Dietary influence on organ size and in vitro oxygen consumption by visceral organs of growing pigs

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1 Livestock Prouction Science 65 (2000) locte/ livprosci Dietry influence on orgn size n in vitro oxygen consumption y viscerl orgns of growing pigs C.M. Nychoti, C.F.M. e Lnge *, B.W. McBrie, S. Leeson, H. Schulze Deprtment of Animl n Poultry Science, University of Guelph, Guelph, Ontrio, Cn N1G 2W1 Receive 3 June 1999; receive in revise form 20 Octoer 1999; ccepte 10 Decemer Astrct Although viscerl orgns represent only out 15% of the pig s oy weight, they ccount for out 45% of whole oy oxygen consumption. The effect of iet on orgn mss n in vitro oxygen consumption y some viscerl orgns ws investigte in stuy using 15 Yorkshire mle cstrtes ( kg initil oy weight). Diets were se on csein-corn strch (CC), rley-cnol mel (BCM) or rley-cnol mel lflf mel (BCM-ALF) n formulte to contin MJ igestile energy (DE) per grm of crue protein. Pigs were fe t 2.6 times mintennce DE requirements twice ily for 3 weeks, then every 3 h for 3 ys prior to tissue smpling. One h fter feeing, pigs were kille n smples of the liver, jejunum, colon n cecum tken immeitely. In vitro oxygen uptke ws etermine polrogrphiclly using n oxygen electroe. Per kg empty oy weight (EBW), weight of the smll intestine i not iffer (P. 0.10) etween tretments. Per kg EBW, weights of liver, colon n cecum were higher (P, 0.05) in BCM- n BCM ALF-fe pigs thn in CC-fe pigs. Weight-specific oxygen consumption y the liver tissue n intestinl mucos ws not influence y iet (P. 0.10). However, weight-specific oxygen consumption ws higher (P, 0.05) in the cecum musculris of pigs fe BCM- n BCM ALF thn in the CC-fe pigs. Per kg of EBW, totl oxygen uptke y the colon of BCM- n BCM ALF-fe pigs ws higher (P, 0.001) thn in CC-fe pigs. The vlues for oxygen consumption y the liver in CC- n BCM-fe pigs were similr (P. 0.10) n lower thn those in the BCM ALF-fe-pigs. In conclusion, chnges in iet composition lter energy expeniture in the liver n intestinl tissue. This ppers lrgely meite vi effects on orgn size n not vi weight-specific oxygen consumption Elsevier Science B.V. All rights reserve. Keywors: Pigs; Viscerl orgns; Oxygen consumption; Diet composition 1. Introuction Although viscerl orgns represent only out 15% of oy weight, they re reporte to ccount for lrge proportion of totl oy energy expeniture *Corresponing uthor. Tel.: , ext. 6477; fx: in frm nimls (Gill et l., 1989; Yen et l., 1989; E-mil ress: elnge@ps.uoguelph.c (C.F.M. e Lnge). Huntington, 1990; Yen, 1997). For instnce, Yen 1 Present ress: Finnfees Interntionl Lt, P.O. Box 777, (1997) estimte the contriution of portl vein- Mrlorough, Wiltshire, SN8 1XN, UK. rine orgns (PVDO) n the liver to whole / 00/ $ see front mtter 2000 Elsevier Science B.V. All rights reserve. PII: S (00)

2 230 C.M. Nychoti et l. / Livestock Prouction Science 65 (2000) niml oxygen consumption to e out 25 n 20%, cstrtes with n verge initil oy weight of respectively, in the growing pig. Two processes, kg were otine from the University of 4 1 nmely N / K pumping n protein turnover, re Guelph Arkell Swine Reserch frm for use in the known to e responsile for the high energy expeni- stuy. They were house in iniviul pens with ture y gut tissues n the liver (Loley, 1988; Kelly sltte plstic flooring in temperture-controlle n McBrie, 1989; McBrie n Kelly, 1990). room (20 228C) n llowe to pt to their new Stuies with ruminnt nimls show tht these environment n iets for minimum of 3 weeks processes re influence y feeing level n iet efore mesurement of in vitro oxygen consumption composition (Burrin et l., 1990; Kelly et l., 1993; in selecte