Canola meal is the defatted meal that remains after oil has been extracted from the seeds of the rapeseed plant, Brassica napus. Canola meal is high in crude protein and amino acids relative to most plant protein sources, and the amino acids in canola meal are well digested by pigs. However, it is also relatively high in fiber, which reduces energy digestibility and digestible energy concentration. New varieties of Brassica napus with a thinner seed coat have been hybridized, which contain less fiber and more protein than conventional rapeseed. The meal produced from these varieties is known as high protein canola meal. No data exist for the digestibility of energy in this source of high protein canola mealwhen fed to pigs. Therefore, an experiment was conducted to determine the apparent total tract digestibility (ATTD) of energy and the concentrations of digestible and metabolizable energy in two sources of high protein canola meal (CM-HP1 and CM-HP2) fed to growing pigs, and to compare these values with values for conventional canola meal (CM-CV) and soybean meal (SBM).
Experimental design
A total of 40 growing barrows with an average initial body weight of 51.5 kg were fed one of five diets.The basal diet contained 97.4% corn. Two sources of high protein canola meal were tested. The CM-HP1 diet contained 71.95% corn and 27.00% CM-HP1, and the CM-HP2 diet contained 72.00% corn and 26.00% CM-HP2. The CM-CV diet contained 60.80% corn and 37.50% conventional canola meal, sourced from traditional Brassica napus. The SBM diet contained 71.50% corn and 26.30% soybean meal. The corn and the test ingredients were the only sources of energy in the diets.
Pigs were fed the experimental diets for a five-day adaptation period, after which feces and urine were collected on days 6 and 11. The energy content of the feces and urine was analyzed to determine the apparent total tract digestibility of energy and the concentration of digestible and metabolizable energy in each ingredient.
High protein canola meal has greater energy digestibility and more DE and ME than conventional canola meal
The apparent total tract digestibility of energy was greatest (P < 0.05) in soybean meal (Table 2). The ATTD of energy in corn was less than that in soybean meal but greater than in any of the sources of canola meal. The ATTD of energy did not differ among the two sources of high protein canola meal, and was greater in both of these sources than in conventional canola meal.
The concentrations of digestible and metabolizable energy were greatest (P< 0.05) in soybean meal and least in conventional canola meal. This was true on both an as-fed and a dry matter basis. CM-HP2 had a greater concentration of digestible energy on an as-fed basis than corn and CM-HP1, which did not differ. On a dry matter basis, CM-HP2 contained more (P< 0.05) digestible energy than CP-HP1, but did not differ from corn. CM-HP2 and corn contained the same amount of metabolizable energy, on both an as-fed and a dry matter basis, and both contained more (P< 0.05) metabolizable energy than CM-HP1.
Key points
- The digestibility of energy was greater in both sources of high protein canola meal than in conventional canola meal, but less than in corn or soybean meal.
- The concentrations of digestible and metabolizable energy differed among the two sources of high protein canola meal, with CM-HP2 containing more DE and ME than CM-HP1. Digestible and metabolizable energy concentrations in CM-HP2 were comparable to those in corn.
- The concentrations of digestible and metabolizable energy in soybean meal are greater than in all three sources of canola meal.
Table 1. Analyzed nutrient composition of two sources of high protein canola meal (CM-HP1 and CM-HP2), conventional canola meal (CM-CV), soybean meal (SBM), and corn, as-fed basis
|
Ingredient |
|||||
|
Item |
CM-HP1 |
CM-HP2 |
CM-CV |
SBM |
Corn |
|
GE, kcal/kg |
4,370 |
4,442 |
4,145 |
4,257 |
3,926 |
|
DM, % |
92.72 |
92.6 |
91.22 |
87.49 |
88.95 |
|
CP, % |
44.87 |
47.54 |
36.79 |
48.27 |
8.63 |
|
Ash, % |
7.05 |
6.52 |
8.14 |
5.57 |
1.06 |
|
AEE1, % |
3.48 |
3.28 |
3.77 |
2.48 |
3.16 |
|
NDF, % |
18.32 |
17.9 |
25.04 |
8.23 |
9.36 |
|
ADF, % |
12.66 |
10.95 |
17.53 |
4.81 |
2.26 |
|
P, % |
1.26 |
1.16 |
1.16 |
0.57 |
0.25 |
|
Ca, % |
0.64 |
0.51 |
1.25 |
0.29 |
0.01 |
|
Indispensable AA, % |
|||||
|
Arg |
2.79 |
2.87 |
2.09 |
3.43 |
0.38 |
|
His |
1.23 |
1.23 |
0.91 |
1.24 |
0.22 |
|
Ile |
1.77 |
1.89 |
1.35 |
2.32 |
0.27 |
|
Leu |
3.18 |
3.31 |
2.53 |
3.73 |
0.94 |
|
Lys |
2.61 |
2.67 |
2.02 |
3.07 |
0.27 |
|
Met |
0.91 |
0.91 |
0.68 |
0.69 |
0.16 |
|
Phe |
1.8 |
1.9 |
1.38 |
2.45 |
0.38 |
|
Thr |
1.85 |
1.84 |
1.49 |
1.82 |
0.27 |
|
Trp |
0.67 |
0.71 |
0.46 |
0.68 |
0.06 |
|
Val |
2.23 |
2.48 |
1.72 |
2.5 |
0.40 |
1AEE = acid hydrolyzed ether extract.
Table 2. Concentrations of gross, digestible, and metabolizable energy, and apparent total tract digestibility (ATTD) of energy in corn, two sources of high protein canola meal (CM-HP1 and CM-HP2), conventional canola meal (CM-CV), and soybean meal (SBM)
|
Item |
Corn |
CM-HP1 |
CM-HP2 |
CM-CV |
SBM |
P-value |
|
GE, kcal/kg as-fed |
3,926 |
4,370 |
4,442 |
4,145 |
4,257 |
N/A |
|
ATTD of GE, % |
86.54b |
78.27c |
81.44c |
69.96d |
92.22a |
< 0.01 |
|
DE, kcal/kg as-fed |
3,347c |
3,312c |
3,627b |
2,798d |
4,000a |
< 0.01 |
|
DE, kcal/kg DM |
3,763bc |
3,572c |
3,917b |
3,067d |
4,572a |
< 0.01 |
|
ME, kcal/kg as-fed |
3,268b |
2,893c |
3,346b |
2,492d |
3,796a |
< 0.01 |
|
ME, kcal/kg DM |
3,674b |
3,120c |
3,613b |
2,732d |
4,339a |
< 0.01 |
a-dMeans within a row lacking a common superscript letter differ (P < 0.05).
This report is based on unpublished research by J. D. Berrocoso, O. J. Rojas, J. Shoulders, J. C. González-Vega, and H. H. Stein.