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Influence of Metabolizable Energy Feeding Sequence and Dietary Protein on Performance and Selected Carcass Traits of Tom Turkeys1
Influence of Metabolizable Energy Feeding Sequence and Dietary Protein on Performance and Selected Carcass Traits of Tom Turkeys1 J. L. SELL Department of Animal Science, Iowa State University, Ames, Iowa 50011
1993 Poultry Science 72:521-534
Because the relative improvements in feed efficiency resulting from increasing dieThe favorable effects on productive tary ME are greatest during the latter performance of growing turkeys by using portion nof the rearing period, greater supplemental fat to increase dietary MEn concentration are well documented concentrations of MEn are commonly used (Touchburn and Naber, 1966; Jensen et al., in growing and finishing diets. Young 1970; Potter et al, 1974; Sell and Owings, animals grow to attain their lipid-free, 1981; Kagan, 1982; Blair and Potter, 1988). mature body mass and then to achieve their inherent fatness (Emmans, 1987). During early periods of growth, priority is given to growth of lipid-free tissue. SubseReceived for publication July 27, 1992. quently, deposition of body fat accelerates. Accepted for publication November 17, 1992. The degree of this acceleration in growing journal Paper Number 1-14987 of the Iowa Agriculture and Home Economics Experiment Station, turkeys depends to a great extent on the MEn concentration of the diet (Salmon, Ames, IA 50011. Project Number 2887. INTRODUCTION
521
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ABSTRACT Two identically designed experiments were done to determine the effects of reducing dietary MEn concentration during late growth and of dietary protein concentration on performance and selected carcass traits of turkey toms. A complete factorial arrangement of three MEn feeding sequences and four dietary protein concentrations was used. The MEn feeding sequences were 102% of MEn concentrations listed by NRC (1984), from 1 to 119 days of age (M), 102% MEn for 1 to 42 days followed by 108% MEn from 42 to 119 days (M-H), and the same as the M-H sequence except the 102% MEn diets were fed from 105 to 119 days (M-H-M). The four dietary protein concentrations were 93, 100, and 107%, of NRC recommended protein concentrations, in which essential amino acid (EAA) levels met or exceeded NRC recommendations, and 107% of NRC, in which the EAA concentrations were at least 107% of NRC recommendations. Feeding diets of the M-H and M-H-M MEn sequence improved feed efficiency (P < .01) in both experiments as compared with the M sequence. Toms fed the M-H or M-H-M sequences in Experiment 1, but not in Experiment 2, were heavier at the finish than those fed the M sequence. Body fat of toms was increased (P < .05) by feeding the M-H MEn sequence, compared with feeding the M or M-H-M sequences in Experiment 1. No dietary MEn effects on body fat were observed in Experiment 2. Dietary protein concentration did not modify the effects of MEn feeding sequence and there were no effects of protein concentration on BW or feed efficiency in either experiment. Fat pad and breast meat weights were affected differently by dietary treatments in the two experiments, possibly because of differences in ambient temperature during the last 3 to 4 wk of the experiments. {Key words: nitrogen-corrected metabolizable energy, dietary protein, turkey toms, performance, carcass composition)
522
SELL
to improve performance and decrease body fat of heavy turkeys may be related to inappropriate amino acid balance. The research reported herein was done to determine whether a reduction in MEn of diets fed during the last 2 wk of the finishing period and selective amino acid supplementation of diets of relatively low or high protein content would reduce body fat of heavy toms without adversely affecting performance and certain carcass traits. MATERIALS AND METHODS In each of two identically designed experiments, 1,320,1-day-old male turkeys were allotted randomly to 44 floor pens, 30 toms per pen. Each pen provided .095 m2 per torn. The toms were reared to 117 days in Experiment 1 and to 119 days in Experiment 2 under continuous lighting with feed and water provided for ad libitum consumption. Twelve treatments were used, consisting of a complete factorial arrangement of four dietary protein-amino acid concentrations and three MEn feeding sequences, as outlined in Table 1. Three of the protein levels were 93, 100, and 107% of the protein concentration recommended by NRC (Diets 93P, 100P, and 107P, respectively). In all instances, these diets were formulated to at least meet NRC recommended EAA concentrations. A fourth protein-amino acid test diet series (Diet 107B) was obtained by formulating Diet 107P to contain at least 107% of the EAA concentrations recommended by NRC. Achieving this goal involved supplementing the Diet 107P with additional DL-Met. On a calculated basis, the concentrations of all other essential amino acids were present in the 107B diet at 107% or more of NRC recommended levels. The three MEn feeding sequences consisted of 1) feeding a diet of moderate MEn content [102% of that listed by NRC from 1 to 119 days of age (Sequence M)]; 2) feeding the moderate-MEn diets from 1 to 42 days of age followed by feeding high-MEn diets [108% of the MEn listed by NRC from 43 to 119 days (Sequence M-H)]; or 3) feeding the moderate-MEn diets from 1 to 42 days, the high-MEn diets from 43 to 105 days,
