2012.90:4916–4924 doi:10.2527/jas2011-4916 Key words: cereal grains, commercial trial, growth performance, pig removal, rice, weanling pigs ABSTRACT: Three experiments were conducted to
Trang 1T M Che, V G Perez, M Song and J E Pettigrew
antibiotic treatment of weaned pigs under commercial conditions
doi: 10.2527/jas.2011-4916 originally published online July 24, 2012
2012, 90:4916-4924.
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Trang 2© 2012 American Society of Animal Science All rights reserved J Anim Sci 2012.90:4916–4924 doi:10.2527/jas2011-4916
Key words: cereal grains, commercial trial, growth performance, pig removal, rice, weanling pigs
ABSTRACT: Three experiments were conducted
to evaluate effects of rice and other cereal grains on
growth performance and health of weanling pigs Pigs
(1,008 in Exp 1 and 3 and 1,004 in Exp 2; 21 d old)
with an initial BW of 5.8 ± 1.0 kg were used Pigs
in each experiment were divided into 3 BW blocks
(heavy, medium, or light) in each of 4 rooms, resulting
in 12 blocks per experiment Each pen within a block
had 20 or 21 pigs and equal sex distribution Pens were
allotted to dietary treatments in a randomized complete
block design Pigs were fed in a 4-phase feeding
program with Phases 1 and 2 of 1 wk each and Phases 3
and 4 of 2 wk each Diets were formulated to meet the
same nutritional standards within each phase In Exp
1, effects of different cereal grains on pig performance
and removal rate (mortality plus morbidity) were
investigated Pigs were fed 4 diets based on corn,
barley, rolled oats, or rice as the only cereal grain Over
a 6-wk period, the ADG of pigs fed rice was greater (P
< 0.01) than those pigs fed barley but not different from
those pigs fed corn or rolled oats Pigs fed corn or rice
did not differ in ADFI, which was greater (P < 0.05)
than those pigs fed barley The overall removal rate of
pigs fed rice or barley was reduced as compared with
those pigs fed rolled oats (P < 0.05), and tended to be less than those pigs fed corn (P = 0.075) Experiment 2
was conducted to determine if the benefi ts observed in Exp 1 could be obtained by feeding rice for less than
6 wk Treatments included rice diets fed for 0, 1, 2, or
4 wk before changing to corn diets All pigs received
a common diet during wk 5 and 6 Pig performance and antibiotic treatments did not differ among dietary treatments However, pigs fed rice for 1, 2, or 4 wk had
a reduced overall removal rate (P < 0.05) compared
with those fed corn Experiment 3 was conducted to investigate if the amount of rice fed in wk 1 could
be reduced without reducing pig performance Rice replaced 0, 50, 75, or 100% of corn in Phase 1 diets All pigs received a common diet from wk 2 to 6 No differences in pig performance or antibiotic treatments among dietary treatments were observed However, pigs
fed the diet with 100% rice had a reduced (P = 0.055)
overall removal rate compared with pigs fed the corn diet Generally, rice and corn improve pig performance
as compared with barley Rice can substitute for corn
in nursery diets without detriment to pig performance and substantially reduces pig removals, even when fed for only 1 wk immediately after weaning
Effect of rice and other cereal grains on growth performance, pig removal, and
anti-biotic treatment of weaned pigs under comme rcial conditions1
T M Che, 2,3 V G Perez, 4 M Song, and J E Pettigrew
Department of Animal Sciences, University of Illinois, Urbana 61801
INTRODUCTION
Rice is a staple cereal grain for human consump-tion and is grown in most tropical and semitropical regions Rice contains more starch and less fi ber com-pared with other cereal grains (Bach Knudsen, 1997; Kim et al., 2007; Vicente et al., 2008) Because of these characteristics, rice might be a good alternative to other cereal grains in diets for nursery pigs Rice-based diets fed to weaned pigs had greater apparent ileal and total tract digestibilities of GE, OM, and fat than corn-based diets (Li et al., 2002; Mateos et al., 2006; Menoyo et
1 The authors thank Illinois Council on Food and Agricultural
Research (Champaign, IL) and National Pork Board (Des Moines,
IA) for their kind support of this research and J Barnes (Department
of Animal Sciences, University of Illinois, Urbana) for her help in
weighing pigs.
2 Corresponding author: tungcheminh@yahoo.com
3 Present address: Department of Animal Production, Faculty of
Animal Science and Veterinary Medicine, Nong Lam University,
Ho Chi Minh City, Vietnam.
4 Present address: Research and Development, ADM Alliance
Nutrition Inc., Quincy, IL 62301.
Received November 14, 2011.
Accepted June 26, 2012.
