effect of protein and lysine levels in the diet on body gain

J. Noblet, Y. Henry and S. Dubois

Composition and Energy Utilization in Growing PigsEffect of Protein and Lysine Levels in the Diet on Body Gain

1987. 65:717-726. J Anim Sci

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EFFECT OF PROTEIN AND LYSINE LEVELS IN THE DIET ON BODY GAIN COMPOSITION AND ENERGY rUTILIZATION IN GROWING PIGS 1

J. Noblet, Y. Henry and S. Dubois 2

Institut National de la Recherche Agronomique St. Gilles 35590 l'Hermitage, France

ABSTRACT

Eight replicates of four Large White littermate female pigs were used to evaluate the effect of protein and lysine levels in the diet on the efficiency of protein and energy utilization. In each replicate, one pig was slaughtered at about 20 kg live weight and the others received three diets that contained (per Meal digestible energy) 37.5 and 2.00 g (diet pl), 37.5 and 2.35 g (diet pL) or 45.0 and 2.35 g (diet PL) of digestible protein and lysine, respectively. Pigs were slaughtered after a 7-wk period. Tissue and chemical composition of the gain and energy and nitrogen gain were determined by using the comparative slaughter technique. Metabolizable energy (ME) intakes were similar in the treatments. Pigs fed the pl diet had a smaller body weight and muscle gain and retained less nitrogen and more lipids than pigs fed pL and PL diets. The decrease in the level of nonessential nitrogen in the diet (pL vs PL) did not affect body weight and muscle gain and the amount of nitrogen retained in muscle tissues. However, pigs given the PL diet had a higher total nitrogen retention and a lower fat deposition and exhibited a higher heat production. For each gram of additional protein catabolized for energy purposes (PL vs pL), heat production was increased by 1.8 kcal. The amount of lysine per unit of muscle gain (38 g/kg) or protein deposited (120 g/kg) was independent of protein and lysine levels in the diet. Estimates of energy (indirect calorimetry) and nitrogen (balance technique) retention were also obtained on the same animals; results were comparable with data obtained by direct measurements. (Key Words: Pigs, Lysine, Protein Intake, Energy Balance, Protein Balance, Body Composition.)

I ntroduction

Feed conversion efficiency and growth rate of pigs fed to appetite are not significantly affected by dietary protein or nonessential nitrogen content when the levels of essential amino acids are maintained adequate to meet the requirements (Wahlstrom and Libal, 1974; Bereskin et al., 1976; Sharda et al., 1976; Easter and Baker, 1980; Noblet et al., 1980; Stahly et al., 1981; Asche et al., 1985). How- ever, most authors have observed a tendency for increased body fatness with low protein diets. The reduction of non-essential nitrogen level in the diet is also associated with a decreased nitrogen loss in urine (Sharda et al.,

1 Appreciation is expressed to EUROLYSINE S.A., 16, rue Ballu, PARIS for providing L-lysine'HCl and DL-tryptophan and for partial funding of this study.

a The authors gratefully acknowledge P. Ecolan, M. Fillaut, J. Lebost and A. Roger for technical assist- ance and Dr. A. J. Lewis (Univ. of Nebraska) for critical evaluation of the manuscript.

Received November 5, 1986. Accepted April 21, 1987.

1976; Russell et al., 1983) and a subsequent lower contr ibut ion of deaminated protein to ME supply. In addition, the efficiency of uti l ization of digestible nutr ients for maintenance or fat deposition is lower for deaminated protein than for carbohydrate or fat (Hoffmann and Schieman, 1971; Schulz, 1975; Just, 1982). A decrease in the dietary protein level and the subsequent enr ichment in carbohydates or fat for the same level of l imiting essential amino acid (i.e., lysine) would allow an improved efficiency of ME uti l ization, resulting in a tendency for increased carcass fatness.

The objective of the present experiment was to study the effects of a reduction in protein level with or without lysine supplementat ion on energy and nitrogen balance in growing pigs. The methods used were comparative slaughter and balance techniques (indirect calorimetry and nitrogen balance). In addition, the effects of protein and amino acid supply on tissue and chemical composit ion of weight gain also were investigated.

