Valine Needs of Male Broilers from 42 to 56 Days of Age

Transcription

1 Valine Needs of Male Broilers from 42 to 56 Days of Age A. Corzo,* E. T. Moran, Jr.,*,1 and D. Hoehler *Department of Poultry Science, Auburn University, Auburn, Alabama 36849; and Degussa Corporation, Kennesaw, Georgia ABSTRACT An experiment was conducted using Ross 0.73% optimized feed conversion. Depot fat removed Ross 308 males to estimate the proportion of dietary valine needed to optimize performance in broilers from from the abdominal cavity after processing was unaltered, and weights of resultant chilled carcasses maximized at 0.73% valine in parallel with final live weight. 42 to 56 d of age. All birds received common feeds from 0 to 42 d, and then experimental diets were given to 56 The amount of fillets recovered from chilled carcasses d of age. A diet consisting of corn, soybean meal, and optimized at 0.73% valine; however, the incidence of distinctive blood streaks in the meat (splash) progressively corn gluten meal (17% CP, 3.25 kcal of ME/g) having increased with valine as did the level of redness apart 0.60% valine served as basal feed. All other essential from streaking, based on light reflectance. Given lysine amino acids were above recommended levels. Successive at 0.85%, a ratio of 0.86 with valine appears to be adequate. additions of 0.07% of L-valine were isonitrogenously substituted for L-glutamic acid up to a total of 0.81%. Regresline (0.67% digestible) for broiler males from 42 to 56 d The presently determined requirement of 0.73% total vasion analysis (95% of response) indicated that valine at 0.72% of the diet maximized body weight gain, whereas of age is slightly higher than the 0.70% recommended by the NRC. (Key words: amino acid requirement, broiler, carcass quality, valine) 2004 Poultry Science 83: INTRODUCTION Valine is a potentially limiting essential acid in cornsoybean meal formulations for growing chickens (Han et al., 1992; Fernandez et al., 1994). This limitation is particularly apparent at older ages when dietary protein decreases and grain extends its contribution. The relatively low proportions of valine and isoleucine in corn protein are accompanied by high leucine. High dietary leucine has been reported to increase the requirements for valine and isoleucine in growing chickens and turkeys (D Mello and Lewis, 1970; Allen and Baker, 1972; Tuttle and Balloun, 1976). Inadequate dietary valine for chicks not only decreases body weight gain and feed conversion but also is accompanied by feather and leg abnormalities (Anderson and Warnick, 1967; Robel, 1977; Farran and Thomas, 1992a,b). Extremely high levels of leucine also lead to feather problems similar in description to those occurring when valine is low (Penz et al., 1984). Leclercq (1998) also observed reduced live performance with broilers deficient in dietary valine, but no mention was made of feather or leg problems. Differences in the expression of a valine 2004 Poultry Science Association, Inc. Received for publication July 10, Accepted for publication January 15, To whom correspondence should be addressed: emoran@acesag. auburn.edu. deficiency may relate to feedstuffs employed and associated leucine. Formulating broiler feed to minimize essential amino acid levels excessive to one another not only improves performance (Waldroup et al., 1976; Baker, 1994; Mack et al., 1999) but also decreases nitrogen excretion and pollution concerns (de Lange, 1993). Assembling a broiler feed having essential amino acids close to their needs for growth and maintenance (Mack et al., 1999) minimizes imbalances among the branched-chain amino acids and nitrogen excretion. The requirement for valine of 0.70% for broilers between 42 and 56 d of age provided by the NRC (1994) is mostly based on modeling and absence of imbalances among the branched-chain amino acids. The purpose of the present experiment was to measure the broiler male s need for valine over this same duration using practical feed ingredients. MATERIALS AND METHODS Commercial source Ross Ross 308 day-old male broilers were randomized into 32 floor pens of an open-sided house having thermostatically controlled curtains and cross ventilation (25 birds/pen; 8 replicates/treatment; m 2 /bird). Each pen contained used litter that had accrued on the floor from one previous experiment and was lightly covered with fresh pine shavings. A core sample of litter (16-cm diameter and 8-cm depth) was re- 946