Trang 3al., 2011) However, rice has received relatively little
at-tention as a potential feedstuff for the animal industries,
particularly the U.S pig industry
Swine diets usually contain a large amount of cereal
grains such as corn, barley, wheat, or oat Among these
ingredients, corn is the most economical source of
nutri-ents in many parts of the world However, other cereal
grains may be considered due to local availability, lower
costs, or specifi c benefi ts in promoting health or growth
performance of young pigs Different cereal grains have
different carbohydrate composition, which may affect
the health of the digestive tract by altering the substrates
for microbial activity Fibrous cereal grains, such as oats,
may stimulate the growth of commensal gut fl ora (Bach
Knudsen et al., 1991), resulting in a healthier digestive
tract On the contrary, results of several studies indicate
benefi ts of rice, which has a very low concentration of
fi ber (Montagne et al., 2003; Hopwood et al., 2004;
Lin-decrona et al., 2004)
The objectives of experiments were 1) to determine
if feeding corn, barley, rolled oats, or rice as the main
energy sources in the nursery pig diets for 6 wk
post-weaning affects growth performance and pig removal
and 2) to examine if the amount of rice to be used in
nursery diets can be reduced without affecting growth
performance, pig removal, and the number of needed
antibiotic treatments of weanling pigs
MATERIALS AND METHODS
All experimental protocols in this study were approved
by the University of Illinois Institutional Animal Care and
Use Committee Three experiments were conducted at a
commercial pig farm that is equipped to support research
Experimental Design, Animals, and Housing
A total of 1,008 crossbred pigs [PIC (Hendersonville,
TN) × Monsanto (West Des Moines, IA)] were used in
each experiment, except in Exp 2, which had 1,004 pigs
Each of 4 rooms at the farm had individual pen feeders
and nipple drinkers and 4 bulk bins There were 12 pens in
each room and a pen measured 1.8 by 3.0 m in size About
275 pigs were placed in each of 4 rooms and divided into
3 groups by BW block (heavy, medium, or light) Each
room was environmentally controlled Individual pigs
from the heavy group were placed rotationally into the 4
pens (20 or 21 pigs per pen) designated for the heavy BW
block Pigs were exchanged among those 4 pens to ensure
the same number of gilts and barrows in each pen Then,
the process of pig allotments was repeated for the medium
and light pigs All pigs not needed were moved to pens
not used in the experiment Once sorted into pens within
a room, all pigs designated for research were weighed
by pen to obtain initial BW After weighing, some pigs were exchanged among pens to ensure the BW differ-ence between any 2 pens within a block was less than 5%
of the mean Pens in which pigs were exchanged were reweighed Pens within a block (similar in BW, sex dis-tribution, and pig number) were allotted to dietary treat-ments in a randomized complete block design
Experimental Diets and Animal Feeding
Diets were formulated to contain levels of all es-sential nutrients that met or exceeded the nutritional requirements of pigs (NRC, 1998) during the nursery period and to have constant levels of ME and standard-ized ileal digestible Lys and other AA Commercially available raw, broken, white rice was purchased as a commodity and used for rice diets Pigs were fed ac-cording to a 4-phase feeding program with Phases 1 and
2 of 1 wk each and Phases 3 and 4 of 2 wk each Phase
1 and 2 diets in Exp 1 were in pellet form, but in Exp
2 and 3, Phase 1 and 2 diets were provided as crumbles whereas Phase 3 and 4 diets in all experiments were in meal form Pigs had ad libitum access to feed and water
at all times
In Exp 1, pigs (21 d old; 6.0 ± 1.3 kg BW) were al-lotted to 4 dietary treatments in which corn, barley, rolled oats, or rice was the only cereal grain The analyzed nu-trient composition of these cereal grains is presented in Table 1 and the ingredient and chemical composition of the experimental diets is shown in Table 2 To evaluate effects of different cereal grains on pig removal, diets used in this experiment did not contain antibiotic growth promoters or zinc oxide at pharmacological levels Experiment 2 was conducted to confi rm the benefi ts
of including rice in diets for weanling pigs that were ob-served in Exp 1 and to determine if the benefi t may be realized if rice is fed for less than 6 wk In Exp 2, pigs (21 d old; 5.5 ± 0.8 kg BW) were allotted to 4 dietary treatments that included rice diets fed for 0, 1, 2, or 4 wk before changing to a corn diet All pigs received a com-mon diet during wk 5 and 6 The ingredient and chemical composition of the experimental diets is shown in Table
3 and the analyzed nutrient composition of corn and rice
Table 1 Analyzed chemical composition of the 4 cereal
grains used in Exp 1 (as-fed basis)1
Item, % Corn Barley Rolled oats Rice
1 Analyzed in duplicate.
Trang 4Che et al.
