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Effects of Excess Methionine or Lysine for Broilers Fed a Corn-Soybean Meal Diet
Effects of Excess Methionine or Lysine for Broilers Fed a Corn-Soybean Meal Diet YANMING HAN and DAVID H. BAKER1 Department of Animal Sciences and Division of Nutritional Sciences, University of Illinois, Urbana, Illinois 61801
1993 Poultry Science 72:1070-1074
(1987a) investigated the effects on chick growth of adding 4.0% excesses of Met, Supplementing animal feeds with crys- Phe, Trp, His, Lys, Tyr, Thr, He, Arg, Val, talline amino acids is a common practice. or Leu to a corn-soybean meal diet. They Using crystalline amino acids allows nutri- reported that these singular excesses tionists to formulate diets with minimal reduced weight gain by 92, 79, 53, 50, 47, amino acid excesses (Waldroup et ah, 1976; 31, 29, 15, 9, 4, and 0%, respectively. Han et al., 1992). However, large amino Recent work with laying hens (Koelkebeck acid excesses could result in impaired et al, 1991) indicated that fortifying a corngrowth performance (Snetsinger and Scott, soybean meal diet with 1.0% excess Lys, 1961; Griminger and Fisher, 1968; Katz Met, Thr, or Trp did not affect feed and Baker, 1975). Edmonds and Baker consumption, egg production, or egg yield, suggesting that considerable tolerance exists in laying hens for excesses of individual amino acids. The purpose of the present study was to investigate the Received for publication November 12, 1992. Accepted for publication February 22, 1993. effects of excess Met or Lys on growth of 1 To whom correspondence should be addressed at young broilers fed a conventional corn328 Mumford Hall, 1301W. Gregory Drive, Urbana, IL soybean meal diet. 61801. INTRODUCTION
1070
Downloaded from http://ps.oxfordjournals.org/ at New York University on December 15, 2014
ABSTRACT Three experiments were conducted to examine the consequences of over-supplementing DL-Met or L-Lys (as L-Lys-HCl) in diets for chicks fed a corn-soybean meal diet (23% CP, 3,200 kcal ME n /kg, .2% supplemental Met) during 1 to 3 wk posthatching. New Hampshire x Columbian male chicks were used in Experiments 1 and 2 and Hubbard x Hubbard males were employed in Experiment 3. The basal diet was supplemented with .5,1.0, 2.0, or 4.0% DL-Met, or .4, .8,1.6, or 3.2% L-Lys in Experiment 1. Weight gain, feed intake, and feed efficiency decreased linearly at supplemental levels of DLMet between 1.0 and 4.0%. Weight gain of chicks fed diets with supplemental LLys levels greater than 1.6% was less than that of chicks fed the basal diet, but feed efficiency was not significantly affected. Adding K2CO3 to the diets containing 1.6 or 3.2% added L-Lys did not improve performance. Experiment 2 evaluated the effect of 1) adding 1.0% Gly or 1.0% L-Thr to the diet supplemented with 2.0% DL-Met; and 2) adding NaHC0 3 to the high-Lys diets in order to buffer the excess chloride provided by L-Lys-HCl. Addition of these amino acids or buffer ameliorated but did not totally correct the negative effects of excess Met or Lys. Experiment 3 examined the tolerance of commercial broilers to supplemental DL-Met or L-Lys levels of .5 or 1.0%. Weight gain and feed efficiency were not affected by these excesses, but feed intake was reduced at the 1.0% level of inclusion of either amino acid. These results suggest that .5% excesses of either Met or Lys are not harmful to young broiler chicks fed cornsoybean meal diets. (Key words: methionine, lysine, broilers, weight gain, feed efficiency)
1071
EXCESS METHIONINE OR LYSINE
MATERIALS AND METHODS
TABLE 1. Composition of corn-soybean meal basal diet1 Ingredients Cornstarch Corn (8.0% CP) Soybean meal (47% CP) Corn oil Dicalcium phosphate Limestone NaCl Mineral mix2 Vitamin mix3 CholineCl (60%) DL-Met J
Percentage to 100.00 42.37 41.68 6.53 2.2 1.00 .40 .15 .20 .10 .20
Diet contained 23% CP and 3,200 kcal ME„/kg diet. 2 Provided the following amounts per kilogram of diet: manganese, 75 mg; iron, 75 mg; zinc, 75 mg; copper, 5 mg; iodine, .75 mg; selenium, .1 mg. Supplied the following amounts per kilogram of diet: vitamin A, 4,400 IU; cholecalciferol, 1,000 IU; vitamin E, 11 IU; vitamin Bj2/ -011 mg; riboflavin, 4.4 mg; d-pantothenic acid, 10 mg; niacin, 22 mg; menadione sodium bisulfite complex, 2.33 mg.
