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Lysine needs of summer-reared male broilers from six to eight weeks of age
Lysine Needs of Summer-Reared Male Broilers from Six to Eight Weeks of Age A. Corzo,* E. T. Moran,* and D. Hoehler *Auburn University, Department of Poultry Science, Auburn, Alabama 36849; and †Degussa Corporation, Kennesaw, Georgia 30144 amount of abdominal fat, and recovery of skinless boneless breast meats were not affected. Measurements on nitrogen balance and plasma levels of total protein, albumin, glucose, and uric acid taken at 49 d from a concurrent study using sample birds in raised-wire cages and identical feeds also failed to define a requirement. However, plasma aspartic transferase increased to a maximum approximating 1.05% lysine, whereas free lysine concentration linearly increased to the highest level. Overall data supported a lysine requirement no less than 0.95% that was greater than the previous minimum of 0.85% obtained under similar terms without heat stress. Suppression of growth from heat stress appears to reduce the absolute need for lysine; however, increased dietary concentration appears necessary to accommodate depressed feed intake and improve its effectiveness.
(Key words: broiler amino acid requirement, heat stress, ideal protein, lysine) 2003 Poultry Science 82:1602–1607
INTRODUCTION Essential amino acid requirements advocated by NRC (1994) for broilers are largely based on experimentation conducted several decades ago. During the interim, rate of broiler growth, and yield and nature of the carcass have all improved. Given these improvements, levels of the most limiting amino acids were increased during formulation and balanced relative to lysine (Agri Stats, 2001). Approximations of an ideal balance of essential amino acids for broilers generally combine the absolute needs for growth and maintenance under optimal terms of production (Baker, 1994; Mack et al., 1999). Decreased feed intake, reduced growth, and altered carcass composition (Adams et al., 1962; Kubena et al., 1972; Cowan and Michie, 1978; Howlider and Rose, 1987; Smith, 1993) together with panting, respiratory alkalosis, and decreased thyroid activity (Dale and Fuller, 1980; Teeter et al., 1985; Leeson, 1986) occur with
2003 Poultry Science Association, Inc. Received for publication February 5, 2003. Accepted for publication June 5, 2003. 1 To whom correspondence should be addressed: emoran@ acesag.auburn.edu.
heat stress. Reduction in the rate of protein synthesis from heat stress (Temim et al., 2000) is expected to alter amino acid need, but the extent and nature of change does not appear to be linear with environmental temperature or broiler age (Hurwitz et al., 1980). Thus, acclimation to heat stress in practice would be of limited effectiveness because summer temperatures are not predictable, and severity of response progressively increases with bird age. Corzo et al. (2002) observed that 0.85% lysine approached optimization for broiler males between 42 and 56 d of age when all other essential amino acids approximated an ideal balance according to Mack et al. (1999). An optimal environment provided exceptionally good performance; however, a clear definition of the precise requirement level was lacking. The objective of present experimentation examined whether such recommended lysine level persists and clarity of definition improves under less favorable, but otherwise similar, summer conditions. Again live performance and carcass quality showed the collective impact of each lysine level from 42 to 56 d of age, whereas nitrogen balance and several plasma measurements revealed their effects during a shorter period at midpoint of experimental phase.
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ABSTRACT Experimentation was conducted to estimate dietary lysine needed to optimize production of summer-reared broilers between 42 to 56 d of age. Male Ross × Ross 308 chicks were placed in floor pens of an open-sided house and provided common feeds from placement to 42 d of age. During the subsequent 42 to 56 d, birds received a corn-soybean meal basal diet (18% CP and 3,250 kcal/kg ME) established to provide limiting essential amino acids favorably balanced near requirement levels with the exception of lysine. Four 0.10% increments of L-lysine isonitrogenously displaced L-glutamic acid from the basal diet to provide analyzed values progressing from 0.85 to 1.25%. Body weight gain and mortality were not altered as dietary lysine increased; however, feed conversion linearly improved. Chilled carcass yield,
LYSINE FOR SUMMER REARED HEAVY BROILERS TABLE 1. Composition of experimental feeds and days of age fed (% as is) 0–21 d
21–42 d
42–56 d1
Corn Soybean meal Poultry oil Corn gluten meal DL-Methionine Lysine sulfate2 Dicalcium phosphate Limestone Sodium chloride L-Threonine L-Arginine L-Glutamic acid L-Tryptophan L-Valine Other3 Calculated analyses CP (%) ME (kcal/g) Lysine (%) Calcium (%) Available phosphorus (%)
54.66 35.39 5.17 — 0.23 0.16 1.91 1.50 0.45 — — — — — to 100%
59.02 31.51 5.12 — 0.19 0.12 1.77 1.40 0.32 — — — — — to 100%
69.48 18.34 2.99 4.46 0.11 0.03 1.30 1.20 0.32 0.12 0.22 0.85 0.01 0.01 to 100%
22.50 3.15 1.24 1.08 0.48
20.50 3.20 1.12 1.00 0.38
18.0 3.25 0.75 0.80 0.35
1
Basal feed from 42 to 56 d of age. Biolys 60 (L-lysine sulfate fermentation product with a minimum content of 47.3% L-lysine, Degussa Corporation, Kennesaw, GA). 3 Vitamin premix, 0.25% (supplied per kilogram of diet: vitamin A, 7,356 IU; vitamin D3, 2,205 IU; vitamin E, 8 IU; cyanocobalamin, 0.02 mg; riboflavin, 5.5 mg; niacin 36 mg; D-pantothenic acid, 13 mg; choline, 501 mg; menadione, 2.2 mg; folic acid, 0.5 mg; pyridoxine, 2 mg; thiamine, 1 mg; biotin 0.1 mg; ethoxiquin, 125 mg); mineral premix 0.25% (supplied mg per kg of diet: manganese, 65; zinc, 55; iron, 6; iodine, 1; copper, 6; selenium, 0.15); coccidiostat, 0.05% (60% salinomycin sodium premix, Roche Vitamins Inc., Parsippany, NJ). 2
MATERIALS AND METHODS Commercial source 1-d-old Ross × Ross 308 male chicks were randomized into floor pens of an opensided house at the Auburn University poultry farm. The house had thermostatically controlled heating, curtains, and cross ventilation (30 pens; 35 birds/pen; 0.118m2/ bird), and birds were reared through the months of June and July. Each pen had fresh pine shavings and was equipped with one hanging feeder and one bell drinker. Chicks were vaccinated for Marek’s disease, Newcastle disease, and infectious bronchitis at the hatchery and at 12 d against infectious bursal disease. All birds received common crumbed and whole pellet feeds from placement to 21 d and 21 to 42 d, respectively, that generally exceeded NRC (1994) nutrient recommendations, particularly lysine (Table 1). At 42 d of age, bird number was equalized among pens (30/pen), and treatments were distributed to establish similar average weights at the start of experimentation. Treatments consisted of five levels of dietary lysine that linearly progressed at 0.10% intervals from a calculated level of 0.75% in the basal to the highest at 1.15%
2 Laboratory of Clinical Pathology, College of Veterinary Medicine, Auburn University, Auburn, AL. 3 Olson Biochemistry Laboratories, South Dakota State University, Brookings, SD.