4918
diets is presented in Table 4 Because of increased
re-moval rates observed in Exp 1, all diets used in Exp 2
contained 55 mg/kg of carbadox (Mecadox 2.5; Phibro
Animal Health, Fairfi eld, NJ) and 4,200 mg/kg of zinc
oxide in addition to the zinc oxide provide by the
micro-mineral premix
Experiment 3 was conducted to examine the benefi t
of rice vs corn observed in the previous experiments and
to determine if the amount of rice used could be reduced
compared with that used in Exp 2 Pigs were weaned
at about 21 d of age with an average initial BW of 5.9 ±
1.0 kg In the treatment diets, rice replaced 0, 50, 75, or
100% of corn in Phase 1 The ingredient and chemical
composition of the Phase 1 diets is shown in Table 5 All pigs received common corn-based diets from Phase 2 to
4 (wk 2 through 6 postweaning) as presented in Table 3 All diets also contained 55 mg/kg of carbadox (Meca-dox 2.5; Phibro Animal Health) and 4,200 mg/kg of zinc oxide in addition to the zinc oxide provide by the micro-mineral premix
Feed Sample Analyses
Feed samples were ground to pass through a 2-mm screen before analysis Cereal grains used in Exp 1 were analyzed in duplicate for DM (Method 934.01;
Table 2 Composition of diets used in Exp 1 (as-fed basis)
Item
Corn Barley RO 1 Rice Corn Barley RO Rice Corn Barley RO Rice Corn Barley RO Rice Ingredient, %
Cereal grains 37.15 36.92 42.16 39.68 43.00 41.81 48.82 45.92 51.91 51.86 59.40 55.56 63.43 61.36 68.15 67.18 Dried whey 22.00 22.00 22.00 22.00 16.00 16.00 16.00 16.00 11.48 11.48 11.48 11.48 – – – – Soybean meal,
dehulled (48% CP)
10.00 10.00 10.00 10.00 18.00 18.00 18.00 18.00 24.00 24.00 24.00 24.00 28.01 28.00 28.00 29.08
Spray-dried
Soy protein concentrate 3 5.00 5.00 5.00 5.00 3.00 3.00 3.00 3.00 – – – – – – – – Fish meal,
select Menhaden
4.11 2.34 0.47 4.67 5.47 5.10 1.25 6.12 6.00 3.05 0.21 6.57 – – – – Soybean oil 3.93 5.51 1.79 1.00 3.90 5.50 1.43 0.50 4.59 6.87 1.67 0.50 5.30 7.59 1.14 0.50
Limestone 0.84 0.85 0.99 0.75 0.56 0.49 0.73 0.46 0.56 0.60 0.80 0.44 0.82 0.68 0.75 0.70 Dicalcium phosphate 0.66 1.00 1.17 0.65 0.93 1.07 1.52 0.91 0.47 1.03 1.30 0.49 1.33 1.47 1.27 1.46 Mineral premix 4 0.35 0.35 0.35 0.35 0.35 0.35 0.35 0.35 0.35 0.35 0.35 0.35 0.35 0.35 0.35 0.35 Vitamin premix 5 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20
L -Lys HCl, 78.8% 0.06 0.09 0.12 0.02 0.16 0.10 0.23 0.11 0.22 0.29 0.33 0.17 0.32 0.20 0.08 0.27
DL -Met, 99.0% 0.11 0.14 0.14 0.09 0.10 0.07 0.11 0.09 0.08 0.10 0.07 0.08 0.08 0.03 – 0.08
L -Thr, 98.5% 0.01 0.02 0.03 0.01 0.09 0.07 0.12 0.10 0.14 0.17 0.19 0.16 0.16 0.12 0.06 0.18 Calculated composition 6
ME, Mcal/kg 3.52 3.52 3.52 3.52 3.49 3.49 3.49 3.49 3.51 3.51 3.51 3.51 3.53 3.53 3.53 3.53 SID 7 indispensable AA, %
Ile 0.87 0.87 0.87 0.87 0.87 0.91 0.87 0.87 0.79 0.78 0.78 0.79 0.70 0.76 0.83 0.69 Lys 1.45 1.45 1.45 1.45 1.45 1.45 1.45 1.45 1.30 1.30 1.30 1.30 1.15 1.15 1.15 1.15 Met 0.41 0.41 0.41 0.41 0.43 0.41 0.41 0.44 0.42 0.41 0.36 0.44 0.35 0.32 0.33 0.37 Thr 0.94 0.94 0.94 0.94 0.94 0.94 0.94 0.94 0.84 0.84 0.84 0.84 0.75 0.75 0.75 0.75 Trp 0.29 0.29 0.30 0.29 0.27 0.29 0.28 0.28 0.23 0.24 0.24 0.24 0.21 0.24 0.26 0.23 Val 1.10 1.11 1.12 1.10 1.03 1.08 1.05 1.04 0.88 0.88 0.89 0.88 0.78 0.87 0.96 0.78
Ca, % 0.90 0.90 0.90 0.90 0.90 0.90 0.90 0.90 0.80 0.80 0.80 0.80 0.80 0.80 0.80 0.80 Available P, % 0.55 0.55 0.55 0.55 0.55 0.55 0.55 0.55 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 Lactose, % 21.00 21.00 21.00 21.00 14.00 14.00 14.00 14.00 7.00 7.00 7.00 7.00 – – – –