RESULTS Methionine or Lys-HCl additions of 1% or greater depressed (P < .05) feed intake compared with the basal control, but weight gains decreased only at the 2 and 4% level of addition (Table 2). Feed efficiency was also lower at the two highest levels of Met, but none of the levels of excess Lys depressed gain:feed ratio. Excess Met at 2 or 4% of the diet was much more (P < .05) growth depressing than that which occurred with 2 or 4% excess Lys-HCl. Supplemental K2CO3 showed no efficacy in reversing the growth and feed intake depressions resulting from 2 or 4% Lys-HCl.
Downloaded from http://ps.oxfordjournals.org/ at New York University on December 15, 2014
One-week-old male chicks resulting from the cross of New Hampshire males and Columbian females were used in Experiments 1 and 2, and Hubbard x Hubbard male chicks were used in Experiment 3. The chicks were fed a standard 23% CP corn-soybean meal starter diet during the 1st wk posthatching. On Day 8 following an overnight deprivation of feed, the chicks were weighed, wingbanded, and allotted to dietary treatments according to procedures described by Sasse and Baker (1974). Chicks were housed in thermostatically controlled starter batteries with raised wire floors, located in a temperature-controlled room. Feed and water were supplied for ad libitum consumption and a 24-h constant light schedule was maintained. Diets were fed to triplicate groups of five chicks from 8 to 22 days posthatching in Experiments 1 and 3, and from 8 to 21 days posthatching in Experiment 2. A corn-soybean meal basal diet (Table 1) was formulated to meet the requirements (National Research Council, 1984) for all nutrients. The basal diet contained .2% crystalline DL-Met, and based upon
ME n , CP, and amino acid analysis of corn and soybean meal (Han and Baker, 1991, 1993), it contained 23% CP, 3,200 kcal ME n , .57% Met, .35% Cys, and 1.38% Lys. Experiment 1 was designed to investigate the tolerance of chicks to excess DLMet (0, .5, 1.0, 2.0, or 4.0% additions) and excess L-Lys (.4, .8, 1.6, or 3.2% additions) as L-Lys-HCl. In addition, K2CO3 was added (isomolar K+ to the Cl~ from LLys-HCl) to the diets supplemented with 1.6 and 3.2% L-Lys to determine whether effects of excess L-Lys-HCl were due to Lys per se or to a shift in acidrbase balance. Because earlier studies with purified diets had demonstrated that Gly or Thr can ameliorate Met toxicity (Katz and Baker, 1975; Harter and Baker, 1978), Experiment 2 was carried out to study the effects of 1) adding 1.0% Gly or 1.0% LThr, or both, to a corn-soybean meal diet supplemented with 2.0% DL-Met; and 2) adding NaHC03 to provide Na + equal to the CI" provided by 3.75% L-Lys-HCl. Experiment 3 was carried out to examine the growth responses of commercial broilers (Hubbard) to supplemental DL-Met levels of .5 and 1.0%, or supplemental LLys (as L-Lys-HCl) levels of .5 and 1.0%. Growth data were subjected to ANOVA procedures appropriate for completely randomized designs (Steel and Torrie, 1980) with pen means as the experimental unit. Differences among treatment means were evaluated by the least significant difference pairwise multiple-comparison procedure (Carmer and Walker, 1985).
1072
HAN AND BAKER
TABLE 2. Effect of excess Met or Lys on growth performance of crossbred chicks, Experiment l 1 Treatment
Feed intake
Weight gain -(g)
410» 407*
273* 281" 2590c 187' 36f 274* 257bc 248' 240dc 240 d ' 228 d
373dc
313* 144* 405* 386** 37gdc 376 d ' 39iabc 3594 8
667 abc 690* 693 a 596e 252' 675* 665*' 656t" 638
12
a f
" Means within columns with no common superscripts differ significantly (P < .05). x Data are means of three groups of five female crossbred chicks from 8 to 22 days posthatching; average initial weight was 79 g. 2 Isomolar K+ to the CI- from supplemental L-Lys-HCl.