orgns. Finegn, 1996). Diets tht re high in fire or other Three iets, se on either CC, BCM or BCM nti-nutritionl fctors re lso known to increse the ALF, were use in this experiment (Tle 1). The mount of enogenous gut nitrogen losses in pigs iets were formulte to meet or excee require- (Butts et l., 1993; Boisen n Moughn, 1996; ments for vitmins n minerls (NRC, 1998) n to Nychoti et l., 1997). The ltter my lso e contin similr igestile energy to crue protein relte to energy expeniture in gut tissues. rtio (0.88 MJ DE per percentge point of iet crue Diet composition, n in prticulr ietry fire protein) se on ingreient compositions ccoring content, influences the mss of viscerl orgns. The to NRC (1998). Unfortuntely, the igestile energy effects of iet on energy expeniture in viscerl to nlyze crue protein rtio iffere etween iets orgns my e meite through effects in viscerl (0.83, 0.99 n 0.97 for the three iets, respectively). orgn mss or energy expeniture per unit of tissue The ltter cn likely e ttriute to the lower thn mss. For exmple, Pon et l. (1988) n Jørgensen nticipte protein level in the rley use in the et l. (1996) showe tht feeing high fire iets BCM n BCM ALF iets. Pigs were given their increse viscerl orgns mss n intestinl length ily fee llownce in two equl mounts (t 0800 reltive to empty oy weight (EBW) compre n 2000 h) n intke ws restricte to 2.6 times the with those fe low fire iets. However, in these mintennce energy requirement (ARC, 1981). Durstuies, effects on energy expeniture per unit of ing the lst 3 ys prior to tissue smpling time, the tissue mss were not etermine. feeing scheule ws chnge to feeing every 3 h The present stuy ws unertken to etermine in so s to minimize fluctutions in nutrient metolism vitro oxygen consumption y viscerl orgns in in viscerl orgns (Loley et l., 1992). growing pigs fe iets se on csein-corn strch (CC) n rley-cnol mel (BCM), known to 2.2. Generl conuct of the stuy inuce low or high enogenous gut nitrogen losses, respectively (Nychoti et l., 1997). A thir, more Five pigs were rnomly ssigne to ech of the extreme iet, se on BCM lflf (BCM ALF), three iets. For the mesurement of in vitro oxygen ws inclue in the present stuy to ccentute the consumption, three pigs were kille per y for 5 influence of iet on gut metolism. The effect of consecutive ys y n intr-cric injection of 10 iet on orgn weights ws lso ssesse. ml ose of soium pentoritone (Euthnl; 300 mg/ml). On ech y, one pig from ech tretment ws picke t rnom n kille 1 h fter feeing. A 2. Mterils n methos time intervl of 3 h ws llowe etween nimls. Smples of liver (left lterl loe), jejunum (2 m 2.1. Animls, housing n iets from stomch), colon (40 cm from cecum) n cecum were tken immeitely fter eth, clene The use of nimls in this stuy ws reviewe n with ice-col Kres Henseleit uffer n plce in pprove y the Animl Cre Committee of the fresh ice-col Kres Henseleit uffer for trnsport to University of Guelph n nimls were cre for the lortory. Mesurement of oxygen consumption ccoring to the guielines of the Cnin Council strte within 20 min of slughter n ws comon Animl Cre. Fifteen growing mle Yorkshire plete in pproximtely 1 h. Duplicte susmples