1 RO = rolled oats diet.
2 Appetein (APC, Inc, Ankeny, IA).
3 Soycomil (Archer Daniels Midland Company, Decatur, IL).
4 Provided as milligrams per kilogram of diet: sodium chloride, 3,000; Zn, 100 from zinc oxide; Fe, 90 from iron sulfate; Mn, 20 from manganese oxide; Cu,
8 from copper sulfate; I, 0.35 from calcium iodide; Se, 0.30 from sodium selenite.
5 Provided per kilogram of diet: retinyl acetate, 2,273 μg; cholecalciferol, 17 μg; DL-α-tocopheryl acetate, 88 mg; menadione sodium bisulfi te complex, 4 mg; niacin, 33 mg; D-Ca-pantothenate, 24 mg; ribofl avin, 9 mg; vitamin B12, 35 μg; and choline chloride, 324 mg.
6 NRC, 1998 (for all ingredients except soybean meal); Illini SAND Soy in Animal Nutrition Databases (for soybean meal; Kusina et al., 2007).
7 SID = standardized ileal digestible.
Trang 5AOAC Int., 2005), CP (Method 990.03; AOAC Int.,
2005), crude fat (Method 920.39; AOAC Int., 2005),
ash (Method 942.05; AOAC Int., 2005), ADF (Method
973.18; AOAC Int., 2005), and NDF (Ankom Method 6;
Eurofi ns, Des Moines, IA) Corn and rice diets in Exp
2 were analyzed for DM, CP, crude fat, ash, and ADF as
described for Exp 1 These diets were also analyzed for
NDF (Holst, 1973), total dietary fi ber (Method 985.29;
AOAC Int., 2005), and AA [Method 982.30 E (a, b, c);
AOAC Int., 2005]
Measurement of Pig Performance, Removal Rate, and Antibiotic Treatment
The initial BW of pigs in each pen was recorded at the commencement of the experiment Subsequent pen weights and feed disappearance measurements were de-termined at d 7, 14, 28, and 42 postweaning The ADG, ADFI, and G:F were calculated on a per-pen basis The number of pigs removed from each pen because
of mortality or morbidity was recorded daily to calculate the removal rate Removal of pigs was done by the farm
Table 3 Composition of corn and rice diets used in Exp 2 (as-fed basis)
Item
Ingredient, %
Soybean meal, dehulled (48% CP) 10.00 10.00 18.00 18.00 24.00 24.00 27.97
Calculated composition 6
SID 7 indispensable AA, %
1 Appetein, APC, Inc (Ankeny, IA).
2 Soycomil (Archer Daniels Midland Company, Decatur, IL).
3 Mecadox 2.5, provided 0.055 g of carbadox per kilogram of diet (Phibro Animal Health, Fairfi eld, NJ).
4 Provided as milligrams per kilogram of diet: sodium chloride, 3,000; Zn, 100 from zinc oxide; Fe, 90 from iron sulfate; Mn, 20 from manganese oxide; Cu,
8 from copper sulfate; I, 0.35 from calcium iodide; and Se, 0.30 from sodium selenite.
5 Provided per kilogram of diet: retinyl acetate, 2,273 μg; cholecalciferol, 17 μg; DL-α-tocopheryl acetate, 88 mg; menadione sodium bisulfi te complex, 4 mg; niacin, 33 mg; D-Ca-pantothenate, 24 mg; ribofl avin, 9 mg; vitamin B12, 35 μg; and choline chloride, 324 mg.
6 NRC, 1998 (for all ingredients except soybean meal; Illini SAND Soy in Animal Nutrition Databases (for soybean meal; Kusina et al., 2007).
7 SID = standardized ileal digestible.
Trang 6Che et al.
