Corn germ is a co-product of the wet milling industry that is available for use in swine diets to partially replace the more expensive corn grain. Results of arecent experiment indicated that including 15% corn germ in diets containing 30% DDGS had no negative effects on pig growth performance, carcass composition, or pork fat quality. However, it is not known if greater quantities of corn germ may be included in diets fed to growing-finishing pigs. Therefore, we conducted an experiment to determine if greater levels of corn germ may be included in diets fed to growing-finishing pigs without negatively affecting growth performance, carcass characteristics, muscle and fat quality, or belly quality. The experiment also determined if the presence of DDGS in the diets influences the responses to the inclusion of corn germ.
A total of 280 pigs with an initial body weight of 42.5 ± 4.6 kg were divided into ten pens and fed one of eight dietary treatments. Corn germ was included at 0, 10, 20, or 30% in diets containing either 0 or 30% DDGS. The experiment lasted for a total of 83 days. Grower diets were providedfor the first 28 days, early finisher diets for the next 28 days, and late finisher diets for the final 27 days. At the conclusion of the experiment, the pig in each pen that had a body weight that was closest to the average body weight for the pen was harvested and its carcass characteristics were determined.
Growth performance
The inclusion of graded levels of corn germ in diets without or with DDGS had no effect on average daily gain, average daily feed intake, gain:feed, or final body weight during the growing, early finishing, late finishing, or the entire experimental period (Table 1).
Pigs fed diets containing no DDGS had a greater (P < 0.01) average daily gain and average daily feed intake than pigs fed diets containing 30% DDGS during the growing and late finishing periods as well as the overall experimental period. In addition, average daily gain was greater (P < 0.01) in the pigs fed no DDGS during the early finishing period. The body weight of the pigs fed no DDGS was greater (P < 0.001) than for pigs fed DDGS at the end of each phase and at the conclusion of the experiment. Average gain:feed values were the same for pigs fed diets without or with DDGS.
Carcass composition and muscle and backfat quality
Inclusion of increasing levels of corn germ to diets containing either 0 or 30% DDGS had no effect on live weight, hot carcass weight, dressing percentage, backfat, loin muscle (LM) area, or fat free lean percentage (Table 2). No interaction between corn germ and DDGS was observed for any of the carcass composition parameters. Pigs fed diets without DDGS had greater (P = 0.05) backfat than pigs fed diets with 30% DDGS, but all other carcass composition measurements were the same for diets without and with DDGS.
There was no effect of inclusion rates of corn germ on most muscle quality measures: marbling, firmness, pH, drip loss, or the subjective color or a* color value of LM. This was true regardless of the level of DDGS in the diet. As graded levels of corn germ were added to the diets without DDGS, there was a decrease (linear and quadratic, P < 0.05) in LM L* value and a trend (linear, P = 0.06) for decreased LM b* values, but this was not the case for diets containing 30% DDGS. LM marbling and firmness were reduced (P < 0.05) in diets containing 30% DDGS as compared with diets containing no DDGS, while all other muscle quality measures were the same for diets containing 0 or 30% DDGS.
Inclusion of corn germ did not affect backfat a* and b* values in pigs fed diets without or with DDGS, or backfat L* values in pigs fed diets with DDGS. However, there was a tendency (linear, P = 0.06) for decreased backfat L* values as corn germ was added to diets containing no DDGS. Backfat L* values for pigs fed 0% DDGS were greater (P < 0.001) than the backfat L* values for pigs fed diets containing 30% DDGS.
Belly quality
In diets containing no DDGS, inclusion of increasing amounts of corn germ increased belly length (quadratic, P < 0.05) and decreased (linear, P< 0.001) belly flop distance (Table 3). In diets containing 30% DDGS, inclusion of increasing amounts of corn germ did not affect belly length or belly flop distance. Belly width and belly weight were not affected by addition of corn germ to the diets regardless of the inclusion level of DDGS.
The inclusion of DDGS did not affect belly length or belly width, but did reduce belly flop distance (P < 0.001). As noted above, this reduction in belly firmness was not ameliorated by the addition of corn germ. There was also a tendency (P = 0.06) for reduced belly weight in pigs fed diets containing 30% DDGS compared with pigs fed no DDGS, but this is likely a result of the reduction in live bodyweight of the DDGS-fed pigs compared with pigs fed no DDGS.