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1974; Moran et al, 1984; Sell et al, 1985, 1989; Hurwitz et al, 1988). Thus, the common use in the commercial industry of growing and finishing diets of high MEn content generally results in market turkeys that are deemed excessively fat. Because the economics of feeding highMEn diets through the finishing period have usually been favorable, little consideration has been given to using diets of relatively low MEn content during the final phases of growth as a means of reducing body fat while maintaining turkey performance. Research has shown that manipulation of dietary protein and amino acid concentrations within practical limits has little influence on the effect of high dietary MEn concentrations, whereby fat content of turkeys is increased. For example, toms fed high-MEn, high-protein diets during the growing and finishing periods deposited body fat to essentially the same extent as those fed high-MEn, low-protein diets (Sell et al, 1985, 1989; Blair et al, 1989a; Ferket and Sell, 1990). In these earlier studies, however, diets of ample or excess protein content were formulated to meet NRC (1984) recommendations for the essential amino acids (EAA). Consequently, the concentrations of most EAA in high-protein diets exceeded those recommended by a substantial margin but, simultaneously, one or two EAA often just met the recommended concentration. In the study of Sell et al (1989), the relative concentrations of some EAA in diets containing 109% of NRC recommended protein levels exceeded NRC requirements by up to 40%, but, in the same diets, the Lys and Met concentrations only met or slightly exceeded the NRC recommendations. Almquist (1952) stated that amino acid requirements of chicks, as percentages of the diet, increased as the concentration of dietary protein increased. Since that time, additional evidence indicates that requirements of certain EAA, stated as a percentage of the diet, increased as dietary protein concentration increased (Boomgaardt and Baker, 1971,1973; Morris et al, 1987; Robbins, 1987; Abebe and Morris, 1990). Thus, the question arises whether the failure of relatively high-protein diets
523
METABOLIZABLE ENERGY FEEDING SEQUENCE AND PROTEIN FOR TOMS TABLE 1. Outline of relative dietary concentrations of protein and MEn used in Experiments 1 and 2 Relative MEn by days of age Dietary ME,, feeding sequence2
1 to 42
(% of NRC, 1984) 93P1 100P 107P 107B 93P 100P 107P 107B 93P 100P 107P 107B
M M M M M-H M-H M-H M-H M-H-M M-H-M M-H-M M-H-M
102 102 102 102 102 102 102 102 102 102 102 102
43 to 105 (% of ME„ NRC, 1984) — 102 102 102 102 108 108 108 108 108 108 108 108
106 to 119 102 102 102 102 108 108 108 108 102 102 102 102
Numerical values indicate the percentages of the dietary protein concentrations recommended by NRC (1984); 107B indicates that concentrations of protein and essential amino acids equaled at least 107% of NRC (1984) recommendations. 2 M and H correspond to 102 and 108%, respectively, of the NRC (1984) guidelines for dietary MEj, concentrations.
values and those determined by laboratory analysis are shown. Crude protein content of the diets was determined by the macro-Kjeldahl procedure and amino acid analyses were done at a commercial laboratory.2 Composition of diets used in Experiment 2 were nearly the same as those of Experiment 1. All diets were fed in mash form. A pen of toms represented an experimental unit, and each of the eight treatments of MEn Sequences M and M-H was assigned to four pens. Because only 44 pens were available for the experiment, each of the four treatments of MEn Sequence M-H-M was assigned to three pens. Body weight and feed consumption data were recorded when toms were 21, 42, 63, 84, 105, and 119 days old. Immediately after the toms were weighed at 119 days of age (117 days of age in Experiment 1), two toms representing average pen weight were selected from each pen. Feed was withdrawn from these toms, but water was provided for approximately 16 h before the toms were processed at the Meat Laboratory, Iowa State University. Experiment Station Chemical Laboratories, Toms were weighed individually, stunned Columbia, MO 65211.
