Performance of growing-finishing pigs fed diets containing Roundup Ready corn (event nk603), a nontransgenic genetically similar corn, or conventional corn lines Y. Hyun, G. E. Bressner, M. Ellis, A. J. Lewis, R. Fischer, E. P. Stanisiewski and G. F. Hartnell J ANIM SCI 2004, 82:571-580. The online version of this article, along with updated information and services, is located on the World Wide Web at: http://www.journalofanimalscience.org/content/82/2/571 www.asas.org DDoowwnnllooaaddeedd ffrroomm wwwwww..jjoouurrnnaallooffaanniimmaallsscciieennccee..oorrgg bbyy gguueesstt oonn DDeecceemmbbeerr 1100,, 22001133 Performance of growing-finishing pigs fed diets containing Roundup Ready corn (event nk603), a nontransgenic genetically similar corn, or conventional corn lines Y. Hyun*, G. E. Bressner*, M. Ellis*1, A. J. Lewis†, R. Fischer†, E. P. Stanisiewski‡, and G. F. Hartnell† *Department of Animal Sciences, University of Illinois, Urbana 61801; †Department of Animal Science, University of Nebraska, Lincoln 68583; and ‡Monsanto Company, St. Louis, MO 63167 ABSTRACT: Twostudieswereconductedattwoloca- in Study 2. The test corns were included at a fixed tionstoevaluategrowthperformanceandcarcasschar- proportion of the diet in both studies. Animals had ad acteristicsofgrowing-finishingpigsfeddietscontaining libitumaccesstofeedandwater.Pigswereslaughtered either glyphosate-tolerant Roundup Ready (event usingstandard proceduresand carcassmeasurements nk603)corn,anontransgenicgeneticallysimilarcontrol weretaken.InStudy1,overallADG,ADFI(as-fedba- corn (RX670), or two conventional sources of non- sis),andgain:feed(G:F)werenotaffected(P>0.05)by transgenic corn (RX740 and DK647). A randomized corn line. In Study 2, there was no effect of corn line completeblockdesign(threeandfourblocksinStudies onoverallADFI(as-fedbasis)orG:Fratio.Inaddition, 1and2,respectively)witha2×4factorialarrangement overall ADG of barrows fed the four corn lines did not of treatments (two genders and four corn lines) was differ(P>0.05);however,overallADGofgiltsfedcorn used. Study 1used 72 barrows and 72gilts (housed in DK647wasgreater(P<0.05)thanthatofpigsfedthe single-gender groups of six; six pens per dietary treat- other corn lines. There was no effect (P > 0.05) of corn ment) with initial and final BW of approximately 22 lineoncarcassyieldorfatnessmeasurementsineither and116kg,respectively.Study2used80barrowsand study.Differencesbetweenbarrowsandgiltsforgrowth 80 gilts (housed in single-gender groups of five; eight andcarcasstraitsweregenerallysimilarforbothstud- pens per dietary treatment) with initial and final BW ies and in line with previous research. Overall, these ofapproximately30and120kg,respectively.Pigswere resultsindicatethatRoundupReadycorn(nk603)gives housed in a modified open-front building in Study 1 equivalentanimalperformancetoconventionalcornfor andinanenvironmentallycontrolledfinishingbuilding growing pigs. Key Words: Carcass, Growth, Pigs, Transgenic Corn 2004 American Society of Animal Science. All rights reserved. J. Anim. Sci. 2004. 82:571–580 Introduction singleprotein,themodified maizeenzyme5-enolpyru- vylshikimate-3-phosphate synthase (mEPSPS). Sub- Genetically enhanced crops offer producers a wide sequently, a second-generation Roundup Ready corn variety of agronomic benefits. For example, the use of (containingeventnk603)hasbeendeveloped.Thiscorn herbicide-tolerant corn, such as Roundup Ready, pro- expresses CP4 EPSPS protein, which is derived from vides the crop producer with flexible and broad-spec- Agrobacteriumsp.(StrainCP4).BothEPSPSandCP4 trum postemergent weed control options. Glyphosate, EPSPS proteins are functionally similar to wild-type whichistheactiveingredientintheherbicideRoundup, plantEPSPSenzymesexceptforamuch-reducedaffin- isoneofthemostwidelyusedherbicides(Sidhuetal., ity for glyphosate (LeBrun et al., 1997). Previous re- 2000). Roundup Ready corn (event GA21) was devel- search has demonstrated Roundup Ready corn to be oped to be tolerant to glyphosate by the insertion of a substantiallyequivalentinnutrientcompositiontothe geneticallyrelatednontransgeniccorn(Stanisiewskiet al., 2001; Taylor et al., 2001). Because finishing pigs consume large quantities of 1Correspondence:216AnimalSciencesLaboratory,1207W.Greg- corn,researchwasconductedtodeterminewhetherpigs ory Dr. (phone: 217-333-6455; fax: 217-333-7861; e-mail: mellis7@ fed diets containing a Roundup Ready corn (event uiuc.edu). nk603) and conventional (nontransgenic) corn have ReceivedFebruary19,2003. AcceptedSeptember24,2003. similar performance. Therefore, the