Net energy content of dry extruded-expelled soybean meal fed with or without enzyme supplementation to growing pigs as determined by indirect calorimetry

Abstract

Two experiments were conducted to determine the NE content of dry extruded-expelled soybean (DESBM) and the effect of a multienzyme carbohydrase (MC) mixture on the NE content of DESBM and to determine the effect of diet design on NE values in growing pigs using indirect calorimetry (IC). In Exp. 1, 24 barrows (19.6 ± 0.51 kg BW) were allotted in a completely randomized design to 4 dietary treatments: a corn–soybean meal basal diet (Diet A), a diet containing Diet A and DESBM in an 80:20 ratio with a constant CP (Diet B), a diet with an 80:20 ratio of Diet A and DESBM with a constant corn:soybean meal ratio (Diet C), and a diet with simple substitution of Diet A with DESBM in an 80:20 ratio (Diet D). Pigs were fed in metabolism crates for a period of 16 d to determine the DE and ME and thereafter were moved into an indirect calorimeter where O2 consumption and CO2 production were measured to determine heat production and fasting heat production. The NE content of DESBM was calculated (difference method) to be 2,632, 2,548 and 2,540 kcal/kg DM in diets B, C, and D, respectively. Respective values obtained with published prediction equations were 2,624, 2,530 and 2,436 kcal/kg. In Exp. 2, 24 barrows (16.9 ± 0.76 kg BW) were randomly allotted to 1 of 4 treatments. The diets were a corn–soybean meal basal diet and a diet containing the basal diet and DESBM in an 80:20 ratio with a constant corn:soybean meal ratio with or without 2 levels (0.05% and 0.1%) of MC. The experimental procedures were similar to those described in Exp. 1. Enzyme supplementation improved (P < 0.0001) the DE, ME, and NE content of the DESBM. Multienzyme carbohydrase at 0.05% and 0.1% of the diet improved NE values of DESBM by 4.9% and 3.7%, respectively. In conclusion, the NE values of DESBM obtained with the IC method were higher than the values obtained with prediction equations; the disparity was least when diets were formulated with a constant CP level. However, as the difference method was used to determine the NE of ingredient, it is more appropriate to maintain a constant ratio between the ingredients. Also, the NE value of DESBM obtained for diets C and D were not different. Hence, the average NE value of DESBM evaluated was 2,544 kcal/kg DM. Enzyme supplementation improved the NE content of DESBM fed to growing pigs.

Full text

3402
INTRODUCTION
Feed is the single most expensive input in com-
mercial pork production, and at least 50% of this cost
can be attributed to supplying energy to the animal.
Of the available energy systems, the NE system pro-
vides a more accurate estimate of the dietary energy
available to the animal (Noblet, 2007). Energy values
of protein-rich feeds are often overestimated when
expressed on a digestible or metabolizable energy
Net energy content of dry extruded-expelled soybean meal fed with or without
enzyme supplementation to growing pigs as determined by indirect calorimetry1
D. E. Velayudhan,* J. M. Heo,*† and C. M. Nyachoti*2
*Department of Animal Science, University of Manitoba, Winnipeg, MB R3T 2N2, Canada; and †Department
of Animal Science and Biotechnology, Chungnam National University, Daejeon 305-764, Republic of Korea
ABSTRACT: Two experiments were conducted to
determine the NE content of dry extruded-expelled
soybean (DESBM) and the effect of a multienzyme
carbohydrase (MC) mixture on the NE content of
DESBM and to determine the effect of diet design
on NE values in growing pigs using indirect calorim-
etry (IC). In Exp. 1, 24 barrows (19.6 ± 0.51 kg BW)
were allotted in a completely randomized design to
4 dietary treatments: a corn–soybean meal basal diet
(Diet A), a diet containing Diet A and DESBM in
an 80:20 ratio with a constant CP (Diet B), a diet
with an 80:20 ratio of Diet A and DESBM with a
constant corn:soybean meal ratio (Diet C), and a diet
with simple substitution of Diet A with DESBM in
an 80:20 ratio (Diet D). Pigs were fed in metabo-
lism crates for a period of 16 d to determine the DE
and ME and thereafter were moved into an indirect
calorimeter where O2 consumption and CO2 pro-
duction were measured to determine heat produc-
tion and fasting heat production. The NE content of
DESBM was calculated (difference method) to be
2,632, 2,548 and 2,540 kcal/kg DM in diets B, C,
and D, respectively. Respective values obtained with
published prediction equations were 2,624, 2,530
and 2,436 kcal/kg. In Exp. 2, 24 barrows (16.9 ±
0.76 kg BW) were randomly allotted to 1 of 4 treat-
ments. The diets were a corn–soybean meal basal
diet and a diet containing the basal diet and DESBM
in an 80:20 ratio with a constant corn:soybean meal
ratio with or without 2 levels (0.05% and 0.1%) of
MC. The experimental procedures were similar to
those described in Exp. 1. Enzyme supplementation
improved (P < 0.0001) the DE, ME, and NE content
of the DESBM. Multienzyme carbohydrase at 0.05%
and 0.1% of the diet improved NE values of DESBM
by 4.9% and 3.7%, respectively. In conclusion, the
NE values of DESBM obtained with the IC method
were higher than the values obtained with prediction
equations; the disparity was least when diets were
formulated with a constant CP level. However, as
the difference method was used to determine the NE
of ingredient, it is more appropriate to maintain a
constant ratio between the ingredients. Also, the NE
value of DESBM obtained for diets C and D were not
different. Hence, the average NE value of DESBM
evaluated was 2,544 kcal/kg DM. Enzyme supple-
mentation improved the NE content of DESBM fed
to growing pigs.