In Experiment 2 (Table 3), 2% added Met reduced (P < .05) all measures of chick performance, and supplemental Gly or Thr showed efficacy in reversing (P < .05) the feed efficiency depression. Only Gly, however, stimulated (P < .05) weight gain of chicks fed the Met-imbalanced diet, although gains of chicks fed the Metimbalanced diet with added Gly was still
inferior (P < .05) to gains of chicks fed the basal diet. Diets supplemented with 1.5 or 3.0% excess Lys (as L-Lys-HCl) depressed all measures of performance, but the 3% level of excess Lys was not more depressing than the 1.5% level (Table 3). With 1.5% excess Lys, supplemental NaHCC>3 increased (P < .05) both feed intake and
TABLE 3. Effects of supplemental Gly and Thr on Met-induced growth depression, and of supplemental sodium bicarbonate on growth depressions resulting from excess Lys-HCl, Experiment 21 Treatment
Weight gain
Feed intake
Gain: feed
326a 263' 263' 240d 257' 295 b 296 b 322 a 290 b 6
683 a 606' 673 a 659* 681 a 611' 622 b ' 627 bc 629* 14
-(g) 1. 2. 3. 4. 5. 6. 7. 8. 9.
Basal diet As 1 + 2.0% DL-Met As 2 + 1.0% Gly As 2 + 1.0% L-Thr As 2 + 1.0% Gly + 1.0% L-Thr As 1 + 1.87% L-Lys-HCl (1.5% Lys) As 1 + 3.75% L-Lys-HCl (3.0% Lys) As 6 + .86% N a H C 0 3 2 As 7 + 1.72% NaHCQ 3 2 Pooled SEM
223 a 159d 177c 158 d 175' 181' 184' 202b 183' 5
"^Means within columns with no common superscripts differ significantly (P < .05). x Data are means of three groups of five female crossbred chicks from 8 to 21 days posthatching; average initial weight was 73 g. 2 Isomolar Na+ to the CI- from supplemental L-Lys-HCl.
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1. Basal diet 2. As 1 + .5% DL-Met 3. As 1 + 1.0% DL-Met 4. As 1 + 2.0% DL-Met 5. As 1 + 4.0% DL-Met 6. As 1 + .5% L-Lys-HCl (.4% Lys) 7. As 1 + 1.0% L-Lys-HCl (.8% Lys) 8. As 1 + 2.0% L-Lys-HCl (1.6% Lys) 9. As 1 + 4.0% L-Lys-HCl (3.2% Lys) 10. As 8 + .76% K 2 C0 3 2 11. As 9 + 1.52% K 2 C0 3 2 Pooled SEM
Gain: feed
EXCESS METHIONINE OR LYSINE
1073
TABLE 4. Effect of excess Met or Lys on growth performance of commercial broilers, Experiment 31 Treatment
Weight gain
1. Basal diet 2. As 1 + .5% DL-Met 3. As 2 + 1.0% DL-Met 4. As 2 + .62% L-Lys-HCl (.5% Lys) 5. As 2 + 1.25% L-LysHCl (1.0% Lys) Pooled SEM
654 656 612 650 593 18
Feed intake (g) 898a 871"" 822' 879*1* 827* 15
Gain: feed (g:kg) 729 753 744 740 717 14
a_c
Means within columns with no common superscripts differ significantly (P < .05). Data are means of three groups of five male Hubbard chicks from 8 to 22 days posthatching; average initial weight was 134 g. 1
DISCUSSION The results of this study confirmed that a large excess of dietary DL-Met is considerably more growth depressing than a large excess L-Lys-HCl when added to a conventional corn-soybean meal diet for either chicks or pigs (Edmonds and Baker, 1987a,b,c). Chicks receiving excess Met or Lys up to 1% of the diet showed no adverse effects on either weight gain or feed efficiency. Above 1% excess Met or Lys, however, weight gain decreased markedly as additional Met was supplemented, whereas excess Lys levels up to 3% of the diet decreased weight gain only marginally. Indeed, doubling the level of excess Lys from 1.5 or 1.6% to 3.0 or 3.2% did not reduce weight gain or feed intake in either Experiment 1 or 2 (Tables 2 and 3). Excess Met causes far greater increases in tissue Met concentration than the Lys that accumulates when excess Lys is fed (Edmonds and Baker, 1987b,c). Upon reaching a certain level of excess dietary Lys, urinary spillage occurs (Austic and
Scott, 1975; Edmonds and Baker, 1987c), and this probably prevents further manifestations of Lys toxicity. Data in Tables 3 and 4 suggest that most of the growth depression caused by 1.5 to 3.2% Lys was due to Lys per se and not due to the HC1 portion of L-Lys-HCl. Additional Gly or Thr was partially effective in ameliorating Met toxicity (Table 3), particularly the feed efficiency depression. Similar results have been observed previously in chick studies with purified diets (Katz and Baker, 1975; Harter and Baker, 1978). Efficacy of Thr probably results from the fact that some of the excess Thr is metabolized to Gly via the aldolase pathway (Baker et ah, 1972; Katz and Baker, 1975). It has been observed previously that modest excesses of Lys tend to depress feed intake but not weight gain (Han and Baker, 1991,1993). This tendency was also evident in the work herein with Hubbard chicks that consumed diets containing .5% excess Met or Lys. This phenomenon probably explains why feed efficiency often continues to respond to Lys or Met supplementation after weight gain has been maximized.