objective of this 571 Downloaded from www.journalofanimalscience.org by guest on December 10, 2013 572 Hyunetal. researchwastocomparegrowthperformanceandcar- pigs,withafloorspaceof1.2m2/pig.Study2wascarried cass quality of growing-finishing pigs fed diets con- outinanenvironmentallycontrolledfinishingbuilding taining either Roundup Ready corn with event nk603, with part-solid, part-slatted floors and used a total of a nontransgenic genetically similar control corn 32 single-gender pens (barrows or gilts) with five pigs (RX670), or two conventional nontransgenic hybrids per pen, giving eight pens per dietary treatment. Pen (RX740 and DK647). dimensions(length×width)were2.6×1.8m,givinga floorspaceof0.94m2/pig.Thetemperaturewithinthe Materials and Methods building was controlled by mechanical ventilation linked to a thermostat set at 24°C during the early This research consisted of two experiments, with stagesofthestudyandreducedto21°Cwhenthepigs Study1beingcarriedoutattheUniversityofNebraska reached an average of 50 kg BW. Temperature and (Lincoln)andStudy2attheUniversityofIllinois(Ur- humiditylevelsinthebuildingwererecordedonadaily bana). Similar experimental designs and approaches basis using Hobo H8 Loggers (Onset Computer Corp., were used at both locations. Experimental protocols Bourne, MA). The average temperature during the were approved by the respective institutional animal study was 22.2 ± 2.53°C and the average relative hu- careandusecommitteesbeforethestartofthestudies. midity was 52.2 ± 12.46%. Pigshadadlibitumaccesstofeedandwaterthrough- Animals and Treatments out the experimental period, which ended after 103 d inStudy1andwhentheaverageBWofallthepensof InStudy1,144crossbred(Danbred×[Danbred×NE pigs within a block reached approximately 120 kg in White line]) pigs (equal numbers of barrows and gilts) Study 2, at which time all pigs in the block were re- with an initial BWof 22.6 ± 0.25 kg wereused, and in moved from the experiment. Study 2, 160 PIC (337 sires × C22 dams) pigs (equal numbers of barrows and gilts) with an initial BW of Data and Sample Collection 29.9 ± 0.54 kg were used. Arandomizedcompleteblock design(threeandfour In both studies, pigsand feeders were weighed and blocks in Studies 1 and 2, respectively) with a 2 × 4 feed intake measured every 2 wk throughout the factorial arrangement of treatments was used. Blocks study, and the amount of feed added to each feeder were based on initial weight and pen location within was recorded to determine ADG, ADFI (as-fed basis), the building. There were two genders (barrows and and gain:feed (G:F).At the end ofthe experiment, all gilts) and four genetic corn lines (a transgenic hybrid pigswereultrasonicallyscannedusinganAlokaModel containingeventnk603,thenontransgeniccontrolcorn 500 B-mode ultrasound scanner fitted with a VST- [RX670], and two conventional hybrids [RX740; As- 5021-3 probe (Corometrics Medical Systems, Wall- grow, Des Moines, IA, and DK647; Dekalb Seeds, De- ingford,CT).Atransversescanimagewastakenover Kalb,IA]).Dietscontainedcornandsoybeanmealand the 10th rib, and backfat depth (over the middle of were fortified with vitamins and minerals to meet or thelongissimusmuscle)andlongissimusmusclearea exceedtheNRC(1998)requirementsfortheweightsof were measured on the scans. pigsused.Thecompositionofthecornsispresentedin Attheendoftheexperiment,thepigsfromthetwo Table 1. In Study 1 (Tables 2 and 3), there were four studies were shipped to different abattoirs and har- dietary phases (Grower I, 22.6 to 42.9 kg BW; Grower vestedusingstandardprocedures.InStudy1,carcass II, 42.9 to 69.7 kg BW;Finisher I, 69.7 to 97.9 kg BW; characteristicsweremeasuredusingtotalbodyelectri- Finisher II, 97.9 to 116.4 kg BW), and the inclusion calconductivity(TOBEC;ModelRIPS4;MeatQuality, rateofthecornwasfixedwithineachphase(68.1,74.2, Inc.,Springfield,IL;Forrestetal.,1989).Carcassmea- 78.1, and 81.8% for Grower I, Grower II, Finisher I, surementsweretaken at24hpostmortem inStudy1 andFinisher II,respectively). Study1 wascarried out andincludedmidlinefatdepths(oppositethefirstrib, for a fixed time period of 103 d, with each diet phase 10th rib, last rib, and last lumbar vertebra), and lon- lasting28d,exceptFinisherII,whichwas19d.Study gissimusmusclearea atthe10thrib.In Study2,car- 2 (Table 4) was carried out over a fixed weight range, cass measurements were taken at 10 h postmortem and there were three dietary phases (Grower [29.9 to and included carcass length (measured from the cra- 50.1kgBW],FinisherI[50.1to78.7kgBW],Finisher nialtipoftheaitchbonetothecranialedgeofthefirst