3 C.M. Nychoti et l. / Livestock Prouction Science 65 (2000) Tle 1 Formultion (g kg Ingreient 21 ), clculte DE content n nlyze composition of the experimentl iets (s fe sis) Diet Csein-corn Brley-cnol Brley-cnol strch mel mel 1 lflf mel Alflf mel 300 Brley Cnol mel Csein Corn strch Sucrose Limestone 6 12 Diclcium phosphte Ft (A/ V len) Ioize slt Vitmin premix Minerl premix Alffloc 20 Clculte DE (MJ/ Kg) Anlyze composition Dry mtter Crue protein Crue fire ADF NDF Vitmin premix supplie (mg kg of finishe fee): retinyl plmitte 5 6.6; choleclciferol ; ll-rc--tocopherol ; menione 5 3.0; choline chlorie ; pntothenic ci ; rioflvin 5 6.0; folic ci 5 2.4; nicotinmie ; thimin 5 1.8; pyrioxine 5 1.8; iotin ; cynocolmin Minerl premix supplie (mg kg of finishe fee): Cu ; Zn ; Fe ; Mn ; I 5 0.3; Se (15 30 mg fresh weight) of liver (thin slices), intct ech gut segment ws issecte, lotte n then mucos (from ech gut segment) n musculris weighe efore scrping off the mucosl tissue using (from cecum only) were issecte out uner 3 10 microscope slie. The mucos n musculris mgnifiction, lotte ry n weighe. Smples tissues were weighe seprtely prior to etermining were then plce in 4 ml of M199 meium (Sigm DM contents y oven rying t 1008C for 12 h Chemicls, St. Louis, MO, USA; meium contine (AOAC, 1990). The ltter vlues were use in Erlies slts, L-glutmine n HEPES uffer) n clculting the totl ry weight of mucos n oxygen consumption ws mesure. The tissues were musculris, respectively, in the gut segments. The mintine t ph 7.4 n 378C uring the mesure- rest of the liver n segments of the gut were clene ment of oxygen uptke for 10 min (Kelly et l., of igest n weighe. 1993). In vitro oxygen uptke ws mesure polrogrphiclly using Clrk-style oxygen electroe 2.3. Clcultions n sttisticl nlysis (Yellow Springs Instruments Inc., Yellow Springs, OH, USA). The ry mtter (DM) contents of the Oxygen consumption ws clculte n exsmples use in etermining the oxygen uptke were presse either s ml of oxygen per g of tissue DM estimte from vlues etermine in similr smples per h (weight-specific oxygen consumption) or s (40 50 mg) tken from the sme loction in the totl ml of oxygen consume y ech orgn per h smple orgns. Another lrger ( 2.5 g) section of reltive to EBW. Weight-specific oxygen consump-

4 232 C.M. Nychoti et l. / Livestock Prouction Science 65 (2000) tion etermine in the cecum musculris ws were otine, ifferences etween mens were ssume to e the sme s tht in the musculris of compre using Duncn s multiple rnge test (Steel the smll intestine n colon for the purposes of n Torrie, 1980). Tretment mens were consiere clculting totl oxygen consumption (Finegn, significntly ifferent t P, ). For clculting EBW, it ws ssume tht gut fill in the CC-, BCM- n BCM ALF-fe pigs ws 3, 5 n 8.2% of BW, respectively (Mohn n e 3. Results Lnge, unpulishe oservtions; Jørgensen et l., 1996). Reltive orgn weights (g/ kg EBW) were All pigs ppere helthy n reily consume clculte y iviing the weight of ech orgn y ll their fee throughout the experiment. The CC- EBW. The t were sujecte to nlysis of vri- n BCM-fe pigs h similr oy weights n nce using the generl liner moels proceure of the EBW t the en of the stuy n were hevier Sttisticl Anlysis System (1985) with iet s the (P, 0.01) compre with those fe the BCM ALF source of vrition. When significnt iet effects iet (Tle 2). With the exception of the smll Tle 2 Boy weight n viscerl orgn weight of growing pigs fe csein-corn strch-(cc), rley-cnol mel-(bcm) or rley-cnol mel lflf mel (BCM ALF)-se iets e Item Diet S.E.M. CC BCM BCM ALF Initil oy weight (kg) Finl oy weight (kg) Empty oy weight (kg) c Wet orgn weights (g kg empty oy weight) Liver Smll intestine Colon Cecum Totl GIT 41.3, c Dry orgn weights (g kg empty oy weight) Liver 4.97, Smll intestine Colon Cecum Totl GIT c Dry weight-mucos (g kg empty oy weight) Smll intestine Colon Cecum c Dry weight-musculris (g kg empty oy weight) Smll intestine Colon Cecum , Mens in the sme row with ifferent superscripts iffer (P, 0.05). c Assume contriution of gut fill to oy weight: 3, 5 n 8.2% for the CC-, BCM- n BCM ALF-fe pigs, respectively (Mohn n e Lnge, unpulishe oservtions; Jørgensen et l., 1996). Gstrointestinl trct; exclues the stomch. e Poole stnr error of the men (N 5 5).