on an 88% dry-matter basis. Feed ingredients used from 42 to 56 d of age were analyzed for amino acids to improve accuracy in formulation, and each complete feed was further analyzed after pelleting (Llames and Fontaine, 1994). As supplementation of L-lysine sulfate increased, L-glutamic acid was isonitrogenously omitted from the basal diet. Levels of all other essential amino acids supplemented to the basal diet were included to attain an ideal relationship with lysine at 0.85%. Feed and water were provided ad libitum, and lighting was continuous. Feed conversions were corrected for mortality. All mortality was gross necropsied to estimate the incidence of sudden death syndrome, ascites, leg problems, or other problems. Experimentation was approved and monitored by the Auburn University Animal Care and Use Committee. At 56 d of age, all birds in floor pens were placed in transportation coops and held about 14 h prior to slaughter. On-line processing was performed in a pilot plant that involved a 9-min kill line followed with a 7min evisceration line. Warm carcasses were static chilled in slush-ice for 4 h followed by removal of depot fat from the abdominal cavity. The front half of each carcass was held on flaked ice overnight for removal of fillets (pectoralis major) and tenders (pectoralis minor) using stationary cones and experienced personnel. Blood contaminating the fillets (blood splash) and tenders exhibiting deep pectoral myopathy (green muscle disease) were itemized. Nitrogen balance of the experimental feeds and their effect on specific plasma measurements were conducted on 90 broilers removed from those reared in the floor pens on common feed to 41 d. The BW of each bird was within the upper and lower 5% of the total flock average. Selected birds were divided into those heavier and lighter than this average, and each group was placed in separate cages of raised-wire floor batteries (2 birds/ cage). Each cage had one trough water and one trough feeder. Room lighting was continuous, and temperatures were similar to those concurrently being experienced by broilers in floor pens. Caged birds received the same experimental feeds as those on the floor from d 43 until d 48. Excreta were collected from d 48 to 49 and subsequently held at −20°C for later lyopholization. Nitrogen retention was calculated from Kjeldahl measurements on feed and excreta. At d 50, heparinized syringes were used to collect blood from the brachial vein, and resultant plasma was held at −70°C for subsequent analyses of albumin, aspartate transferase, glucose, total protein, and uric acid2 as well as concentrations of free amino acids.3 Data were statistically evaluated by ANOVA in a completely randomized design. Computations used the general linear model procedure of SAS software (1988). Mean separation procedure was performed by orthogonal polynomial techniques. Regression analysis was used to estimate the nature and extent of lysine response. Percentage data for carcass and mortality were
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Ingredient
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CORZO ET AL. TABLE 2. Amino acid analysis of experimental diets fed to broilers from 42 to 56 d of age, 88% dry-matter basis1 Intended lysine (%) Amino acid
0.75
0.85
0.95
1.05
1.15
Lysine Arginine Methionine Cystine TSAA Threonine Isoleucine Valine Tryptophan Glutamic acid
0.80 1.21 0.42 0.35 0.77 0.75 0.70 0.81 0.18 4.04
0.95 1.29 0.44 0.36 0.80 0.78 0.73 0.86 0.17 4.03
1.04 1.29 0.44 0.36 0.80 0.78 0.75 0.88 0.17 3.82
1.15 1.27 0.48 0.36 0.84 0.81 0.71 0.86 0.15 3.58
1.25 1.29 0.44 0.36 0.80 0.79 0.74 0.86 0.17 3.40
1 Representative samples were analyzed in duplicate by Degussa Corporation Applied Technology Chemical Group, Allendale, NJ. Only lysine and those other amino acids possibly limiting and supplemented to the basal are shown.
RESULTS AND DISCUSSION The environment when Corzo et al. (2002) estimated 0.85% lysine as being satisfactory for broiler males from 42 to 56 d of age averaged 18°C and 61% RH, whereas summer conditions in present experimentation corresponded to 28°C and 74% RH. The building, pens, and strain of broiler used were identical; however, the proportions of basal ingredients were marginally altered to accommodate differences in feedstuff composition and intended amino acid levels. Analyses of each experimental feed indicated that lysine consistently exceeded intended levels by approximately 0.10% (Table 2), whereas all other amino acids and crude protein (18.4%; SD = 0.11 at 88% DM) remained similar. The essential amino acids likely to be limiting and supplemented to
the basal generally agreed with those reported by Corzo et al. (2002). In turn, a fixed error in the supplementation of lysine to the experimental feeds seemed to be the most likely reason for the differences between calculated and actual levels. Accordingly, each of the intended lysine levels was increased by 0.10%, i.e., from 0.75, 0.85, 0.95, and 1.05% to 0.85, 0.95, 1.05, and 1.15%, respectively, and is presented as such. Summer conditions encountered between 42 and 56 d of age led to reduced overall live performance (grand means: 3,803 g weight and 1.96 feed/gain) than reported by Corzo et al. (2002) when more favorable terms existed (4,264 g weight and 1.86 feed/gain). Increasing dietary lysine with broiler males reared in a summer environment in the present experimentation did not substantially alter feed intake, BW gain, and mortality between 42 to 56 d of age. However, a linear decrease in the conversion of feed to live weight gain was evident with birds fed the basal level of 0.85% lysine through to
TABLE 3. Live performance and mortality of broiler males from 42 to 56 d of age in response to progressive levels of dietary lysine while being reared in a summer environment1 Body weight (g) Lysine, % 0.85 0.95 1.05 1.15 1.25 SEM (24 df) Contrast Linear Quadratic R2
Consumption (g)
Final
Gain
Feed
3,774 3,767 3,859 3,785 3,828 56.2
1,142 1,132 1,227 1,149 1,201 56.8
3,066 3,067 3,068 2,905 2,975 57.4
NS NS 0.37
NS NS 0.15
Lysine
Feed conversion2 42 to 56 d
23 2.71 26 2.71 29 2.53 31 2.56 34 2.50 0.6 0.089 Orthogonal polynomials4
NS NS 0.24
*** NS 0.91
* NS 0.26
0 to 56 d
Mortality3 total (%)
2.00 2.00 1.96 1.95 1.91 0.027
4.1 6.5 5.6 6.4 6.5 1.08
* NS 0.41
NS NS 0.18
1 Live performance grand means preceding experimentation corresponded to 42 d live weight of 2,629 g with feed/gain from 0 to 42 d of 1.69. Experimental values represent least square means of six pens each having ca. 28 birds. The average temperature through experimentation was 28 ± 2°C, and RH was 74 ± 8%. All cubic responses were not significant (P > 0.05). 2 Feed conversion values corrected for mortality. 3 Means corresponding to sudden death syndrome, ascites, leg problems, and other causes, due to lysine effects were not significant (P < 0.05). 4 NS, P > 0.05; *P < 0.05; ***P < 0.001.