II[78.7to119.4kgBW]),andtheinclusionrateofthe ribadjacenttothefirstthoracicvertebra),midlinefat cornlineswasfixedwithineachphase(70,74,and77% depths(oppositethefirstrib,lastrib,andlastlumbar for Grower, Finisher I, and Finisher II, respectively). vertebra), 10th-rib fat depth (measured over the lon- Dietswerechangedbetweenphaseswhentheaverage gissimusmuscleatthree-quartersofthedistancefrom weight of all pigs in a block reached the designated the midline), and longissimus muscle depth and area weight of 50 and 80 kg, respectively. at the 10th rib. InStudyl,thepigswerehousedinamodified-open- Musclequalitymeasurementstakenonthecutsur- front building with 24 pens (pen dimensions [length × faceofthelongissimusmuscleatthe10thribincluded width]were4.8m×1.5m),andeachpencontainedsix pH, firmness and marbling scores (NPPC, 1991), and Downloaded from www.journalofanimalscience.org by guest on December 10, 2013 Transgeniccornfeedingtoswine 573 Table 1. Nutrient composition of the corn lines (as-fed basis) Cornlinea Item,% nk603 RX670 DK647 RX740 Drymatter 87.8 88.3 85.4 86.5 Crudeprotein 7.35 7.90 7.85 8.13 Crudefat 3.75 3.77 3.43 4.13 ADF 2.9 3.0 3.5 3.8 NDF 9.1 9.6 10.3 9.5 Crudefiber 2.6 2.1 2.7 1.9 Crudeash 7.35 7.35 7.35 7.35 Aminoacidcomposition: Arginine 0.29 0.29 0.36 0.26 Histidine 0.21 0.21 0.23 0.22 Isoleucine 0.22 0.23 0.24 0.26 Leucine 0.84 0.93 0.93 1.04 Lysine 0.23 0.25 0.25 0.24 Methionine 0.19 0.17 0.18 0.18 Cysteine 0.18 0.20 0.24 0.24 Phenylalanine 0.36 0.37 0.38 0.40 Tyrosine 0.27 0.23 0.25 0.25 Threonine 0.29 0.30 0.30 0.30 Tryptophan 0.05 0.06 0.06 0.06 Valine 0.31 0.32 0.34 0.35 ank603 = transgenic Roundup Ready corn; RX670 = nontransgenic control corn; RX740 and DK647 = conventionalcornhybrids. Minolta L* (lightness), a* (red-green scale), and b* Inbothstudies,thechemicalcompositionofthelon- (yellow-blue scale) values in Study l and color and gissimus muscle was determined on a subsample of firmness and marbling scores in Study 2 (NPPC, threepigs randomlyselectedfromwithin eachpen.A 1991, 2000). longissimus muscle sample was taken at the 10th rib Table 2. Composition of Grower I and Grower II diets—Study 1 (as-fed basis) Cornlineindieta nk603 RX670 DK647 RX740 Ingredient,% GrowerI GrowerII GrowerI GrowerII GrowerI GrowerII GrowerI GrowerII Corn 68.07 74.21 68.07 74.21 68.07 74.21 68.07 74.21 Soybeanmeal(dehulled) 26.00 20.25 26.00 20.25 26.00 20.25 26.00 20.25 Tallow 3.00 3.00 3.00 3.00 3.00 3.00 3.00 3.00 Dicalciumphosphate 1.25 0.85 1.25 0.85 1.25 0.85 1.25 0.85 Limestone 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 Salt 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 Vitaminpremixb 0.70 0.70 0.70 0.70 0.70 0.70 0.70 0.70 Tracemineralpremixc 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 Tyland 0.13 0.13 0.13 0.13 0.13 0.13 0.13 0.13 L-Lysine(cid:1)HCl 0.05 0.06 0.05 0.06 0.05 0.06 0.05 0.06 Chemicalcomposition,%e ME,kcal/kgf 3,464 3,480 3,464 3,480 3,464 3,480 3,464 3,480 Crudeprotein 17.79 15.63 18.16 16.04 18.35 16.00 18.32 16.04 Calcium 0.70 0.60 0.70 0.60 0.70 0.60 0.70 0.60 Phosphorus 0.60 0.50 0.60 0.50 0.60 0.50 0.60 0.50 Lysine 0.95 0.80 0.96 0.82 0.96 0.82 0.96 0.82 ank603=transgenicRoundupReadycorn;RX670=nontransgeniccontrolcorn;RX740andDK647=conventionalcornhybrids. bThevitaminpremixsuppliedperkilogramofdiet:vitaminA(asretinylacetate),3,088IU;vitaminD (ascholecalciferol),386IU;vitamin 3 E(asα-tocopherolacetate),15IU;vitaminK(asmenadionesodiumbisulfite),2.3mg;riboflavin,3.9mg;D-pantothenicacid,15.4mg;niacin, 23.3mg;choline,77.2mg;vitaminB ,15.4(cid:1)g. 12 cThetracemineralpremixsuppliedperkilogramofdiet:Zn(asZnO),110mg;Fe(asFeSO (cid:1)H O),110mg;Mn(asMnO),22mg;Cu(as 4 2 CuSO (cid:1)H O)11mg;I(asCa(IO )(cid:1)H O),0.22mg;Se(asNa SeO ),0.3mg. 4 2 3 2 2 3 dTylan-40(ElancoAnimalHealth,Indianapolis,IN);tosupply110g/kgtylosininthefinalfeed. eCalculatedvaluesbasedonanalyzedvaluesforthecornandsoybeanmealsamplesused. fBasedonvaluesfromNRC(1998). Downloaded from www.journalofanimalscience.org by guest on December 10, 2013 574 Hyunetal. Table 3. Composition of Finisher I and Finisher II diets—Study l (as-fed basis) Cornlineindieta nk603 RX670 DK647 RX740 Ingredient,% FinisherI FinisherII FinisherI FinisherII FinisherI FinisherII FinisherI FinisherII Corn 78.11 81.79 78.11 81.79 78.11 81.79 78.11 81.79 Soybeanmeal(dehulled) 16.25 12.75 16.25 12.75 16.25 12.75 16.25 12.75 Tallow 3.00 3.00 3.00 3.00 3.00 3.00 3.00 3.00 Dicalciumphosphate 0.93 0.75 0.93 0.75 0.93 0.75 0.93 0.75 Limestone 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 Salt 0.30 0.30 0.30 