Experimental Procedure

Experimental Design. Eight replicates of

717 J. Anim. Sci. 1987.65:717-726


718 NOBLET ET AL.

four Large White l ittermate female pigs were used in the experiment. In each replicate, pigs were chosen at weaning (about 25 d of age), and fed individually a standard diet to equalize body weights during the post-weaning phase. At about 20 kg live weight (mean: 19.5 + .5 kg), one pig was slaughtered (control) and the three others were given three different diets composed of corn and soybean meal (table 1). Two diets (low protein - low lysine, or pl; and low protein-high lysine, or pL) supplied less protein than recommended [37.5 g digestible protein/Mcal digestible energy (DE); INRA, 1984]. Diet pl was inadequate in lysine (2.00 g/Mcal DE) while diet pL was fortified with L- lysine HC1 and DL-tryptophan to meet lysine and other essential amino acid requirements (2.35 g lysine/Mcal DE; INRA, 1984). The third diet (high protein-high lysine, or PL) had protein, lysine and other essential amino acid

levels that met or exceeded requirements (45 and 2.35 g/Mcal DE for digestible protein and lysine, respectively). After a 7-wk period, animals were slaughtered. The comparative slaughter method was used to measure the amount, nature and localization of weight gain and retention.

In addition, energy (indirect calorimetry) and nitrogen (N) balances were carried out on six of the eight replicates during three, 2-wk periods (wk 1 and wk 4, wk 2 and wk 5 and wk 3 and wk 6). Week 0 was considered as the first week of the experiment. Each animal was measured during one of these three periods, the three periods for each treatment (pl, pL or PL) being represented once in a series of three replicates. One respiration chamber was used for the experiment with successive replicates. In addition to the effect of dietary treatment, the results of the balance measurements provided

TABLE 1. COMPOSITION AND ANALYSIS OF DIETS

Diet

pl pL PL

37.5 a 37.5 a 45.0 a Item 2.00 b 2.35 b 2.35 b

Composition (%) Yellow corn 75.35 76.35 69.75 Soybean meal 16.40 16.40 21.50 Corn gluten meal 1.50 Beet molasses 3.00 3.00 3.00 Dicalcium phosphate 2.20 2.20 2.20 Calcium carbonate 1.20 1.20 1.20 Salt .50 .50 .50 Trace minerals, vitamins and amino acids mixture c .35 .35 .35

Analyzed levels (as fed) Gross energy, kcal/kg 3,827 3,833 3,849 Crude protein, % 15.3 15.3 17.8 Ash, % 5.1 5.1 5.4 Crude fiber, % 2.0 2.0 2.3 Neutral detergent fiber, % 8.2 8.1 8.1 Acid detergent fiber, % 2.2 2.3 2.3 Lipid, % 3.2 3.2 2.9 Lysine, % .67 .80 .81 Threonine, % .52 .52 .63 Tryptophan, % (calculated) .17 .17 .17

aDigestible protein, g/Mcal DE. bLysine, g/Mcal DE.

Cprovided per kg of diet: Zn, 120 rag: Fe, 44 rag; Cu, 5 nag; Co, .08 mg; Mn, 15 mg; Se, .18 mg; I, .8 mg; vitamin A, 5,000 IU; vitamin D, 1,000 IU; vitamin E, 10 IU; riboflavin, 4 mg; panthotenic acid, 10 mg; choline, 5 rag; vitamin B,2, 20 ~g; biotin, 200 #g; DL - tryptophan, .3 g (diets pl and pL); glycine, 1.5 g (diet pl); lysine, 1.5 g (1.9 g L-lysine-HCl; diet pL).


EFFECT OF DIETARY PROTEIN AND LYSINE ON PIGS 719

information about the effect of week of experiment and interaction between week of experiment and dietary treatment.

Housing and Feeding. Pigs were housed individually in fiat-deck cages in a temperature- controlled room (20 + 2 C). During energy and N balances, the pigs were kept individually in metabolism cages located in respiration cham- bers (Noblet et al., 1985). The temperature within the chamber was 22 C, this temperature being at or above the critical temperature (Close and Mount, 1978). Food was offered in dry pellets, in two meals (0900 and 1500) and adjusted each day on the basis of 120 g of feed/kg metabolic body weight (w'TS). This feeding level corresponded to 80 to 100% of ad libitum intake. Body weight was the mean of the three individual weights within a replicate. The pigs were weighed each week. Feed refusals and spillage were collected. Water was available ad libitum. For each treatment, samples of feed were collected each week and analyzed for moisture content. For each replicate, an aliquot of the feed given during the whole experiment was also prepared for analysis.