2 DIETARY VALINE FOR SIX- TO EIGHT-WEEK-OLD BROILERS 947 TABLE 1. Composition of experimental feeds and days duration fed, % as is Common feeds Basal feed Ingredient 0 21 d d d Corn Soybean meal Poultry oil Corn gluten meal 8.00 DL-Methionine Lysine sulfate Dicalcium phosphate Limestone Sodium chloride L-Threonine 0.31 L-Arginine 0.39 L-Tryptophan 0.04 L-Isoleucine 0.27 L-Glycine 1.00 L-Glutamic acid 2.00 Other 2 to 100% to 100% to 100% Calculated analyses CP (%) ME (kcal/g) Lysine (%) Calcium (%) Available phosphorus (%) Biolys 60 (L-lysine sulfate, a fermentation product with a minimum content of 47.3% L-lysine, Degussa Corporation, Kennesaw, GA). 2 Vitamin premix, 0.25% (supplied per kg of diet): vitamin A, 7,356 IU; vitamin D 3, 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). moved from the direct center of each pen at 42 and 56 d of age. Samples were frozen ( 20 C) in vapor-proof bags and ground in a high-speed blender. Kjeldahl nitrogen contents were measured on a fresh basis 2 followed by moisture determination using oven drying for 2 d at 120 C. Chicks had been vaccinated for Marek s disease, Newcastle disease, and infectious bronchitis at the hatchery, and then an additional immunization against infectious bursal disease was administered at 12 d. Common feeds from 0 to 21 and 21 to 42 d of age were given in crumb and whole pellet forms, respectively (Table 1). At 42 d of age, birds were individually weighed, and numbers among pens were equalized (23 birds/pen). Treatments were assigned to pens in a manner that led to a similar average and distribution of bird weights at the start of experimentation. Treatments consisted of the four dietary valine levels that linearly progressed at 0.07% intervals from 0.60%, as provided by the basal feed to 0.81%. Corn, soybean meal, and corn gluten meal were analyzed for their amino acid contents and used as the basis of formulation. Samples of complete feeds obtained from all pens were analyzed to reaffirm expected amino acid levels (Llames and Fontaine, 1994). Formulation of the basal feed minimized the level of valine (0.60%) with lysine at 0.85%. All other essential amino acids were formulated to be above recommended levels. As supplementation of L-valine increased, corres- 2 Degussa Corp., Applied Technology Chemical Group, Allendale, NJ. ponding decreases in L-glutamic acid from the basal level provided isonitrogenous feeds. Feed and water were ad libitum, and lighting was continuous. Feed conversions were corrected for mortality. All cases of mortality were gross-necropsied and categorized as sudden death syndrome, ascites, leg problems, or due to other reasons. At 56 d of age all birds were placed in transportation coops and held 14 h prior to slaughter. Online 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. Warm carcasses were static chilled in TABLE 2. Amino acid analysis of experimental diets fed to broilers from 42 to 56 d of age, 88% dry matter basis 1 Intended valine (%) Amino acid Valine Lysine Arginine Methionine TSAA Threonine Leucine Isoleucine Tryptophan 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 diet are shown. Grand means of the other amino acids are: histidine = 0.32; phenylalanine = 0.66; glycine = 1.41; serine = 0.66; proline = 1.01; glutamic acid = 4.28.