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transformed to arcsine square root percentages for analysis.
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LYSINE FOR SUMMER REARED HEAVY BROILERS TABLE 4. Chilled carcass yield of broiler males that received progressive supplemental lysine from 42 to 56 d of age while being reared in a summer environment1 Abdominal fat2 Lysine %
Weight (g)
0.85 0.95 1.05 1.15 1.25 SEM (24 df)
Carcass without abdominal fat3
Carcass (%)
72 74 75 74 74 1.8
Contrast Linear Quadratic R2
Weight (g)
Carcass (%)
2.68 2,634 2.73 2,649 2.70 2,689 2.78 2,613 2.69 2,663 0.075 36.0 Orthogonal polynomials4
NS NS 0.06
NS NS 0.10
69.9 70.2 69.7 69.6 69.8 0.27
NS NS 0.32
NS NS 0.23
1.25%, representing almost an 8% improvement (Table 3). Subsequent evaluations of the carcass after processing indicated that the improved feed conversion from increasing lysine was not associated with a change in body composition. Depot fat removed from the abdominal cavity and yield of resulting chilled carcasses were unaltered (Table 4) as also were the amounts of fillets and tenders (Table 5). Blood contaminating the fillets and deep pectoral myopathy of tenders were both evident, but incidence was not altered by dietary lysine. Broilers removed from floor pens and placed in raise wire cages to evaluate lysine treatments on a unit-day basis at midpoint led to mixed results. Nitrogen retention measured during d 48 to 49 was not significantly altered as lysine increased nor was uric acid concentration in the plasma. Aspartate transferase was maximized, however, when birds received 1.05% lysine, which suggested an accentuated manipulation of inter-
mediate nitrogen (Table 6). Dietary lysine also altered plasma concentrations of total protein, albumin, and glucose, but these responses were related to BW of the broiler and are open to interpretation (Table 7). Levels of free amino acids in circulation reflect a combination of supply by the feed and removal for tissue use. Plasma lysine significantly increased with its dietary inclusion (Table 8). Acute response of circulating lysine to its supplementation relates to the extent of dietary limitation (Pesti et al., 1984) and availability from feed (Brake et al., 1998). Concurrent changes in the other essential amino acids are assumed to reflect their use and limitation relative to lysine. Several of the amino acids that were added to the basal diet could have been equally limiting to enable a numerical increase to 1.05% lysine and thereafter a decrease. Presumably, the existing overall balance approximated ideality and minimized extensive expression on an individual basis.
TABLE 5. Yield and quality of breast fillets (pectoralis major) and tenders (pectoralis minor) of broiler males that received progressive supplemental lysine from 42 to 56 d of age while being reared in a summer environment1 Fillets Lysine % 0.85 0.95 1.05 1.15 1.25 SEM (24 df) Contrast Linear Quadratic R2
Tenders 2
Weight (g)
Carcass (%)
Blood (%)
624 625 644 626 635 14.0
23.7 23.6 23.9 23.9 23.8 0.25
0.0 0.5 0.5 1.4 0.5 0.48
NS NS 0.22
NS NS 0.17
NS NS 0.28
Weight (g)
Carcass (%)
133 5.1 136 5.1 139 5.2 134 5.1 136 5.1 2.9 0.06 Orthogonal polynomials4 NS NS 0.22
NS NS 0.08
Total breast 3
Myopathy (%)
Weight (g)
Carcass (%)
2.0 2.4 1.5 4.3 2.3 1.06
758 762 783 760 771 16.8
28.7 28.7 29.1 29.0 28.9 0.29
NS NS 0.16
NS NS 0.27
Values are the least square means of six pens each providing ca. 28 carcasses. All cubic responses were not significant (P > 0.05). Incidence of blood contaminating the meat (“blood slash”). 3 Incidence of myopathy (“green muscle disease”). 4 NS, P > 0.05. 1 2
NS NS 0.19
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1 Values are the least square means of six pens each providing ca. 28 carcasses. All cubic responses were nonsignificant (P > 0.05). 2 Depot fat removed from the abdominal cavity of carcasses without neck and giblets after 4 h of slush-ice chilling expressed on an absolute basis and relative to its entire weight. 3 Chilled carcass without abdominal fat expressed on an absolute basis and relative to the full-fed live weight. 4 NS, P > 0.05.
