Soybean meal is a rich source of digestible amino acids for pigs. However, soybeans contain antinutritional factors such as antigenic proteins, oligosaccharides, lectins, and trypsin inhibitors that make soybeans and conventional soybean meal unsuitable for feeding to weanling pigs in great quantities. Therefore, animal protein is usually included in starter diets for pigs. Because soy protein is less expensive than the animal protein, strategies to reduce the antinutritional factors in soy products have been explored. Fermentation of soybean meal with bacteria such as Aspergillus oryzae and Lactobacillus subtilis eliminates many antinutritional factors, and studies have shown that fermented soybean meal is well-tolerated by weanling pigs. However, there is a lack of data on the digestibility of energy and amino acids in fermented soybean meal. Two experiments were, therefore, conducted to measure the concentration of DE and ME and the digestibility of amino acids in fermented soybean meal and to compare these values to values obtained in conventional soybean meal and fish meal.
Energy concentration and digestibility of energy and other nutrients
The first experiment was designed to determine the energy concentration, the N-balance, and the apparent total tract digestibility (ATTD) of energy and nutrients in fermented soybean meal, conventional soybean meal, and fish meal. The source of fermented soybean meal that was used was PepSoyGen® (Nutra Ferma, Sioux City, SD), which is produced by fermentation of SBM in the presence of Aspergillus oryzae and Lactobacillus subtilis. The conventional soybean meal was sourced from Rose Acre Farms (Seymour, IN), and the fish meal was prepared from menhaden fish (Menhaden Select, Omega Protein, Houston, TX). A local source of corn was also used (Table 1).
Four diets were formulated. The basal diet contained 96.4% corn. Three additional diets were formulated by mixing corn with 28.0% fermented soybean meal, 31% conventional soybean meal, or 24% fish meal.
Conventional soybean meal had greater (P < 0.01) concentrations of digestible, metabolizable, and net energy on a dry matter basis than the other ingredients (Table 2).Fermented soybean meal had a greater concentration (P < 0.01) of digestible, metabolizable, and net energy than fish meal, and the concentration of metabolizable and net energy on a dry matter basis in fermented soybean meal was not different from that in corn.
The ATTD of gross energy in fermented soybean meal was comparable to that in corn and conventional soybean meal, and greater (P < 0.01) than in fish meal.
The ATTD of N was not different among fermented soybean meal, conventional soybean meal, and fish meal, but the ATTD of N in corn was less (P < 0.01) than in the other ingredients. Fermented soybean meal had the greatest (P < 0.01) ATTD of acid-hydrolyzed ether extract (fat) of all ingredients and corn had the least concentration, while conventional soybean meal and fish meal were not different. The ATTD of ash was greater (P < 0.01) in conventional soybean meal than in all other ingredients, followed by fermented soybean meal, fish meal, and corn, respectively.
Fermented soybean meal contains highly digestible amino acids
The second experiment was designed to determine the standardized ileal digestibility (SID) of crude protein and amino acids in fermented soybean meal and compare these values to the SID of amino acids in conventional soybean meal and fish meal. Four diets were formulated. Three diets were cornstarch-based with fermented soybean meal, conventional soybean meal, or fish meal as the only source of amino acids in each diet. The fourth diet was N-free and was used to estimate basal endogenous losses of crude protein and amino acids.
The SID of crude protein was not different among fermented soybean meal, conventional soybean meal, and fish meal (Table 3). The SID of most indispensable amino acids did not differ between fermented soybean meal and conventional soybean meal, with the only exceptions being methionine and valine, for which the SID was greater (P < 0.01) in fermented soybean meal than in conventional soybean meal. The SID of almost all indispensable amino acids was greater (P < 0.01) in fermented soybean meal than in fish meal. The exceptions were lysine, threonine, and tryptophan, where the digestibility was not different between fermented soybean meal and fish meal. The SID for the mean of indispensable amino acids was not different in fermented soybean meal and conventional soybean meal, but the SID of indispensable AA was less (P < 0.01) in fish meal than in the two sources of soybean meal.
Key points
- The concentration of digestible, metabolizable, and net energy in fermented soybean meal was less than in conventional soybean meal, but greater than in fish meal.
- Energy digestibility in fermented soybean meal was not different from that in corn and conventional soybean meal, and greater than in fish meal.
- The standardized ileal digestibility of most amino acids was not different for fermented soybean meal and conventional soybean meal, but the SID of most amino acids is greater in fermented soybean meal than in fish meal.
- Fermented soybean meal can be used as a source of energy and digestible amino acids in diets fed to weanling pigs.