Nutrient Digestibility, N Retention and Respiratory Exchanges. Pigs were kept in the respiratory chamber for a 7-d period. Feces were collected daily, pooled and at the end of the period, weighed, mixed, subsampled and freeze-dried for analysis. Similarly, urine was collected daily, pooled and, at the end of the period, weighed and sampled for analysis. Water that condensed in the chamber was weighed and sampled at the end of the period. Finally, an aliquot of the outgoing air was bubbled through a sulfuric acid solution. Determination of N content in condensed water and outgoing air allowed determination of N losses in the air. Oxygen consumption and carbon dioxide production were measured daily. Heat production was calculated from gas exchanges and urinary N losses according to the formula proposed by Brouwer (1965).

In each replicate, feed and feces were analyzed for moisture, ash, N and fat according to AOAC (1975) methods. Gross energy was measured using an adiabatic bomb calorimeter. Nitrogen in urine, condensed water and outgoing air was measured on fresh material, whereas energy content of urine was obtained after freeze-drying approximately 50 ml in small polyethylene bags. A composite sample of each diet, obtained from the combination of samples

of the eight successive replicates was analyzed for crude fiber, cell wall components (Van Soest and Wine, 1967), amino acids and N (AOAC, 1975). Metabolizable energy (ME) intakes were calculated as the difference between energy values of feed intake and those of feces, urine and methane. Methane production was estimated from previous experiments (Noblet et al., 1985) as .4% of gross energy intake. Nitrogen retention was calculated as the difference between N intake and N in feces, urine, condensed water and outgoing air. Retained energy and its partition between protein and fat were calculated according to the method described by Noblet et al. (1985).

Comparative Slaughter Method. After a 16 h-fast, body weight (BW) was determined and animals were sacrificed by electrical stunning and exsanguination. At slaughter, blood, bristles and visceral organs were collected separately and weighed. The digestive tract was weighed after emptying. A fraction including head, feet and tail was also constituted and weighed. Each half of the eviscerated carcass was weighed immediately after slaughter and after a 20-h chilling. On the day after slaughter, one-half of each carcass was dissected in four fractions: muscles (including intermuscular fat), adipose tissues, skin and bones. These different fractions were weighed and placed in plastic bags and stored at -20 C. For each pig, the different fractions were finely ground and homogenized separately. From homogenates of these fractions, aliquots of the following compartments were prepared: muscles, carcass (muscles, fatty tissues, skin and bones), non-carcass (blood, bristles, organs and head + feet + tail) and empty body weight (EBW: carcass + non-carcass). Each compartment was analyzed for dry matter, ash, N, ether extract (referred to as lipid) and gross energy according to AOAC (1975) methods. Protein content was estimated as 6.25 times the N content. Finally, an aliquot of freeze-dried samples of empty body was constituted for each dietary treatment (eight pigs/sample) and analyzed for amino acid content.

Anatomical and chemical composition of experimental animals at the beginning of the experiment were calculated for each replicate from composition of the control littermate. It was assumed that the composition of EBW and the ratio EBW: BW were identical for littermates. The weight and amount of nutrients and energy


720 NOBLET ET AL.

in the different compartment gains were obtained as the differences between the values measured on experimental animals at the end of the experiment and those predicted at the beginning of the experiment.

Two feces and urine collections were carried out on each animal during the respiration chamber trials. Digestible energy and ME content of each diet over the 7-wk experimental period were calculated for each pig as the mean of both values thus obtained. Heat production (comparative slaughter method) was then com- puted as the difference between ME intake and retained energy in the empty body. Results are expressed either as kcal/d or kca l .d - t .kg

W -'Ts . Metabolic body weight corresponded to the mean of weekly metabolic body weights.