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CORZO ET AL. TABLE 6. Nitrogen retention (49 d), plasma aspartate transferase and uric acid values (50 d) of broiler males having heavy and light body weights at 48 d of age after receiving feeds having progressive lysine from 43 d of age, while being reared in a summer environment1 Nitrogen Intake (mg)
Excretion (mg)
Lysine % 0.85 0.95 1.05 1.15 1.25 SEM
NS 5,753 5,735 5,862 5,368 5,385 195.0
NS 3,225 3,188 3,402 2,887 3,086 172.9
Linear Quadratic R2 Body weight2 Heavy Light SEM
* NS 0.18 NS 5,640 5,583 120.1
NS NS 0.21 NS 3,205 3,111 110.6
Retention (%)
Retention (mg/kg BW)
NS NS 44.0 0.97 44.9 0.98 41.4 0.92 45.5 0.95 42.2 0.87 2.76 0.070 Orthogonal polynomials3 NS NS 0.18 NS 43.0 44.2 1.70
NS NS 0.14 NS 0.90 0.97 0.044
Aspartatetransferase (IU/L)
Uric acid (mg/dL)
NS 241 254 265 248 227 14.4
NS 4.9 4.1 4.3 4.5 4.1 0.45
NS * 0.15 NS 258 236 9.2
NS NS 0.20 NS 4.7 4.1 0.28
1 Data represents a total of 45 cages each with two birds. Data are given as least-square means of the main factor contrasts given that their interactions were not significant (P > 0.05). All cubic responses were not significant (P > 0.05). 2 Body weight corresponds to groups above and below the total average where heavy = 2,306 g and light = 2,119 g; SEM = 16.4. 3 NS, P > 0.05; *P > 0.05.
Overall data in the present experimentation did not provide a level of lysine that could be considered as a definitive requirement for heat-stressed broilers. Feed conversion was the only measurement that was clearly responsive to lysine, and a linear improvement occurred. All other measurements were not statistically significant, and many numerically attained maximum or minimum values corresponding to a minimum of 0.95% lysine. Corzo et al. (2002) also observed a lack of response to dietary lysine with broilers in an optimal
environment. The requirement approximated 0.85% lysine and also arose from numerical indications of a few measurements, whereas linearity with feed conversion was indicated. Perhaps, this lack of definition resulted from imposing an ideal balance to avoid subsequent expression of limitation by any one essential amino acid as lysine increased. The increased concentration of lysine needed with heat stress appears to be an absolute accommodation to decreased feed consumption and to provide support for existing growth.
TABLE 7. Plasma total protein, albumin, and glucose values of broiler males having heavy and light body weights at 50 d of age receiving feeds with progressive lysine while being reared in a summer environment1 Total protein (g/dL) Lysine %
Heavy
2
Light
0.85 0.95 1.05 1.15 1.25 SEM
3.8 2.9 3.0 3.3 3.3 0.16
3.2 3.3 3.4 3.6 3.6 0.21
Contrast Linear Quadratic R2
NS ** 0.50
NS NS 0.12
Albumin (g/dL) 2
Heavy
Light
1.54 1.28 1.27 1.38 1.28 1.46 1.35 1.46 1.42 1.48 0.082 0.071 Orthogonal polynomials3 NS * 0.28
* NS 0.21
Glucose (mg/dL) Heavy
Light
281 279 267 245 271 7.8
248 258 270 276 256 8.6
* NS 0.38
NS * 0.25
1 Data represents a total of 45 cages each with two birds. Analyses was performed separately for high and low body weights because of significant interactions involving lysine level and body weight category (albumin P < 0.05; glucose P < 0.05; total protein P < 0.05). All cubic responses were not significant (P > 0.05). 2 Body weight corresponds to groups above and below the total average where heavy = 2,306 g and light = 2,119 g; SEM = 16.4. 3 NS, P > 0.05; *P < 0.05; **P < 0.01.
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Contrasts
Plasma
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LYSINE FOR SUMMER REARED HEAVY BROILERS
TABLE 8. Plasma free amino acid concentrations (nanomoles/mL) of broiler males at 50 d of age receiving feeds having progressive lysine from 43 d of age, while being reared in a summer environment1 Lysine % 0.85 0.95 1.05 1.15 1.25 SEM Contrast Linear Quadratic Cubic R2
Lys
Arg
Met
Thr
Val
Ile
150 257 270 293 310 33.7
614 612 527 581 569 30.8
89 90 91 86 78 4.8
966 946 895 872 970 86.3
145 147 160 153 130 9.3
64 73 81 79 64 6.5
*** NS NS 0.63
NS NS NS 0.47
NS NS NS 0.35
NS NS NS 0.26
NS * NS 0.46
Leu
Phe
Ser
Gly
Trp
Tyr
His
233 64 167 243 59 152 252 68 162 251 62 176 224 64 156 16.8 3.8 7.7 Orthogonal polynomials2
495 475 573 565 625 32.6
798 775 772 763 746 32.9
46 28 37 61 29 6.7
166 157 150 162 155 12.3
105 104 100 84 97 3.8
NS * NS 0.48
NS NS NS 0.26
Cys
NS NS NS 0.35
NS NS * 0.45
*** NS NS 0.62
NS NS NS 0.15
NS NS *** 0.66
NS NS NS 0.11
** NS * 0.74
1
Values represent the least-square means of analyses on pooled samples represented by three replicates per level of lysine. NS, P > 0.05; *P < 0.05; **P < 0.01; ***P < 0.001.