REFERENCES Austic, R. E., and R. L. Scott, 1975. Involvement of food intake in the lysine-arginine antagonism in chicks. J. Nutr. 105:1122-1131. Baker, D. H., T. M. Hill, and A. J. Kleiss, 1972. Nutritional evidence concerning formation of glycine from threonine in the chick. J. Anim. Sci. 34:582-586.
Downloaded from http://ps.oxfordjournals.org/ at New York University on December 15, 2014
weight gain, but NaHCC»3 was without effect on chicks fed 3% excess Lys. In Experiment 3 (Table 4), fast-growing commercial broiler chicks responded to .5 or 1.0% excesses of Met or Lys in the same fashion as slower growing crossbred chicks. The highest level of addition of either amino acid depressed (P < .05) feed intake, but neither weight gain nor feed efficiency was reduced.
1074
HAN AND BAKER Harter, R. G., and D. H. Baker, 1978. Factors affecting methionine toxicity and its alleviation in the chick. J. Nutr. 108:1061-1070. Katz, R. S., and D. H. Baker, 1975. Methionine toxicity in the chick: nutritional and metabolic implications. J. Nutr. 105:1168-1175. Koelkebeck, K. W., D. H. Baker, Y. Han, and C. M. Parsons, 1991. Effect of excess lysine, methionine, threonine, and tryptophan on production performance of laying hens. Poultry Sci. 70: 1651-1653. National Research Council, 1984. Nutrient Requirements of Poultry. 8th rev. ed. National Academy Press, Washington, DC. Sasse, C. E., and D. H. Baker, 1974. Factors affecting sulfate-sulfur utilization by the young chicks. Poultry Sci. 53:652-662. Snetsinger, D. C, and H. M. Scott, 1961. Efficacy of glycine and arginine in alleviating the stress induced by dietary excesses of single amino acids. Poultry Sci. 40:1675-1681. Steel, R.G.D., and J. H. Torrie, 1980. Principles and Procedures of Statistics. A Biometrical Approach, 2nd ed. McGraw-Hill Book Co., New York, NY. Waldroup, P. W., R. J. Mitchell, J. R. Payne, and K. R. Hazen, 1976. Performance of chicks fed diets formulated to minimize excess levels of essential amino acids. Poultry Sci. 55:243-253.
Downloaded from http://ps.oxfordjournals.org/ at New York University on December 15, 2014
Carmer, S. G., and W. M. Walker, 1985. Pairwise multiple comparisons of treatment means in agronomic research. J. Agron. Educ. 14:19-26. Edmonds, M. S., and D. H. Baker, 1987a. Comparative effects of individual amino acid excesses when added to a corn-soybean meal diet: effects on growth and dietary choice in the chick. J. Anim. Sci. 65:699-705. Edmonds, M. S., and D. H. Baker, 1987b. Amino acid excesses for young pigs: effects of excess methionine, tryptophan, threonine or leucine. J. Anim. Sci. 64:1664-1671. Edmonds, M. S., and D. H. Baker, 1987c. Failure of excess dietary lysine to antagonize arginine in young pigs. J. Nutr. 117:1396-1401. Griminger, P., and H. Fisher, 1968. Methionine excess and chick growth. Poultry Sci. 47:1271-1273. Han, Y., and D. H. Baker, 1991. Lysine requirements of fast- and slow-growing broiler chicks. Poultry Sci. 70:2108-2114. Han, Y., and D. H. Baker, 1993. Effects of sex, heat stress, body weight and genetic strain on the dietary lysine requirement of broiler chicks. Poultry Sci. 72:701-708. Han, Y., H. Suzuki, C. M. Parsons, and D. H. Baker, 1992. Amino acid fortification of a low-protein corn and soybean meal diet for chicks. Poultry Sci. 71:1168-1178.