Statistical Analysis. Within each replicate, there were differences in ME intake between animals due to feed spillage or refusals and to the slightly higher ME content of PL diet. The data were therefore adjusted and analyzed by covariance with ME intake (kcal/d or kcal-d -1 -kg W -'Ts ) as a covariate. Main effects considered in the analysis were dietary treatments and replicates. The effect of stage of growth (i.e., week number) was tested in the balance technique data. Newman-Keuls' multi- ple range test was used to partition treatment means.

R esu Its

Apparent digestibility of energy and N

increased (P.10) of an interaction between treatment and week number, the pooled data for each dietary treatment are presented in table 2. Digestibility coefficients of energy and N were higher for diet PL, the difference being significant only for N. This resulted in higher DE (P


The amount of lysine per kg muscle gain was not affected by dietary treatments and ranged from 37 to 39 g.

At similar daily ME intakes, daily retention of dry matter and ash, as determined by the comparative slaughter technique, were not affected (P>.10) by dietary treatment (table 4). Addit ion of lysine to the pl diet resulted in an increase in protein deposit ion (P

722 NOBLET ET AL.

TABLE 4. EFFECT OF DIETARY PROTEIN AND LYSINE LEVELS ON NUTRIENT BALANCE AND CHEMICAL COMPOSITION OF GAIN IN GROWING PIGS

(COMPARATIVE SLAUGHTER TECHNIQUE)

Diet

Item pl pL PL SD a

Daily retention Dry matter, g 297.3 307.4 300.9 Protein, g 90.9 c 103.9 d 110.1 e Ash, g 17.6 20.3 20.0 Lipid, g 186.8 c 175.3 d 167.7 d Energy, kcal 2,254 2,257 2,191

Empty body gain, composition Dry matter, % 47.40 c 44.75 d 44.59 d Protein, % 14.52 c 15.50 d 16.20 d Ash, % 2.81 3.04 2.90 Lipid, % 29.72 c 25.65 d 25.12 d Energy, kcal/kg 3,589 e 3,315 cd 3,267 d

Carcass gain, composition b Dry matter, % 51.55 c 48.68 d 49.19 d Protein, % 14.72 c 16.24 d 16.34 d Ash, % 2.83 2.90 2.81 Lipid, % 34.18 c 29.20 d 29.40 d Energy, kcal/kg 4,046 c 3,693 d 3,710 d

4.9 4.7 2.3 9.0

75

1.92 .62 .34

2.30 218

1.90 .78 .20

2.50 21

astandard deviation.

bchilled carcass.

c'd'eMeans on the same line with superscripts that do not have a common letter differ (P


values obta ined in mature rats or pigs (Hoff- mann and Schiemann, 1971) or calculated f rom biochemical models (Schulz, 1975), conf i rm that the eff ic iency of ut i l izat ion of ME f rom protein for maintenance or fat deposit ion is lower than f rom carbohydrates. However, the addit ional heat loss varies between .6 and .9 kcal/g. The dif ference between both sets of data suggests that the metabol ism of animals is also affected by the level of non-essential N in the diet. This hypothes is is consistent with the higher prote in turnover associated with an increased protein supply (Reeds et al., 1981). In addit ion, the mass of visceral organs and b lood seems to be higher in pigs fed a high protein diet (Stahly et al., 1979; present results). Considering that heat loss associated with maintenance requi rements is highly correlated with the importance of such meta-

bol ical ly active tissues (Koong et al., 1982; Tess et al., 1984), pigs fed the PL diet would then exhib i t a higher heat product ion related to maintenance requirements.

Our data show that in order to achieve similar ME intakes, pigs fed the PL diet must be given 41 kcal more DE per day than pigs fed the pL diet. This di f ference corresponds to the energy content of addit ional loss of ammonia in ur ine (i.e., equivalent to 36 g of protein). In other words, energy loss in ur ine was increased by about 1.1 kcal for each addit ional gram of prote in deaminated. Just (1982) and J. M. Perez (personal communicat ion) found similar values in growing pigs.