4920
crew according to standard protocols for the farm If pigs
were determined to be runts, they were culled The
num-ber of antibiotic treatments per pen was also recorded
daily in Exp 2 and 3 but not in Exp 1 During the
experi-mental period, several antibiotics were used for disease
treatments [Ceftiofur, 5.0 mg/kg BW (Pharmacia and
Up-john Co., NY); Penicillin G Procaine, 6,000 units/kg BW
(Durvet Inc., Blue Springs, MO); and Tylosin, 8.0 mg/kg
BW (Elanco Animal Health, Indianapolis, IN)] The
pro-duction system had experienced an acute outbreak of
por-cine reproductive and respiratory syndrome in sow farms
that supplied this nursery shortly before these
experi-ments were conducted There was also an active enteric
infection that was diagnosed as caused by Escherichia
coli in Exp.1 and by Salmonella in Exp 2 and 3.
Statistical Analysis
Data were analyzed as a randomized complete block
design by ANOVA using the MIXED procedure (SAS
Inst Inc., Cary, NC) The pen was considered the
ex-perimental unit There were 4 rooms and 3 BW blocks
(heavy, medium, and light) in each of the 4 rooms,
re-sulting in 12 blocks per experiment Blocks were
con-sidered random effects Treatment differences were
compared using the least squares means with a Tukey
adjustment Pig removals and number of antibiotic
treat-ments were compared by χ2 analysis Treatment effects
were considered signifi cant at P ≤ 0.05 whereas a trend
for a treatment effect was noted when P < 0.10.
RESULTS
Experiment 1
From d 0 to 7 postweaning, pigs fed corn had a
greater ADG than those fed barley (P < 0.05) or rice (P <
0.01; Table 6) Similarly, pigs fed corn consumed more
feed than those fed barley (P < 0.05) or rice (P < 0.001)
The ADFI of pigs fed rolled oats was also greater than
Table 4 Analyzed nutrient composition of corn and rice
diets used in Exp 2 (as-fed basis)1
Item
Phase 1 Phase 2 Phase 3 Phase 4 Corn Rice Corn Rice Corn Rice Corn
DM 89.62 89.59 88.81 89.56 87.66 88.70 88.40
CP 22.37 22.24 22.32 22.61 20.95 21.56 20.09
Crude fat 5.50 4.76 5.98 5.67 4.94 4.21 6.64
Total dietary fi ber 7.93 4.16 8.28 4.30 8.27 4.61 10.34
NDF 16.65 6.41 14.14 6.73 20.1 10.73 42.59
ADF 2.29 1.46 2.56 1.81 2.41 1.78 2.79
Ash 7.12 6.40 6.81 6.58 6.01 5.48 5.11
Indispensable AA, %
Arg 1.27 1.40 1.32 1.44 1.32 1.41 1.30
His 0.59 0.58 0.57 0.56 0.54 0.50 0.52
Ile 0.94 0.99 0.95 1.00 0.93 0.93 0.87
Leu 2.02 1.93 1.91 1.82 1.81 1.63 1.70
Lys 1.53 1.49 1.46 1.46 1.45 1.42 1.37
Met 0.44 0.45 0.44 0.48 0.43 0.53 0.37
Phe 1.04 1.06 1.01 1.03 0.96 0.93 0.95
Thr 1.05 1.03 1.03 1.01 0.94 0.97 0.87
Trp 0.33 0.32 0.30 0.30 0.24 0.26 0.25
Val 1.29 1.32 1.16 1.25 1.04 1.09 0.98
1 Analyzed in duplicate.
Table 5 Composition of Phase 1 diets used in Exp 3
(as-fed basis)
Item Rice-0% Rice-50% Rice-75% Rice-100% Ingredient, %
Dried whey 22.00 22.00 22.00 22.00 Soybean meal, dehulled
(48% CP)
10.00 10.00 10.00 10.00 Spray-dried animal plasma 1 8.00 8.00 8.00 8.00 Soy protein concentrate 2 5.00 5.00 5.00 5.00 Fish meal, Select Menhaden 4.01 4.17 4.25 4.33
Dicalcium phosphate 0.67 0.69 0.69 0.70 Carbadox premix 3 1.00 1.00 1.00 1.00
Mineral premix 4 0.35 0.35 0.35 0.35 Vitamin premix 5 0.20 0.20 0.20 0.20
L -Lys HCl, 78.8% 0.07 0.05 0.05 0.04
DL -Met, 99.0% 0.11 0.11 0.12 0.12
Calculated composition 6
SID 7 indispensable AA, %
Available P, % 0.55 0.55 0.55 0.55 Lactose, % 21.00 21.00 21.00 21.00
1 Appetein, APC, Inc (Ankeny, IA).
2 Soycomil (Archer Daniels Midland Company, Decatur, IL).
3 Mecadox 2.5, provided 0.055 g of carbadox per kilogram of diet (Phibro Animal Health, Fairfi eld, NJ).
4 Provided as milligrams per kilogram of diet: sodium chloride, 3,000; Zn, 100 from zinc oxide; Fe, 90 from iron sulfate; Mn, 20 from manganese oxide; Cu, 8 from copper sulfate; I, 0.35 from calcium iodide; and Se, 0.30 from sodium selenite.