0.30 0.30 0.30 0.30 0.30 Vitaminpremixb 0.70 0.70 0.70 0.70 0.70 0.70 0.70 0.70 Trace-mineralpremixc 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 Tyland 0.13 0.13 0.13 0.13 0.13 0.13 0.13 0.13 L-Lysine(cid:1)HCl 0.08 0.08 0.08 0.08 0.08 0.08 0.08 0.08 Chemicalcomposition,%e ME,kcal/kgf 3,479 3,487 3,479 3,487 3,479 3.487 3,479 3,487 Crudeprotein 13.53 12.41 13.96 12.46 13.92 12.42 14.14 12.65 Calcium 0.60 0.55 0.60 0.55 0.60 0.55 0.60 0.55 Phosphorus 0.50 0.45 0.50 0.45 0.50 0.45 0.50 0.45 Lysine 0.69 0.60 0.71 0.62 0.71 0.62 0.71 0.62 ank603=transgenicRoundupReadycorn;RX670=nontransgeniccontrolcorn;RX740andDK647=conventionalcornhybrids. bThevitaminpremixsuppliedperkilogramofdiet:vitaminA(asretinylacetate),3,088IU;vitaminD (ascholecalciferol),386IU;vitamin 3 E(asα-tocopherolacetate),15IU;vitaminK(asmenadionesodiumbisulfite),2.3mg;riboflavin,3.9mg;D-pantothenicacid,15.4mg;niacin, 23.3mg;choline,77.2mg;vitaminB ,15.4(cid:1)g. 12 cThetracemineralpremixsuppliedperkilogramofdiet:Zn(asZnO),110mg;Fe(asFeSO (cid:1)H O),110mg;Mn(asMnO),22mg;Cu(as 4 2 CuSO (cid:1)H O)11mg;I(asCa(IO )(cid:1)H O),0.22mg;Se(asNa SeO ),0.3mg. 4 2 3 2 2 3 dTylan-40(ElancoAnimalHealth,Indianapolis,IN);tosupply110g/kgtylosininthefinalfeed. eCalculatedvaluesbasedonanalyzedvaluesforthecornandsoybeanmealsamplesused. fBasedonvaluesfromNRC(1998). from 18 pigs per treatment (nine barrows and nine RX670, RX740, and DK647), block, and gender × corn gilts)inStudy1and24pigspertreatment(12barrows line interaction. Least squares means were evaluated and 12 gilts) in Study 2. Longissimus samples were using the PDIFF and STDERR options of SAS. homogenized and analyzed for protein, fat, and mois- ture using the procedures of Novakofski et al. (1989). Results and Discussion Corn samples from each line were collected before thestartoftheexperimentfornutrientanalysis(Table Growth Performance 1). Also, a soybean meal sample was collected at the In Study 1, ADG, ADFI, and G:F were not affected feed mill during the production of each dietary phase (P > 0.05) by corn line (Table 5). In Study 2 (Table 6), for the determination of crude protein and amino there was a corn line × gender interaction for ADG in acid concentrations. thegrowingphase(P<0.05)andintheoverallgrowth period (P < 0.05) as well as for G:F in the Finisher I Sample Analysis phase (P< 0.01).For barrows,there wasno effect (P> Cornandsoybeanmealsamplesweregroundthrough 0.05) of corn line on ADG during any phase; however, a1-mmscreenbeforeanalysis.Ingredientsampleswere gilts fed DK647 grew faster (P < 0.05) than those fed analyzed in duplicate for crude protein according to theotherlinesfortheoverallgrowthperiodandfaster AOAC(1995)procedures.Sampleswerehydrolyzedfor thanthosefeddietswithnk603andRX740inthegrow- 20husing6NHClat107°Cbeforeseparationofamino ingperiod(Table6).DuringFinisherI,barrowsfeddiet acidsbyion-exchangeHPLC.Afterelution,aminoacids nk603 had a higher G:F than those fed RX670 and were quantified fluorometrically using o-phthalalde- DK647, whereas gilts fed hybrid DK647 had a higher hyde as a derivatization reagent (AOAC, 1995). G:F than those fed RX670 (Table 6). However, there wasnoeffect(P>0.05)ofcornlineonG:Ffortheoverall Statistical Analysis growth period (Table 6). Different approaches to diet formulation were used Pen was the experimental unit in both studies. All in these two studies. In Study 1, the inclusion rate of data(growth,carcass,meatquality,andchemicalcom- allingredientswasthesameforalldietswithinaphase. position)wereanalyzedasarandomizedcompleteblock Thisapproachhasthepotentialdisadvantagethatthe design using PROC MIXED procedures of SAS (SAS variationinnutrientcompositionofthetestdietscould Institute, Inc., Cary, NC). The effects included in the produce differences in animal performance indepen- modelweregender(barrowsandgilts),cornline(nk603, dent of any effect of corn line per se. However, differ- Downloaded from www.journalofanimalscience.org by guest on December 10, 2013 Transgeniccornfeedingtoswine 575 I K s I 0070535092050 0707 a r 0932670100031 6456 n ( Finishe 77.13.4.2.0.0.0.0.0.0.0.0.0. 