5 C.M. Nychoti et l. / Livestock Prouction Science 65 (2000) intestine, the BCM- n BCM ALF-fe pigs h Tle 3 hevier (P, 0.05) viscerl orgns reltive to EBW In vitro weight-specific oxygen consumption (ml/ g DM/ h) y the liver n gstrointestinl trct mucos n musculris tissues in compre with those fe the CC iet (Tle 2). On growing pigs fe csein-corn strch-(cc), rley-cnol mel- DM sis, the effect of iet on the reltive weights (BCM) or rley-cnol mel lflf mel (BCM ALF)-se of viscerl orgns ws significnt only in the liver iets (P, 0.05) n colon (P, 0.01). However, numeri- Tissue Diet S.E.M. clly, it ws lrger in the smll intestine, cecum n CC BCM BCM ALF totl gut of BCM ALF-fe pigs thn CC-fe pigs. The mucosl tissue in the colon of BCM- n Liver BCM ALF-fe pigs ws hevier (P, 0.01) thn in Mucosl tissue the CC-fe pigs (Tle 2). In the cecum, there ws Jejunum tenency (P, 0.067) towrs hevier mucosl Colon tissue in BCM ALF-fe pigs compre with CC-fe pigs. In the musculris tissue, iet ws significnt Cecum Musculris tissue (P, 0.05) only in the smll intestine; musculris c c Cecum tissue ws hevier in the BCM ALF-fe pigs thn in BCM- n CC-fe pigs, oth of which were similr. Poole stnr error of the men (N 5 5). Mens in the sme row with ifferent superscripts iffer The reltive contriution of mucos to the totl ry (P, 0.05). weight of the gut segments ws influence y iet in the jejunum (P, 0.05) n colon (P, 0.01), ut not in the cecum (P. 0.10). The ry mucos weight represente (men6s.e.) , Tle n of the totl ry Totl in vitro oxygen consumption (ml/ h/ kg empty oy weight) weight of the jejunum in CC-, BCM- n BCM y the viscerl orgns n gstrointestinl mucos n musculris ALF-fe pigs, respectively. These respective vlues tissues in growing pigs fe csein-cornstrch-(cc), rley cnol mel-(bcm) or rley-cnol mel lflf mel (BCM ALF)- were , n se iets in the colon. In the cecum, the ry mucos weight Tissue Diet S.E.M. s proportion of the totl ry cecum weight verge cross tretments. CC BCM BCM ALF Dietry tretment i not influence weight-specific Liver c c oxygen consumption in the liver or mucosl tissue of Smll intestine c jejunum, colon n cecum (P. 0.10, Tle 3). Colon Cecum Weight-specific respirtion in the musculris tissue Totl GIT ws higher (P, 0.05) in the BCM- n BCM ALFfe pigs, compre with the CC-fe pigs (Tle 3). Mucosl tissue Per kg of EBW, totl oxygen consumption ws Smll intestine c ffecte y ietry tretment in the liver (P, 0.05) Colon n colon (P, 0.001), n ws numericlly higher Cecum in the cecum n totl gut of BCM- n BCM Musculris tissue c c, ALF-fe pigs compre with CC-fe pigs (Tle 4). Smll intestine c Totl oxygen consumption y the liver in CC- n Colon c c, BCM-fe pigs were similr (P. 0.10) n lower Cecum (P, 0.05) thn in the BCM ALF-fe-pigs. Totl Assume contriution of gut fill to oy weight: 3, 5 n oxygen consumption y the mucosl tissue of the 8.2% for the CC-, BCM- n BCM ALF-fe pigs, respectively colon ws lower (P, 0.05) in the CC-fe pigs thn (Mohn n e Lnge, unpulishe oservtions; Jørgensen et l., 1996). in the BCM- n BCM ALF-fe pigs, which in turn Poole stnr error of the men (N 5 5). were similr (P. 0.10). Diet composition h no c, Mens in the sme row with ifferent superscripts iffer effect (P. 0.10) on the totl mount of oxygen (P, 0.05).

