3Drumstick defects correspond to broken bone and bruise, respectively. ... 5Defects on the back and thigh correspond to bruise, torn skin, scratched skin, and ...
Arginine Need of Heavy Broiler Males: Applying the Ideal Protein Concept A. Corzo,* E. T. Moran, Jr.,*,1 and D. Hoehler† *Department of Poultry Science, Auburn University, Auburn, Alabama 36849; and †Degussa Corporation, Kennesaw, Georgia 30144 were optimized at 0.98% arginine. Weight of the chilled carcass was optimized at 1.00% arginine, whereas depot fat that had been removed from the abdominal cavity continued to decrease to the highest level of supplementation. Additional total arginine to 1.05% was needed to maximize weight recovery of fillets and total breast meat. An arginine requirement for nutritional purposes approximating 1.00% as advocated by NRC (1994) is in general agreement with present results for live production and meat yield; however, carcass incidence of skin scratch infections and parts defects from processing stresses continually responded until the highest level to suggest that additional amounts would be needed for immunological and connective tissue challenges.
ABSTRACT An experiment was conducted to determine arginine need of male broilers between the ages of 42 to 56 d, in conjunction with dietary protein approaching a previously advocated ideal amino acid pattern. Ross × Ross 308 chicks were reared in floor pens (32 pens with 35 birds each) of an open-sided house on common feeds until 42 d of age. From 42 to 56 d of age, birds were fed a corn-soybean meal diet (17% CP, 3,250 kcal/kg ME, and 0.85% lysine) having basal arginine at 0.80%, and then progressive additions of 0.15% were made until 1.25% was reached to form the dietary treatments. Final body weight together with body weight gain and feed conversion through the 42-to-56-d experimental period
(Key words: amino acid balance, arginine, broiler requirement, carcass quality, ideal protein) 2003 Poultry Science 82:402–407
The present experiment assessed male broiler requirements for arginine from 42 to 56 d of age. All other dietary essential amino acids approached an ideal balance as advocated by Mack et al. (1999) within the limit of practicality, using a previously established level of lysine as the basis of formulation (Corzo et al., 2001). Measurements not only involved live performance and quality of resultant carcasses but also employed nitrogen balance conducted at the beginning.
INTRODUCTION The balance of essential amino acids one to the other alters the requirements of broiler chickens (Waldroup et al., 1976; Hurwitz et al., 1978; Baker, 1994; Mack et al., 1999). Lysine level is usually the basis of balance and for estimating the requirements of many amino acids when experimenting to establish a value that is absent. Arginine is one of the amino acids that has not been estimated for broilers between 6 and 8 wk of age, and formal measurement of arginine is needed. The involvement of arginine in immunity (Collier and Vallance, 1989) and wound healing (Efron and Barbul, 1998), as well as its essentialness to maintenance and growth of broilers (Dean and Scott, 1965; Allen and Baker, 1972; Burton and Waldroup, 1979; Cuca and Jensen, 1990), have been well documented. The amount of dietary lysine has been shown to alter the rate of arginine catabolism in chicks (Jones, 1964; Boorman and Fisher, 1966) and appears to be important to establishing its requirement for the broiler (Brake et al., 1994; Brake et al., 1998).
MATERIALS AND METHODS Commercial source Ross × Ross 308 male 1-d-old chicks were randomized into floor pens of an open-sided house having thermostatically controlled heating, curtains, and cross-ventilation (32 pens; 35 birds/pen; 0.118 m2/bird). 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 again at 12 d of age for infectious bursal disease. Birds received common crumbled and whole pellet feeds from placement to 21 d and 21 to 42 d, respectively, each of which were formulated to satisfy NRC (1994) nutrient recommendations (Table 1). At 42 d of age, bird number was equalized among pens (27 per pen), and then treatments were assigned to pens to provide a similar distribution of average bird weight
2003 Poultry Science Association, Inc. Received for publication August 19, 2002. Accepted for publication October 24, 2002. 1 To whom correspondence should be addressed: emoran@ acesag.auburn.edu.