5 Provided per kilogram of diet: retinyl acetate, 2,273 μg; cholecalciferol,
17 μg; DL-α-tocopheryl acetate, 88 mg; menadione sodium bisulfi te com-plex, 4 mg; niacin, 33 mg; D-Ca-pantothenate, 24 mg; ribofl avin, 9 mg; vita-min B12, 35 μg; and choline chloride, 324 mg.
6 NRC, 1998 (for all ingredients except soybean meal); Illini SAND Soy in Animal Nutrition Databases (for soybean meal; Kusina et al., 2007).
7 SID = standardized ileal digestible.
Trang 7pigs fed rice (P < 0.05) From d 7 to 14 postweaning,
pigs fed rice had a greater ADFI than those fed rolled
oats (P < 0.05) From d 14 to 28 postweaning, pigs fed
rice had greater ADG and ADFI than those fed barley
(P < 0.001) From d 28 to 42 postweaning, pigs fed rice
had a greater ADG than those fed barley (P < 0.05).
Over the entire 6-wk period, the ADG of pigs fed
rice was greater than those pigs fed barley (P < 0.001)
but not different from those fed corn or rolled oats Pigs
fed barley grew more slowly (P < 0.01) than those fed
corn Pigs fed corn and rice had ADFI that was not dif-ferent, but the ADFI for both of these groups was greater
(P < 0.05) than the ADFI of pigs fed barley No
differ-ence in G:F was observed among treatments at any
phas-es or for the overall period The overall removal rate of
pigs fed rice (3.6%) or barley (3.6%) was reduced (P <
0.05) compared with those fed rolled oats (8.3%) and
tended to be less (P = 0.075) than those pigs fed corn
(7.1%; Figure 1A)
Experiment 2
The ADG, ADFI, and G:F of pigs fed rice diets for
1, 2, or 4 wk was not different (P > 0.10) from values
calculated for pigs fed the corn diet during any phases or the overall period (Table 7) However, pigs fed the rice diet for 4 wk postweaning had a greater G:F than those
fed the corn diet from d 14 to 28 postweaning (P < 0.05).
Pigs fed rice diets for 1 (3.6%), 2 (4.0%), or 4 wk
(5.2%) postweaning had a reduced overall removal rate (P
< 0.05) compared with those fed the corn diet (10.3%;
Fig-ure 1B) No differences (P = 0.892) were observed in the
number of antibiotic treatments (Figure 2A)
Experiment 3
No differences (P > 0.10) in ADG, ADFI, and G:F
among treatments were observed during any phases or over the 6-wk period (Table 8) However, pigs fed the
diet in which rice replaced all the corn tended (P = 0.055)
Table 6 Effects of different cereal grains on growth
per-formance of pigs during 6 wk postweaning (Exp 1)
Item
Dietary treatments 1
SED P-value
Corn Barley Rolled oats Rice
d 0 to 7
ADG, g 125 a 102 b 117 ab 98 b 7 0.002
ADFI, g 146 a 127 bc 139 ab 120 c 6 <0.001
d 7 to 14
ADFI, g 214 ab 200 ab 194 b 218 a 9 0.035
d 14 to 28
ADG, g 354 ab 328 b 348 ab 374 a 10 0.001
ADFI, g 496 a 459 b 487 ab 511 a 11 <0.001
d 28 to 42
ADG, g 506 ab 480 b 503 ab 516 a 13 0.049
d 0 to 42
ADG, g 331 a 307 b 323 ab 337 a 7 <0.001
ADFI, g 495 a 462 b 489 ab 504 a 11 0.005
a−cMeans within a row with different superscript letters differ (P < 0.05).
1 12 pens/treatment; initial BW: 6.0 ± 1.3 kg.
Figure 1 (A) Effects of different cereal grain-based diets on the overall pig removals during 6 wk postweaning There were 252 pigs per treatment (Exp.1)
(B) Effects of feeding rice for 1, 2, or 4 wk on the overall pig removal during 6 wk postweaning Pigs were fed corn-based diets for 6 wk or rice-based diets for 1 (Rice-1), 2 (Rice-2), or 4 (Rice-3) wk postweaning All pigs were fed a common corn-based diet during wk 5 and 6 There were 251 pigs per treatment (Exp.2) (C) Effects of feeding rice with 0 (Rice-0%), 50 (Rice-50%), 75 (Rice-75%), and 100% (Rice-100%) replacement of corn in Phase1 diet on the overall pig removal during 6 wk postweaning (Exp.3) All pigs were fed a common corn-based diet in Phases 2, 3, and 4 (wk 2 through 6 postweaning) There were 252 pigs per treatment a,bMeans with different superscript letters within each experiment differ (P < 0.05).