Degradat ion of digestible prote in in excess of requi rements for energy purposes results, therefore, in an increased energy loss in urine and an elevated heat loss associated with

TABLE 5. EFFECT OF DIETARY PROTEIN AND LYSINE LEVEL ON NITROGEN AND ENERGY BALANCE IN GROWING PIGS (COMPARATIVE SLAUGHTER TECHNIQUE)

Diet

Item pl pL PL SD a

Nitrogen balance Lysine intake, g/d 10.8 d 12.8 e 12.9 e Nitrogen intake, g/d 39.4 d 39.4 d 45.6 e Nitrogen retained, g/d 14.5 d 16.7 e 17.8 f

% of N digested 44.4 d 52.0 e 44.8 d % of N intake 36.9 d 43.1 e 38.6 e

Nitrogen retained In carcass, g/d 11.4 d 13.6 e 13.7 e In muscles, grid 8.2 d 10.1 e 10.2 e

Energy balance (kcal/d) DE intake 5,456 d 5,450 d 5,491 e ME intake 5,264 5,264 5,264 Retained energy 2,254 2,257 2,190

% of DE 41.3 41.5 39.9 % of ME 42.8 42.9 41.7 As protein b 518 d 592 e 633 f As fat c 1,736 d 1,665 de 1.557 e

Heat production 3,010 3,007 3,074 Mean BW "~s 13.96 d 14.34 e 14.40 e

Energy balance (kcalokg W -'Ts -d - l ) DE intake 383.4 d 383.0 d 385.8 e ME intake 369.8 369.8 369.8 Retained energy 156.1 159.5 155.7

As protein 37.5 d 41.1 e 43.6 f As fat 118.5 d 118.3 d 112.1 e

Heat production 213.8 210.4 214.2

.2

.6

.7 3.2 2.6

.6

.5

16

75

1.4 27 93 75

.16

1.1

5.1 1.7 6.2 5.1

astandard deviation.

bCalculated as protein gain X 5.7.

CCalculated as retained energy - energy retained as protein.

d'e'fMeans on the same line with superscripts that do not have a common letter differ (P

724 NOBLET ET AL.

TABLE 6. COMPARISON OF ENERGY BALANCE DATA OBTAINED FROM RESPIRATORY CALORIMETRY AND COMPARATIVE SLAUGHTER TECHNIQUES

Indirect Comparative slaughter Item calorimetry a technique b

Mean BW "Ts , kg 15.2 14.3 ME intake, kcal.kg W -'Ts -d -1 375.3 (374.8) c 374.8 Retained energy, kcal,kg W -'~s .d -1 174.3 (171.9) c 158.1

As protein 46.6 40.9 As fat 127.7 117.2

Heat production, kcal.kg W -'Ts .d -1 201.0 (202.9) c 216.7 N intake, g/d 44.7 (42.0) d 42.0 Nrctained, g/d 19.6 (18.5) d 16.5 N losses, g/d 25.1 (23.5) d 25.5

aFrom wk 1 to 6; 36 measurements on 18 animals (two per pig). bFrom wk 0 to 6; 18 measurements on 18 animals.

CExtrapolated to 7 wk of experiment (+ 4 kcal/kg W "~s per wk of experiment) and 374.8 kcal ME intake (.3 kcal heat production per additional kcal ME). (J. Noblet and C. Karege, unpublished data).

dcorrected to 42.0 g/d N intake and assuming that the ratio N retained:N intake is 40% (table 5).

utilization of ME and changes in metabolism. To obtain a similar energy retention in the pL and PL treatments, pigs fed the PL diet would require a daily supplement of 97 and 140 kcal ME and DE, respectively (assuming that the efficiency of ME utilization for energy deposition is 70% in both treatments and that the ME:DE ratio is equivalent to the values presented in table 2). These values represent 1.9 and 2.6% additional ME and DE, respectively, or about .8 and 1.0% more ME and DE, respectively per one percentage increase in protein level. However, the energy sparing effect due to reduced nonessential N level in the diet increases fat deposition (present experiment). There- fore, it will produce small effects on growth rate (about 11 g of fat between treatments pL and PL, table 5). Consequently, even if the reduction of protein level in the diet is associated with a better efficiency of utilization of ME as shown by Just (1982) and as found in our experiment, it does not significantly affect feed efficiency (Russell et al., 1983; present results).