3,39413.0.0.0. vitami 1mg;I U; 1 I O) RX740 FinisherI 74.0018.003.522.340.770.750.060.050.050.010.050.350.10 3,38215.030.520.540.78 cetate),15 (cid:1)CuSOH42 a s Grower 65.0027.503.062.100.850.850.040.020.020.010.050.350.15 3,36918.530.610.581.02 ocopherol mg;Cu(a α-t 22 II 0024260281050 6787 (as O), Finisher 77.017.20.73.00.70.60.00.10.00.00.00.30.1 3,39513.50.40.40.6 taminE(cid:1)15.4g.n(asMn vi,2M Table4.Compositionofthediets—Study2(as-fedbasis) aCornlineindiet nk603RK670DK647 Ingredient,%GrowerFinisherIFinisherIIGrowerFinisherIFinisherIIGrowerFinisherI Corn65.0074.0077.0065.0074.0077.0065.0074.00Soybeanmeal(dehulled)28.8019.2015.3027.4317.8013.5030.1921.10Wheatmiddlings2.433.123.843.984.695.780.000.05Soybeanoil1.441.581.801.261.381.632.482.75Dicalciumphosphate0.920.780.680.850.730.630.920.82Limestone0.800.730.680.850.780.740.800.71(cid:1)-LysineHCl0.010.040.030.040.060.060.000.00L-Methionine0.030.060.110.020.050.090.050.08DLThreonine0.020.040.090.020.050.100.010.04Tryptophan0.000.000.020.000.010.020.000.00bTylan0.050.050.000.050.050.000.050.05cTrace-mineralpremix0.350.350.350.350.350.350.350.35dVitaminpremix0.150.100.100.150.100.100.150.10eChemicalcomposition,%fME,kcal/kg3,3703,3833,3953,3703,3833,3953,3703,383Crudeprotein18.5314.9513.5818.4614.9213.4318.4814.97Calcium0.610.520.470.610.520.470.610.52Phosphorus0.580.530.500.610.550.530.570.51Lysine1.020.780.671.020.780.671.020.78 ank603=transgenicRoundupReadycorn;RX670=nontransgeniccontrolcorn;RX740andDK647=conventionalcornhybrids.bTylan-40(ElancoAnimalHealth,Indianapolis,IN);tosupply44g/kgtylosininthefinalfeed.cThevitaminpremixsuppliedperkilogramofdiet:vitaminA(asretinylacetate),3,088IU;vitaminD(ascholecalciferol),386IU;3(asmenadionesodiumbisulfite),2.3mg;riboflavin,3.9mg;-pantothenicacid,15.4mg;niacin,23.3mg;choline,77.2mg;vitaminBD1(cid:1)dThetracemineralpremixcontained84%saltandsuppliedperkilogramofdiet:Zn(asZnO),110mg;Fe(asFeSOHO),110mg;42(cid:1)Ca(IO)HO),0.22mg;Se(asNaSeO),0.3mg.3223eCalculatedvaluesbasedonanalyzedvaluesforthecornandsoybeanmealsamplesused.fBasedonvaluesfromNRC(1998). Downloaded from www.journalofanimalscience.org by guest on December 10, 2013 576 Hyunetal. Table 5. Least squares means for effects of corn line and gender on growth performance—Study l Cornlineindieta Gender Item nk603 RX670 DK647 RX740 SEM Barrow Gilt SEM Numberofpens 6 6 6 6 — 12 12 — Initialweight,kg 22.5 22.6 22.6 22.6 0.03 22.8 22.4 0.02 Finalweight,kg 116.4 116.5 116.7 116.2 1.48 121.1b 111.7c 1.05 GrowerI(28dfrom22.6to42.9kg) Averagedailygain,g 724 716 748 715 13.3 750b 710c 9.4 Averagedailyfeedintake,kgd 1.45 1.42 1.47 1.42 0.023 1.48 1.40 0.016 Gain:feed 0.50 0.50 0.51 0.50 0.004 0.50 0.50 0.003 GrowerII(28dfrom42.9to69.7kg) Averagedailygain,g 945 956 956 957 13.9 1025b 882c 9.9 Averagedailyfeedintake,kgd 2.27 2.31 2.26 2.28 0.042 2.46b 2.11c 0.030 Gain:feed 0.42 0.41 0.42 0.42 0.003 0.42 0.42 0.002 FinisherI(28dfrom69.7to97.9kg) Averagedailygain,g 1,019 984 1,022 1,016 21.1 1,061b 956c 14.9 Averagedailyfeedintake,kgd 2.90 2.92 2.84 2.86 0.066 3.11b 2.65c 0.047 Gain:feed 0.35 0.35 0.35 0.36 0.004 0.34c 0.36b 0.003 FinisherII(19dfrom97.9to116.4kg) Averagedailygain,g 983 973 976 967 23.9 1,010b 940c 16.9 Averagedailyfeedintake,kgd 3.19 3.09 3.11 3.06 0.067 3.32b 2.91c 0.047 Gain:feed 0.31 0.32 0.31 0.32 0.005 0.30c 0.32b 0.003 Overall(103dfrom22.6to116.4kg) Averagedailygain,g 912 912 910 909 13.9 956b 866c 9.8 Averagedailyfeedintake,kgd 2.39 2.38 2.36 2.35 0.043 2.53b 2.21c 0.030 Gain:feed 0.38 0.38 0.39 0.39 0.003 0.38c 0.39b 0.002 ank603=transgenicRoundupReadycorn;RX670=nontransgeniccontrolcorn;RX740andDK647=conventionalcornhybrids. b,cWithinatreatmentandrow,meanswithoutacommonsuperscriptletterdiffer(P<0.05). dAs-fedbasis. Table 6. Least squares means for effects of corn line and gender on growth performance—Study 2 Cornlineindieta Gender Item nk603 RX670 DK647 RX740 SEM Barrow Gilt SEM Numberofpens 8 8 8 8 — 16 16 — Initialweight,kg 30.0 30.2 29.8 29.7 0.26 30.1 29.8 0.18 Finalweight,kg 119.4 118.4 121.8 118.0 1.31 123.1d 115.7e 0.92 Grower(29.9to50.1kg) Averagedailygain,gb Barrow 818d 789def 801de 821d 30.2 — — — Gilt 710f 772def 850d 717ef — — — — Averagedailyfeedintake,kgh 1.64 1.71 1.77 1.68 0.052 1.74 1.66 0.037 Gain:feed 0.47 0.46 0.47 0.46 0.011 0.47 0.46 0.008 FinisherI(50.1to78.7kg) Averagedailygain,g 968 996 1,053 1,007 27.0 1,061d 950e 19.1 Averagedailyfeedintake,kgh 2.37 2.59 2.59 2.51 0.064 2.68d 2.35e 0.046 Gain:feedb Barrow 0.42de 0.38g 0.39fg 0.40efg 0.008 — — — Gilt 0.40defg 0.39fg 0.42d 0.41def — — — — FinisherII(78.7to119.4kg) Averagedailygain,g 1,069 1,011 1,042 1,017 25.5 1,071d 999e 18.0 Averagedailyfeedintake,kgh 3.05 3.01 3.00 2.94 0.064 3.18d 2.81e 0.045 Gain:feed 0.35 0.34 0.35 0.35 0.006 0.34e 0.36d 0.004 Overall(29.9to119.4kg) Averagedailygain,gc Barrow 1017d 981d 975d 1009d 20.3 — — — Gilt 892e 904e 996d 881e — — — — Averagedailyfeedintake,kgh 2.46 2.52 2.54 2.46 0.042 2.63d 2.35e 0.030 Gain:feed 0.39 0.37 0.39 0.38 0.004 0.38e 0.39d 0.003 