6 234 C.M. Nychoti et l. / Livestock Prouction Science 65 (2000) consume y mucosl tissue of the smll intestine sen et l., 1996). Per kg EBW, the wet weights of n cecum, lthough vlues for the cecum mucos colon n cecum rnge from 15.5 to 17.5 n 2.22 in the BCM- n BCM ALF-fe pigs were numeri- to 2.94 g, respectively, which grees closely with the clly higher thn in the CC-fe pigs (Tle 4). vlues (17.23 n 2.83 g, respectively) reporte y Dietry tretment ffecte (P, 0.05) the clculte Jørgensen et l. (1996) for pigs fe high fire iets. totl mount of oxygen consume y the musculris The weights of the smll intestine reltive to EBW tissue of the smll intestine, colon n cecum were not ffecte y iet composition n were (Tle 4). The musculris tissue of ll segments in much higher in the present stuy compre with the the BCM ALF-fe pigs consume higher (P. 0.05) vlues oserve y Jørgensen et l. (1996) 32.8 vs. mounts of oxygen thn in the CC-fe pigs g kg EBW). This lrge ifference in smll intestine weight etween stuies my prtly e ttriute to pig genotype effects. For exmple, 4. Discussion Quiniou n Nolet (1995) emonstrte lrger ifferences in weights of viscerl orgns etween pig Previous reserch inictes tht the liver n genotypes fe similr iets n t similr oy PVDO ccount for 25 n 20% of whole niml weight. The BCM n BCM ALF iets, which h oxygen consumption, respectively, lthough they reltively more fire content thn the CC iet, h represent only out 15% of oy weight in growing the gretest impct on the cecum n colon. The pigs (Yen et l., 1989; Yen n Niener, 1992; Yen, ltter is most likely ue to the istension n 1997). Feeing pigs iets tht increse orgn mss lengthening of the hingut where most of the firous will concomitntly le to increse energy expeni- fee components re igeste vi microil fermenture in viscerl orgns s reporte y Pon et l. ttion (Pon et l., 1988; Jørgensen et l., 1996; (1988) n Jørgensen et l. (1996). It is uncler Rert, 1996). whether this response is prtly meite through In the present stuy, the impct of iet on the chnges in energy expeniture per unit of tissue evelopment of the mucsculris n mucos tissue of mss. This informtion is importnt in etermining if the intestines ws lso exmine. The oserve ry mesurements of only orgn mss in future stuies jejunl mucos weight contriute to pproximtely will e sufficient for preicting energy expeniture in of the totl jejunl ry weight; this vlue viscerl orgns. grees closely with vlues of reporte in In previous stuies it ws estlishe tht enog- sheep fe concentrte-se iets (Rompl n enous gut nitrogen losses n rtes of gut protein Hogln, 1987; Finegn, 1996). The contriution of synthesis in the colon were higher in pigs fe BCM mucosl ry weight to the totl ry weight in the thn CC iets (Nychoti et l., 1997; Nychoti, colon of sheep (rnge ) reporte y 1998). Becuse the sme iets were use in the Finegn (1996) is somewht lrger thn tht seen in current stuy, ssocitions etween these previously the present stuy. The oserve trens in mucosl mesure spects of nutrient metolism n energy evelopment re consiste with the effects of iet expeniture in viscerl orgns coul e estlishe. composition on the site of igestion n nutrient In the present stuy, ll pigs were kille 1 h post sorption when pigs re fe the type of iets use in feeing for mesurement of oxygen uptke pproxi- the current experiment (Rert, 1996). The CC iet is mtely 2 h fter feeing; this is time intervl tht highly igestile t the ilel level (Nychoti et l., correspons to the intervl use in the protein 1997) n is likely to e ssocite with more synthesis stuy (Nychoti, 1998; Nychoti et l., evelopment of the mucos in this segment of the 1998). gut, thus fcilitting nutrient sorption. Reltively, In the current stuy, BCM- n BCM ALF-fe lrger proportion of the BCM n BCM ALF iets pigs h hevier viscerl orgns thn CC-fe pigs. is igeste y microil fermenttion in the hin gut This is consistent with previous reserch suggesting n specificlly in the colon, which stimulte tht feeing prcticl high fire iets cuses n mucosl evelopment in this segment of the gut increse in viscerl orgn mss in rts, pigs n (Pon et l., 1988; Jørgensen et l., 1996; Rert, sheep (Kelly et l., 1993; Zho et l., 1995; Jørgen- 1996).