and then the moderate-MEn diets from 106 to 119 days (Sequence M-H-M). Adjustments in nutrient and MEn concentrations of the diets were made according to six age categories: 1 to 21, 22 to 42, 43 to 63, 64 to 84, 85 to 105, and 106 to 119 days. In instances of the age categories of 21 to 42, 43 to 63, and 64 to 84 days, which did not correspond to age categories listed by NRC, protein, amino acid, and MEn values used to determine dietary concentration for the current study were obtained by extrapolation. National Research Council requirements given for the periods of 1 to 4 wk and 16 to 20 wk were used in formulating diets for the age periods of 1 to 21 and 106 to 117 days, respectively. The ingredient composition and MEn, CP, and amino acid contents of the starter diets (1 to 21 days) of Experiment 1 are presented in Tables 2 and 3, respectively, and the analogous data for the finisher diets (106 to 119 days) are presented in Tables 4 and 5, respectively. In the instances of CP and amino acids, calculated
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Dietary protein1
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SELL TABLE 2. Ingredient composition of turkey starter diets, Experiment 1 Relative concentration of dietary protein1
Ingredients
93 M
100 M
107 M
107B M
Corn (7.71% CP) Soybean meal (47.7% CP) Dehydrated alfalfa meal (17% CP) Feather meal (78% CP) Animal-vegetable fat2 Dicalcium phosphate Limestone Salt-mineral premix 3 Vitamin premix 4 L-lysineHCl DL-methionine Stafac®5
45.77 41.79 3.00 2.00 2.41 2.36 1.67 .30 .30 .15 .21 .05
39.75 47.08 3.00 2.00 3.39 2.32 1.66 .30 .30
33.92 52.09 3.00 2.00 4.32 2.29 1.64 .30 .30
33.96 52.00 3.00 2.00 4.30 2.29 1.64 .30 .30
.15 .05
.09 .05
.16 .05
(%)
TABLE 3. Concentrations of MEn, protein, and amino acids in turkey starter diets, Experiment 1 Relative concentration of dietary protein1 93 M
100 M 2
Concentration
CaP
ME„, kcal/kg
2,850
2,850
Protein TSSA Met Lys Arg His He Leu Phe + Tyr Thr Trp Val
26.06 26.51 1.05 1.04 .56 .60 1.60 1.61 1.87 1.83 .71 .65 1.30 1.22 2.19 2.27 2.29 2.27 1.04 1.05 .33 .33 1.47 1.40
28.00 28.15 1.05 1.02 .57 .58 1.64 1.64 2.03 1.98 .71 .75 1.42 1.31 2.33 2.37 2.46 2.44 1.12 1.13 .37 .37 1.59 1.46
Det
Cal
107 M Cal
Det
Det
107B M Cal
Det
2,850
2,850 . . .
29.96 29.99 1.05 1.05 .54 .52 1.79 1.76 2.19 2.13 .77 .80 1.53 1.44 2.47 2.53 2.62 2.61 1.20 1.18 .39 .40 1.70 1.64
29.96 29.62 1.12 1.13 .61 .59 1.78 1.74 2.19 2.10 .77 .79 1.53 1.38 2.47 2.49 2.69 2.57 1.20 1.19 .39 .41 1.69 1.56
\ju)
'Numerical values indicate percentage of the dietary protein concentration recommended by NRC (1984); 107B indicates that concentrations of protein and essential amino acids equaled at least 107% of NRC (1984) recommendations; M indicates 102% of MEn concentration listed by NRC (1984). 2 Cal = calculated values; Det = values determined by laboratory analysis.
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'Numerical values indicate percentages of the dietary concentration recommended by NRC (1984); 107B indicates that concentrations of protein and essential amino acids equaled at least 107% of NRC (1984) recommendations; M indicates 102% of ME n concentration listed by NRC (1984). 2 Fatty acid composition, as percentage methyl esters: Cjgo, 17.64; Cig.j, 1.47; Cjgo, 9.61; Cjgi, 31.3; Cjg^, 33.89; C18:3, 3.63; others, 2.46. 3 Supplied per kilogram of diet: Mn, 70 mg; Zn, 40 mg; Fe, 37 mg; Cu, 6 mg; Se, .15 mg; NaCl(I), 2.60 g. 4 Supplied per kilogram of diet: vitamin A, 5,000 IU; cholecalciferol, 1,500 IU; vitamin E, 15 IU; vitamin B12, 11 /ig; menadione sodium bisulfite, 1.8 mg; riboflavin, 2.7 mg; pantothenic acid, 7 mg; niacin, 75 mg; choline, 509 mg; folic acid, 550 \t%; biotin 75 ^g; ethoxyquin, .0045%. 5 Contains 44 g virginiamycin/kg; SmithKline Beecham, Exton, PA 19341.