1993 Poultry Science 72:1070-1074
(1987a) investigated the effects on chick growth of adding 4.0% excesses of Met, Supplementing animal feeds with crys- Phe, Trp, His, Lys, Tyr, Thr, He, Arg, Val, talline amino acids is a common practice. or Leu to a corn-soybean meal diet. They Using crystalline amino acids allows nutri- reported that these singular excesses tionists to formulate diets with minimal reduced weight gain by 92, 79, 53, 50, 47, amino acid excesses (Waldroup et ah, 1976; 31, 29, 15, 9, 4, and 0%, respectively. Han et al., 1992). However, large amino Recent work with laying hens (Koelkebeck acid excesses could result in impaired et al, 1991) indicated that fortifying a corngrowth performance (Snetsinger and Scott, soybean meal diet with 1.0% excess Lys, 1961; Griminger and Fisher, 1968; Katz Met, Thr, or Trp did not affect feed and Baker, 1975). Edmonds and Baker consumption, egg production, or egg yield, suggesting that considerable tolerance exists in laying hens for excesses of individual amino acids. The purpose of the present study was to investigate the Received for publication November 12, 1992. Accepted for publication February 22, 1993. effects of excess Met or Lys on growth of 1 To whom correspondence should be addressed at young broilers fed a conventional corn328 Mumford Hall, 1301W. Gregory Drive, Urbana, IL soybean meal diet. 61801. INTRODUCTION
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Downloaded from http://ps.oxfordjournals.org/ at New York University on December 15, 2014
ABSTRACT Three experiments were conducted to examine the consequences of over-supplementing DL-Met or L-Lys (as L-Lys-HCl) in diets for chicks fed a corn-soybean meal diet (23% CP, 3,200 kcal ME n /kg, .2% supplemental Met) during 1 to 3 wk posthatching. New Hampshire x Columbian male chicks were used in Experiments 1 and 2 and Hubbard x Hubbard males were employed in Experiment 3. The basal diet was supplemented with .5,1.0, 2.0, or 4.0% DL-Met, or .4, .8,1.6, or 3.2% L-Lys in Experiment 1. Weight gain, feed intake, and feed efficiency decreased linearly at supplemental levels of DLMet between 1.0 and 4.0%. Weight gain of chicks fed diets with supplemental LLys levels greater than 1.6% was less than that of chicks fed the basal diet, but feed efficiency was not significantly affected. Adding K2CO3 to the diets containing 1.6 or 3.2% added L-Lys did not improve performance. Experiment 2 evaluated the effect of 1) adding 1.0% Gly or 1.0% L-Thr to the diet supplemented with 2.0% DL-Met; and 2) adding NaHC0 3 to the high-Lys diets in order to buffer the excess chloride provided by L-Lys-HCl. Addition of these amino acids or buffer ameliorated but did not totally correct the negative effects of excess Met or Lys. Experiment 3 examined the tolerance of commercial broilers to supplemental DL-Met or L-Lys levels of .5 or 1.0%. Weight gain and feed efficiency were not affected by these excesses, but feed intake was reduced at the 1.0% level of inclusion of either amino acid. These results suggest that .5% excesses of either Met or Lys are not harmful to young broiler chicks fed cornsoybean meal diets. (Key words: methionine, lysine, broilers, weight gain, feed efficiency)
1071
EXCESS METHIONINE OR LYSINE
MATERIALS AND METHODS
TABLE 1. Composition of corn-soybean meal basal diet1 Ingredients Cornstarch Corn (8.0% CP) Soybean meal (47% CP) Corn oil Dicalcium phosphate Limestone NaCl Mineral mix2 Vitamin mix3 CholineCl (60%) DL-Met J
Percentage to 100.00 42.37 41.68 6.53 2.2 1.00 .40 .15 .20 .10 .20
Diet contained 23% CP and 3,200 kcal ME„/kg diet. 2 Provided the following amounts per kilogram of diet: manganese, 75 mg; iron, 75 mg; zinc, 75 mg; copper, 5 mg; iodine, .75 mg; selenium, .1 mg. Supplied the following amounts per kilogram of diet: vitamin A, 4,400 IU; cholecalciferol, 1,000 IU; vitamin E, 11 IU; vitamin Bj2/ -011 mg; riboflavin, 4.4 mg; d-pantothenic acid, 10 mg; niacin, 22 mg; menadione sodium bisulfite complex, 2.33 mg.