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403
DIETARY ARGININE FOR SIX- TO EIGHT-WEEK-OLD BROILERS TABLE 1. Composition of experimental feeds and days of age fed (% as is) Ingredient
0–21 d
21–42 d
42–56 d1
Corn Soybean meal Poultry oil Corn gluten meal DL-Methionine Biolys2 Dicalcium phosphate Limestone Sodium chloride L-Threonine L-Glutamic acid L-Isoleucine L-Tryptophan L-Valine Other3
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%
78.07 8.82 0.79 7.00 0.10 0.62 1.35 1.23 0.32 0.18 0.80 0.06 0.06 0.05 to 100%
22.50 3.15 1.24 0.90 1.08 0.48
20.50 3.20 1.12 0.75 1.00 0.38
17.0 3.25 0.85 0.75 0.80 0.35
Calculated analyses CP (%) ME (kcal/g) Lysine (%) TSAA (%) Calcium (%) Available phosphorus (%) 1
Basal feed from 42 to 56 d of age. Biolys 60 (L-lysine sulfate a fermentation product, with a minimum content of 47.3% L-lysine, Degussa Corporation, Kennesaw, GA). 3 Vitamin premix, 0.25% (supplied per kg 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/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
at the start of the experiment. Treatments consisted of four dietary levels of arginine that progressed equally from 0.80% as provided by the basal feed to 1.25%. Feed ingredients used from 42 to 56 d of age were corn, soybean meal, and corn gluten meal and were analyzed for protein bound and supplemented amino acids according to Llames and Fontaine (1994). Formulation of the basal diet not only minimized arginine content (0.80%) but assured levels of all other essential amino acids in a manner that would approach an optimal balance as estimated by Mack et al. (1999), considering the practical limitations of not using a semipurified diet thus resembling industry applications. Amounts of all essential amino acids were established using an optimum of 0.85% lysine (Corzo et al., 2001) as the basis of balance. L-Arginine-HCl was added to the basal diet at the expense of an isonitrogenous equivalent of L-glutamic acid. Feed and water were offered ad libitum, and lighting was continuous. Feed conversions were corrected for mortality. Mortality was gross necropsied and categorized as due to sudden death syndrome, ascites, leg problems, or other reasons. Experimental procedures were monitored by the Auburn University Animal Welfare Board. Nitrogen balance of the experimental feeds was measured separately from influence on live production. At 39 d of age, 96 birds were removed from the broiler floor population such that their individual body weights were
2
CM-2002, Minolta Corp., Ramsay, NJ.
within 5% of the total average. These birds were divided into groups that were heavier (heavy) or lighter (light) than the average, and then each group was placed in raised-wire floor batteries (two birds per cage). Battery cages contained one trough waterer and one trough feeder. Room lighting was continuous, and temperatures were similar to those concurrently experienced by broilers that were maintained on the floor. Caged birds received each of the experimental feeds until d 42. Excreta were collected through d 42 to 43 and held frozen at −20°C for later lyophilization. Nitrogen retention was calculated from semi-Kjeldahl measurements on feed and excreta. 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 scaled-down version of a commercial plant that involved a 9-min kill line followed by a 7-min evisceration line. Resulting warm carcasses were static chilled in slush-ice for 4 h. Then, the depot fat was removed from the abdominal cavity, and defects central to grade were itemized by type and location. Removal of the fillets (pectoralis major) and tenders (pectoralis minor) was accomplished by experienced personnel and use of stationary cones. Incidence of blood contaminating the fillets and tenders exhibiting myopathy were noted during measurement. Light reflectance of fillets originating from the right side of the carcass were measured at the center of the skin side 24 h after removal from carcass using hand-held spectrophotometer.2 Data were evaluated by ANOVA in a completely randomized design. Computations were by the general linear
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CORZO ET AL. TABLE 2. Actual amino acid analysis of experimental diets fed to broilers from 42 to 56 d of age (88% dry matter basis)1 Intended arginine % Amino acid
0.80
0.95
1.10
1.25
Arginine Lysine Methionine Cystine TSAA Threonine Isoleucine Valine Tryptophan Leucine Glutamic acid
0.78 0.86 0.42 0.37 0.78 0.71 0.64 0.77 0.18 1.81 3.67
0.91 0.84 0.43 0.37 0.80 0.71 0.65 0.78 0.18 1.83 3.53
1.11 0.89 0.44 0.32 0.77 0.74 0.69 0.80 0.19 1.82 3.51
1.25 0.86 0.43 0.33 0.76 0.72 0.66 0.77 0.19 1.76 3.22
1 Representative samples were analyzed in duplicate by Degussa Corporation Applied Technology Chemical Group, Allendale, NJ.
model procedure of SAS software (1988). Mean separation procedure was performed by orthogonal polynomial techniques. Regression analysis was used to estimate the optimal level of arginine (95% of the upper asymptote) whenever a significant quadratic response (P < 0.05) was detected. All percentage data for carcass defects and mortality were transformed to arcsine square root percentages for analysis.