METABOLIZABLE ENERGY FEEDING SEQUENCE AND PROTEIN FOR TOMS
525
TABLE 4. Ingredient composition of turkey finisher diets, Experiment 1 Relative concentration of dietary protein1 Ingredients
93 M
100 M 107 M 107B M
Corn (6.98% CP) Soybean meal (48.8% CP) Meat and bone meal (50.1% CP) Feather meal (78% CP) Animal-vegetable fat2 Dicalcium phosphate Limestone Salt-mineral premix 3 Vitamin premix 4 L-lysineHCl DL-methionine Stafac®5
75.46 11.65 4.00 3.00 3.60 .75 .70 .30 .30 .17 .045 .025
71.88 14.81 4.00 3.00 4.19 .73 .69 .30 .30 .05 .025 .025
93 H
100 H 107 H 107B H
(%)
.01 .025
68.42 17.79 4.00 3.00 4.74 .71 .68 .30 .30 .18 .03 .025
70.59 12.39 4.00 3.00 7.76 .77 .69 .30 .30 .16 .045 .025
67.01 15.55 4.00 3.00 8.34 .75 .68 .30 .30 .04 .027 .025
63.57 18.52 4.00 3.00 8.89 .73 .67 .30 .30
63.55 18.52 4.00 3.00 8.89 .73 .67 .30 .30
.01 .025
.03 .025
Numerical values indicate percentages of the dietary protein concentration recommended by NRC (1984); 107B indicates that concentrations of protein and essential amino acids equaled at least 107% of NRC (1984) recommendations; M indicates 102% and H indicates 108% of MEn concentration listed by NRC (1984). 2 Fatty acid composition, as percentage methyl esters: C\(,Q, \7.(A; C\&\, 1A7; CJS-O' 9.61; Cjgi, 31.3; Cj8-2/ 33.89; C18:3, 3.63; others, 2.46. ^Supplied per kilogram of diet: Mn, 70 mg; Zn, 40 mg; Fe, 37 mg; Cu, 6 mg; Se, .15 mg; NaCl(I), 2.60 g. Supplied per kilogram of diet: vitamin A, 5,000 IU; cholecalciferol, 1,500 IU; vitamin E, 15 IU; vitamin B^, 11 ng; menadione sodium bisulfite, 1.8 mg; riboflavin, 2.7 mg; pantothenic acid, 7 mg; niacin, 75 mg; choline, 509 mg; folic acid, 550 pg; biotin, 75 tig; ethoxyquin, .0045%. 5 Contains 44 g virginiamycin/kg; SmithKline Beecham, Exton, PA 19341.
TABLE 5. Concentrations of MEn, protein, and amino acids in moderate MEn turkey finisher diets, Experiment 1 Relative concentration of dietary protein1 93 M1 Det 2
100 M
107 M Det
107B M Cal
Det
Nutrient
CaP
MEn, kcal/kg
3,264
3,264
3,264
3,264 . . .
Protein TSSA Met Lys Arg His lie Leu Phe + Tyr Thr Trp Val
15.34 15.62 .60 .73 .30 .28 .80 .90 .95 1.03 .33 .38 .66 .61 1.39 1.41 1.38 1.19 .63 .62 .14 .16 .76 .86
16.50 16.64 .62 .73 .28 .28 .80 .81 .99 1.13 .41 .37 .68 .73 1.48 1.51 1.48 1.30 .68 .66 .15 .18 .83 .93
17.67 18.05 .64 .76 .28 .29 .85 .87 1.22 1.16 .40 .45 .80 .73 1.56 1.58 1.58 1.40 .72 .73 .17 .19 1.00 .87
17.67 18.27 .66 .78 .30 .36 .86 .94 1.22 1.29 .40 .48 .80 .77 1.56 1.59 1.58 1.43 .72 .72 .19 .18 .99 .88
Cal
Det
Cal
Numerical values indicate percentages of the dietary protein concentration recommended by NRC (1984); 107B indicates that levels of protein and essential amino acids equaled at least 107% of NRC (1984) recommendations; M indicates 102% of ME„ concentration listed by NRC (1984). 2 Cal = calculated values; Det = values determined by laboratory analysis.
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68.38 17.85 4.00 3.00 4.75 .71 .68 .30 .30
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SELL
RESULTS Experiment 1
Because of a conflict of dates to process toms of Experiment 1, terminal body weight and feed consumption data were recorded at 117 days instead of 119 days of age, and the toms were processed at 118 days of age. Body weight, feed efficiency (feed:gain), and carcass trait data are presented according to treatment means in Table 6 and as main effect means in Table 7. There were no significant effects (P > .05) of dietary protein concentration on
3 Hobart Manufacturing Co., Des Moines, IA 50318.
117-day BW, feed efficiency, or carcass traits measured. There were favorable effects (P < .05) of MEn feeding sequence, whereby MEn sequences M-H and M-H-M improved BW and feed efficiency (P < .05) compared with the continuous M feeding sequence. Reducing the dietary MEn concentration for the age interval of 106 to 117 days (Sequence M-H-M) did not significantly affect performance of toms as compared with Sequence M-H. An interaction between protein concentration and MEn sequence was indicated (P = .081) for BW. However, there were no consistent patterns observed that could be related causally to this interaction. Mortality totaled 8.8% and was distributed among the treatment groups. Carcass yield, stated as percentage of live weight, was not affected by protein concentration or MEn feeding sequence. Statistical analysis revealed a protein concentration by MEn feeding sequence interaction effect on carcass yield. A perusal of these data, however, showed that the interaction occurred because of inconsistencies among the treatments. These inconsistencies had no meaningful pattern. In comparison with toms fed Sequence M, toms fed Sequence M-H had heavier fat pads (P < .01). Fat pad weight and percentage of live weight of toms fed Sequence M-H-M were slightly greater than those of toms fed Sequence M, but were less than those of toms fed Sequence M-H. Protein concentration did not affect fat pad of the toms, and no interaction was observed between protein concentration and MEn feeding sequence. Also, no treatment effects were observed for weight or percentage yields of breast meat. Data obtained from chemical analysis of the carcasses (Tables 8 and 9) show that only the percentages of water and fat were affected (P < .05) by treatments. Carcasses of toms fed the MEn Sequence M-H contained less water and more fat than those of toms fed either Sequences M or M-H-M. In the instance of carcass fat, the main effect means of Sequence M and M-H-M treatment groups were similar. Protein concentration did not affect carcass composition, and there were no effects of MEn feeding sequence on carcass protein or ash.