Key words: dry extruded-expelled soybean meal, enzyme, NE, pig
© 2015 American Society of Animal Science. All rights reserved. J. Anim. Sci. 2015.93:3402–3409
doi:10.2527/jas2014-8514
1
The authors thank R. Stuski and D. Ramos for animal care
and A. Karamanov for technical assistance. Support for this re-
search was provided by the Agri-Food Research and Development
Initiative and Manitoba Pork Council.
2Corresponding author: Martin.Nyachoti@umanitoba.ca
Received September 16, 2014.
Accepted April 15, 2015.
Published July 17, 2015

NE of dry extruded-expelled SBM for pigs 3403
system (Noblet et al., 1994). These discrepancies in
measurement of available energy have a drastic effect
on the economics of pig production, and there is, there-
fore, an ongoing interest in adopting the NE system.
Soybean contains certain antinutritional factors
whose detrimental effects could be signicantly re-
duced by heat treatment during meal processing (Pe-
rilla et al., 1997). One such process is the combination
of extrusion with expelling, which produces the dry
extruded-expelled soybean meal (DESBM). However,
published data pertaining to the energy values of DES-
BM for grower pigs are limited.
Nonstarch polysaccharides (NSP) are complex
carbohydrates that form the main component of di-
etary ber. Pigs lack enzymes to digest such com-
pounds. Moreover, NSP are known to reduce nutrient
utilization in nonruminant animals. In vitro studies
have shown that combinations of carbohydrases were
more effective in NSP depolymerization of oil seed
meals than when the individual carbohydrases were
used (Meng et al., 2005). Although multienzyme prep-
arations have been shown to improve performance
and nutrient utilization in pigs (Omogbenigun et al.,
2004; Emiola et al., 2009), only limited data are avail-
able on the effect of the exogenous enzyme on the NE
aspect in growing pigs. Thus, the aim of this study was
to determine the NE content of DESBM in growing
pigs using either indirect calorimetry (IC) or predic-
tion equations and to determine the effect of a multi-
enzyme (MC) mixture on the NE content of DESBM.
MATERIALS AND METHODS
All experimental procedures were reviewed and ap-
proved by the University of Manitoba Animal Care Com-
mittee, and pigs were cared for according to the guide-
lines of the Canadian Council on Animal Care (2009).
Animals and Diets
In Exp.1, 24 growing male pigs (Yorkshire ×
Landrace × Duroc) with an average initial BW of
19.6 ± 0.51 kg (mean ± SD) were acquired from the
Gleanlea Swine Research Unit, University of Mani-
toba. Pigs were individually housed for 16 d in adjust-
able metabolism crates (1.80 × 0.60 m) with smooth
transparent plastic sides and plastic-covered expanded
metal sheet ooring in a temperature-controlled room
(22°C ± 2°C). The diets were formulated to meet NRC
(1998) requirements for growing pigs. Four test diets
(Table 1) were corn–soybean meal basal diet (Diet A),
a diet containing Diet A and DESBM in an 80:20 ratio
with a constant CP content compared with the basal
diet (Diet B), a diet with an 80:20 ratio of basal diet
and DESBM with a constant corn:soybean meal ratio
(Diet C), and a diet with simple substitution of basal
diet with DESBM in an 80:20 ratio (Diet D).