RESULTS AND DISCUSSION The level of arginine calculated to be in each experimental diet was in agreement with actual analyses (Table 2). Live performance of broiler males from placement to initiation of experimentation was favorable. Pen environments during the subsequent 42 to 56 d of age when the progressive levels of dietary arginine were provided also enabled a favorable live performance (Table 3). As arginine consumption increased, body weight gain and feed conversion improved to an optimum approximating 0.98%; however, mortality in total as well as deaths attributable to sudden death syndrome, ascites, and leg problems were all similar.
The level of dietary arginine that had been provided before processing also affected chilled carcass yield (Table 4). Not only did the amount of chilled carcass increase in the same manner as live weight with progressive arginine, but the percentage yield increased as well. A large proportion of this improvement to relative yield could be attributed to reducing amounts of depot fat removed from the abdominal cavity. The level of arginine needed to maximize the amount of chilled carcass approximated 1.00%, which was similar to that needed for optimizing live performance. The incidence of several defects appearing with the chilled carcass was influenced by dietary arginine (Table 5). Scratching of thigh and back skin that had occurred with the live bird did not differ among all treatments; however, the incidence of scratches that had become infected decreased as dietary arginine progressed to the highest level. Given the relationship of arginine to nitrous oxide generation (Efron and Barbul, 1998), an indirect need for immunological purposes is indicated. Also obvious was the decreased incidence of dislocation of the wing joints as arginine increased to its highest level, whereas broken drumsticks were opposite. Both defects largely
TABLE 3. Live performance and mortality type of broiler males from 42 to 56 d of age in response to progressive levels of dietary arginine1 Body weight (g)
Consumption (g)
Arginine (%)
Final
Gain
Feed
Arginine
0.80 0.95 1.10 1.25 SEM (27 df)
3,906 4,003 4,000 3,925 24.3
1,183 1,274 1,265 1,194 20.7
3,114 3,166 3,051 2,979 31.9
25 30 34 37 0.3
Contrast Linear Quadratic R2
NS ** 0.58
NS *** 0.37
** * 0.49
*** ** 0.97
Feed conversion2 42 to 56 d
Mortality (%)3
0 to 56 d
SDS
Ascites
Leg
Other
Total
2.75 1.85 2.53 1.82 2.57 1.79 2.71 1.80 0.053 0.009 Orthogonal polynomials
2.1 4.2 3.7 3.0 0.11
1.2 0.2 1.4 1.4 0.09
0.0 0.3 0.6 0.3 0.05
0.3 0.6 0.0 0.3 0.05
3.6 5.3 5.7 5.0 0.62
NS NS 0.11
NS NS 0.09
NS NS 0.07
NS NS 0.07
NS NS 0.09
NS ** 0.33
* NS 0.21
1 Values represent observed means of eight pens each having ca. 25 birds. The average temperature was 19 ± 2°C, and relative humidity was 71 ± 16% through experimentation. All cubic responses were not significant (P > 0.05). 2 Feed conversion values corrected for mortality. 3 Mortality causes were classified as sudden death syndrome (SDS), ascites, leg problems, corresponding to other causes, and totals. NS P > 0.05; *P < 0.05; **P < 0.01; ***P < 0.001.
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DIETARY ARGININE FOR SIX- TO EIGHT-WEEK-OLD BROILERS TABLE 4. Chilled carcass yield of broiler males that received progressive levels of dietary arginine from 42 to 56 d of age1 Abdominal fat2
Carcass without abdominal fat3
Arginine (%)
Weight (g)
Carcass (%)
0.80 0.95 1.10 1.25 SEM (27 df)
79 76 73 70 1.7
2.77 2.61 2.50 2.44 0.059
Contrast Linear Quadratic R2
** NS 0.33
Weight (g)
Carcass (%)
2,774 2,847 2,856 2,814 17.4 Orthogonal polynomials
*** NS 0.39
70.7 70.9 71.4 71.3 0.17
NS ** 0.54
* NS 0.25
1 Values are the observed means of eight pens each providing ca. 25 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. NS P > 0.05; *P < 0.05; **P < 0.01; ***P < 0.001.