Table 1. Analyzed nutrient composition of fermented soybean meal (FSBM), conventional soybean meal (SBM-CV), fish meal, and corn, as-fed basis
|
|
Ingredient |
|||
|
Item |
FSBM |
SBM-CV |
Fish meal |
Corn |
|
GE, kcal/kg |
4,533 |
4,281 |
4,589 |
3,938 |
|
DM, % |
91.0 |
89.39 |
91.80 |
87.04 |
|
CP, % |
53.91 |
50.20 |
63.98 |
7.44 |
|
Ca, % |
0.27 |
0.23 |
4.96 |
0.01 |
|
P, % |
0.83 |
0.69 |
3.05 |
0.24 |
|
Ash, % |
7.10 |
5.85 |
17.86 |
1.20 |
|
AEE, % |
1.50 |
1.39 |
9.33 |
2.20 |
|
NDF, % |
8.45 |
5.40 |
- |
6.56 |
|
ADF, % |
4.97 |
3.42 |
- |
1.76 |
|
Starch, % |
0.90 |
0.61 |
- |
55.77 |
|
Carbohydrates, % |
|
|
|
|
|
Glucose |
0.33 |
0.00 |
- |
- |
|
Sucrose |
0.00 |
8.77 |
- |
- |
|
Maltose |
0.00 |
0.20 |
- |
- |
|
Fructose |
0.54 |
0.00 |
- |
- |
|
Stachyose |
0.06 |
6.23 |
- |
- |
|
Raffinose |
0.00 |
1.29 |
- |
- |
|
Indispensable AA, % |
|
|
|
|
|
Arg |
3.59 |
3.61 |
3.58 |
0.33 |
|
His |
1.34 |
1.33 |
1.41 |
0.19 |
|
Ile |
2.45 |
2.35 |
2.54 |
0.24 |
|
Leu |
4.11 |
3.79 |
4.17 |
0.75 |
|
Lys |
3.15 |
3.17 |
4.76 |
0.24 |
|
Met |
0.73 |
0.69 |
1.66 |
0.14 |
|
Phe |
2.64 |
2.46 |
2.35 |
0.31 |
|
Thr |
2.00 |
1.85 |
2.34 |
0.23 |
|
Trp |
0.71 |
0.66 |
0.59 |
0.05 |
|
Val |
2.60 |
2.50 |
3.03 |
0.33 |
|
Total AA |
50.86 |
47.55 |
54.56 |
6.31 |
Table 2. Concentration of digestible and metabolizable energy and apparent total tract digestibility (ATTD) of energy, DM, and nutrients in corn, fermented soybean meal (FSBM), conventional soybean meal (SBM-CV), and fish meal, as-fed basis
|
Item |
Corn |
FSBM |
SBM-CV |
Fish meal |
P-value |
|
GE intake, kcal |
3,388a |
1,275c |
1,546b |
1,112d |
< 0.01 |
|
GE in feces, kcal |
388.5a |
148.8b |
150.1b |
172.2b |
< 0.01 |
|
GE in urine, kcal |
100.1 |
123.3 |
115.8 |
93.5 |
0.63 |
|
DE, kcal/kg |
3,439c |
3,910b |
4,069a |
3,513c |
< 0.01 |
|
DE, kcal/kg DM |
3,951c |
4,296b |
4,553a |
3,827c |
< 0.01 |
|
ME, kcal/kg |
3,324bc |
3,441b |
3,698a |
3,132c |
< 0.01 |
|
ME, kcal/kg DM |
3,819b |
3,781b |
4,137a |
3,412c |
< 0.01 |
|
NE, kcal/kg |
2,469c |
2,666b |
2,832a |
2,394c |
< 0.01 |
|
NE, kcal/kg DM |
2,864b |
2,951b |
3,193a |
2,626c |
< 0.01 |
|
ATTD of GE, % |
88.6a |
88.2a |
90.3a |
84.0b |
< 0.01 |
|
ATTD of DM, % |
89.1a |
86.9a |
89.5a |
81.6b |
< 0.01 |
|
ATTD of N, % |
76.0b |
91.3a |
91.8a |
91.6a |
< 0.01 |
|
ATTD of ether extract, % |
28.5c |
71.9a |
56.9b |
49.9b |
< 0.01 |
|
ATTD of ash, % |
60.3c |
68.3b |
78.7a |
64.3bc |
< 0.01 |
a-dMeans within a row lacking a common superscript letter differ (P < 0.05).
Table 3. Apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of CP and AA in fermented soybean meal (FSBM), conventional soybean meal (SBM-CV), and fish meal by weanling pigs
| AID |
SID |
|||||||
|
Ingredient |
|
Ingredient |
|
|||||
|
Item |
FSBM |
SBM-CV |
Fish meal |
P-value |
FSBM |
SBM-CV |
Fish meal |
P-value |
|
CP, % |
64.5 |
59.7 |
61.9 |
0.5 |
79.9 |
79.6 |
76.1 |
0.54 |
|
Indispensable AA, % |
||||||||
|
Arg |
87.6a |
86.1a |
77.4b |
< 0.01 |
94.2a |
94.2a |
86.1b |
< 0.01 |
|
His |
83.6a |
81.9a |
75.4b |
< 0.01 |
89.3a |
89.1a |
82.3b |
0.01 |
|
Ile |
82.1a |
77.7b |
75.1b |
< 0.01 |
87.5a |
84.7ab |
81.7b |
< 0.01 |
|
Leu |
82.1a |
76.8b |
75.5b |
< 0.01 |
87.6a |
84.3ab |
82.2b |
0.02 |
|
Lys |
76.2 |
77.0 |
76.0 |
0.86 |
82.2 |
84.2 |
81.1 |
0.24 |
|
Met |
85.6a |
79.2b |
79.9b |
< 0.01 |
90.6a |
85.7b |
82.8b |
< 0.01 |
|
Phe |
83.4a |
78.9b |
72.3c |
< 0.01 |
88.6a |
85.8a |
79.7b |
< 0.01 |
|
Thr |
72.0a |
64.5b |
66.7b |
0.01 |
83.4 |
79.6 |
79.0 |
0.14 |
|
Trp |
82.7a |
81.9a |
77.7b |
0.02 |
89.4 |
89.6 |
86.8 |
0.25 |
|
Val |
77.7a |
69.4b |
69.4b |
< 0.01 |
85.6a |
80.5b |
78.4b |
< 0.01 |
|
Mean indispensable AA |
81.1a |
77.4b |
74.4b |
< 0.01 |
87.6a |
85.8a |
81.7b |
< 0.01 |
|
Mean of all AA |
74.1a |
69.8ab |
64.0b |
0.01 |
86.2a |
85.7a |
78.4b |
0.03 |
a-dMeans within a row lacking a common superscript letter differ (P < 0.05).
This report is based on unpublished research from the University of Illinois.