In Exp. 2, 24 growing male pigs (Yorkshire × Land-
race × Duroc) with an average initial BW of 16.9 ± 0.76
kg (mean ± SD) were acquired from Gleanlea Swine
Research Unit, University of Manitoba, and were
housed individually in adjustable metabolism crates
(1.80 × 0.60 m) with smooth transparent plastic sides
and plastic-covered expanded metal sheet ooring in a
temperature-controlled room (22°C ± 2°C) for a period
of for 16 d. The experimental diets in this study were
formulated to contain a constant ratio between corn and
Table 1. Ingredient and calculated and analyzed com-
position of the experimental diets, Exp. 11
Item
Diet A,
basal
Diet B,
constant CP
Diet C,
constant
corn:
soybean
Diet D,
substitution
Ingredient, % of diet
Corn 67.40 67.66 53.31 53.92
S oybean meal
(44% CP) 28.20 8.57 22.30 22.56
DESBM20.00 20.00 20.00 19.94
Soybean oil 0.84 0.00 0.84 0.67
Limestone 1.00 1.00 1.00 0.80
M onocalcium
phosphate
0.70 0.70 0.70 0.56
Salt 0.50 0.50 0.50 0.40
V itamin-mineral
premix31.00 1.00 1.00 0.80
Lys-HCl 0.06 0.11 0.00 0.05
dl-Met 0.00 0.07 0.00 0.00
l-Trp 0.00 0.09 0.05 0.00
Titanium dioxide 0.30 0.30 0.30 0.30
Calculated composition
DE, kcal/kg 3,436 3,510 3,557 3,571
ME, kcal/kg 3,276 3,365 3,382 3,394
CP, % 18.00 18.00 22.85 22.99
Analyzed composition
DM, % 90.0 90.0 90.0 90.0
CP, % 18.2 18.0 21.8 22.7
GE, kcal/kg 3,940 4,028 4,078 4,086
Ash, % 4.7 4.3 5.1 5.0
NDF, % 9.7 10.4 10.4 11
ADF, % 3.2 4.4 4.3 4.4
Starch, % 42.5 33.1 35.2 33.5
Ether extract, % 4.2 5.1 5.1 5.2
1As-fed basis.
2DESBM = dry extruded expelled soybean meal. Analyzed composition
of DESBM: CP = 40.0%, GE = 4,703kcal/kg, DM = 93.0%, ash = 5.7%,
NDF = 14.9%, ADF = 9.2%, starch = 1.7%, and EE = 9.9%.
3Supplied the following per kilogram of nished feed: vitamin A, 2,000
IU; vitamin D, 200 IU; vitamin E, 40 IU; vitamin K, 2 mg; choline, 350
mg; pantothenic acid, 14 mg; riboavin, 7 mg; folic acid, 1 mg; niacin, 21
mg; thiamin, 1.5 mg; vitamin B6, 2.5 mg; biotin, 70 mg; vitamin B12, 20
mg; Cu, 25 mg; Zn, 150 mg; Fe, 100 mg; Mn, 50 mg; I, 0.4 mg; Se, 0.3 mg.

Velayudhan et al.
3404
soybean meal because a difference method was used to
determine the NE of ingredient, and hence, it is more
appropriate to maintain a constant ratio between the
ingredients. The diets were formulated to meet NRC
(1998) requirements for growing pigs. The 4 test diets
(Table 2) were a corn–soybean meal basal diet (Diet A),
a diet containing Diet A and DESBM in an 80:20 ratio
with a constant corn:soybean meal ratio (Diet B), Diet B
+ 0.05% MC (Diet C), and Diet B + 0.1% MC (Diet D).
The MC used was a mixture of carbohydrases provided
by Canadian Bio-System Inc. (Calgary, Alberta, Can-
ada). The DESBM used in these studies was obtained
from Jordan Mills (Winkler, MB, Canada).
Experimental Design and Procedure
Both experiments were conducted in 2 consecu-
tive periods (12 pigs per each period) using the same
facility and similar experimental conditions and pro-
cedures because only 2 respiration chambers were
available for this study. Pigs were assigned to 1 of 4
experimental diets in a completely randomized design
to give 3 replicates per diet (per period).
Pigs were fed their respective diets at 550 kcal ME/
kg BW0.60 per day on the basis of BW on d 1, 5, and 10,
which was close to ad libitum intake. During the study,
pigs were fed at 0830 h and were trained to consume
their daily feed allowance within 1 h. Pigs had unlim-
ited access to water via a low-pressure nipple through-
out the study. Pigs were fed experimental diets for 16 d,
including 10 d for adaptation to feed and environmental
conditions. During the last 6 d of each feeding period,
total fecal and urine collection were performed for the
estimation of DE and ME as described previously by
Woyengo et al. (2010b). From d 11 to 16, feces was
collected once daily in the morning and were stored at
−20°C. Collection of urine commenced on the morning
of d 11 and ended on the morning of d 16. Urine was
collected once daily in the morning (in jugs containing
10 mL of 6 N HCl to minimize N losses) and weighed. A
sample (10% of the total weight) was obtained, strained
through glass wool, and stored at −20°C.