7 C.M. Nychoti et l. / Livestock Prouction Science 65 (2000) The lck of iet composition effects on weight- current stuy) is much higher thn in mture slow specific oxygen consumption in mucos tissues growing niml (s s for those use in the sheep oserve in the present stuy is in goo greement stuies). with results of previous stuies with their livestock Previous reserch (Burrin et l., 1990; Kelly et l., species (Burrin et l., 1990; Kelly et l., 1993; 1993; Finegn, 1996) with sheep hs shown tht totl Finegn, 1996). The higher weight-specific oxygen gut oxygen consumption is ffecte more y mss consumption y the musculris tissue of pigs fe the chnges thn y weight-specific oxygen consump- BCM ALF n BCM iets thn in pigs fe the CC tion. The present t re in line with these oserviet is likely to e reflection of the mount of tions, prticulrly with respect to totl oxygen con- (unigeste) mteril tht is move through the sumption in the liver n colon. As iscusse erlier, igestive trct. Due to constrints on equipment, it the higher oxygen consumption in the musculris ws not possile to mesure oxygen consumption in tissue of the GIT segments of BCM- n BCM the musculris tissue t the vrious loctions in the ALF-fe pigs compre with the CC-fe pigs ws intestine. For clculting totl oxygen consumption likely ue to ifferences in the mount of effort in the smll intestine n colon, it ws ssume tht require to move igest through the igestive trct. weight-specific oxygen consumption ws similr s An increse motor ctivity in the colons of pigs fe tht in the cecum musculris which is in etween iets with low igestiilities hs een reporte the smll intestine n the colon. However, totl (Fiormonti n Bueno, 1980). clculte oxygen consumption in the vrious gut The higher totl oxygen consumption y the colon segments is rther insensitive to vrition in weight- oserve in the BCM- n BCM ALF-fe pigs in specific oxygen consumption in musculris tissue. the present stuy (Tle 4) compre with the CC- This is ecuse of the reltively smll contriution of fe pigs, n higher totl oxygen consumption y the musculris tissue weight to totl intestinl weight liver in BCM ALF-fe pigs thn in the two other n the low weight-specific oxygen consumption in tretment groups, support erlier finings tht feemusculris tissue s compre with mucos tissue. ing high fire iets increses oxygen consumption y Moreover, oxygen consumption ws only mesure viscerl orgns. Although iet composition i not in one specific segment of the liver, smll intestine, ffect weight-specific oxygen consumption in viscercolon n cecum. Since the metolic rte my l orgns, totl oxygen consumption ws ffecte iffer etween the segments of these tissues, reltive, minly ecuse of iet effects on orgn size. These rther thn solute, ifferences in in vitro oxygen results suggest tht feeing iets tht increse orgn consumption etween tretments shoul e consi- mss will lso le to increse energy expeniture ere. y these orgns. This increse in energy expeniture To our knowlege, similr t on in vitro oxygen my e ssocite with increse protein synthesis consumption in the intestine n liver re not rtes in viscerl orgns n enhnce enogenous ville for pigs. Weight-specific in vitro oxygen gut nitrogen losses when pigs re fe iets tht consumption y mucosl tissue in the