Key points
- Corn germ has no detrimental effects on pig growth performance, carcass composition, or carcass quality.
- For all growth performance measures, and most carcass composition and belly quality measures, the level of DDGS in the diet has no effect on the response of pigs to increasing inclusion rates of corn germ.
- Feeding corn germ to finishing pigs may result in reduced belly firmness even if no DDGS is included in the diet. Feeding corn germ also does not ameliorate the reduction of belly firmness in pigs fed diets containing 30% DDGS.
Table 1. Growth performance of pigs fed diets containing graded levels of corn germ (CG) and either 0 or 30% distillers dried grains with solubles (DDGS)
|
|
Diet |
P-value |
|||||||||||||
|
|
0% DDGS |
30% DDGS |
0% DDGS |
30% DDGS |
|||||||||||
|
Item |
0% CG |
10% CG |
20% CG |
30% CG |
0% CG |
10% CG |
20% CG |
30% CG |
DDGS |
Corn germ |
DDGS × CG |
Linear |
Quad. |
Linear |
Quad. |
|
Growing period |
|||||||||||||||
|
Initial BW, kg |
40.97 |
40.99 |
40.80 |
41.21 |
41.42 |
40.86 |
40.93 |
41.11 |
0.87 |
0.96 |
0.98 |
0.88 |
0.80 |
0.80 |
0.63 |
|
ADG, kg |
0.97 |
1.00 |
1.04 |
1.02 |
0.91 |
0.93 |
0.92 |
0.91 |
<0.001 |
0.46 |
0.47 |
0.07 |
0.31 |
0.95 |
0.70 |
|
ADFI, kg |
2.07 |
2.22 |
2.18 |
2.05 |
1.87 |
2.00 |
1.89 |
1.95 |
<0.01 |
0.49 |
0.81 |
0.82 |
0.15 |
0.75 |
0.67 |
|
G:F, kg/kg |
0.48 |
0.46 |
0.48 |
0.51 |
0.51 |
0.47 |
0.49 |
0.47 |
0.91 |
0.65 |
0.57 |
0.37 |
0.33 |
0.38 |
0.78 |
|
Final BW, kg |
68.26 |
68.97 |
69.90 |
69.76 |
66.94 |
66.79 |
66.57 |
66.67 |
<0.001 |
0.90 |
0.72 |
0.21 |
0.66 |
0.81 |
0.89 |
|
Early finishing period |
|||||||||||||||
|
ADG, kg |
1.03 |
1.00 |
1.04 |
0.97 |
0.96 |
0.95 |
0.96 |
0.94 |
<0.01 |
0.42 |
0.75 |
0.24 |
0.48 |
0.85 |
0.95 |
|
ADFI, kg |
2.65 |
2.73 |
2.63 |
2.64 |
2.56 |
2.48 |
2.52 |
2.50 |
0.14 |
1.00 |
0.93 |
0.80 |
0.80 |
0.82 |
0.83 |
|
G:F, kg/kg |
0.39 |
0.38 |
0.41 |
0.38 |
0.38 |
0.39 |
0.39 |
0.39 |
0.90 |
0.95 |
0.89 |
0.84 |
0.80 |
0.81 |
0.85 |
|
Final BW, kg |
97.06 |
96.96 |
98.90 |
96.87 |
93.70 |
93.26 |
93.37 |
93.10 |
<0.001 |
0.81 |
0.83 |
0.81 |
0.45 |
0.77 |
0.95 |
|
Late finishing period |
|||||||||||||||
|
ADG, kg |
1.09 |
1.00 |
1.02 |
1.02 |
0.96 |
0.94 |
0.99 |
0.97 |
<0.001 |
0.18 |
0.30 |
0.14 |
0.06 |
0.65 |
0.98 |
|
ADFI, kg |
3.39 |
3.39 |
3.32 |
3.33 |
3.09 |
3.14 |
3.19 |
3.10 |
<0.001 |
0.94 |
0.76 |
0.51 |
0.94 |
0.82 |
0.38 |
|
G:F, kg/kg |
0.32 |
0.30 |
0.31 |
0.31 |