On d 16, 2 pigs each were transferred to the calo-
rimetric chambers (1.22 × 0.61 × 0.91 m metallic box
with a glass door on the front side and a valve at the
bottom to collect urine; Columbus Instruments, Co-
lumbus, OH) for 36 h of heat production (HP) and fast-
ing heat production (FHP) measurement based on O2
consumption, CO2 production, and urine output. Pigs
were brought into the calorimetric chambers within 1 h
of consuming their daily ration, and HP was measured
continuously for 24 h (fed state) followed by 12 h (fast-
ing state) of FHP measurement. The following sets of 2
pigs were moved to the indirect calorimetry chambers
every 2 d (d 18, 20, 22, 24, and 26). Fresh water was
available in the chambers at all times, and urine voided
during the 24- and 12-h periods was collected sepa-
rately, weighed, subsampled, and stored at −20°C until
required for nitrogen analysis. During collection the
chambers were approached through the back side so as
to avoid disturbance to the pig. Temperature within the
chamber was maintained at 22°C ± 1°C, and personnel
movement in the chamber room was limited to avoid
distressing pigs during HP and FHP measurements.
Table 2. Ingredients and analyzed compositions of the
experimental diets, Exp. 21
Item Basal
Constant
corn:SBM
without
MC2
Constant
corn:SBM
with 0.05%
MC
Constant
corn:SBM
with 0.1%
MC
Ingredients, % of diet
Corn 67.40 53.31 53.31 53.31
S oybean meal
(44%) 28.20 23.30 23.30 23.30
DESBM30.00 20.00 20.00 20.00
Vegetable oil 0.84 0.84 0.84 0.84
Limestone 1.00 1.00 1.00 1.00
M onocalcium
phosphate
0.70 0.70 0.70 0.70
Salt 0.50 0.50 0.50 0.50
V itamin-mineral
premix41.00 1.00 1.00 1.00
Lys-HCl 0.06 0.00 0.00 0.00
l-Trp 0.00 0.05 0.05 0.05
Titanium oxide 0.30 0.30 0.30 0.30
Analyzed composition
DM, % 89.0 90.0 90.0 90.0
CP, % 17.3 22.0 22.5 22.4
GE, kcal/kg 3,899 4,027 4,037 4,027
Ash, % 4.5 5.3 5.2 5.1
NDF, % 10.9 10.8 9.9 10.7
ADF, % 3.2 4.4 4.3 4.4
Starch, % 42.1 35.7 35.5 33.6
Ether extract, % 4.3 5.1 5.1 5.2
Total NSP,5 % 9.5 10.8 10.5 10.2
1As-fed basis.
2Enzyme complex supplied 1,700 units of cellulase, 1,100 units of pectin-
ase, 240 units of mannanase, 30 units of galactanase, 1,200 units of xylanase,
360 units of glucanase, 1,500 units of amylase, 120 units of protease.
3DESBM = dry extruded-expelled soybean meal. Analyzed composi-
tion of DESBM: CP = 40.0%, GE = 4,703 kcal/kg, DM = 93.0%, ash =
5.7%, NDF = 14.9%, ADF = 9.2%, starch = 1.7%, and EE = 9.9%.
4Supplied the following per kilogram of nished feed: vitamin A, 2,000
IU; vitamin D, 200 IU; vitamin E, 40 IU; vitamin K, 2 mg; choline, 350
mg; pantothenic acid, 14 mg; riboavin, 7 mg; folic acid, 1 mg; niacin, 21
mg; thiamin, 1.5 mg; vitamin B6, 2.5 mg; biotin, 70 mg; vitamin B12, 20
mg; Cu, 25 mg; Zn, 150 mg; Fe, 100 mg; Mn, 50 mg; I, 0.4 mg; Se, 0.3 mg.
5NSP = nonstarch polysaccharides

NE of dry extruded-expelled SBM for pigs 3405
Sample Preparation and Analysis
Fecal samples were oven-dried at 50°C over a 5-d
period and were nely ground before chemical analy-
sis. Urine samples from metabolism crates and calo-
rimetry chambers were thawed and pooled separately
for each pig, sieved through cotton gauze, and ltered
with glass wool.