ank603=transgenicRoundupReadycorn;RX670=nontransgeniccontrolcorn;RX740andDK647=conventionalcornhybrids. bCornline×genderinteraction(P<0.05). cCornline×genderinteraction(P<0.01). d,e,f,gWithinatreatmentandaninteraction,meanswithoutacommonsuperscriptletterdiffer(P<0.05). hAs-fedbasis. Downloaded from www.journalofanimalscience.org by guest on December 10, 2013 Transgeniccornfeedingtoswine 577 Table 7. Least squares means for the effects of corn line and gender on ultrasound and carcass measurement—Study 1 Cornlineindieta Gender Item nk603 DK647 RX670 RX740 SEM Barrow Gilt SEM Numberofpens 6 6 6 6 — 12 12 — Ultrasoundmeasurements Backfatthickness,cm 2.10 2.05 2.07 2.07 0.008 2.31e 1.84f 0.057 Longissimusmusclearea,cm2 48.4 47.9 48.9 46.8 0.88 48.1 47.9 0.62 Backfatthickness,cm 1strib 4.74 4.75 4.81 4.76 0.153 4.94e 4.59f 0.108 10thrib 3.08 2.98 2.97 3.00 0.075 3.27e 2.74f 0.053 Lastrib 3.50 3.38 3.43 3.61 0.103 3.65e 3.31f 0.073 Lastlumbar 2.36 2.31 2.27 2.31 0.076 2.53e 2.10f 0.054 Longissimusmusclearea,cm2 56.6 58.6 56.6 55.3 2.02 55.2 58.3 1.43 TOBECmeasurements Hotcarcassweight,kg 88.8 89.0 88.7 88.4 1.27 92.1e 85.3f 0.898 Hamweight,kg 10.7 10.3 10.1 10.2 0.12 10.2 10.2 0.09 Loinweight,kg 12.0 12.1 11.9 11.7 0.15 12.0 11.8 0.10 Shoulderweight,kg 12.3 12.4 12.3 12.2 0.17 12.5 12.2 0.12 Primal,%b 38.9 39.0 38.9 38.7 0.37 37.8f 40.0e 0.26 Totalfat-freelean,kgc 42.1 42.4 42.2 42.6 0.60 45.1 44.0 0.42 Percentageoffat-freeleanc 47.6 47.5 47.7 48.2 0.50 49.0f 51.5e 0.42 Leangain,g/dd 338 341 339 343 5.5 345 336 3.9 ank603 = transgenic Roundup Ready corn; RX670 = nontransgenic control corn; RX740 and DK647 = conventionalcornhybrids. bCalculatedasthetotalweightoftheprimals(ham,loin,andshoulder)dividedbythehotcarcassweight. cEstimatedfromtotalbodyelectricalconductivity(TOBEC)scans. dLeangain=(finalfat-freelean−initialfat-freelean)/103d;initialfat-freelean0.95×[−3.95+(0.418× liveweight,kg)]. e,fWithinatreatmentandrow,meanswithoutacommonsuperscriptdiffer(P<0.05). encesinnutrientcompositionamongthetestdietswere performanceof animalson oneof theconventional hy- small (Tables 2 and 3). In Study 2, the corn inclusion brids rather than being due to any negative effect of level was fixed within a phase. Diets were formulated the Roundup Ready corn on growth. Diets based on to thesame nutrientcomposition resultingin variable DK647hadthelowestinclusionofwheatmiddlingsand inclusionratesacrossthecornlinedietsforotheringre- the highest inclusion of soybean oil (Table 4), and this dients, particularly soybean meal, wheat middlings, potentially could have contributed to the observed dif- andsoybeanoil.Thisapproachhasthepotentialdisad- ferenceinoverallgrowthrateamongcornlinesingilts. vantage that variation in ingredient inclusion rate However, it is unlikely that the inclusion rate differ- could affect growth. However, differences among the encesinthisstudy,whichwererelativelysmall,would dietsforthefourcornlinesiningredientinclusionrates have affected the relative growth of pigs on the four were relatively small (Table 4) and were unlikely to test corn treatments. have affected animal performance. Therearelimiteddatainthescientificliteraturecom- Thus,resultsforbothgendersinStudylandbarrows paring transgenic with nontransgenic conventional in Study 2 suggest that the Roundup Ready corn gave corn fed to pigs. However, research carried out with equivalent growth performance to the nontransgenic poultryhasshownresultssimilartothepresentstudy, control corn (RX670) and the conventional hybrids withnodifferencesingrowthrate,feedconversioneffi- tested. For the gilts in Study 2, during the overall ciency, or fat pad weight among broilers fed Roundup growth period one of the commercial corns (DK647) elicitedgreater(P>0.05)growthratesbutsimilarfeed Ready corn (event GA21 or nk603), the nontransgenic controlcorn,orconventionalcornhybrids(Sidhuetal., efficiencies than the other three hybrids. The growth 2000; Taylor et al., 2001). rate of gilts fed DK647 was similar to that of barrows Inbothstudies,barrowshadhigher(P<0.05)overall on the same treatment, a finding that is contrary to most studies that have compared castrates and gilts ADFIandADGthangilts(Tables5and6).Inaddition, (Cromwelletal.,1993;Hahnetal.,1995;Stanisiewski gilts had higher (P < 0.01) G:F ratio than barrows in et al., 2001). In addition, for the overall growth period Finishers I and II and overall (Tables 5 and 6). These giltsinStudy2fednk603cornhadperformancesimilar results are similar to those of most previous research to those fed the other two lines tested (RX670 and thathasevaluatedthegrowthperformanceofcastrates RX740). Thus, the difference in growth