intestine of increse viscerl orgn mss (Nychoti et l. 1997, sheep fe either forge- or concentrte-se iets 1998). These oservtions inicte tht employing for 8 weeks ws reporte y Finegn (1996) to e feeing strtegies tht reuce viscerl orgn mss 7.56 vs in the jejunum, 4.79 vs in the cn increse the efficiency of converting ietry cecum n 5.77 vs ml/g/h in the colon, energy n protein into eile pork proucts. respectively. The t otine in the current stuy grees closely with the results seen in the colon n cecum ut not in the jejunum. Species ifferences 5. Conclusion n ifferences in the stge of evelopment n growth rtes my explin the ifferences in weight- Diet composition hs no effect on weight-specific specific oxygen consumption seen in the jejunum of energy expeniture y the liver, smll intestine, pigs compre with the vlues reporte for the colon n cecum. However, the totl mount of sheep. It is likely tht the emn for nutrient supply energy expene y liver n colon is influence y in young fst growing pig (s for those use in the iet composition minly ecuse of iet composition

8 236 C.M. Nychoti et l. / Livestock Prouction Science 65 (2000) effects on the orgn mss. Such effects my le to mechnisms of thermogenesis in selecte tissues. Proc. Nutr. Soc. 48, sustntil increse in the lrey isproportionl Kelly, J.M., Southorn, B.G., Kelly, C.E., Millign, L.P., McBrie, contriution of these orgns to whole oy energy B.W., Quntifiction of in vitro n in vivo energy expeniture, thus reucing the efficiency of convert- metolism of the gstrointestinl trct of fe or fste sheep. ing ietry energy into eile pork proucts. Cn. J. Anim. Sci. 73, Loley, G.E., Protein turnover n energy metolism in nimls: interctions in lenness n oesity. In: Leclerq, B., Whitehe, C.C. (Es.), Lenness in Domestic Birs. Genetic, Acknowlegements Metolic n Hormonl Aspects. Butterworths Co INRA, pp Loley, G.E., Hrris, P.M., Skene, P.A., Brown, D.S., Milne, E., We thnk Lin Trouten-Rfor, Mnfre Hnsel Cler, A.G., Anerson, S.E., Grlick, P.J., Nevison, I., Conn Kim Couenys for their excellent technicl nell, A., Responses in tissue protein synthesis to su- n ssistnce. Finncil support ws provie y Finlrge supr-mintennce intke in ruminnt lms: comprison of nfees Interntionl, Mrlorough, UK n the Ntu- ose n continuous infusion techniques. Br. J. Nutr. 68, rl Sciences n Engineering Reserch Council of McBrie, B.W., Kelly, J.M., Energy cost of sorption n Cn. metolism in the ruminnt gstrointestinl trct n liver: review. J. Anim. Sci. 68, NRC, Nutrient Requirements of Swine, 9th Eition. Ntionl Acemy Press, Wshington, DC. References Nychoti, C.M., Nutritionl Significnce of Enogenous Gut Nitrogen Losses in Growing Pigs. University of Guelph, AOAC, Officil Methos of Anlysis, 15th Eition. As- Guelph, Ontrio, Cn, PhD Thesis. socition of Officil Anlyticl Chemists, Arlington, VA. Nychoti, C.M., e Lnge, C.F.M., McBrie, B.W., Effect of Agriculturl Reserch Council, The Nutrient Requirements iet composition on frctionl rtes of protein synthesis in the of Pigs. Commonwelth Agriculturl Bureu, Slough, UK. viscerl orgns of growing pigs. J. Anim. Sci. 76 (Suppl. 