Trang 8Che et al.
4922
to have a reduced overall removal rate (2.0%) compared
with pigs fed the corn diet (5.2%) Partial replacement of
corn with rice did not reduce pig removal (Figure1C) No
difference among treatments was observed for the
num-ber of antibiotic treatments (Figure 2B)
DISCUSSION
Rice is characterized by its high starch content and
low fi ber content; therefore, it may have a major impact
on the digestibility of dietary nutrients and microbial
populations by providing fewer substrates for bacterial
fermentation in the large intestine Indeed, rice-based
diets have greater apparent ileal and total tract nutrient
digestibilities than diets based on other cereal grains
(Pluske et al., 2007; Kim et al., 2008; Menoyo et al.,
2011).Also, rice, when compared with other cereal
grains, including barley, may improve pig health as it
re-duces intestinal colonization of pathogens and the
sever-ity of enteric bacterial diseases (Hampson et al., 2000;
Lindecrona et al., 2004) Although benefi cial effects of
rice have been demonstrated in university research,
ef-fects of rice and other cereal grains on growth
perfor-mance and health of weaned pigs fed under commercial
conditions in the Unites States have not been reported
The better growth performance, which was observed
in pigs fed the diets containing rice compared with those fed the diets containing barley, is likely a result of an increased ADFI because the G:F of pigs fed rice was not different from those pigs fed barley Our performance data during Phase 1 were consistent with those reported
Table 7 Effects of feeding rice for 1, 2, or 4 wk
post-weaning on growth performance of weaned pigs (Exp 2)
Item
Dietary treatments 1
SED P-value
Corn Rice-1 Rice-2 Rice-3
d 0 to 7
G:F, g/kg 878 852 887 854 34 0.662
d 7 to 14
G:F, g/kg 859 872 868 857 29 0.942
d 14 to 28
G:F, g/kg 638 b 652 ab 662 ab 695 a 17 0.013
d 28 to 42
G:F, g/kg 601 619 603 612 15 0.616
d 0 to 42
G:F, g/kg 741 746 750 747 14 0.920
a,bMeans within a row with different superscript letters differ (P < 0.05).
1 12 pens/treatment; initial BW: 5.5 ± 0.8 kg; pigs fed corn-based diets for 6
wk or rice-based diets for 1 (Rice-1), 2 (Rice-2), or 4 (Rice-3) wk
postwean-ing followed by corn-based diets All pigs were fed a common corn-based diet
during wk 5 and 6.
Table 8 Effects on pig growth performance of feeding
Phase 1 diets, in which rice replaced 0, 50, 75, or 100%
of corn, in Exp 31 Item
Replacement level, 2 %
SED P-value
Rice-0% Rice-50% Rice-75% Rice-100%
d 0 to 7
d 7 to 14
d 14 to 28
d 28 to 42
d 0 to 42
1 12 pens/treatment; initial BW: 5.9 ± 1.0 kg.
2 Pigs fed diets in which corn was replaced with 0 0%), 50 (Rice-50%), 75 (Rice-75%), and 100% (Rice-100%) in wk 1 postweaning.
Figure 2 Effects of feeding rice on the number of antibiotic treatments of
weaned pigs during 6 wk postweaning (A) Pigs were fed corn-based diets for
6 wk or rice-based diets for 1 (Rice-1), 2 (Rice-2), or 4 (Rice-3) wk postwean-ing followed by corn-based diets All pigs were fed a common corn-based diet during wk 5 and 6 There were 251 pigs per treatment (Exp 2) (B) Pigs were fed diets in which corn was replaced by 0 0%), 50 50%), 75 (Rice-75%), and 100% (Rice-100%) of rice in Phase 1 diet only All pigs were fed a common corn-based diet in Phases 2, 3, and 4 (wk 2 through 6 postweaning; Exp 2) There were 252 pigs per treatment The data for Exp 1 are not shown because the number of antibiotic treatments was not recorded No differences were observed on the number of antibiotic treatments among dietary treatments
in these experiments.