2
Adams, R. L., F. N. Andrews, E. E. Gardiner, W. E. Fontaine, and C. W. Carrick. 1962. The effects of environmental temperature on the growth and nutritional requirements of the chick. Poult. Sci. 41:588–594. Agri Stats. 2001. Annual Live Production. Agri Stats, Inc. Fort Wayne, IN. Baker, D. H. 1994. Ideal protein and amino acid requirement of broiler chicks. Pages 21–24 in Proceedings of the California Nutrition Conference. Fresno, CA. Brake, J., D. Balnave, and J. J. Dibner. 1998. Optimum dietary arginine:lysine ratio for broiler chickens is altered during heat stress in association with changes in intestinal uptake and dietary sodium chloride. Br. Poult. Sci. 39:639–647. Corzo, A., E. T. Moran, Jr., and D. Hoehler. 2002. Lysine need of heavy broiler males applying the ideal protein concept. Poult. Sci. 81:1863–1868. Cowan, P. J., and W. Michie. 1978. Environmental temperature and broiler performance: the use of diets containing increased amounts of protein. Br. J. Nutr. 40:311–315. Dale, N. M., and H. L. Fuller. 1980. Effect of diet composition on feed intake and growth of chicks under heat stress. II. Constant vs. cycling temperatures. Poult. Sci. 59:1434–1441. Howlider, M. A. R., and S. P. Rose. 1987. Temperature and the growth of broilers. World’s Poul. Sci. J. 43:228–237. Hurwitz, S., M. Weiselberg, U. Eisner, I. Bartov, G. Resisenfeld, M. Sharvit, I. Nir, and S. Bornstein. 1980. The energy requirements and performance of growing chickens and turkeys as affected by environmental temperature. Poult. Sci. 59:2290–2299. Kubena, L. F., B. D. Lott, J. W. Deaton, F. N. Reece, and J. D. May. 1972. Body composition of chicks as influenced by
environmental temperature and selected dietary factors. Poult. Sci. 51:511–522. Llames, C. R., and J. Fontaine. 1994. Determination of amino acids in feeds: Collaborative Study. J. AOAC Int. 77:1362–1402. Leeson, S. 1986. Nutritonal considerations of poutry during heat stress. World’s Poult. Sci. J. 42:69–81. Mack, S., D. Bercovici, G. De Groote, B. Leclercq, M. Lippens, M. Pack, J. B. Schutte, and S. Van Cauwenberghe. 1999. Ideal amino acid profile and dietary lysine specification for broiler chickens of 20 to 40 days of age. Br. Poult. Sci. 40:257–265. National Research Council. 1994. Nutrient Requirements of Poultry. 9th rev. ed. National Academy Press, Washington DC. Pesti, G. M., B. Leclercq, A. M. Chagneau, and T. Cochard. 1994. Comparative responses of genetically lean and fat chickens to lysine, arginine and non-essential amino acid supply. II. Plasma amino acid responses. Br. Poult. Sci. 35:697–707. SAS Institute. 1988. SAS/STAT User’s Guide. Release 6.03 ed. SAS Institute Inc., Cary, NC. Smith, M. O. 1993. Parts yield of broilers under cycling high temperatures. Poult. Sci. 73:1146–1150. Teeter, R. G., M. O. Smith, F. N. Owens, S. C. Arp, S. Sangah, and J. E. Breazile. 1985. Chronic heat stress and respiratory alkalosis occurrence and treatment in broiler chicks. Poult. Sci. 61:1060–1064. Temim, S., A. Chagneau, R. Peresson, and S. Tesseraud. 2000. Chronic heat exposure alters protein turnover of three different skeletal muscles in finishing broiler chikens fed 20 or 25% protein diets. J. Nutr. 130:813–819.
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REFERENCES
(Key words: broiler amino acid requirement, heat stress, ideal protein, lysine) 2003 Poultry Science 82:1602–1607
INTRODUCTION Essential amino acid requirements advocated by NRC (1994) for broilers are largely based on experimentation conducted several decades ago. During the interim, rate of broiler growth, and yield and nature of the carcass have all improved. Given these improvements, levels of the most limiting amino acids were increased during formulation and balanced relative to lysine (Agri Stats, 2001). Approximations of an ideal balance of essential amino acids for broilers generally combine the absolute needs for growth and maintenance under optimal terms of production (Baker, 1994; Mack et al., 1999). Decreased feed intake, reduced growth, and altered carcass composition (Adams et al., 1962; Kubena et al., 1972; Cowan and Michie, 1978; Howlider and Rose, 1987; Smith, 1993) together with panting, respiratory alkalosis, and decreased thyroid activity (Dale and Fuller, 1980; Teeter et al., 1985; Leeson, 1986) occur with
2003 Poultry Science Association, Inc. Received for publication February 5, 2003. Accepted for publication June 5, 2003. 1 To whom correspondence should be addressed: emoran@ acesag.auburn.edu.
heat stress. Reduction in the rate of protein synthesis from heat stress (Temim et al., 2000) is expected to alter amino acid need, but the extent and nature of change does not appear to be linear with environmental temperature or broiler age (Hurwitz et al., 1980). Thus, acclimation to heat stress in practice would be of limited effectiveness because summer temperatures are not predictable, and severity of response progressively increases with bird age. Corzo et al. (2002) observed that 0.85% lysine approached optimization for broiler males between 42 and 56 d of age when all other essential amino acids approximated an ideal balance according to Mack et al. (1999). An optimal environment provided exceptionally good performance; however, a clear definition of the precise requirement level was lacking. The objective of present experimentation examined whether such recommended lysine level persists and clarity of definition improves under less favorable, but otherwise similar, summer conditions. Again live performance and carcass quality showed the collective impact of each lysine level from 42 to 56 d of age, whereas nitrogen balance and several plasma measurements revealed their effects during a shorter period at midpoint of experimental phase.