occurred after death and were the consequences of stresses imposed by automated plucking and evisceration, respectively, from on-line processing at the poultry farm of Auburn University. A relationship between arginine and these bone defects can be rationalized considering the extensive involvement of this amino acid with collagen and connective tissue. Extensive amounts of connective tissue are used at the growth plate of the epiphysis and to stabilize the shaft, once formed. The response to dietary arginine with all the aforementioned defects continues to the highest level tested and suggests possible needs in excess of requirements for live performance when challenging circumstances exist. Breast meat deboned from the carcass represents a composite of the fillets and tenders. Fillets dominate and correspond to the pectoralis major on each side of the keel
that are emphasized during broiler growth to improve wing downstroke for flight and balance (Acar et al., 1993). Increasing dietary arginine in the present experiment led to increasing amounts of fillets that optimized at a greater level (1.05%) than observed with live weights and carcasses (Table 6). Although meat quality in terms of blood contamination was unaltered, Light reflectance L* and b* values indicated a progressively greater lightness and yellowness, respectively, as arginine content of preslaughter feed had increased. Alterations in fillet light reflectance may indirectly relate to the influence of arginine on muscle creatine content and associated energy reserves (Keshavarz and Fuller, 1971a,b). Tenders correspond to the pectoralis minor and are located immediately below the pectoralis major to act in opposition and provide wing upstroke. Its lesser size relates to its reduced need for strength to act as such
TABLE 5. Percentage defects with carcasses from broiler males that had received progressive levels of arginine from 42 to 56 d of age1 Wings2
Drums3
Breast4
Arginine (%)
Dislocated
Broken
Bruised
Broken
Bruised
0.80 0.95 1.10 1.25 SEM (27 df)
17.2 12.1 13.3 10.5 2.23
1.0 0.5 0.5 0.5 0.25
22.1 26.3 22.5 19.3 3.26
0.5 1.6 1.0 3.5 0.99
1.0 2.3 1.5 2.9 0.69
Contrast Linear Quadratic R2
* NS 0.14
NS NS 0.02
NS NS 0.08
* NS 0.16
NS NS 0.20
Bruised
Back-thigh5
Broken
5.4 8.9 7.9 9.1 6.0 6.8 9.1 7.2 0.24 0.23 Orthogonal polynomials NS NS 0.05
NS NS 0.03
Bruised
Tear
Scratched
Infection
Grade6 A
8.6 15.4 11.8 11.3 0.29
2.0 5.0 5.0 3.8 0.40
3.5 5.4 3.6 4.1 0.16
2.0 1.1 1.0 0 0.07
47.6 41.5 48.5 50.4 3.78
NS NS 0.10
NS NS 0.03
NS NS 0.03
* NS 0.12
NS NS 0.10
1 Values of observed means of eight pens each providing ca. 25 carcasses. Statistical analysis used transformed values (arcsine √ %), whereas the respective SEM values were estimates derived from actual percentages. All cubic responses were nonsignificant (P > 0.05). 2 Wings defects correspond to join dislocation, broken bones, and bruise, respectively. 3 Drumstick defects correspond to broken bone and bruise, respectively. 4 Breast defects correspond to bruise and broken clavicle, respectively. 5 Defects on the back and thigh correspond to bruise, torn skin, scratched skin, and infection of skin scratches, respectively. 6 Proportion of carcasses without major defects. NS P > 0.05; *P < 0.05.
406
CORZO ET AL. TABLE 6. Yield and quality of breast fillets (pectoralis major) from broiler males that received progressive levels of dietary arginine from 42 to 56 d of age1 Yield Arginine (%)
Weight (g)
Carcass (%)
0.80 0.95 1.10 1.25 SEM (27 df)
656 683 681 681 6.4
23.6 23.9 23.8 24.2 0.14
Contrast Linear Quadratic R2
* * 0.45
Blood2 total (%)
Light reflectance (CIE)3 L*
4.5 57.8 3.9 58.1 5.1 58.8 4.8 58.4 0.02 0.27 Orthogonal polynomials
* NS 0.23
NS NS 0.02
* NS 0.22
a*
b*
1.40 1.50 1.58 1.42 0.107
8.73 8.88 9.10 9.02 0.120
NS NS 0.07
* NS 0.16
1 Values represent observed means of eight pens each providing ca. 25 carcasses. All cubic responses were nonsignificant (P > 0.05). 2 Incidence of blood contaminating meat. 3 Increasing values relate to increasing lightness for L*, redness for a*, and yellowness for b*. NS P > 0.05; *P < 0.05.