Diet and fecal DM was determined according to
the AOAC (1990; method 925.09) by oven-drying 5
g of sample at 102°C overnight. The GE content of
DESBM, diets, feces, and urine was measured using an
adiabatic bomb calorimeter (model 6400, Parr Instru-
ment, Moline, IL) that had been calibrated using ben-
zoic acid as a standard. Nitrogen content in diets, feces,
and urine was determined using the combustion meth-
od (method 990.03; AOAC, 1990) using the LECO N
analyzer (model CNS-2000; LECO Corp., St. Joseph,
MI), and CP was calculated as nitrogen × 6.25. Crude
fat in diet and ingredient samples was determined after
hexane extraction (method 920.39; AOAC, 1990) in an
extraction apparatus. Starch content in the diets was
measured using an assay kit (Megazyme Total Starch
assay kit; Megazyme International Ltd., Wicklow, Ire-
land). The ADF and NDF contents in diets were de-
termined according to the method of Goering and Van
Soest (1970), and ash content was determined accord-
ing to AOAC (1990; method 942.05).
To determine the GE of urine, 0.5 g of cellulose
was dried at 100°C for 24 h, 2 mL of urine sample
were added over it, and the weight of the resulting mix-
ture was recorded. The urine-cellulose mixture along
with a sample of pure cellulose was again dried in an
oven at 50°C for 24 h and then weighed for estima-
tion of urine DM. The GE of the dried urine-cellulose
mixture and pure cellulose were determined using an
adiabatic bomb calorimeter as described above, from
which the GE of urine samples were calculated by the
difference method (Fleischer et al., 1981).
Calculations
Heat production (Brouwer, 1965), FHP (Brouwer,
1965), retained energy (RE; Noblet et al., 1994), DMI,
and NE values (Noblet et al., 1994) were calculated
using the following equations:
HP = 3.87 × O2 + 1.20 × CO2
− 1.43 × urinary nitrogen, [1]
where HP is in kilocalories, O2 = oxygen consumption
in liters, and CO2 = carbon dioxide production in liters.
FHP = 3.87 × O2 + 1.20 × CO2
− 1.43 × urinary nitrogen, [2]
where FHP is in kilocalories, O2 = oxygen consumption
in liters, and CO2 = carbon dioxide production in liters.
RE = ME − HP, [3]
where RE is in kilocalories per day, ME is in kilocalo-
ries per day, and HP is in kilocalories per day.
DMI = feed intake × feed DM, [4]
where DMI is in kilograms, feed intake is in kilograms,
and feed DM is a percentage.
NE = (RE + FHP)/DMI, [5]
where NE is in kilocalories per kilogram DM, RE is
in kilocalories per day, FHP is in kilocalories per day,
and DMI is in kilograms. Digestible energy (Noblet
and Perez, 1993), ME (May and Bell, 1971), and NE
were also calculated according to the following pre-
diction equations. The average calculated NE from Eq.
[8] to [13] (Noblet et al., 1994) was used in the study:
DE = 949 + (0.789 × GE)
− (43 × % Ash) − (41 × % NDF), [6]
ME = DE × [1.012 − (0.0019 × % CP)], [7]
NE = 0.843 × DE − 463, [8]
NE = 0.700 × DE + 1.61 × EE + 0.48
× ST– 0.91 × CP − 0.87 × ADF, [9]
NE = 0.870 × ME − 442, [10]
NE = 0.726 × ME + 1.33 × EE + 0.39
× ST − 0.62 × CP − 0.83 × ADF, [11]
NE = 2,790 + 4.12 × EE + 0.81 × ST
− 6.65 × Ash − 4.72 × ADF, [12]
NE = 2875 + 4.38 × EE + 0.67 × ST
− 5.50 × Ash– 2.01 × (NDF − ADF)
− 4.02 × ADF, [13]
where NE is in kilocalories per kilogram DM, ME is
in kilocalories per kilogram DM, DE is in kilocalories
per kilogram DM, EE = ether extract in % DM, ST =

Velayudhan et al.
3406
starch in % DM, CF = crude ber in % DM, and ADF
is in % DM.
The energy content of DESBM was calculated us-
ing the difference method (Woyengo et al., 2010b) by
subtracting the NE contribution of the basal diet from
the NE of the diets containing 20% DESBM. The NE
of test DESBM was calculated as follow:
NEDESBM
(kcal/kg DM) = NEBasal diet
− [(NEBasal diet
− NEDiet containing DESBM)
/0.2]. [14]
Statistical Analysis
All data for both experiments were subjected to
the mixed procedures of SAS (SAS Inst. Inc., Cary,
NC). Effects of diet and period were included in the
model for statistical analysis. The effect of period was
not statistically signicant in either study; therefore, it
was not included in the nal model. The individual pig
was considered as the experimental unit, and probabil-
ity of P < 0.05 was considered signicant.