RESULTS Methionine or Lys-HCl additions of 1% or greater depressed (P < .05) feed intake compared with the basal control, but weight gains decreased only at the 2 and 4% level of addition (Table 2). Feed efficiency was also lower at the two highest levels of Met, but none of the levels of excess Lys depressed gain:feed ratio. Excess Met at 2 or 4% of the diet was much more (P < .05) growth depressing than that which occurred with 2 or 4% excess Lys-HCl. Supplemental K2CO3 showed no efficacy in reversing the growth and feed intake depressions resulting from 2 or 4% Lys-HCl.
Downloaded from http://ps.oxfordjournals.org/ at New York University on December 15, 2014
One-week-old male chicks resulting from the cross of New Hampshire males and Columbian females were used in Experiments 1 and 2, and Hubbard x Hubbard male chicks were used in Experiment 3. The chicks were fed a standard 23% CP corn-soybean meal starter diet during the 1st wk posthatching. On Day 8 following an overnight deprivation of feed, the chicks were weighed, wingbanded, and allotted to dietary treatments according to procedures described by Sasse and Baker (1974). Chicks were housed in thermostatically controlled starter batteries with raised wire floors, located in a temperature-controlled room. Feed and water were supplied for ad libitum consumption and a 24-h constant light schedule was maintained. Diets were fed to triplicate groups of five chicks from 8 to 22 days posthatching in Experiments 1 and 3, and from 8 to 21 days posthatching in Experiment 2. A corn-soybean meal basal diet (Table 1) was formulated to meet the requirements (National Research Council, 1984) for all nutrients. The basal diet contained .2% crystalline DL-Met, and based upon
ME n , CP, and amino acid analysis of corn and soybean meal (Han and Baker, 1991, 1993), it contained 23% CP, 3,200 kcal ME n , .57% Met, .35% Cys, and 1.38% Lys. Experiment 1 was designed to investigate the tolerance of chicks to excess DLMet (0, .5, 1.0, 2.0, or 4.0% additions) and excess L-Lys (.4, .8, 1.6, or 3.2% additions) as L-Lys-HCl. In addition, K2CO3 was added (isomolar K+ to the Cl~ from LLys-HCl) to the diets supplemented with 1.6 and 3.2% L-Lys to determine whether effects of excess L-Lys-HCl were due to Lys per se or to a shift in acidrbase balance. Because earlier studies with purified diets had demonstrated that Gly or Thr can ameliorate Met toxicity (Katz and Baker, 1975; Harter and Baker, 1978), Experiment 2 was carried out to study the effects of 1) adding 1.0% Gly or 1.0% LThr, or both, to a corn-soybean meal diet supplemented with 2.0% DL-Met; and 2) adding NaHC03 to provide Na + equal to the CI" provided by 3.75% L-Lys-HCl. Experiment 3 was carried out to examine the growth responses of commercial broilers (Hubbard) to supplemental DL-Met levels of .5 and 1.0%, or supplemental LLys (as L-Lys-HCl) levels of .5 and 1.0%. Growth data were subjected to ANOVA procedures appropriate for completely randomized designs (Steel and Torrie, 1980) with pen means as the experimental unit. Differences among treatment means were evaluated by the least significant difference pairwise multiple-comparison procedure (Carmer and Walker, 1985).
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HAN AND BAKER
TABLE 2. Effect of excess Met or Lys on growth performance of crossbred chicks, Experiment l 1 Treatment
Feed intake
Weight gain -(g)
410» 407*
273* 281" 2590c 187' 36f 274* 257bc 248' 240dc 240 d ' 228 d
373dc
313* 144* 405* 386** 37gdc 376 d ' 39iabc 3594 8
12
a f
" Means within columns with no common superscripts differ significantly (P < .05). x Data are means of three groups of five female crossbred chicks from 8 to 22 days posthatching; average initial weight was 79 g. 2 Isomolar K+ to the CI- from supplemental L-Lys-HCl.