1), Boisen, S., Moughn, P.J., Dietry influences on enogen- 171, Astrct. ous ilel protein n mino ci loss in the pig review. Nychoti, C.M., e Lnge, C.F.M., Schulze, H., Estimting Act Agric. Scn. Sect. A. Animl Sci. 46, enogenous mino ci flows t the terminl ileum n true Burrin, D.G., Ferrel, C.L., Britton, R.A., Buer, M.L., Level ilel mino ci igestiilities in feestuffs for growing pigs of nutrition n viscerl orgn size in sheep. Br. J. Nutr. 64, using the homorginine metho. J. Anim. Sci. 75, Nychoti, C.M., e Lnge, C.F.M., McBrie, B.W., Schulze, H., Butts, C.A., Moughn, P.J., Smith, W.C., Reynols, G.W., Grrick, Significnce of enogenous gut protein losses in the D.J., The effect of foo ry mtter intke on the nutrition of growing pigs: review. Cn. J. Anim. Sci. 77, enogenous ilel mino ci excretion etermine uner peptie limenttion in the 50 kg liveweight pig. J. Sci. Foo Pon, W.G., Jung, H.G., Vrel, V.H., Effects of ietry fire Agric. 62, on young ult geneticlly len, oese n contemporry pigs: Finegn, E.J., The Role of Gut Tissue in Energy Meto- oy weight, crcss mesurements, orgn weights n igest lism of Growing Lms Fe Forge or Concentrte Diets. content. J. Anim. Sci. 66, University of Guelph, Guelph, Ontrio, Cn, MSc Thesis. Quiniou, N., Nolet, J., Preiction of tissulr oy com- Fiormonti, J., Bueno, L., Motor ctivity in the lrge position from protein n lipi eposition in growing pigs. J. intestine of the pig relte to ietry fire n retention. Br. J. Anim. Sci. 73, Nutr. 43, Rert, A., Influence of the nture of crohyrte intke on Gill, M., Frnce, J., Summers, M., McBrie, B.W., Millign, L.P., the sorption chronology of reucing sugrs n voltile ftty Simultion of the energy costs ssocite with protein cis in pigs. Repro. Nutr. Dev. 36, turnover n N,K -trnsport in growing lms. J. Nutr. 119, Rompl, R.E., Hogln, T.A., Effect of level of liment tion on viscerl orgn mss n morphology n N 1,K 1 Huntington, G.B., Energy metolism in the igestive trct enosinetriphosphtse ctivity of intestinl mucos in lms. n liver of cttle: influence of physiologicl stte n nutri- J. Anim. Sci. 65, tion. Repro. Nutr. Dev. 30, Sttisticl nlysis system. In: SAS User s Guie: Sttistics, Jørgensen, H., Zho, X.-Q., Eggum, B.O., The influence of Version 5. SAS Institute Inc, Cry, NC. ietry fire n environmentl temperture on the evelop- Steel, R.G.D., Torrie, J.H., Principles n Proceures of ment of the gstrointestinl trct, igestiility, egree of Sttistics: A Biometric Approch, 2n Eition. McGrw-Hill fermenttion in the hin-gut n energy metolism in pigs. Book Compny, New York, NY. Br. J. Nutr. 75, Yen, J.T., Oxygen consumption n energy flux of porcine Kelly, J.M., McBrie, B.W., The soium pump n other splnchnic tissues. In: Lplce, J.P., Fevrier, C., Breu, A.

9 C.M. Nychoti et l. / Livestock Prouction Science 65 (2000) (Es.), Proceeings of the VIIth Interntionl Symposium on consumption y portl vein-rine orgns n y whole Digestive Physiology in Pigs. INRA, St-Gilles, Frnce, pp. niml in conscious growing swine. Proc. Soc. Exp. Biol. Me , EAAP Puliction No , Yen, J.T., Niener, J.A., Influence of crox on fsting Zho, X.-Q., Jørgensen, H., Eggum, B.O., The influence of oxygen consumption y portl vein-rine orgns n y the ietry fire on oy composition, viscerl orgn weight, whole niml in growing pigs. J. Anim. Sci. 70, igestiility n energy lnce in rts house in ifferent Yen, J.T., Neiner, J.A., Hill, D.A., Pon, W.G., Oxygen therml environments. Br. J. Nutr. 74,