3 948 CORZO ET AL. TABLE 3. Live performance and mortality of broiler males from 42 to 56 d of age in response to progressing levels of dietary valine 1 Body weight (g) Consumption (g) Feed conversion 2 Mortality Valine % Final Gain Feed Valine 42 to 56 d 0 to 56 d total (%) ,191 1,222 3, ,352 1,381 3, ,421 1,450 3, ,410 1,435 3, SEM (27 df) Orthogonal polynomials 3 Linear *** *** *** *** *** *** NS Quadratic ** ** * * *** ** NS Cubic NS NS NS NS NS NS * R Live performance grand means preceding experimentation corresponded to 42 d live weight of 2,971 g with a feed per gain from 0 to 42 d of Values represent the least square means of 8 pens each having ca. 22 birds. The average temperature through experimentation was 14 ± 3 C. 2 Feed conversion values corrected for mortality. 3 NS, P > 0.05; *P < 0.05; **P < 0.01; ***P < slush ice for 4 h, and then depot fat was removed from the abdominal cavity and defects itemized by type and location. Fillets (pectoralis major) and tenders (pectoralis minor) were removed 24 h later using stationary cones and experienced commercial personnel. Incidence of fillets marred with blood and tenders exhibiting myopathy were noted. Light reflectance (CIE scale) was measured at the center of the skin side of each fillet from the right half of every carcass using a hand-held spectrophotometer. 3 Data were evaluated by ANOVA in a randomized complete block design. Blocks corresponded to areas of the house used for live production. Computations employed the GLM procedure of SAS software (1988). Mean separation procedure was performed by orthogonal polynomial techniques. Regression analysis was used to estimate valine requirements (95% of maximum or minimum response) when a quadratic response was statistically significant (P < 0.05). Percentage data corresponding to mortality and carcass defects were transformed to arcsine % for analysis. RESULTS AND DISCUSSION The level of calculated valine for all feeds was in close agreement with analyses performed on the experimental feeds (Table 2). Isoleucine level for all feeds was considered satisfactory given the estimated requirement of 0.66 to 0.74% obtained in previous experimentation under identical terms (Corzo et al., 2002a); whereas total leucine averaged 1.65% and in excess of the 0.93% recommended by NRC (1994). Live performance of broiler males from placement to the initiation of experimentation was favorable (Footnote 1,Table 3). Increasing valine concentration in the basal feed given from 42 to 56 d of age improved 3 Model CM-2002, Minolta Corp., Ramsay, NJ. body weight gain to an optimum approximating 0.72% and feed conversion to 0.73%. Mortality was generally low, and incidences of sudden death syndrome (grand mean = 0.7%; SEM = 0.52), ascites (grand mean = 0.2%; SEM = 0.25), leg problems (grand mean = 0.3%; SEM = 0.50), and other problems (grand mean = 0.6%; SEM = 0.41) were not affected by dietary valine. Anderson and Warnick (1967), Robel (1977), and Farran and Thomas (1992a) described the occurrence of concave primary wing feathering that bent away from the body with rachises slightly broader and more pliable than normal with valine-deficient chicks. Any indication of abnormal feathering corresponding to that previously observed was not apparent; however, broilers in the present experiment were 42 to 56 d of age as opposed to 0 to 3 wk when feather development would have been particularly extensive. Benefit from supplementing L-valine to the basal feed extended to carcass measurements (Table 4). Amount of chilled carcass, but not yield, increased in parallel with final live weight to an optimum of 0.73%; however, depot fat removed from the abdominal cavity was unaltered. Leclercq (1998) also failed to observe any change in body fatness that could be attributed to valine adequacy. Quality of the whole carcass was subjectively estimated on the basis of primary defects associated with grade. Dietary valine had no effect on all obvious defects with the exception of scratches located on the back and thighs that minimized when valine approximated 0.74%. Skin scratching generally reflects increased population dynamics or reduced protection from feather cover. Although appearance of the feathers seemed normal, their quantity and ability to protect the skin is unknown. Farran and Thomas (1992a) reported that inadequate dietary valine reduced feather crude protein content and altered the proportions of many amino acids other than the branched-chained ones. Breast meat removed from the carcass was separated into fillets (pectoralis major) and tenders (pectoralis mi-

4 DIETARY VALINE FOR SIX- TO EIGHT-WEEK-OLD BROILERS 949 TABLE 4. Chilled carcass yield and quality of broiler males that received progressing levels of dietary valine from 42 to 56 d of age 1 Abdominal fat 2 Carcass without abdominal fat 3 Weight Carcass Weight Carcass Back scratch 4 Grade A Valine % (g) (%) (g) (%) (%) (%) , , , , SEM (27 df) Orthogonal polynomials 5 Linear NS NS *** NS NS NS Quadratic NS NS ** NS NS NS Cubic NS NS NS NS * NS R Values are the observed means of 8 pens each providing ca. 22 carcasses. 2 Depot fat removed from the abdominal cavity of carcasses without neck and giblets after 4hofslush-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 Proportion of carcasses having scratches on the back thigh area. 5 NS, P > 0.05; *P < 0.05; **P < 0.01; ***P < nor). Increasing dietary valine led to increasing amounts of fillets that optimized at 0.73% dietary valine; however, their proportion to the carcass was unaffected (Table 5). Incidence of fillets having distinct contamination from vascular rupture (blood splash) was apparent and observed to progressively increase with level of valine. Our experience has been that blood splash is generally located in the immediate area of the clavicle and related to preslaughter trauma. Measurement of fillet light reflectance at the center of the fillet and away from the clavicles indicated that redness (a*) also increased with increased levels of valine. A relationship between the 2 is suggested from their correlation (r = 0.33; P < 0.056). Possible red blood cell hemolysis at the primary trauma site and diffusion of associated heme may have occurred during the interim 48 h between death and measurement of light reflectance. An explanation for a relationship between incidence and valine level is elusive. Alteration of tenders as occurred with fillets was not significant (P = 0.09), and incidence of deep pectoral myopathy ( green muscle disease ) was low and unrelated to dietary valine level. Nitrogen balance had been previously employed by Corzo et al. (2002b) as a means of defining essential amino adequacy for broilers between 42 and 56 d of age using sample birds in cages for 1 d at midpoint. Results were specific for that day and often lacked definition because TABLE 5. Yield and quality of breast fillets (pectoralis major) and tenders (pectoralis minor) of broiler males that had received progressing levels of dietary valine from 42 to 56 d of age 1 Pectoralis major (fillets) Pectoralis minor (tenders) Yield Yield Light reflectance 3 Weight Carcass Blood 2 Weight Carcass Myopathy 4 Valine % (g) (%) total (%) L* a* b* (g) (%) total (%) SEM (27 df) Orthogonal polynomials 5 Linear *** NS * NS * NS NS NS NS Quadratic ** NS NS NS NS NS NS NS NS Cubic NS NS NS NS NS NS NS NS NS R Values represent observed means of 8 pens each providing ca. 22 carcasses. 2 Incidence of blood contaminating meat. 3 Increasing CIE values for L*, a*, and b* correspond to increasing lightness, redness, and yellowness, respectively. 4 Incidence of myopathy (green muscle disease). 5 NS, P > 0.05; *P < 0.05; **P < 0.01; ***P <