In Experiment 2 (Table 3), 2% added Met reduced (P < .05) all measures of chick performance, and supplemental Gly or Thr showed efficacy in reversing (P < .05) the feed efficiency depression. Only Gly, however, stimulated (P < .05) weight gain of chicks fed the Met-imbalanced diet, although gains of chicks fed the Metimbalanced diet with added Gly was still
inferior (P < .05) to gains of chicks fed the basal diet. Diets supplemented with 1.5 or 3.0% excess Lys (as L-Lys-HCl) depressed all measures of performance, but the 3% level of excess Lys was not more depressing than the 1.5% level (Table 3). With 1.5% excess Lys, supplemental NaHCC>3 increased (P < .05) both feed intake and
TABLE 3. Effects of supplemental Gly and Thr on Met-induced growth depression, and of supplemental sodium bicarbonate on growth depressions resulting from excess Lys-HCl, Experiment 21 Treatment
Weight gain
Feed intake
Gain: feed
326a 263' 263' 240d 257' 295 b 296 b 322 a 290 b 6
-(g) 1. 2. 3. 4. 5. 6. 7. 8. 9.
Basal diet As 1 + 2.0% DL-Met As 2 + 1.0% Gly As 2 + 1.0% L-Thr As 2 + 1.0% Gly + 1.0% L-Thr As 1 + 1.87% L-Lys-HCl (1.5% Lys) As 1 + 3.75% L-Lys-HCl (3.0% Lys) As 6 + .86% N a H C 0 3 2 As 7 + 1.72% NaHCQ 3 2 Pooled SEM
223 a 159d 177c 158 d 175' 181' 184' 202b 183' 5
"^Means within columns with no common superscripts differ significantly (P < .05). x Data are means of three groups of five female crossbred chicks from 8 to 21 days posthatching; average initial weight was 73 g. 2 Isomolar Na+ to the CI- from supplemental L-Lys-HCl.
Downloaded from http://ps.oxfordjournals.org/ at New York University on December 15, 2014
1. Basal diet 2. As 1 + .5% DL-Met 3. As 1 + 1.0% DL-Met 4. As 1 + 2.0% DL-Met 5. As 1 + 4.0% DL-Met 6. As 1 + .5% L-Lys-HCl (.4% Lys) 7. As 1 + 1.0% L-Lys-HCl (.8% Lys) 8. As 1 + 2.0% L-Lys-HCl (1.6% Lys) 9. As 1 + 4.0% L-Lys-HCl (3.2% Lys) 10. As 8 + .76% K 2 C0 3 2 11. As 9 + 1.52% K 2 C0 3 2 Pooled SEM
Gain: feed
EXCESS METHIONINE OR LYSINE
1073
TABLE 4. Effect of excess Met or Lys on growth performance of commercial broilers, Experiment 31 Treatment
Weight gain
1. Basal diet 2. As 1 + .5% DL-Met 3. As 2 + 1.0% DL-Met 4. As 2 + .62% L-Lys-HCl (.5% Lys) 5. As 2 + 1.25% L-LysHCl (1.0% Lys) Pooled SEM
654 656 612 650 593 18
Feed intake (g) 898a 871"" 822' 879*1* 827* 15
Gain: feed (g:kg) 729 753 744 740 717 14
a_c
Means within columns with no common superscripts differ significantly (P < .05). Data are means of three groups of five male Hubbard chicks from 8 to 22 days posthatching; average initial weight was 134 g. 1
DISCUSSION The results of this study confirmed that a large excess of dietary DL-Met is considerably more growth depressing than a large excess L-Lys-HCl when added to a conventional corn-soybean meal diet for either chicks or pigs (Edmonds and Baker, 1987a,b,c). Chicks receiving excess Met or Lys up to 1% of the diet showed no adverse effects on either weight gain or feed efficiency. Above 1% excess Met or Lys, however, weight gain decreased markedly as additional Met was supplemented, whereas excess Lys levels up to 3% of the diet decreased weight gain only marginally. Indeed, doubling the level of excess Lys from 1.5 or 1.6% to 3.0 or 3.2% did not reduce weight gain or feed intake in either Experiment 1 or 2 (Tables 2 and 3). Excess Met causes far greater increases in tissue Met concentration than the Lys that accumulates when excess Lys is fed (Edmonds and Baker, 1987b,c). Upon reaching a certain level of excess dietary Lys, urinary spillage occurs (Austic and
Scott, 1975; Edmonds and Baker, 1987c), and this probably prevents further manifestations of Lys toxicity. Data in Tables 3 and 4 suggest that most of the growth depression caused by 1.5 to 3.2% Lys was due to Lys per se and not due to the HC1 portion of L-Lys-HCl. Additional Gly or Thr was partially effective in ameliorating Met toxicity (Table 3), particularly the feed efficiency depression. Similar results have been observed previously in chick studies with purified diets (Katz and Baker, 1975; Harter and Baker, 1978). Efficacy of Thr probably results from the fact that some of the excess Thr is metabolized to Gly via the aldolase pathway (Baker et ah, 1972; Katz and Baker, 1975). It has been observed previously that modest excesses of Lys tend to depress feed intake but not weight gain (Han and Baker, 1991,1993). This tendency was also evident in the work herein with Hubbard chicks that consumed diets containing .5% excess Met or Lys. This phenomenon probably explains why feed efficiency often continues to respond to Lys or Met supplementation after weight gain has been maximized.