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ABSTRACT Experimentation was conducted to estimate dietary lysine needed to optimize production of summer-reared broilers between 42 to 56 d of age. Male Ross × Ross 308 chicks were placed in floor pens of an open-sided house and provided common feeds from placement to 42 d of age. During the subsequent 42 to 56 d, birds received a corn-soybean meal basal diet (18% CP and 3,250 kcal/kg ME) established to provide limiting essential amino acids favorably balanced near requirement levels with the exception of lysine. Four 0.10% increments of L-lysine isonitrogenously displaced L-glutamic acid from the basal diet to provide analyzed values progressing from 0.85 to 1.25%. Body weight gain and mortality were not altered as dietary lysine increased; however, feed conversion linearly improved. Chilled carcass yield,
LYSINE FOR SUMMER REARED HEAVY BROILERS TABLE 1. Composition of experimental feeds and days of age fed (% as is) 0–21 d
21–42 d
42–56 d1
Corn Soybean meal Poultry oil Corn gluten meal DL-Methionine Lysine sulfate2 Dicalcium phosphate Limestone Sodium chloride L-Threonine L-Arginine L-Glutamic acid L-Tryptophan L-Valine Other3 Calculated analyses CP (%) ME (kcal/g) Lysine (%) Calcium (%) Available phosphorus (%)
54.66 35.39 5.17 — 0.23 0.16 1.91 1.50 0.45 — — — — — to 100%
59.02 31.51 5.12 — 0.19 0.12 1.77 1.40 0.32 — — — — — to 100%
69.48 18.34 2.99 4.46 0.11 0.03 1.30 1.20 0.32 0.12 0.22 0.85 0.01 0.01 to 100%
22.50 3.15 1.24 1.08 0.48
20.50 3.20 1.12 1.00 0.38
18.0 3.25 0.75 0.80 0.35
1
Basal feed from 42 to 56 d of age. Biolys 60 (L-lysine sulfate fermentation product with a minimum content of 47.3% L-lysine, Degussa Corporation, Kennesaw, GA). 3 Vitamin premix, 0.25% (supplied per kilogram of diet: vitamin A, 7,356 IU; vitamin D3, 2,205 IU; vitamin E, 8 IU; cyanocobalamin, 0.02 mg; riboflavin, 5.5 mg; niacin 36 mg; D-pantothenic acid, 13 mg; choline, 501 mg; menadione, 2.2 mg; folic acid, 0.5 mg; pyridoxine, 2 mg; thiamine, 1 mg; biotin 0.1 mg; ethoxiquin, 125 mg); mineral premix 0.25% (supplied mg per kg of diet: manganese, 65; zinc, 55; iron, 6; iodine, 1; copper, 6; selenium, 0.15); coccidiostat, 0.05% (60% salinomycin sodium premix, Roche Vitamins Inc., Parsippany, NJ). 2
MATERIALS AND METHODS Commercial source 1-d-old Ross × Ross 308 male chicks were randomized into floor pens of an opensided house at the Auburn University poultry farm. The house had thermostatically controlled heating, curtains, and cross ventilation (30 pens; 35 birds/pen; 0.118m2/ bird), and birds were reared through the months of June and July. Each pen had fresh pine shavings and was equipped with one hanging feeder and one bell drinker. Chicks were vaccinated for Marek’s disease, Newcastle disease, and infectious bronchitis at the hatchery and at 12 d against infectious bursal disease. All birds received common crumbed and whole pellet feeds from placement to 21 d and 21 to 42 d, respectively, that generally exceeded NRC (1994) nutrient recommendations, particularly lysine (Table 1). At 42 d of age, bird number was equalized among pens (30/pen), and treatments were distributed to establish similar average weights at the start of experimentation. Treatments consisted of five levels of dietary lysine that linearly progressed at 0.10% intervals from a calculated level of 0.75% in the basal to the highest at 1.15%
2 Laboratory of Clinical Pathology, College of Veterinary Medicine, Auburn University, Auburn, AL. 3 Olson Biochemistry Laboratories, South Dakota State University, Brookings, SD.
on an 88% dry-matter basis. Feed ingredients used from 42 to 56 d of age were analyzed for amino acids to improve accuracy in formulation, and each complete feed was further analyzed after pelleting (Llames and Fontaine, 1994). As supplementation of L-lysine sulfate increased, L-glutamic acid was isonitrogenously omitted from the basal diet. Levels of all other essential amino acids supplemented to the basal diet were included to attain an ideal relationship with lysine at 0.85%. Feed and water were provided ad libitum, and lighting was continuous. Feed conversions were corrected for mortality. All mortality was gross necropsied to estimate the incidence of sudden death syndrome, ascites, leg problems, or other problems. Experimentation was approved and monitored by the Auburn University Animal Care and Use Committee. At 56 d of age, all birds in floor pens were placed in transportation coops and held about 14 h prior to slaughter. On-line processing was performed in a pilot plant that involved a 9-min kill line followed with a 7min evisceration line. Warm carcasses were static chilled in slush-ice for 4 h followed by removal of depot fat from the abdominal cavity. The front half of each carcass was held on flaked ice overnight for removal of fillets (pectoralis major) and tenders (pectoralis minor) using stationary cones and experienced personnel. Blood contaminating the fillets (blood splash) and tenders exhibiting deep pectoral myopathy (green muscle disease) were itemized. Nitrogen balance of the experimental feeds and their effect on specific plasma measurements were conducted on 90 broilers removed from those reared in the floor pens on common feed to 41 d. The BW of each bird was within the upper and lower 5% of the total flock average. Selected birds were divided into those heavier and lighter than this average, and each group was placed in separate cages of raised-wire floor batteries (2 birds/ cage). Each cage had one trough water and one trough feeder. Room lighting was continuous, and temperatures were similar to those concurrently being experienced by broilers in floor pens. Caged birds received the same experimental feeds as those on the floor from d 43 until d 48. Excreta were collected from d 48 to 49 and subsequently held at −20°C for later lyopholization. Nitrogen retention was calculated from Kjeldahl measurements on feed and excreta. At d 50, heparinized syringes were used to collect blood from the brachial vein, and resultant plasma was held at −70°C for subsequent analyses of albumin, aspartate transferase, glucose, total protein, and uric acid2 as well as concentrations of free amino acids.3 Data were statistically evaluated by ANOVA in a completely randomized design. Computations used the general linear model procedure of SAS software (1988). Mean separation procedure was performed by orthogonal polynomial techniques. Regression analysis was used to estimate the nature and extent of lysine response. Percentage data for carcass and mortality were
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Ingredient
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1604
CORZO ET AL. TABLE 2. Amino acid analysis of experimental diets fed to broilers from 42 to 56 d of age, 88% dry-matter basis1 Intended lysine (%) Amino acid
0.75
0.85
0.95
1.05
1.15
Lysine Arginine Methionine Cystine TSAA Threonine Isoleucine Valine Tryptophan Glutamic acid
0.80 1.21 0.42 0.35 0.77 0.75 0.70 0.81 0.18 4.04
0.95 1.29 0.44 0.36 0.80 0.78 0.73 0.86 0.17 4.03
1.04 1.29 0.44 0.36 0.80 0.78 0.75 0.88 0.17 3.82
1.15 1.27 0.48 0.36 0.84 0.81 0.71 0.86 0.15 3.58
1.25 1.29 0.44 0.36 0.80 0.79 0.74 0.86 0.17 3.40
1 Representative samples were analyzed in duplicate by Degussa Corporation Applied Technology Chemical Group, Allendale, NJ. Only lysine and those other amino acids possibly limiting and supplemented to the basal are shown.
