Distillers dried grains with solubles, or DDGS, is a co-product from the dry-grind ethanol production. It is increasingly in demand for use in livestock feeding, including diets fed to pigs. Conventional DDGS (DDGS-CV) contains approximately 27% crude protein. A high protein DDGS (DDGS-HP) product, containing 38 to 40% crude protein, has recently been developed by Lincolnway Energy by using front end separation that allows for fractionation of the corn kernel before it is fermented. The nutritional value for pigs of the resulting DDGS-HP has, however, not yet been fully described.
Therefore, two experiments were conducted. The objective of the first experiment was to determine the concentrations of digestible energy (DE) and metabolizable energy (ME) and the apparent total tract digestibility (ATTD) of energy in DDGS-HP and DDGS-CV fed to growing pigs. In the second experiment, the standardized ileal digestibility (SID) of crude protein and amino acids in DDGS-CV and DDGS-HP were compared.
Experimental design
In the first experiment, three diets were formulated: a basal diet based on corn and two diets containing either DDGS-HP or DDGS-CV. A total of 24 growing barrows were randomly allotted to the three diets. Feed consumption was recorded daily. After an adaptation period of seven days, urine and feces were collected for five days and analyzed for gross energy to determine energy digestibility and calculate concentrations of DE and ME in each ingredient.
In the second experiment, eighteen growing barrows with an average initial body weight of approximately 75 kg were used. The barrows had cannulas installed in the distal ileum to facilitate the collection of ileal digesta. Three diets were formulated: two diets containing either DDGS-HP or DDGS-CV as the sole source of crude protein and amino acids, and a nitrogen-free diet that was used to measure basal endogenous losses of amino acids. Pigs were fed the diets for a five day adaptation period, then ileal digesta were collected for eight hours each on days 6 and 7 and analyzed for amino acids to calculate SID of amino acids.
Energy digestibility
On an as-fed basis, DDGS-HP contained 3,826 kcal/kg DE and 3,698 kcal/kg ME (Table 1). The DE and ME concentrations in DDGS-HP were greater (P < 0.05) than the DE and ME in DDGS-CV and in corn, which did not differ from each other.
On a dry matter basis, DDGS-HP contained 4,424 kcal/kg DE and 4,275 kcal/kg ME. The concentrations of DE and ME in DDGS-HP did not differ from DDGS-CV, but were greater (P < 0.05) than DE and ME in corn.
The ATTD of gross energy was 84.85% in DDGS-HP, which was less (P < 0.05) than the ATTD of GE in corn, but not different from the ATTD of GE in DDGS-CV.
Amino acid digestibility
The SID values of lysine, methionine, phenylalanine, leucine, and glutamic acid were greater (P < 0.05) in DDGS-HP than in DDGS-CV. There was also a tendency for the average SID of all dispensable amino acids and the SID of valine and tyrosine to be greater in DDGS-HP than in DDGS-CV, but there were no other differences in the SID of crude protein or amino acids between the two sources of DDGS.
Key points
- Conventional or high protein DDGS can replace corn in swine diets without reducing the concentration of DE or ME in the diets.
- The SID of crude protein and amino acids is the same or greater in DDGS-HP compared with DDGS-CV.
- Differences between DDGS-HP and DDGS-CV in concentrations of DE and ME, as well as in SID of some AA, may be due to the processing method and technology used to produce these sources.
Table 1. Digestible energy (DE) and metabolizable energy (ME) and the apparent total tract digestibility (% ATTD) of energy in corn, high protein DDGS (DDGS-HP), and conventional DDGS (DDGS-CV) by growing pigs
|
|
Ingredient |
||||
|
Item |
Corn |
DDGS-HP |
DDGS-CV |
SEM |
P-value |
|
As-fed basis |
|||||
|
DE, kcal/kg |
3,413b |
3,826a |
3,568b |
83 |
0.008 |
|
ME, kcal/kg |
3,339b |
3,698a |
3,426b |
87 |
0.023 |
|
DM basis |
|||||
|
DE, kcal/kg |
3,975b |
4,424a |
4,148ab |
96 |
0.013 |
|
ME, kcal/kg |
3,889b |
4,275a |
3,983ab |
101 |
0.036 |
|
ATTD of GE, % |
89.81a |
84.85b |
81.70b |
1.09 |
<0.001 |
a,b Means within a row that do not have a common superscript differ, P < 0.05.
Table 2. Standardized ileal digestibility of crude protein and amino acids in high protein DDGS (DDGS-HP) and conventional DDGS (DDGS-CV) by growing pigs
|
|
Source of DDGS |
|||
|
Items |
DDGS-HP | DDGS-CV |
SEM |
P-value |
|
CP, % |
78.7 |
77 |
2.60 |
0.647 |
|
Indispensable AA, % |
||||
|
Arg |
87.4 |
89.4 |
2.83 |
0.621 |
|
His |
82.2 |
79.6 |
1.07 |
0.115 |
|
Ile |
81.9 |
78.4 |
1.26 |
0.080 |
|
Leu |
89.2a |
84.7b |
0.97 |
0.009 |
|
Lys |
76.2a |
69.5b |
1.71 |
0.020 |
|
Met |
87.2a |
83.3b |
1.05 |
0.026 |
|
Phe |
85.5a |
81.8b |
0.97 |
0.022 |
|
Thr |
75.0 |
73.7 |
0.93 |
0.363 |
|
Trp |
79.5 |
80.2 |
1.44 |
0.746 |
|
Val |
81.1x |
77.6y |
1.20 |
0.070 |
|
Total |
83.8x |
80.7y |
1.03 |
0.059 |
|
Dispensable AA, % |
||||
|
Ala |
84.5 |
81.8 |
1.42 |
0.214 |
|
Asp |
72.9 |
71.8 |
1.12 |
0.504 |
|
Cys |
74.9 |
73.2 |
0.88 |
0.202 |
|
Glu |
87.5a |
83.1b |
1.17 |
0.024 |
|
Gly |
71.2 |
77.3 |
7.70 |
0.592 |
|
Ser |
81.8 |
80.9 |
0.88 |
0.468 |
|
Tyr |
86.5x |
83.9y |
0.93 |
0.080 |
|
Total |
82.0 |
79.9 |
1.46 |
0.346 |
|
All AA |
82.9 |
80.3 |
1.19 |
0.158 |
a,b Means within a row with different superscripts differ (P ≤ 0.05).
x,y Means within a row with different superscripts tend to differ (P ≤ 0.10).
This report is based on unpublished research by Charmaine Espinosa and H. H. Stein.