Trang 9by Hopwood et al (2004) who observed that rice did not
alter BW gain of weaned pigs compared with that of pigs
fed pearl barley in a 10-d experiment However, there
has been little research conducted to compare feeding of
rice and barley for a longer period of time; therefore, the
improved growth performance of pigs fed a rice-based
diet for 6 wk postweaning requires further investigation
Li et al (2002) observed that replacement of raw
corn with 50 or 100% raw brown rice in postweaning
diets for pigs did not affect ADG (400 or 350 vs 360
g/d) In a 5-wk study by Mateos et al (2006), nursery
pigs fed cooked rice had greater ADG and ADFI than
those fed cooked corn However, these improvements
were largely due to the addition of oat hulls (a source
of fi ber) to the rice and corn diets because there were no
differences in ADG (307 vs 306 g/d) between pigs fed
cooked rice and those fed cooked corn if oat hulls were
not included On the other hand, the effect of oat hulls
on the pig growth response to cereal grain-based diets
may be varied Kim et al (2008) reported that addition
of oat hulls to extruded rice- or wheat-based diets did
not affect the pig growth performance Results of the
present experiments are in agreement with the previous
data and indicate that rice can replace corn in nursery
pig diets without affecting pig performance and is better
than barley as it improves growth rate of pigs
The reduced removal rate of pigs fed rice-based diets
compared with pigs fed corn-based diets refl ects improved
health, even when rice was fed to pigs for only 1 wk after
weaning However, it was interesting to note that partial
replacement of corn with rice in the Phase 1 diet did not
af-fect pig removal rate Diets based on rice reduced the
occur-rence of diarrhea as compared with similar diets, in which
a fi ber source (McDonald et al., 1999, 2001) or a fi
ber-containing feed ingredient (Pluske et al., 2003; Hopwood
et al., 2004) was added Results from those studies clearly
indicate that the fi ber components added to rice-based diets
may reduce the effectiveness of rice on pig health In
agree-ment with these observations, the current data indicated
that only complete replacement of other cereal grains with
rice decreased pig removal Although reducing the number
of pigs removed, rice had no effect on the number of
antibi-otic treatments needed This implies that feeding rice may
alleviate the removal of dead and morbid pigs, but
medi-cal treatments are needed as pigs reared under commercial
conditions are usually exposed to multiple pathogens
Feeding rice or barley to pigs reduced pig removal
compared with feeding corn to the same extent in Exp 1
and this made the data diffi cult to interpret on the basis
of fi ber because rice contains almost no fi ber whereas
barley contains the most fi ber of the cereal grains tested
The fi ber present in barley provides more substrates for
microbial fermentation, which leads to increased
pro-duction of VFA This may reduce the pH in the large
in-testine to levels that are unfavorable for growth of patho-gens (Montagne et al., 2003) In a study testing effects
of soluble and insoluble dietary fi ber in pigs challenged
with pathogenic E coli, Perez et al (2010) reported that
addition of insoluble fi ber to a typical weaning diet re-sulted in faster recovery from colibacillosis diarrhea, but soluble fi ber was not benefi cial However, barley-based diets fed to pigs had a negative impact on health of pigs (Hopwood et al., 2004) because barley contains a
great-er level of soluble nonstarch polysaccharides, which in-creased viscosity of digesta, resulting in a greater inci-dence of diarrhea and proliferation of potential harmful bacteria (McDonald et al., 2001; Montagne et al., 2004) Therefore, other unidentifi ed factors, apart from the fi -ber, in rice or barley may contribute to the decreased pig removals and further investigation of barley and rice under commercial conditions should be undertaken The “rice factor,” an imprecisely defi ned component
of rice, appears to have specifi c physiological effects that may be protective against enteric diseases (Macleod
et al., 1995) In particular, the rice factor may inhibit the cystic fi brosis transmembrane conductance regulator (Mathews et al., 1999), which is the fi nal step in the
cas-cade of events through which some E coli toxins cause
diarrhea (Nagy and Fekete, 1999; Francis, 2002) Re-sults of previous studies also demonstrated that feeding
a rice-based diet improved enteric health through a
re-duction in the excretion period of Brachyspira pilosicoli
(Lindecrona et al., 2004) and the incidence of diarrhea (Mateos et al., 2006) Perhaps it is possible that the rice factor is the mechanism that is responsible for the re-duced removal rate of pigs fed diets based on rice com-pared with that of pigs fed diets based on corn, which was observed in our experiments Further research on this topic is needed
In general, among the 4 cereal grains tested, rice and corn improved ADG and ADFI of pigs over the experi-mental period as compared with barley Rice can substi-tute for corn in diets for nursery pigs without detrimental effects on growth performance Including rice in early nursery diets may improve pig health, at least under the conditions of this study, as it reduced pig removal rate as compared with pigs fed diets containing corn or rolled oats However, postmortem examinations of dead and morbid pigs should be conducted to elucidate the causes
of pig removal and provide a better understanding of the benefi cial effects of rice
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