5 950 CORZO ET AL. TABLE 6. Litter moisture and nitrogen changes from 42 to 56 d of age for broiler males that had received feed with progressing levels of dietary valine 1 42 Days 56 Days N(%) N(%) N(%) Moisture Dry Moisture Dry Moisture Dry Valine % (%) As is matter (%) As is matter (%) As is matter SEM Orthogonal polynomials 2 Linear NS NS NS NS NS NS NS NS NS Quadratic NS NS NS NS NS NS NS NS NS R Values represent the least square means of 8 replicate pens. All cubic responses were nonsignificant (P > 0.05). 2 NS, P > TABLE 7. Quadratic regression equations of measurements having significant quadratic response by broiler males after receiving progressing dietary levels of valine from 42 to 56 d of age Response criterion Equation 1 R 2 CV Requirement 2 Final body weight (g) y = 1, ,254 (Val) 10,604 (Val) Body weight gain (g) y = 3, ,781 (Val) 9, (Val) Feed consumption (g) y = 3, ,399 (Val) 11,488 (Val) to 56 d feed conversion (g/g) y = (Val) (Val) Total feed conversion (g/g) y = (Val) (Val) Chill carcass weight (g) y = ,272 (Val) 6, (Val) Fillet weight (g) y = , (Val) 2, (Val) Prediction equation based on total dietary valine. 2 Total dietary valine requirement estimates are 95% of response. of inability to employ sufficient numbers and inherent variability associated with the procedures. In the present experiment, litter samples were taken at the beginning and end of the experimental period as an alternate means of estimating balance using nitrogen accrual through the entire 2-wk period (Table 6). This approach further provided an assessment of valine in terms of the relationship between valine adequacy and pollution potential. Even though inherent variability associated with subsampling and differentials among pens implicit with mortality did not yield a significant relationship with dietary valine, a numerical minimization of litter nitrogen occurred between 0.67 and 0.74% valine to support amino acid balance as a meaningful component to pollution control. All results taken together indicate a similar need for valine (Table 7). Broiler males from 42 to 56 d of age exhibited optimal live performance, carcass yield, meat yield, and meat quality when receiving dietary valine at a total level of 0.73% (0.67% digestible). This value is slightly higher than the 0.70% recommended by NRC (1994) for broilers of the same age. The level of leucine that could affect this requirement is not known; however, corn gluten meal employed in present experiment led to a leucine level about 1.5 times its requirement, which is slightly higher than practical application. An optimum ratio of valine with lysine in the present experiment approximated REFERENCES Allen, N. K., and D. H. Baker Quantitative efficacy of dietary isoleucine and valine for chick growth as influenced by variable quantities of excess dietary leucine. Poult. Sci. 51: Anderson, H. C., and R. E. Warnick Gross abnormalities in chicks fed amino acid deficient diets. Poult. Sci. 46: Baker, D. H Ideal protein and amino acid requirement of broiler chicks. Pages in Proceedings of the California Nutrition Conference, Fresno, California. Corzo, A., E. T. Moran, Jr., and D. Hoehler. 2002a. Isoleucine need of broiler males from 42 to 56 days of age. Poult. Sci. 81(Suppl. 1):104. (Abstr.) Corzo, A., E. T. Moran, Jr., and D. Hoehler. 2002b. Lysine need of heavy broiler males applying the ideal protein concept. Poult. Sci. 81: De Lange, C. F. M Formulation of diets to minimize the contribution of livestock to environmental pollution. Pages 9 21 in Proceedings of the Arkansas Nutrition Conference. Fayetteville, AR. D Mello, J. P. F., and D. Lewis Amino acid interactions in chick nutrition. 2. The interrelationship between leucine, isoleucine, and valine. Br. Poult. Sci. 11: Farran, M. T., and O. P. Thomas. 1992a. Valine deficiency. 1. The effect of feeding a valine-deficient diet during the starter period on performance and feather structure of male broiler chicks. Poult. Sci. 71: Farran, M. T., and O. P. Thomas. 1992b. Valine deficiency. 2. The effect of feeding a valine-deficient diet during the starter

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