0.31 |
0.30 |
0.31 |
0.31 |
0.91 |
0.22 |
0.91 |
0.59 |
0.14 |
0.76 |
0.37 |
|
Final BW, kg |
126.43 |
123.88 |
126.36 |
124.51 |
119.74 |
118.70 |
120.10 |
119.19 |
<0.001 |
0.51 |
0.95 |
0.63 |
0.82 |
0.97 |
0.97 |
|
Entire period |
|||||||||||||||
|
ADG, kg |
1.03 |
1.00 |
1.03 |
1.00 |
0.94 |
0.94 |
0.95 |
0.94 |
<0.001 |
0.42 |
0.86 |
0.54 |
0.91 |
0.92 |
0.83 |
|
ADFI, kg |
2.82 |
2.90 |
2.83 |
2.79 |
2.62 |
2.65 |
2.65 |
2.62 |
<0.001 |
0.66 |
0.89 |
0.53 |
0.32 |
1.00 |
0.62 |
|
G:F, kg/kg |
0.36 |
0.35 |
0.36 |
0.37 |
0.36 |
0.35 |
0.36 |
0.36 |
0.71 |
0.22 |
0.75 |
0.43 |
0.16 |
0.99 |
0.73 |
Table 2. Carcass composition, muscle quality, and backfat quality of pigs fed diets containing graded levels of corn germ (CG) and either 0 or 30% distillers dried grains with solubles (DDGS)
|
|
Diet |
P-value |
|||||||||||||
|
|
0% DDGS |
30% DDGS |
0% DDGS |
30% DDGS |
|||||||||||
|
Item |
0% CG |
10% CG |
20% CG |
30% CG |
0% CG |
10% CG |
20% CG |
30% CG |
DDGS |
CG |
DDGS x CG |
Linear |
Quad. |
Linear |
Quad. |
|
Carcass composition |
|||||||||||||||
|
Live wt, kg |
121.6 |
118.4 |
122.5 |
118.3 |
116.4 |
114.6 |
114.1 |
115.6 |
<0.01 |
0.69 |
0.65 |
0.58 |
0.81 |
0.78 |
0.49 |
|
Hot carcass wt, kg |
96.1 |
93.7 |
96.8 |
93.4 |
92.0 |
91.0 |
89.8 |
91.4 |
<0.01 |
0.78 |
0.56 |
0.55 |
0.78 |
0.74 |
0.49 |
|
Dressing, % |
79.1 |
79.2 |
79.0 |
78.9 |
79.0 |
79.4 |
78.7 |
79.1 |
0.90 |
0.63 |
0.76 |
0.69 |
0.85 |
0.78 |
0.96 |
|
Backfat, cm |
2.0 |
1.9 |
2.1 |
2.1 |
1.6 |
2.0 |
1.8 |
1.7 |
0.05 |
0.88 |
0.19 |
0.61 |
0.56 |
0.81 |
0.11 |
|
LM area, sq. cm |
56.1 |
53.2 |
53.0 |
54.9 |
53.1 |
53.2 |
51.1 |
53.8 |
0.18 |
0.34 |
0.81 |
0.58 |
0.13 |
1.00 |
0.40 |
|
FFL,1 % |
54.7 |
55.1 |
53.8 |
54.8 |
56.1 |
54.4 |
55.1 |
56.1 |
0.16 |
0.72 |
0.58 |
0.63 |
0.87 |
0.83 |
0.16 |
|
Muscle quality |
|||||||||||||||
|
Subjective color2 |
2.1 |
2.3 |
2.4 |
2.2 |
2.5 |
2.1 |
2.2 |
2.2 |
1.00 |
0.79 |
0.11 |
0.52 |
0.15 |
0.20 |
0.15 |
|
Marbling3 |
1.3 |
1.3 |
1.4 |
1.4 |
1.1 |
1.0 |
1.1 |
1.2 |
0.02 |
0.78 |
0.97 |
0.56 |
1.00 |
0.56 |
0.51 |
|
Firmness4 |
2.8 |
2.9 |
3.1 |
3.0 |
2.5 |
2.7 |
2.4 |
2.1 |
<0.01 |
0.61 |
0.27 |
0.38 |
0.62 |
0.10 |
0.22 |
|
24-h pH, LM |
5.5 |
5.6 |
5.6 |
5.6 |
5.7 |
5.6 |
5.6 |
5.6 |
0.31 |
0.84 |
0.06 |
0.12 |
0.27 |
0.30 |
0.15 |
|
48-h drip loss, % |
5.9 |
3.8 |
4.0 |
3.6 |
4.6 |
5.0 |
4.5 |
5.6 |
0.40 |
0.71 |
0.32 |
0.11 |
0.35 |
0.52 |
0.68 |
|
LM color, L*5 |
51.3 |
47.0 |
47.6 |