RESULTS AND DISCUSSION The environment when Corzo et al. (2002) estimated 0.85% lysine as being satisfactory for broiler males from 42 to 56 d of age averaged 18°C and 61% RH, whereas summer conditions in present experimentation corresponded to 28°C and 74% RH. The building, pens, and strain of broiler used were identical; however, the proportions of basal ingredients were marginally altered to accommodate differences in feedstuff composition and intended amino acid levels. Analyses of each experimental feed indicated that lysine consistently exceeded intended levels by approximately 0.10% (Table 2), whereas all other amino acids and crude protein (18.4%; SD = 0.11 at 88% DM) remained similar. The essential amino acids likely to be limiting and supplemented to
the basal generally agreed with those reported by Corzo et al. (2002). In turn, a fixed error in the supplementation of lysine to the experimental feeds seemed to be the most likely reason for the differences between calculated and actual levels. Accordingly, each of the intended lysine levels was increased by 0.10%, i.e., from 0.75, 0.85, 0.95, and 1.05% to 0.85, 0.95, 1.05, and 1.15%, respectively, and is presented as such. Summer conditions encountered between 42 and 56 d of age led to reduced overall live performance (grand means: 3,803 g weight and 1.96 feed/gain) than reported by Corzo et al. (2002) when more favorable terms existed (4,264 g weight and 1.86 feed/gain). Increasing dietary lysine with broiler males reared in a summer environment in the present experimentation did not substantially alter feed intake, BW gain, and mortality between 42 to 56 d of age. However, a linear decrease in the conversion of feed to live weight gain was evident with birds fed the basal level of 0.85% lysine through to
TABLE 3. Live performance and mortality of broiler males from 42 to 56 d of age in response to progressive levels of dietary lysine while being reared in a summer environment1 Body weight (g) Lysine, % 0.85 0.95 1.05 1.15 1.25 SEM (24 df) Contrast Linear Quadratic R2
Consumption (g)
Final
Gain
Feed
3,774 3,767 3,859 3,785 3,828 56.2
1,142 1,132 1,227 1,149 1,201 56.8
3,066 3,067 3,068 2,905 2,975 57.4
NS NS 0.37
NS NS 0.15
Lysine
Feed conversion2 42 to 56 d
23 2.71 26 2.71 29 2.53 31 2.56 34 2.50 0.6 0.089 Orthogonal polynomials4
NS NS 0.24
*** NS 0.91
* NS 0.26
0 to 56 d
Mortality3 total (%)
2.00 2.00 1.96 1.95 1.91 0.027
4.1 6.5 5.6 6.4 6.5 1.08
* NS 0.41
NS NS 0.18
1 Live performance grand means preceding experimentation corresponded to 42 d live weight of 2,629 g with feed/gain from 0 to 42 d of 1.69. Experimental values represent least square means of six pens each having ca. 28 birds. The average temperature through experimentation was 28 ± 2°C, and RH was 74 ± 8%. All cubic responses were not significant (P > 0.05). 2 Feed conversion values corrected for mortality. 3 Means corresponding to sudden death syndrome, ascites, leg problems, and other causes, due to lysine effects were not significant (P < 0.05). 4 NS, P > 0.05; *P < 0.05; ***P < 0.001.
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transformed to arcsine square root percentages for analysis.
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LYSINE FOR SUMMER REARED HEAVY BROILERS TABLE 4. Chilled carcass yield of broiler males that received progressive supplemental lysine from 42 to 56 d of age while being reared in a summer environment1 Abdominal fat2 Lysine %
Weight (g)
0.85 0.95 1.05 1.15 1.25 SEM (24 df)
Carcass without abdominal fat3
Carcass (%)
72 74 75 74 74 1.8
Contrast Linear Quadratic R2
Weight (g)
Carcass (%)
2.68 2,634 2.73 2,649 2.70 2,689 2.78 2,613 2.69 2,663 0.075 36.0 Orthogonal polynomials4
NS NS 0.06
NS NS 0.10
69.9 70.2 69.7 69.6 69.8 0.27
NS NS 0.32
NS NS 0.23
1.25%, representing almost an 8% improvement (Table 3). Subsequent evaluations of the carcass after processing indicated that the improved feed conversion from increasing lysine was not associated with a change in body composition. Depot fat removed from the abdominal cavity and yield of resulting chilled carcasses were unaltered (Table 4) as also were the amounts of fillets and tenders (Table 5). Blood contaminating the fillets and deep pectoral myopathy of tenders were both evident, but incidence was not altered by dietary lysine. Broilers removed from floor pens and placed in raise wire cages to evaluate lysine treatments on a unit-day basis at midpoint led to mixed results. Nitrogen retention measured during d 48 to 49 was not significantly altered as lysine increased nor was uric acid concentration in the plasma. Aspartate transferase was maximized, however, when birds received 1.05% lysine, which suggested an accentuated manipulation of inter-
mediate nitrogen (Table 6). Dietary lysine also altered plasma concentrations of total protein, albumin, and glucose, but these responses were related to BW of the broiler and are open to interpretation (Table 7). Levels of free amino acids in circulation reflect a combination of supply by the feed and removal for tissue use. Plasma lysine significantly increased with its dietary inclusion (Table 8). Acute response of circulating lysine to its supplementation relates to the extent of dietary limitation (Pesti et al., 1984) and availability from feed (Brake et al., 1998). Concurrent changes in the other essential amino acids are assumed to reflect their use and limitation relative to lysine. Several of the amino acids that were added to the basal diet could have been equally limiting to enable a numerical increase to 1.05% lysine and thereafter a decrease. Presumably, the existing overall balance approximated ideality and minimized extensive expression on an individual basis.
TABLE 5. Yield and quality of breast fillets (pectoralis major) and tenders (pectoralis minor) of broiler males that received progressive supplemental lysine from 42 to 56 d of age while being reared in a summer environment1 Fillets Lysine % 0.85 0.95 1.05 1.15 1.25 SEM (24 df) Contrast Linear Quadratic R2
Tenders 2
Weight (g)
Carcass (%)
Blood (%)
624 625 644 626 635 14.0
23.7 23.6 23.9 23.9 23.8 0.25
0.0 0.5 0.5 1.4 0.5 0.48
NS NS 0.22
NS NS 0.17
NS NS 0.28
Weight (g)
Carcass (%)
133 5.1 136 5.1 139 5.2 134 5.1 136 5.1 2.9 0.06 Orthogonal polynomials4 NS NS 0.22
NS NS 0.08
Total breast 3
Myopathy (%)
Weight (g)
Carcass (%)
2.0 2.4 1.5 4.3 2.3 1.06
758 762 783 760 771 16.8
28.7 28.7 29.1 29.0 28.9 0.29
NS NS 0.16
NS NS 0.27
Values are the least square means of six pens each providing ca. 28 carcasses. All cubic responses were not significant (P > 0.05). Incidence of blood contaminating the meat (“blood slash”). 3 Incidence of myopathy (“green muscle disease”). 4 NS, P > 0.05. 1 2
NS NS 0.19
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1 Values are the least square means of six pens each providing ca. 28 carcasses. All cubic responses were nonsignificant (P > 0.05). 2 Depot fat removed from the abdominal cavity of carcasses without neck and giblets after 4 h of slush-ice chilling expressed on an absolute basis and relative to its entire weight. 3 Chilled carcass without abdominal fat expressed on an absolute basis and relative to the full-fed live weight. 4 NS, P > 0.05.