rate between andgilts(Labroueetal.,1994;HahnandBaker,1995; thecornlinesforgiltswasmoreafunctionofthebetter Hyun and Ellis, 2001). Downloaded from www.journalofanimalscience.org by guest on December 10, 2013 578 Hyunetal. Table 8. Least squares means for the effects of corn line and gender on ultrasound and carcass measurements, and longissimus muscle quality and composition—Study 2 Cornlineindieta Gender Item nk603 RX670 DK647 RX740 SEM Barrow Gilt SEM Numberofpens 8 8 8 8 — 16 16 — Ultrasoundmeasurements Backfatthickness,cm 1.50 1.47 1.50 1.48 0.034 1.63d 1.34e 0.024 Longissimusmusclearea,cm2b Barrow 45.9e 44.1efg 42.8fgh 44.5ef 0.92 — — — Gilt 40.3hi 41.5ghi 43.3efg 39.9i — — — — Carcassmeasurements Coldcarcassweight,kgb Barrow 89.9e 86.8e 87.4e 89.7e 1.78 — — — Gilt 80.4f 81.4f 88.6e 80.1f — — — — Dressingpercent 71.3 71.0 72.2 71.9 0.68 71.8 71.4 0.48 Carcasslength,cm 84.8 84.1 85.0 84.1 0.39 84.7 84.4 0.28 Backfatthickness,cm 1strib 4.08 4.08 4.15 3.95 0.109 4.21d 3.91e 0.077 Lastrib 2.25 2.30 2.28 2.25 0.091 2.44d 2.09e 0.064 Lastlumbarvertebra 1.79 1.73 1.85 1.71 0.080 1.99d 1.55e 0.056 10thrib 1.94 1.90 1.94 1.86 0.100 2.13d 1.69e 0.071 Longissimusmusclearea,cm2 42.2 42.9 43.4 41.9 0.85 42.2 42.9 0.60 Longissimusmusclecolorc 2.29 2.25 2.26 2.20 0.117 2.26 2.24 0.083 Longissimusmusclefirmnessbc Barrow 2.15ef 2.30ef 2.73e 2.33ef 0.192 — — — Gilt 2.40e 2.33ef 1.75f 2.20ef — — — — Longissimusmusclemarblingc 1.43 1.41 1.15 1.14 0.112 1.36 1.21 0.079 Chemicalcompositionoflongissimusmuscle,%d Moisture 73.16 73.34 73.42 73.23 0.140 73.12 73.45 0.099 Protein 23.39 23.35 23.13 22.92 0.241 23.33 23.06 0.170 Fat 2.77 2.78 2.46 2.83 0.160 2.79 2.62 0.113 ank603=transgenicRoundupReadycorn;RX670=nontransgeniccontrolcorn;RX740andDK647=conventionalcornhybrids. bCornline×genderinteraction(P<0.05). cEvaluatedon5-or6-pointscales.Color:1=lightto6=dark;firmness:1=softto5=veryfirm;marbling:1=devoidto6=abundant. dBasedonasubsampleofthreepigsperpen. e,f,g,h,iWithinatreatmentandaninteraction,meanswithoutacommonsuperscriptletterdiffer(P<0.05). Carcass Characteristics also shown similar lean growth rates for barrows and gilts. There was no effect (P > 0.05) of corn line on any InStudy2,cornline×genderinteractions(P<0.05) of the carcass measures taken in Study l (Table 7). were detected for ultrasound longissimus muscle area Additionally, none of the TOBEC measurements dif- and cold carcass weight (Table 8). Barrows fed hybrid fered(P>0.05)amongthecornlines(Table7).InStudy DK647 had lower (P < 0.05) longissimus muscle area 1,TOBECmeasurementsforhotcarcassweight,shoul- than those fed nk603, whereas gilts fed DK647 had derweight,andtotalleanweightweregreaterforbar- greater longissimus muscle areathan those fed nk603 rowsthangilts.However,giltshadagreaterpercentage and RX740 (Table 8). However, there was no corn line of primal cuts and percentage fat-free lean than bar- × gender interaction (P > 0.05) for longissimus muscle rows(Table7).TheTOBECestimatesofprimalweights area measured on the carcass (Table 8). For barrows, weresimilartothedirectlymeasuredwholesaleprimal there wasno effectof corn lineon cold carcassweight, weights reported by Gu et al. (1992) and Cisneros et whereasgiltsthatwerefedhybridDK647hadheavier al.(1996).Inaddition,Unruhetal.(1996)reportedthat (P<0.01)carcassweightsthanthosefedtheothercorn when barrows and gilts were fed to an end weight of lines(Table8).However,therewasnocornline×gender 127kg,theprimalpercentagewasgreateringiltsthan interaction (P > 0.05) for dressing percent, suggesting in barrows. In the current study, the higher shoulder that variation in cold carcass weight for gilts resulted weightforbarrowswasaresultoftheirgreaterslaugh- from differences in live weight at slaughter. terweightthangilts(121vs.112kg,respectively).Pre- Inbothstudies,barrowshadgreater(P<0.05)back- vious studies have shown that at a similar slaughter fat thickness than gilts; however, there was no differ- weight,giltsproducecarcasseswithagreaterpercent- ence (P > 0.05) between the genders for longissimus ageofleanthanbarrows(Cromwelletal.,1993;Unruh muscleareameasuredonthecarcass(Tables7and8). etal.,1996).Carcassfat-freeleangain,calculatedfrom The difference in backfat depth between barrows and TOBEC measurements, was not affected (P > 0.05) by giltswassimilartotheresultsofCromwelletal.(1993) eithergenderorcornline(Table7).Moststudieshave andHahnetal.