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electrically, and the jugular veins were severed. Carcasses were deplumed after a 2-min scald at 60 C and were eviscerated. During evisceration, abdominal fat pads, including adipose tissue around the gizzard, were removed and weighed. After evisceration, carcasses without neck and giblets were placed in ice water and chilled for 21 to 22 h. Chilled carcasses were removed from ice water, drained, and weighed. Breast meat without skin was removed from each carcass and weighed. The carcasses and breasts of the two toms from each pen were placed in a plastic bag and frozen at -20 C. In preparation for chemical analysis, an electric meat saw (Model 50-12)3 was used to cut the frozen carcasses into pieces that would pass down the throat of a Buffalo N066BX, worm-gear meat grinder. After four passages through the grinder, the ground turkey was blended (Model VCM40 Blender)3 for 2 min. Subsamples of this blend were taken for determination of carcass protein, fat, water, and ash. Because many responses to dietary treatments differed between Experiments 1 and 2, data of each experiment were analyzed separately. Two-way analyses of variance were done to determine main effects and interactions of dietary proteinamino acid concentration and MEn feeding sequence by using the General Linear Models program (SAS Institute, 1985).
METABOLIZABLE ENERGY FEEDING SEQUENCE AND PROTEIN FOR TOMS
527
TABLE 6. Influence of dietary protein, amino acid balance, and sequence of dietary MEn on performance and selected carcass traits of toms, Experiment 1
Dietary protein 1
M2 M M M M-H M-H M-H M-H M-H-M M-H-M M-H-M M-H-M
Source of variation Protein level (P) ME sequence (S) P x S
Carcass yield
(kg per torn)
11.59 11.81 12.24 11.70 12.33 12.12 11.74 12.19 11.91 12.29 12.37 12.13 .19
2.59 2.56 2.54 2.59 2.42 2.44 2.44 2.38 2.48 2.49 2.46 2.45 .022
(% of live weight) 79.8 78.8 80.8 80.4 78.7 78.5 78.8 80.8 79.4 80.1 79.0 79.5 .5
.54 .001 .33
.23 .15 .042
.86 .043 .081
Breast meal
Fal: pad (g per torn)
(% of live weight) .87 1.03 1.10 1.05 1.48 1.55 1.31 1.14 1.08 1.37 1.17 1.08 .12
(g per torn)
96.9 118.8 127.9 118.5 181.6 181.4 144.6 134.2 127.2 163.3 138.6 126.0 15.6 Probabilities — .24 .23 .002 .003 .29 .42
2,151 2,091 2,306 2,120 2,340 2,171 2,014 2,188 2,298 2,194 2,255 2,247 82
(% of live weight) 19.37 18.15 19.88 18.78 19.08 18.49 18.14 18.58 19.46 18.33 19.17 19.38 .47
.47 .45 .22
.13 .37 .57
(% of carcass) 24.29 23.04 24.62 23.38 24.24 23.58 23.01 23.25 24.50 22.88 24.28 24.37 .60 .15 .59 .61
!Diet 93P contained NRC (1984) recommended essential amino acid concentrations and Diets 107B were supplied with sufficient methionine to achieve the same proportional increase as the increase in dietary protein. 2 M and H indicate the diets containing 102 and 108%, respectively, of the ME n concentrations listed by NRC (1984) for comparable ages.