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CORZO ET AL. TABLE 6. Nitrogen retention (49 d), plasma aspartate transferase and uric acid values (50 d) of broiler males having heavy and light body weights at 48 d of age after receiving feeds having progressive lysine from 43 d of age, while being reared in a summer environment1 Nitrogen Intake (mg)
Excretion (mg)
Lysine % 0.85 0.95 1.05 1.15 1.25 SEM
NS 5,753 5,735 5,862 5,368 5,385 195.0
NS 3,225 3,188 3,402 2,887 3,086 172.9
Linear Quadratic R2 Body weight2 Heavy Light SEM
* NS 0.18 NS 5,640 5,583 120.1
NS NS 0.21 NS 3,205 3,111 110.6
Retention (%)
Retention (mg/kg BW)
NS NS 44.0 0.97 44.9 0.98 41.4 0.92 45.5 0.95 42.2 0.87 2.76 0.070 Orthogonal polynomials3 NS NS 0.18 NS 43.0 44.2 1.70
NS NS 0.14 NS 0.90 0.97 0.044
Aspartatetransferase (IU/L)
Uric acid (mg/dL)
NS 241 254 265 248 227 14.4
NS 4.9 4.1 4.3 4.5 4.1 0.45
NS * 0.15 NS 258 236 9.2
NS NS 0.20 NS 4.7 4.1 0.28
1 Data represents a total of 45 cages each with two birds. Data are given as least-square means of the main factor contrasts given that their interactions were not significant (P > 0.05). All cubic responses were not significant (P > 0.05). 2 Body weight corresponds to groups above and below the total average where heavy = 2,306 g and light = 2,119 g; SEM = 16.4. 3 NS, P > 0.05; *P > 0.05.
Overall data in the present experimentation did not provide a level of lysine that could be considered as a definitive requirement for heat-stressed broilers. Feed conversion was the only measurement that was clearly responsive to lysine, and a linear improvement occurred. All other measurements were not statistically significant, and many numerically attained maximum or minimum values corresponding to a minimum of 0.95% lysine. Corzo et al. (2002) also observed a lack of response to dietary lysine with broilers in an optimal
environment. The requirement approximated 0.85% lysine and also arose from numerical indications of a few measurements, whereas linearity with feed conversion was indicated. Perhaps, this lack of definition resulted from imposing an ideal balance to avoid subsequent expression of limitation by any one essential amino acid as lysine increased. The increased concentration of lysine needed with heat stress appears to be an absolute accommodation to decreased feed consumption and to provide support for existing growth.
TABLE 7. Plasma total protein, albumin, and glucose values of broiler males having heavy and light body weights at 50 d of age receiving feeds with progressive lysine while being reared in a summer environment1 Total protein (g/dL) Lysine %
Heavy
2
Light
0.85 0.95 1.05 1.15 1.25 SEM
3.8 2.9 3.0 3.3 3.3 0.16
3.2 3.3 3.4 3.6 3.6 0.21
Contrast Linear Quadratic R2
NS ** 0.50
NS NS 0.12
Albumin (g/dL) 2
Heavy
Light
1.54 1.28 1.27 1.38 1.28 1.46 1.35 1.46 1.42 1.48 0.082 0.071 Orthogonal polynomials3 NS * 0.28
* NS 0.21
Glucose (mg/dL) Heavy
Light
281 279 267 245 271 7.8
248 258 270 276 256 8.6
* NS 0.38
NS * 0.25
1 Data represents a total of 45 cages each with two birds. Analyses was performed separately for high and low body weights because of significant interactions involving lysine level and body weight category (albumin P < 0.05; glucose P < 0.05; total protein P < 0.05). All cubic responses were not significant (P > 0.05). 2 Body weight corresponds to groups above and below the total average where heavy = 2,306 g and light = 2,119 g; SEM = 16.4. 3 NS, P > 0.05; *P < 0.05; **P < 0.01.
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Contrasts
Plasma
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LYSINE FOR SUMMER REARED HEAVY BROILERS
TABLE 8. Plasma free amino acid concentrations (nanomoles/mL) of broiler males at 50 d of age receiving feeds having progressive lysine from 43 d of age, while being reared in a summer environment1 Lysine % 0.85 0.95 1.05 1.15 1.25 SEM Contrast Linear Quadratic Cubic R2
Lys
Arg
Met
Thr
Val
Ile
150 257 270 293 310 33.7
614 612 527 581 569 30.8
89 90 91 86 78 4.8
966 946 895 872 970 86.3
145 147 160 153 130 9.3
64 73 81 79 64 6.5
*** NS NS 0.63
NS NS NS 0.47
NS NS NS 0.35
NS NS NS 0.26
NS * NS 0.46
Leu
Phe
Ser
Gly
Trp
Tyr
His
233 64 167 243 59 152 252 68 162 251 62 176 224 64 156 16.8 3.8 7.7 Orthogonal polynomials2
495 475 573 565 625 32.6
798 775 772 763 746 32.9
46 28 37 61 29 6.7
166 157 150 162 155 12.3
105 104 100 84 97 3.8
NS * NS 0.48
NS NS NS 0.26
Cys
NS NS NS 0.35
NS NS * 0.45
*** NS NS 0.62
NS NS NS 0.15
NS NS *** 0.66
NS NS NS 0.11
** NS * 0.74
1
Values represent the least-square means of analyses on pooled samples represented by three replicates per level of lysine. NS, P > 0.05; *P < 0.05; **P < 0.01; ***P < 0.001.
2
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