In recent years, ethanol plants have begun extracting more oil from the solubles left over after fermentation. The resulting low oil distillers dried grains with solubles (DDGS) contain less digestible energy (DE) and metabolizable energy (ME) than traditional DDGS.
The fat content of the diet affects the digestibility of energy and nutrients. Because the production of low oil DDGS is a relatively new development, it has not been established that digestibility values are the same across suppliers. Therefore, an experiment was conducted to measure the apparent total tract digestibility (ATTD) of neutral detergent fiber (NDF) and the concentration of DE and ME among DDGS samples from different suppliers.
Experimental design
The experiment used eight sources of DDGS obtained from different suppliers, and these were labeled DDGS A, DDGS B, DDGS C, DDGS D, DDGS E, DDGS G, DDGS H, and DDGS I.
A total of 72 barrows with an average initial body weight of 18.1 kg were split into nine groups. Each group was fed a corn-based basal diet or one of eight diets containing corn and each source of DDGS. Feed consumption was recorded daily, and urine and fecal material were collected following a seven-day adaptation period to the diets. Urine and feces were analyzed to determine the ATTD of NDF and the concentrations of DE and ME in each diet. Values for each source of DDGS were then calculated using the difference procedure.
Results
The ATTD of NDF in DDGS was greater (P < 0.05) in DDGS D than in DDGS E, G, and H (Table 1).
The concentrations of gross energy (GE) and DE did not differ among the eight sources of DDGS when normalized to an 88% dry matter basis. The mean GE was 4,702 kcal/kg and the mean DE was 3,210 kcal/kg. The mean DE:GE ratio was 70.7%.
The ME concentration was greatest (P < 0.05; 3,142 kcal/kg) in DDGS D and least (P < 0.05; 2,769 kcal/kg) in DDGS E, but did not differ among the other sources of DDGS. The mean ME:DE ratio was 92.0%, and the mean ME:GE was 61.1%.
Key points
- The average concentration of gross energy, digestible energy, and metabolizable energy in low oil DDGS was 4,702, 3,210, and 2,953 kcal/kg respectively.
- Only small differences in GE, DE, and ME were observed among the eight different sources.
- The ATTD of NDF differed among sources of DDGS, but these differences did not appear to affect the digestibility of energy.
Table 1. Energy values and NDF digestibility in 8 sources of distillers dried grains with solubles (DDGS), normalized to 88% DM basis
|
|
DDGS |
|
|
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|
Item, % |
A |
B |
C |
D |
E |
G |
H |
I |
Mean |
SEM |
P-value |
|
Energy values, kcal/kg |
|||||||||||
|
GE |
4,963 |
4,798 |
4,858 |
4,824 |
4,613 |
4,645 |
4,462 |
4,455 |
4,702 |
188 |
N/A |
|
DE |
3,142 |
3,243 |
3,309 |
3,363 |
3,069 |
3,254 |
3,203 |
3,098 |
3,210 |
84 |
0.076 |
|
ME |
2,894ab |
2,963ab |
3,038ab |
3,142a |
2,769b |
2,988ab |
2,976ab |
2,857ab |
2,953 |
76 |
0.027 |
|
Energy digestibility and metabolizability |
|||||||||||
|
DE to GE ratio |
68.4 |
70.3 |
73.0 |
74.3 |
67.9 |
71.6 |
69.7 |
70.1 |
70.7 |
1.8 |
0.102 |
|
ME to DE ratio |
92.1 |
91.3 |
91.7 |
93.6 |
90.2 |
91.8 |
92.9 |
92.2 |
92.0 |
0.9 |
0.215 |
|
ME to GE ratio |
63.0ab |
64.2ab |
67.0ab |
69.4a |
61.3b |
65.7ab |
64.8ab |
64.6ab |
65.0 |
1.6 |
0.035 |
|
ATTD of NDF |
65.0ab |
62.0ab |
65.6ab |
68.0a |
57.0b |
55.3b |
55.6b |
59.9ab |
61.1 |
2.3 |
0.001 |
a-bWithin a row, means without a common superscript differ (P < 0.05).
This report is based on unpublished research by Su A Lee and Hans H. Stein.