Experiment 2 Dietary protein concentration had no effect on 119-day BW or feed efficiencies in Experiment 2 (Tables 10 and 11). Body weights also were not affected by ME n feeding sequence. Feed efficiencies, however, were improved (P < .001) by Sequences M-H and M-H-M, compared with the Sequence M, irrespective of dietary protein concentration. No significant protein concentration by ME n feeding sequence interaction was observed for 119-day BW and feed efficiencies. Mortality was not affected by dietary treatments and totalled 12.6% during the 119-day experiment. Both dietary protein concentration and ME n sequence affected (P < .01) eviscerated carcass yield (Tables 10 and 11). In the instance of protein, feeding diets containing 100% or more of the concentrations recommended by NRC (Diets 100P, 107P, and 107B) increased percentage carcass yield as compared with the Diet 93P. Carcass yield
also was increased for toms fed Sequence M-H, especially compared with the carcass yields of toms fed Sequence M. Neither weight of fat pad per torn nor fat pad as a percentage of body weight was affected by protein concentration or ME n feeding sequence. However, weight and percentage yield of breast meat and eviscerated carcass yield were affected by dietary protein. Feeding Diets 100P, 107P, or 107B increased breast meat weight and percentage yield, compared with feeding the Diet 93P, and this protein concentration effect occurred irrespective of ME n feeding sequence. The ME n feeding sequence did not affect breast meat yield. Proximate analyses of the eviscerated carcasses showed that dietary treatments did not influence water, protein, fat, or ash content (Tables 12 and 13). DISCUSSION Although many responses to dietary treatments were the same in Experiments
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93P 100P 107P 107B 93P 100P 107P 107B 93P 100P 107P 107B SEM
Dietary 117-•day ME„ lvlE, n Feed: feeding 2 Body sequence weight gain
528
SELL
TABLE 7. Main effect means showing effects of dietary protein and sequence of dietary MEn on performance and selected carcass traits of toms, Experiment 1 117- day Body weight
Feed: gain
Carcass yield
(kg per torn)
(8=8)
(% of live weight)
(g per torn)
(% of live weight)
(g per torn)
(% of live weight)
(% of carcass weight)
Dietary protein 1 93P 100P 107P 107B
11.94 12.05 12.07 11.99
2.50 2.50 2.48 2.48
79.3 79.1 79.4 80.0
136.0 153.7 137.8 126.2
1.15 1.31 1.20 1.09
2,260 2,149 2,174 2,180
19.29 18.33 18.97 18.88
24.33 23.19 23.87 23.60
Dietary ME n sequence 2 M M-H M-H-M
11.80 12.09 12.16
2.57 2.42 2.46
79.9 79.1 79.4
114.7 161.6 139.1
1.01 1.38 1.18
2,158 2,179 2,243
19.00 18.59 19.03
23.78 23.52 23.94
Main effect
Fat : pad
Breast mieat
1 and 2, there were several instances in which treatment responses differed. The latter phase of Experiment 1 occurred during late June and, at this time, ambient temperature and relative humidity were high. Average daily high temperature was 31.7 C during the last 3 wk of the Experiment 1. In contrast, daily high temperatures during the last 3 wk of Experiment 2, which was completed in February, averaged 14.4 C. Ostensibly, these dissimilar ambient conditions resulted in differences between the two experiments in some performance and carcass characteristics of the same strain of toms fed identically formulated diets. For example, toms of Experiment 1 averaged 12.0 kg each at 117 days of age as compared with 13.4 kg each at 119 days for toms of Experiment 2. Accompanying the differences in BW were differences in carcass traits, whereby the heavier toms of Experiment 2 had greater carcass and breast meat yields and more body fat. Notwithstanding the differences b e tween experiments, no main effects of feeding diets containing protein concentrations ranging from 93 to 107% of those recommended by NRC were observed for BW, feed efficiency, or fat content of the body in either experiment. Proportional supplementation of the Diet 107P with
Met also had no discernible influence on these response criteria. The lack of effect of protein concentration on BW and feed efficiency of heavy toms agrees with results obtained by others. Spencer (1984) reported that turkeys fed diets containing 90% of NRC (1977) recommended protein concentrations and supplemented with Met and Lys grew as rapidly and efficiently as those fed diets with recommended protein concentrations. Sell et al. (1989) found that diets containing 90% of NRC (1984) recommended protein concentrations and supplemented with EAA to meet NRC requirements supported rate and efficiency of growth of toms comparable to those obtained with diets of greater protein content. Sell et al (1989) also observed no effect of diets containing 90% or more of the NRC recommended protein concentrations on proximate composition of carcasses of 20-wk-old toms. Increasing the potentially limiting EAA (Met plus Cys) content of diets containing 107% of the protein concentration recommended by NRC proportional to the exira
piuieiii y/ /o) (LSICI
J.U, U) U.1G n o t
influence performance of toms, compared with Diets 100P or 107P. Compared with Diet 107P, relatively small additions of Met were required in Diet 107B (.05% in the starter, .02% in the finisher) to achieve
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!Diets 93P contained NRC (1984) recommended essential amino acid concentrations and Diets 107B were supplied with sufficient methionine to achieve the same proportional increase as the increase in dietary protein. 2 M and H indicate the diets containing 102 and 108%, respectively, of the ME n concentrations listed by NRC (1984) for comparable ages.