A decreased level of nonessential N in the diet does not significantly affect growth rate or feed efficiency, but the amount of nitrogen retained in the body is lower (Sharda et al., i976; Russell et al., 1983; present experiment). In fact, muscle growth and N retained in muscles seem to be independent of the level of nonessential N per se. Therefore, N retained in

the non-carcass compartment is lower with low protein diets (table 5). Our results also show that when lysine is the limiting factor in the diet, the amount of lysine per unit of weight gain (19 g/kg), muscle gain (38 g/kg) or protein retained (120 g/kg) is constant and independent of protein and lysine levels in the diet. Similar conclusions were given by Stahly et al. (1979, 1981) and Asche et al. (1985).

Lysine content of empty body protein was similar in the three treatments and averaged 7.3%, which is close to values reported in literature (Wiesemuller and Poppe, 1974). Therefore, it can be calculated that lysine retained in the empty body represents about 60% of the lysine intake and 70% of the ileal lysine (85% availability; Laplace et al., 1985) in corn-soybean diets over the growing phase (20 to 55 kg body weight). Finally, free lysine ap- pears to be used as efficiently for growth and protein deposition as the lysine contained in protein. Nevertheless, as shown by Batterham and O'Neil (1978) and Partridge et al. (1985), there is evidence that the efficiency of utilization of free lysine is poorer when feed is given once daily compared with several meals.

In agreement with other data (Just et al., 1982), heat production as measured by the indirect calorimetry method is lower than by the comparative slaughter technique. In spite of probable systematic errors in the indirect calorimetry method (Just et al., 1982), one



reason for the discrepancy would be the lower level of activity of the pigs when in the respira- t ion chamber in cages, as compared with outs ide condi t ions in f lat-decks (personal observat ion). Since heat product ion direct ly associated with a normal level of activity may represent 15% of fasting heat p roduct ion (Nienaber et al., 1985), a large propor t ion of the dif ference in heat p roduct ion observed between both methods could be accounted for by dif ferences in level of activity. In addit ion, ambient temperature was constant and prob- ably slightly higher with in the respirat ion chamber (22 C vs 18 to 22 C). Therefore, pigs kept in a f lat-deck env i ronment were at or below their lower critical temperature (Close and Mount , 1978), with a subsequent increased heat product ion. As reported by Just et al. (1982), est imates of N retent ion are lower when measured by the comparat ive slaughter technique, as compared with the balance techn ique (table 6). The main exp lanat ion for the discrepancy is that N losses (feces, ur ine) are usual ly under-est imated, with a subsequent over-est imation of N retent ion. The di f ference found in the present exper iment (12.1%) is comparable to the mean l i terature value (16%) given by Just et al. (1982).

Literature Cited

AOAC. 1975. Official Methods of Analysis (12th Ed.). Association of Official Analytical Chemists, Washington, DC.

Asche, G. L., A. J. Lewis, E. R. Peo, Jr. and J. D. Grenshaw. 1985. The nutritional value of normal and high lysine corns for weanling and growing- finishing swine when fed at four lysine levels. J. Anim. Sci. 60:1412.

Batterham, E. S. and G. N. O'Neill. 1978. The effect of frequency of feeding on the response by growing pigs tO supplements of free lysine. Br. J. Nutr. 39:265.

Bereskin, B., R. J. Davey and W. H. Peters. 1976. Genetic, sex and diet effects on pig growth and feed use. J. Anita. Sei. 43:977.

Brouwer, E. 1965. Report of sub-committee on constants and factors. In: K. L. Blaxter (Ed.). Energy Metabolism, Eur. Assoc. Anim. Prod. No. 77. pp 441--443. Academic Press, London.

Close, W. H. and L. E. Mount. 1978. The effects of plane of nutrition and environmental temperature on the energy metabolism of the growing pig. 1. Heat loss and critical temperature. Br. J. Nutr. 40:413.

Easter, R. A. and D. H. Baker. 1980. Lysine and protein levels in corn-soybean meal diets for growing-finishing swine. J. Anita. Sci. 50:467.

Hoffmann, L. and R. Schiemann. 1971. Verdaulichkeit

und Energie Kennzahlen yon Futter stoffen beim Huhfi. Arch. Tierernaehr. 21:65.

INRA 1984. L'alimentation des Animaux Monogas- triques: Proc, Lapin, Volailles. INRA, Paris.

Just, A. 1982. The net energy value of crude (catabolized) protein for growth in pigs. Livest. Prod. Sci. 9:349.