RESULTS AND DISCUSSION
Experiment 1: Net Energy Content of DESBM
in Growing Pigs
Practical diet formulations need to be adequately
exible to accommodate price and feedstuffs available
while maintaining the required nutritive balance and
adequacy (van Heugten et al., 2000). This signies the
importance of formulation of swine rations utilizing
the most precise nutrient composition values for in-
gredients. The DESBM sample used for the current
study was locally obtained from Jordan Mills, Mani-
toba, Canada. A comparison of the analyzed nutrient
composition of DESBM (Tables 1 and 2) used in the
current experiment with studies by Woodworth et
al. (2001) in which the DESBM used was produced
and provided by Insta-Pro International (Des Moines,
IA) showed similar values for DM, GE, and ash, but
with a high CP and low EE in the latter. This varia-
tion could be attributed to the various factors involved
during the meal processing, namely, the temperature,
time, or moisture content. Similar variations for CP
and EE, but with comparable concentrations of NDF
and ADF, were seen in studies by Baker and Stein
(2009). In studies by Opapeju et al. (2006), in which
2 batches of DESBM from the same source were used,
DESBM showed similar EE content but slightly high-
er CP. This higher CP (40% vs. 43%) content may be
due to lower moisture content when compared with
that of the present study (93% vs. 97% DM).
The average energy contents of diets determined
using the total collection method (Table 3) were 3,472
kcal/kg DM for DE and 3,386 kcal/kg DM for ME.
The ME:DE ratio in the current study (0.98; average
value for the 4 diets) is in accordance with previous
studies. Noblet and van Milgen (2004) reported that
in most circumstances for complete feed, the ME:DE
ratio would be approximately 0.96.
The DE value of DESBM obtained in the present
study ranged from 3,384 to 3,443 kcal/kg DM. Baker
and Stein (2009) reported a higher DE value of 3,827
kcal/kg DM for extruded-expelled SBM from conven-
tional soybeans. The probable reason for this observa-
tion could be the variation in BW of pigs used for the
studies and also lower CP content for DESBM used
Table 3. Energy balance in growing pigs and energy
values of diets and DESBM determined by the indirect
calorimetry method, Exp. 11
Item
Dietary treatment2
SEM P-valueA B C D
Energy value of diets, kcal/kg DM
DE 3,481 3,462 3,472 3,473 9.4 0.586
ME 3,392 3,378 3,386 3,386 6.2 0.431
HP32,007 1,930 2,038 2,000 53.0 0.637
FHP41,547 1,424 1,508 1,468 54.0 0.513
RE51,385 1,448 1,348 1,386 52.9 0.686
NE62,932a2,872b2,855b2,853b5.7 0.001
Efciencies of NE
NE/ME 0.87a0.85b0.84b0.84b0.003 0.002
NE/DE 0.84a0.83a,b 0.82b0.82b0.004 0.002
Energy value of DESBM, kcal/kg DM:
DE —3,384b3,438a3,443a10.6 0.011
ME —3,324 3,363 3,361 12.7 0.097
NE7— 2,632a2,548b2,540b7.2 0.001
a,bMeans not sharing a common superscript are signicantly different
(P < 0.05).
1n = 6.
2Diet A = corn–soybean meal basal diet; Diet B = a diet containing Diet
A and dry extruded-expelled soybean meal (DESBM) in 80:20 ratio with a
constant CP; Diet C = a diet with 80:20 ratio of Diet A and DESBM with a
constant corn:soybean meal ratio; Diet D = a diet with simple substitution
of Diet A with DESBM in 80:20 ratio.
3Heat production = (3.87 × O2 + 1.20 × CO2 − 1.43 × urinary N)/DMI.
4Fasting heat production = (3.87 × O2 + 1.20 × CO2 − 1.43 × urinary
N)/DMI.
5Retained energy = (ME intake − HP)/DMI.
6Net energy = (RE + FHP)/DMI.
7NE of DESBM was calculated using the difference method by
subtracting the NE contribution of the basal diet from the NE of the diets
containing 20% DESBM (Woyengo et al., 2010b).

NE of dry extruded-expelled SBM for pigs 3407
in the present study compared with the latter. In the
current study, pigs with an initial BW = 19.6 ± 0.51
kg were used, whereas pigs with an initial BW = 38.6
± 3.46 kg were used in the study by Baker and Stein
(2009). In growing pigs, the digestibility coefcient
of energy or DE:GE ratio increases with increasing
BW (Noblet and Shi, 1994). Also, Woodworth et al.