METABOLIZABLE ENERGY FEEDING SEQUENCE AND PROTEIN FOR TOMS
529
TABLE 8. Influence of dietary protein, amino acid balance, and sequence of dietary MEn on proximate composition of eviscerated torn carcasses, Experiment 1
Dietary protein 1
Eviscerated carcass Water
Protein
66.65 66.32 65.74 65.48 64.48 64.59 64.65 65.32 66.05 64.83 65.97 65.72 .51
18.82 18.56 18.35 18.37 18.28 18.42 18.34 18.38 18.74 18.35 18.90 18.53 .26
Fat •
M M M M M-H M-H M-H M-H M-H-M M-H-M M-H-M M-H-M
Protein (P) ME sequence (S) P x S
.75 .006 .42
Ash
(%)
10.75 11.08 11.99 12.26 12.93 12.74 13.33 13.35 10.86 12.96 10.92 12.21 .78 Probabilities .77 .46 .31 .026 .66 .68
3.01 3.33 3.38 3.59 3.55 3.35 3.17 3.14 3.29 3.32 3.57 3.28 .17 .94 .90 .15
1 Diets 93P contained NRC (1984) recommended essential amino acid concentrations and Diets 107B were supplied with sufficient methionine to achieve the same proportional increase as the increase in dietary protein. 2 M and H indicate the diets containing 102 and 108%, respectively, of the ME n concentrations listed by NRC (1984) for comparable ages.
the desired proportional increases in TSAA of the diet. These small additions, however, translated into greater differences when expressed as a percentage of dietary protein. In the instance of the starter diet, the added Met increased the TSAA content of the Diet 107B to 3.73% of the protein as compared with 3.50% TSAA in Diet 107F. Corresponding values for the finisher diets were 1.70 and 1.58% of the protein, respectively. The percentages of TSAA in the protein recommended by NRC for starter and finisher diets are 3.75 and 1.70% respectively. The concentrations of all other EAA in the protein of Diets 107P and 107B met or exceeded those recommended by NRC for comparable ages. The data obtained herein show that striving for a proportional balance of EAA in the 107% protein diet did not affect torn performance. In this sense, the data do not support the concept that EAA requirements for growing turkeys should be increased proportionally with dietary protein, at least with respect to protein concentrations that exceed those recommended by NRC and the use of extra Met
to achieve the proportional increase in the potentially most limiting EAA. Research with chickens suggested that requirements of EAA should be expressed as a percentage of protein (Almquist, 1952; Morris et al., 1987; Abebe and Morris, 1990). The majority of the diets evaluated in these earlier studies, however, contained protein concentrations that were less than those recommended by NRC and extrapolation of the findings to high-protein diets may not be appropriate. A main effect of dietary protein was observed with carcass yield and breast meat yield of toms in Experiment 2. Yields of eviscerated carcass and breast meat of toms fed Diets 100P, 107P, and 107B were greater than those of toms fed Diet 93P. This effect of dietary protein was not observed in Experiment 1. Toms of Experiment 2, however, gained weight more rapidly during the late stages of growth, ostensibly because of comparatively low ambient temperatures. Because of this rapid late growth, rate of breast meat development and associated needs for dietary protein and EAA would be greater
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(% of NRC, 1984) 93P 100P 107P 107B 93P 100P 107P 107B 93P 100P 107P 107B SEM Source of variation
Dietary ME feeding sequence 2
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TABLE 9. Main effect means showing effects of dietary protein and sequence of dietary MEn on proximate composition of eviscerated torn carcasses. Experiment 1 Eviscerated carcass Main effect
Protein Fat
Ash
(%) 65.70 65.29 65.37 65.52
18.60 18.45 18.52 18.43
11.57 12.20 12.21 12.54
3.28 3.34 3.36 3.35
66.07 64.72 65.65
18.54 18.36 18.62
11.49 13.07 11.77
3.32 3.31 3.36
JDiets 93P contained NRC (1984) recommended essential amino acid concentrations and Diets 107B were supplied with sufficient methionine to achieve the same proportional increase as the increase in dietary protein. 2 M and H indicate the diets containing 102 and 108%, respectively, of the ME n concentrations listed by NRC (1984) for comparable ages.