Just, A., J. A. Fernandez and H. Jorgensen. 1982. Nitrogen balance studies and nitrogen retention. In: J. P. Laplace, T. Corring, A. Rerat (Ed.). Digestive Physiology in the Pig. Les Colloques de I'INRA. 12:111.

Koong, L. J., J. A. Nienaber, J. C. Pekas and J. T. Yen. 1982. Effects of plane of nutrition on organ size and fasting heat production in pigs. J. Nutr. 112:1638.

Laplace, J. P., B. Darcy-Vrillon and M. Picard. 1985. Evaluation de la disponibilite des acides amines. Choix raisonne d'une methode. Journ. Rech. Porcine Ft. 17:353.

Nienaber, J. A., Y. R. Chen and G. L. Hahn. 1985. Energetics of activity using indirect calorimetry. In: P, W. Moe, H. F. Tyrrell and P. J. Reynolds (Ed.) Energy Metabolism of Farm Animals. Eur. Assoc. Anim. Prod. No. 32.

Noblet, J. and Y. Henry. 1977. Consequences d'une reduction du taux de matieres azotees sur le niveau de consommation et les performances de croissance chez le porc selon l'equilibre en acides amines et la concentration en energie d regime. Ann. Zootech. 26:379.

Nobler, J., Y. Henry and D. Bourdon. 1980. Influence d'une reduction du taux d'azote indifferencie sur le niveau d'ingestion alimentaire et les performances de croissance du porc femeUe selon la concentration et la nature des substrats energeti- ques dans le regime. Ann. Zootech. 29:103.

Noblet, J., J. Le Dividich and T. Bikawa. 1985. Interaction between energy level in the diet and environmental temperature on the utilization of energy in growing pigs. J. Anim. Sci. 61:452.

Partridge, I. G., A. G. Low and H. D. Keal. 1985. A note on the effect of feeding frequency on nitrogen use in growing boars given diets with varying levels free lysine. Anim. Prod. 40: 375.

Reeds, P. J., M. F. Fuller, A. Cadenhead, G. E. Lobley and J. D. McDonald. 1981. Effects of changes in the intakes of protein and non-protein energy on whole-body protein turnover in growing pigs. Br. J. Nutr. 45:539.

Russell, L. E., G. L. Cromwell and T. S. Stahly. 1983. Tryptophan, threonine, isoleucine and methionine supplementation of a 12% protein, lysine- supplemented, corn-soybean meal diet for growing pigs. J. Anita. Sci. 56:1115.

Schulz, A. R. 1975. Computer-based method for calculation of the available energy of proteins. J. Nutr. 105:200.

Sharda, D. P., D. C. Mahan and R. F. Wilson. 1976. Limiting amino acids in low-protein corn-soybean meal diets for growing-finishing swine. J. Anim. Sci. 42:1175.

Stahly, T. S., G. L. Cromwell and M. P. Aviotti. 1979. The effect of environmental temperature and dietary lysine source and level on the performance and carcass characteristics of growing swine. J. Anim. Sci. 49:1242.


726 NOBLET ET AL.

Stahly, T. S., G. L. Cromwell and J. R. Overfield. 1981. Interactive effects of season of year and dietary fat supplementation, lysine source and lysine level on the performance of swine. J. Anlm. Sci. 53:1269.

Tess, M. W., G. E. Dickerson, J. A. Nienaber and C. L. Ferreli. 1984. The effects of body compos[tion on fasting heat production in pigs. J. Anim. Sci. 58:99.

Van Soest, P. H. and R. R. Wine. 1967. Use of deter- gents in the analysis of f ibrous feeds. IV. Deter-

mination of plant cell-wall constituents. J. Assoc. Off. Anal. Chem. 50:50.

Wahlstrom, R. C. and G. W. Libal. 1974. Gain, feed efficiency and carcass characteristics of swine fed supplemental lysine and methionine in corn-soybean meal diets during the growing and finishing periods. J. Anim. Sci. 38:1261.

Wiesemuller, W. and S. Poppe. 1974. Untersuchungen zum aminosautenbedarf yon mastschweinen (Borge) 5. Einfluss der aminosaurenernahrung auf den protei-nansatz. Arch. Tierernaehr. 24:535.


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