REFERENCES Austic, R. E., and R. L. Scott, 1975. Involvement of food intake in the lysine-arginine antagonism in chicks. J. Nutr. 105:1122-1131. Baker, D. H., T. M. Hill, and A. J. Kleiss, 1972. Nutritional evidence concerning formation of glycine from threonine in the chick. J. Anim. Sci. 34:582-586.
Downloaded from http://ps.oxfordjournals.org/ at New York University on December 15, 2014
weight gain, but NaHCC»3 was without effect on chicks fed 3% excess Lys. In Experiment 3 (Table 4), fast-growing commercial broiler chicks responded to .5 or 1.0% excesses of Met or Lys in the same fashion as slower growing crossbred chicks. The highest level of addition of either amino acid depressed (P < .05) feed intake, but neither weight gain nor feed efficiency was reduced.
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HAN AND BAKER Harter, R. G., and D. H. Baker, 1978. Factors affecting methionine toxicity and its alleviation in the chick. J. Nutr. 108:1061-1070. Katz, R. S., and D. H. Baker, 1975. Methionine toxicity in the chick: nutritional and metabolic implications. J. Nutr. 105:1168-1175. Koelkebeck, K. W., D. H. Baker, Y. Han, and C. M. Parsons, 1991. Effect of excess lysine, methionine, threonine, and tryptophan on production performance of laying hens. Poultry Sci. 70: 1651-1653. National Research Council, 1984. Nutrient Requirements of Poultry. 8th rev. ed. National Academy Press, Washington, DC. Sasse, C. E., and D. H. Baker, 1974. Factors affecting sulfate-sulfur utilization by the young chicks. Poultry Sci. 53:652-662. Snetsinger, D. C, and H. M. Scott, 1961. Efficacy of glycine and arginine in alleviating the stress induced by dietary excesses of single amino acids. Poultry Sci. 40:1675-1681. Steel, R.G.D., and J. H. Torrie, 1980. Principles and Procedures of Statistics. A Biometrical Approach, 2nd ed. McGraw-Hill Book Co., New York, NY. Waldroup, P. W., R. J. Mitchell, J. R. Payne, and K. R. Hazen, 1976. Performance of chicks fed diets formulated to minimize excess levels of essential amino acids. Poultry Sci. 55:243-253.
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Carmer, S. G., and W. M. Walker, 1985. Pairwise multiple comparisons of treatment means in agronomic research. J. Agron. Educ. 14:19-26. Edmonds, M. S., and D. H. Baker, 1987a. Comparative effects of individual amino acid excesses when added to a corn-soybean meal diet: effects on growth and dietary choice in the chick. J. Anim. Sci. 65:699-705. Edmonds, M. S., and D. H. Baker, 1987b. Amino acid excesses for young pigs: effects of excess methionine, tryptophan, threonine or leucine. J. Anim. Sci. 64:1664-1671. Edmonds, M. S., and D. H. Baker, 1987c. Failure of excess dietary lysine to antagonize arginine in young pigs. J. Nutr. 117:1396-1401. Griminger, P., and H. Fisher, 1968. Methionine excess and chick growth. Poultry Sci. 47:1271-1273. Han, Y., and D. H. Baker, 1991. Lysine requirements of fast- and slow-growing broiler chicks. Poultry Sci. 70:2108-2114. Han, Y., and D. H. Baker, 1993. Effects of sex, heat stress, body weight and genetic strain on the dietary lysine requirement of broiler chicks. Poultry Sci. 72:701-708. Han, Y., H. Suzuki, C. M. Parsons, and D. H. Baker, 1992. Amino acid fortification of a low-protein corn and soybean meal diet for chicks. Poultry Sci. 71:1168-1178.