47.9 |
46.6 |
48.4 |
48.3 |
47.8 |
0.29 |
0.50 |
<0.01 |
0.02 |
0.01 |
0.38 |
0.24 |
|
LM color, a*5 |
7.9 |
8.2 |
7.9 |
7.2 |
8.1 |
7.9 |
8.1 |
8.0 |
0.60 |
0.81 |
0.79 |
0.29 |
0.37 |
0.97 |
0.95 |
|
LM color, b*5 |
3.7 |
2.7 |
2.6 |
2.3 |
3.0 |
3.2 |
3.2 |
2.9 |
0.53 |
0.53 |
0.52 |
0.06 |
0.52 |
0.89 |
0.61 |
|
Backfat color |
|||||||||||||||
|
Fat color, L*5 |
75.0 |
73.9 |
74.4 |
73.7 |
73.1 |
73.2 |
72.1 |
72.9 |
<0.001 |
0.16 |
0.12 |
0.06 |
0.54 |
0.35 |
0.36 |
|
Fat color, a*5 |
4.0 |
4.3 |
3.5 |
3.8 |
4.2 |
3.5 |
4.2 |
3.8 |
0.90 |
0.84 |
0.18 |
0.37 |
0.91 |
0.79 |
0.65 |
|
Fat color, b*5 |
4.0 |
3.9 |
3.8 |
3.8 |
4.3 |
4.2 |
3.9 |
4.0 |
0.19 |
0.63 |
0.97 |
0.56 |
0.97 |
0.28 |
0.67 |
1FFL, % = as calculated from NPPC (1999): pounds fat free lean = 8.588 – (21.896 × 10th rib fat depth, in.) + (0.465 × HCW, lb.) + (3.005 × 10th rib loin muscle area, sq. in.), (pounds FFL / HCW) × 100 = %FFL.
2National Pork Producers Council (NPPC) color scale (1 to 6): 1 = pale pinkish gray to white; 6 = dark purplish red.
3NPPC marbling scale (1 to 10): 1 = devoid; 10 = abundant.
4NPPC firmness scale (1 to 5): 1 = very soft; 5 = very firm and dry.
5As measured on a Minolta Chromameter.
Table 3. Belly quality of pigs fed diets containing graded levels of corn germ (CG) and either 0 or 30% distillers dried grains with solubles (DDGS)
|
|
Diet |
P-value |
|||||||||||||
|
|
0% DDGS |
30% DDGS |
|
0% DDGS |
30% DDGS |
||||||||||
|
Item |
0% CG |
10% CG |
20% CG |
30% CG |
0% CG |
10% CG |
20% CG |
30% CG |
DDGS |
CG |
DDGS × CG |
Linear |
Quad. |
Linear |
Quad. |
|
Belly length, cm |
57.05 |
59.21 |
58.75 |
56.51 |
57.23 |
56.69 |
56.44 |
56.67 |
0.12 |
0.56 |
0.36 |
0.65 |
0.03 |
0.67 |
0.71 |
|
Belly width, cm |
22.91 |
23.70 |
23.93 |
23.44 |
24.18 |
24.39 |
24.13 |
23.50 |
0.31 |
0.81 |
0.85 |
0.59 |
0.40 |
0.50 |
0.58 |
|
Belly wt, kg |
5.10 |
5.36 |
5.51 |
5.16 |
5.11 |
5.22 |
4.92 |
4.88 |
0.06 |
0.51 |
0.44 |
0.71 |
0.11 |
0.24 |
0.70 |
|
Flop distance1, cm |
17.37 |
14.28 |
11.66 |
9.98 |
8.10 |
9.45 |
7.37 |
6.22 |
<0.001 |
0.01 |
0.26 |
<0.001 |
0.64 |
0.26 |
0.42 |
1A flop test was performed by draping a centered belly lengthwise over a suspended, stainless steel rod with the skin side down. The distance from skin surface to skin surface was measured at a standardized point, 10 cm down from the stainless steel rod.
This research report is based on unpublished research by J. W. Lee, F. McKeith, and H. H. Stein.