and to apparent emphasis on growth. Although tenders progressively increased in weight with dietary arginine, their proportion to the carcass was least when the fillet amount was maximized. Tenders undergo myopathy with extenuated wing activity and growth (Wight et al., 1979; Richardson et al., 1980; Siller, 1985); however, their improved development with increasing dietary arginine was not a factor to accentuate expression of this problem in the present experiment. Nitrogen balance experimentation solely relates to use of dietary protein by male broilers in cages between 42 and 44 d of age (Table 7). Although addition of arginine greatly reduces nitrogen excretion of adult males receiving nitrogen-free feed, this advantage relates to relief of body catabolism in support of a continuous need for feather reformation (Muramatsu and Okamura, 1979) rather than retention implicit with growth. Growing male
broilers in the present experiment did not improve nitrogen retentions in response to progressive increases in arginine, nor did differences in body weight have any influence that could be statistically supported. Given the early age when nitrogen balance measurements were conducted and favorable improvements shown to occur with broilers on the floor, absence of substantiation might have related to extensive variance associated with these techniques. An overview of measurements that enabled a defined requirement for arginine indicated that an increasing need progressed from live performance to skinless, boneless breast meat (Table 8). Live weight and feed conversion were optimized at 0.98% arginine, whereas weight of the chilled carcass was optimized at 1.00%, which agrees with NRC recommendations (1994). Maximization of breast fillets and total breast meat upon combining the
TABLE 7. Nitrogen balance of broiler males between 42 and 44 d of age receiving feeds with progressive levels of dietary arginine1 Intake (mg)
Excretion (mg)
Retention (%)
Retention (mg/kg BW)
Arginine (%) 0.80 0.95 1.10 1.25 SEM Linear Quadratic R2
* 5,834 5,446 5,340 5,421 142.1 * NS 0.34
NS 2,061 1,912 1,765 1,813 111.2 NS NS 0.22
NS 64.4 64.9 66.9 66.5 2.08 NS NS 0.10
NS 1.33 1.28 1.27 1.30 0.058 NS NS 0.29
Body weight2 Heavy Light SEM
* 5,701 5,319 101.0
* 2,013 1,762 79.5
NS 64.5 66.9 1.48
NS 1.26 1.33 0.042
Contrasts
1 Data represent a total of 48 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 nonsignificant (P > 0.05). 2 Body weight corresponds to groups above and below the total average in which heavy = 2,901 g, and light = 2,633 g, SEM = 21.6. NS P > 0.50; *P < 0.05.
407
DIETARY ARGININE FOR SIX- TO EIGHT-WEEK-OLD BROILERS TABLE 8. Regression equations of measurements with broiler males that had significant quadratic responses to progressive levels of dietary arginine from 42 to 56 d of age Response criteria BW (g) BW gain (g) F/G Carcass weight (g) Fillet weight (g) Breast weight (g)
Equation1 1,806.8 + 4,291.3 (arg) − 2,082.6 (arg) −621.8 + 3,696.1 (arg) − 1,795.7 (arg)2 6.716 − 8.103 (arg) + 3.924 (arg)2 1,323.6 + 2,922.7 (arg) − 1,387.2 (arg)2 294.6 + 713.5 (arg) − 325.1 (arg)2 414.2 + 761.6 (arg) − 343.5 (arg)2 2
R2
CV
Linear
Quadratic
Requirement2
Arg:Lys
0.24 0.36 0.28 0.26 0.23 0.24
2.26 4.62 5.71 2.12 3.03 2.83
NS NS NS NS * *
** *** ** ** * *
0.98 0.98 0.98 1.00 1.05 1.05
1.15 1.15 1.15 1.18 1.24 1.24
1
Prediction equation based on total dietary arginine. Total dietary arginine requirement estimates are 95% of asymptote. NS P > 0.05; *P < 0.05; **P < 0.01; ***P < 0.001. 2
tenders required an increase to 1.05%. The ratio of arginine to lysine was shown to be adequate at a minimum of 1.15. Decreases in the incidence of skin infections with the carcass and alterations to integrity of parts dependant on connective tissue associated with the carcass all responded to the highest level of arginine tested. Arginine is intricately involved in immunological processes as well as connective tissue to suggest that the need beyond live production could occur when the live broiler is confronted with extensive microbial challenges or stabilization to the physical stresses of on-line processing.
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