(2001) reported similar results wherein the DE content
for DESBM in growing pigs (initial BW 41 kg) was
4,120 and 4,210 kcal/kg (as-fed basis) for hulled and
dehulled meals, respectively.
In the present study, HP values among treatments
(i.e., A, B, C, and D) were, on average, 1,994 kcal/kg
DM. Noblet et al. (1994) reported a similar HP value
of 2,062 kcal/kg DM for growing pigs. The average
FHP obtained in the present study was 1,487 kcal/kg
DM, which is comparable to that obtained by Noblet
et al. (1994): 179 kcal/kg BW0.6 for 35 kg pigs (equiv-
alent to 1,517 kcal/kg DM of feed).
The NE content of DESBM obtained with pub-
lished equations was 2,624, 2,530, and 2,436 kcal/kg
DM in diets B, C, and D, respectively. Even though
published prediction equations for estimating NE
content in swine diets have been supported by some
recent studies (Ayoade et al., 2012), others have re-
ported contradictory results (Kil et al., 2011). In the
current study, the discrepancy for higher NE values for
the IC method compared with those from the predic-
tion equations could be due to not taking into account
the physical activity of the animals while measuring
FHP. Physical activity could be dened as standing
up, standing, eating, walking, lying down, and sitting
(Rijnen et al., 2003). About 8% of ME intake may be
dissipated by physical activity in growing pigs (Ren-
audeau et al., 2013). A similar variation for NE values
has been reported by Heo et al. (2014), wherein the
NE content of canola meal determined using the IC
method was approximately 5.9% higher than the val-
ues obtained using the published prediction equations.
The results from the present study show that the
NE values of DESBM obtained with the IC method
were higher than those obtained with prediction equa-
tions. The discrepancy between the determination
technique used and values from prediction equations
was 0.3%, 0.7%, and 4.1% when diets were formu-
lated with constant protein, a constant corn:soybean
meal ratio, and the simple substitution technique, re-
spectively. The NE values obtained from the 2 diet
formulation techniques, namely, the constant protein
content or the constant corn:soybean meal ratio, were
different (P < 0.001). Also, the NE values of DESBM
obtained when diets were formulated with a constant
corn:soybean meal ratio and the simple substitution
technique were similar. Hence, the average NE value
of DESBM evaluated was 2,544 kcal/kg DM. How-
ever, for routine NE determination in which the dif-
ference method is used to obtain the NE value for
ingredients, diets should be formulated to contain a
constant ration of other energy-yielding components.
Experiment 2: Effect of Enzyme on NE Content
of DESBM in Growing Pigs
Nonstarch polysaccharides are partially hydro-
lyzed by supplementing NSP-degrading carbohy-
drases (Parkkonen et al., 1997; Nortey et al., 2007),
and therefore, the nutrients entrapped by ber get re-
leased. Supplementation with a carbohydrase mixture
has been shown to improve energy and nutrient digest-
ibility in various feedstuffs fed to pigs (Omogbenigun
et al., 2004; Emiola et al., 2009). In an in vitro incuba-
tion study, Slominski et al. (2006) established that a
carbohydrase mixture containing cellulase, pectinase,
mannanase, xylanase, and glucanase is effective in de-
grading cell wall polysaccharides and improving ener-
gy digestibility in axseed. Nonstarch polysaccharides
degrading enzymes in swine diets help in dietary ber
degradation, thereby increasing the digestibility of
nutrients (i.e., CP, crude fat, and/or starch), resulting
in higher energy digestibility (Bedford and Schulze,
1998). In the present study, the carbohydrase complex
used contained enzymes that can target several NSP in
the diet, including arabinoxylans, β-glucans, arabino-
galactans, mannans, galactomannans, and pectic poly-
saccharides. The multicarbohydrase complex used
in the current study has been shown to improve the
nutrient digestibility in broilers (Meng and Slomin-
ski, 2005; Meng et al., 2006; Woyengo et al., 2010a).
As for swine, reports of improvement in nutrient uti-
lization following carbohydrase supplementation are
variable (Adeola and Cowieson, 2011; Cozannet et al.,
2012). In the current study, enzyme supplementation
(Table 4) increased the DE content of the diet by 1.2%
and 0.6%, ME by 1.5% and 1.2%, and NE by 0.9%
and 0.7% for 0.05% and 0.1% enzyme, respectively.
Cozannet et al. (2012) reported comparable results
wherein multienzyme preparation (xylanase and glu-
canase) improved the DE of diets even though it was
quantitatively low (0.09 MJ/kg DM). In the same study
by Cozannet et al. (2012), the ME and NE value of di-
ets were also improved (0.7% and 0.9%, respectively),
although not statistically analyzed. The enzyme effect
is also consistent with the observations of Cowieson
and Ravindran (2008), wherein supplementation with
an enzyme cocktail of xylanase, amylase, and prote-
ase in broiler diets improved apparent metabolizable
energy (AME) by an average of 3%. Similar results
were reported in broiler chickens fed corn soybean

Velayudhan et al.