(1995);however,inthoseexperiments, Downloaded from www.journalofanimalscience.org by guest on December 10, 2013 Transgeniccornfeedingtoswine 579 Table9.Leastsquaresmeansfortheeffectsofcornlineandgenderonlongissimusmusclequalityandcomposition— Study l Cornlineindieta Gender Item nk603 RX670 DK647 RX740 SEM Barrow Gilt SEM Numberofpens 6 6 6 6 — 12 12 — Longissimusmusclequalitymeasurements Marblingb 2.00 2.03 2.00 2.00 0.014 2.00 2.01 0.010 Firmnessb 2.08 2.22 1.93 2.08 0.096 2.04 2.12 0.068 UltimatepH 5.64 5.60 5.63 5.63 0.016 5.65d 5.61e 0.012 MinoltaL* 50.69 50.59 50.78 49.75 0.623 50.37 50.53 0.440 Minoltaa* 7.40 7.17 6.71 7.20 0.262 7.12 7.12 0.185 Minoltab* 2.58 2.51 2.39 2.11 0.294 2.43 2.37 0.208 Chemicalcompositionofthelongissimusmuscle,%c Protein 23.51 23.78 23.48 23.74 0.216 23.77 23.49 0.153 Fat 2.99 2.20 3.06 3.08 0.247 3.08 2.59 0.174 Moisture 72.53 72.71 72.40 72.31 0.262 72.37 72.60 0.185 ank603=transgenicRoundupReadycorn;RX670=nontransgeniccontrolcorn;RX740andDK647=conventionalcornhybrids. bEvaluatedusingafive-pointscale:1=softanddevoidofmarblingto5=firmandabundantorgreatermarbling. cBasedonasubsampleofthreepigsperpen. d,eWithinatreatmentandrow,meanswithoutacommonsuperscriptletterdiffer(P<0.05). gilts had greater longissimus muscle area than bar- Musclequalityandcompositionmeasurementswere rows, which is in contrast tothe results of the present generally similar (P > 0.05) for barrows and gilts in studies.Thelackofagendereffectonlongissimusmus- both studies (Tables 8 and 9) with the exception that cleareacould,inpart,beduetodifferencesinslaughter inStudy1ultimatepHvaluesweregreater(P<0.05)for liveweightbetweenbarrowsandgilts.However,fitting barrows than gilts (Table 9); however, the differences live weight at slaughter as a covariate in the model betweenthegenderswassmall.Mostpreviousstudies removed the gender difference in carcass weight, but have indicated that meat quality measurements, in- it did not produce a difference (P > 0.05) among the cluding ultimate pH, are similar for barrows and gilts genders in longissimus muscle area. (Unruh et al., 1996; Nold et al., 1999). Implications Longissimus Muscle Quality These studies demonstrated that the feeding value In Study 1, there was no effect (P < 0.05) of corn ofRoundupReadycorn(containingeventnk603,which lineonanymusclequalityorcompositionmeasurement expressestheCP4EPSPSprotein)issimilartothatof (Table 9). Similarly, in Study 2, longissimus muscle the nontransgenic control corn and the conventional chemical composition and color and marbling scores corn lines tested. Therefore, Roundup Ready corn weresimilar(P>0.05)acrosscornlines(Table8).There (eventnk603)whenusedinswinedietscanbeexpected was an interaction (P < 0.05) between corn line and tohaveeffectsongrowthperformanceandcarcasschar- gender for longissimus muscle firmness. For barrows, acteristics comparable to those of conventional corn. there was no effect (P < 0.05) of corn line on muscle firmness; however, gilts fed DK647 had lower scores, Literature Cited indicating softer muscle, than those fed nk603 (Table 8).Thereisnoobviousexplanationforthisinteraction. AOAC.1995.OfficialMethodsofAnalysis.16thed.Assoc.Offic.Anal. GiltsfedDK647didgrowfasterthangiltsfedtheother Chem.,Arlington,VA. corns (Table 6), but there were no treatment interac- Cisneros,F.,M.Ellis,F.K.McKeith,J.McCaw,andR.L.Fernando. tions(P>0.05)formusclecolorscoresandfatcontent, 1996.Influenceofslaughterweightongrowthandcarcasschar- acteristics,commercialcuttingandcuringyields,andmeatqual- twofactorsthatcanbeassociatedwithmusclefirmness. ity of barrows and gilts from two genotypes. J. Anim. Sci. Nevertheless, there was no evidence from these two 74:925–933. studies of any negative effect of the test corn (nk603) Cromwell,G.L.,T.R.Cline,J.D.Crenshaw,T.D.Crenshaw,R.C. Ewan,C.R.Hamilton,A.J.Lewis,D.C.Mahan,E.R.Miller, onporkquality.ThisfindingissimilartothatofStani- J.E.Pettigrew,L.F.Tribble,andT.L.Veum.1993.Thedietary siewski et al. (2001), who reported no effects of a proteinand(or)lysinerequirementofbarrowsandgilts.J.Anim. RoundupReadycorn(eventGA21)comparedwithcon- Sci.71:1510–1519. ventional hybrids on chemical composition of muscle. Forrest,J.C.,C.H.Kuei,M.W.Orcutt,A.P.Schinckel,J.R.Stouffer, Pork quality is of increasing importance to the swine and M. D. Judge. 1989. Areview of potential new methods of on-lineporkcarcassevaluation.J.Anim.Sci.67:2164–2170. industry, and these results suggest no difference be- Gu,Y.,A.P.Schinckel,andT.G.Martin.1992.Growth,development, tweentheRoundupReadyhybridtestedrelativetothe andcarcasscompositioninfivegenotypesofswine.J.Anim.Sci. conventional corns for longissimus muscle quality. 70:1719–1729. Downloaded from www.journalofanimalscience.org by guest on December 10, 2013