and 25)a
Soybean meal
Profile 10
Profile 25
SE
8-h Rumen degradation (%)
24-h Rumen degradation (%)
D.M.
C.P.
D.M.
C.P.
34.83Bb
30.53ABa
26.25Aa
1.409
23.57C
17.53B
9.08A
1.013
70.20B
57.87A
56.74A
2.421
61.14b
44.72a
50.82AB
4.772
a
Means in the same column with different letters are significantly different: A,B,C Ð.(P