3408
diets where a multicarbohydrase enzyme cocktail sig-
nicantly improved the AMEn content (Meng and Slo-
minski, 2005). The FHP values obtained in the present
trials were not affected by dietary treatment and were
close to those obtained by Noblet et al. (1994; 0.750
MJ·d−1·kg−0.60).
An effect of enzyme supplementation on the en-
ergy content of DESBM was observed in the current
study. Enzyme addition increased the NE value of
the test ingredient by 110 kcal/kg DM, on average. A
similar NE value for DESBM was obtained in Exp. 1
(Diet B). The CP content for Diet B (Exp. 1) was about
18% lower than that in Diets C and D in the current
experiment. Lower dietary CP reduces deamination of
excess AA and the consecutive production and excre-
tion of urea in urine and lowers body protein turnover
and HP of the animals (Le Bellego et al., 2001). In
addition, the energy costs associated with synthe-
sis, excretion, and urea metabolism of excess dietary
N represent a measurable energy loss to the animal.
Consequently, at a given DE or ME intake, NE supply
and therefore energy gain are greater for low-CP diets
(Noblet et al., 2001). Overall, supplementation with
MC at 0.05% and 0.1% of the diet improved NE val-
ues of DESBM by 4.9% and 3.7%, respectively. How-
ever, we are unable to explain why pigs fed a greater
(i.e., 0.1%) level of MC had signicantly lower energy
content of DESBM (i.e., DE, ME, and NE) compared
with those fed 0.05% MC in the diets.
In summary, when the NE content of DESBM
determined using IC was compared with the values
from prediction equations, the discrepancy between
the determination techniques used was 0.3%, 0.7%,
and 4.1% when diets were formulated with constant
protein, a constant corn:soybean meal ratio, and a sim-
ple substitution technique, respectively. The NE val-
ues obtained from the 2 diet formulation techniques,
namely, constant protein content and the constant
corn:soybean meal ratio, were not similar, whereas
those obtained from diets formulated with a constant
corn:soybean meal ratio and the simple substitution
technique were similar. Hence, the average NE value
of DESBM evaluated was 2,544 kcal/kg DM. Also,
supplementation of diets with enzyme improved the
energy content of DESBM. For the DESBM, enzyme
supplementation at 0.05% and 0.1% of the diet im-
proved NE content by 4.9% and 3.7%, respectively.
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Table 4. Energy balance of pigs and energy values of
diets and DESBM determined by the indirect calorim-
etry method, Exp. 21
Item
Dietary treatment
SEM P-valueBasal
Constant
corn:
SBM
without
MC2
Constant
corn:
SBM
with
0.05% MC
Constant
corn:
SBM
with
0.1% MC
Energy value of diets, kcal/kg DM
DE 3,365b3,361b3,401a3,381a,b 11.0 0.011
ME 3,260bc 3,245c3,295a3,283a,b 5.4 0.001
HP31,595 1,606 1,620 1,594 352.9 0.990
FHP41,231 1,184 1,173 1,154 349.1 0.820
RE51,665 1,639 1,675 1,688 353.5 0.951
NE62,897a2,823b2,848b2,842b8.1 0.001
Efciencies of NE
NE/ME 0.89a0.87b0.87b0.87b0.003 0.001
NE/DE 0.86a0.84b0.84b0.84b0.002 0.001
Energy value of DESBM, kcal/kg DM:
DE — 3,345c3,548a3,445b14.9 0.001
ME — 3,184c3,434a3,375b12.7 0.001
NE7— 2,527c2,652a2,621b6.9 0.001
a–cMeans not sharing a common superscript are signicantly different
(P < 0.05).
1n = 6.
2MC = multienzyme carbohydrase.
3Heat production = (3.87 × O2 + 1.20 × CO2 − 1.43 × urinary N)/DMI.
4Fasting heat production = (3.87 × O2 + 1.20 × CO2 − 1.43 × urinary
N)/DMI.
5Retained energy = (ME intake − HP)/DMI.
6Net energy = (RE + FHP)/DMI.
7NE of dry extruded-expelled soybean meal (DESBM) was calculated us-
ing the difference method by subtracting the NE contribution of the basal diet
from the NE of the diets containing 20% DESBM (Woyengo et al., 2010b).

NE of dry extruded-expelled SBM for pigs 3409
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