for toms of Experiment 2 than for toms of Experiment 1. Toms fed Diet 93P in Experiment 2 consumed the same amount of feed per kilogram of weight gain as those fed Diets 100P, 107P, or 107B. Consequently, the intake of protein and EAA of toms fed Diet 93P in Experiment 2 may have been inadequate to support optimum development of breast muscle. It is noteworthy that the main effect mean BW of toms fed Diets 93P and 100P in Experiment 2 differed by .25 kg per torn (P < .15) and mean breast meat weight of the same treatment groups differed by about .27 kg per torn (P < .001). Thus, breast meat development, in this instance, was a more sensitive criterion for adequacy of Diet 93P than was BW. The influence of MEn feeding sequence on BW differed between the two experiments. In Experiment 1, feeding high MEn concentrations from 43 to 105 (Sequence M-H-M) or from 43 to 117 days (Sequence M-K) increased 117-day BW, whereas the same MEn regimens did not significantly alter 119-day BW in Experiment 2. Again, differences in ambient temperatures during the last 3 wk of the experiments probably influenced the outcome by alter-
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Dietary protein1 93P 100P 107P 107B Dietary MEn sequence2 M M-H M-H-M
Water
ing rate of gain and final BW. It is noteworthy that the effects of MEn feeding sequence were similar in the two experiments when torn BW were similar. For example, feeding high-MEn diets after 42 days of age resulted in a favorable effect (P < .05) in Experiment 1 when 117-day-old toms weighed an average of 12.0 kg each and in Experiment 2 when 105-day-old toms averaged 11.4 kg each (data not shown). In the latter instance, however, the relative differences in BW among MEn feeding sequence treatment groups decreased during the last 14 days of the experiment and, as a result, the main effect of ME n sequence on 119-day BW was not significant. Feeding sequences involving high MEn after 42 days of age improved feed efficiency by about the same magnitude in both experiments, compared with feeding moderate MEn throughout (Sequence M). Also, there was no significant effect on feed efficiency when MEn was reduced (Sequence M-H-M) during the last 12 and 14 days of Experiments 1 and 2, respectively. This decrease in dietary MEn during late growth, however, was effective in reducing the amount of fat pad and percentage of carcass fat in Experiment 1 but not in Experiment 2. In fact, fat pad development and percentage of fat in the carcasses of toms fed moderate MEn (Sequence M) throughout in Experiment 2 were not different from those observed for toms fed Sequences M-H-M or M-H. These results indicate that ambient temperature, growth rate, or stage of body development, or a combination of these factors, influenced the response of toms to MEn feeding sequence in terms of body fat. Toms of Experiment 1, finished under high-temperature conditions, not only were approximately 1.4 kg per torn lighter at the finish than those of Experiment 2, but had, on the average, smaller fat pads (1.19 versus 1.40% of BW) and less carcass fat (12.11 versus 13.29%). The relative importance of stage of development (BW) and the possible impact of ambient temperature on the energy intake and metabolic use of energy in determining body fatness and its responsiveness to dietary MEn manipulation cannot be determined from this study.
METABOLIZABLE ENERGY FEEDING SEQUENCE AND PROTEIN FOR TOMS
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TABLE 10. Influence of dietary protein, amino acid balance, and sequence of dietary MEn on performance and selected carcass traits of toms, Experiment 2
Dietary protein 1
Dietary 119-•day ME„ feeding Body Feed: sequence 2 weight gam
(% of NRC, 1984) M M M M M-H M-H M-H M-H M-H-M M-H-M M-H-M M-H-M
SEM Source of variation Protein level (P) ME n sequence (S) P x S
fe:R)
13.03 13.54 13.31 13.46 13.34 13.52 13.63 13.54 13.32 13.31 13.69 13.53 .17
2.58 2.58 2.65 2.60 2.46 2.48 2.45 2.44 2.56 2.49 2.43 2.52 .03
.15 .35 .76
.94 .001 .11
(% of live weight) 81.8 82.9 82.1 83.8 82.6 84.6 83.6 85.0 82.5 83.6 83.7 83.5 .49 .001 .004 .45
Breast meat
Fat: pad (% of live weight) 1.23 157.5 1.31 173.2 200.2 1.50 1.22 159.2 1.45 190.8 1.28 173.0 1.57 213.0 1.28 169.0 1.81 235.0 1.48 191.3 1.43 186.0 1.25 165.6 .13 18.3 Probabilities .13 .16 .27 .28 .38 .41 (g per torn)
(g per torn) 2,412 2,695 2,874 2,740 2,584 2,853 2,777 2,866 2,591 2,725 2,697 2,848 63 .001 .14 .16
(% of live weight) 19.10 20.36 21.57 20.95 19.62 21.21 20.47 21.75 20.02 21.09 20.86 21.54 .40
(% of carcass weight) 23.36 24.56 26.25 25.02 23.75 25.06 24.51 25.57 24.26 25.24 24.93 25.79 .48
.011 .42 .21
.001 .58 .13
^iets 93P contained NRC (1984) recommended essential amino acid concentrations and Diets 107B were supplied with sufficient methionine to achieve the same proportional increase as the increase in dietary protein. 2 M and H indicate the diets containing 102 and 108%, respectively, of the MEn concentrations listed by NRC (1984) for comparable ages.
TABLE 11. Main effect means showing effects of dietary protein and sequence of dietary MEn on performance and selected carcass traits of toms, Experiment 2 119-day Main effect
Dietary protein 1 93P 100P 107P 107B Dietary MEj, sequence 2 M M-H M-H-M
Feed: gain
Carcass yield
(kg per (g=g) torn)
(% of live weight)
(g per torn)
(% of live weight)
(g per torn)
(% of live weight)
(% of carcass weight)
13.22 13.47 13.53 13.51
2.53 2.52 2.52 2.52
82.3 83.7 83.1 84.2
194.4 179.2 199.7 164.6
1.47 1.34 1.51 1.25
2,523 2,760 2,790 2,815
19.54 20.87 20.98 21.40
23.75 24.93 25.57 25.43
13.33 13.51 13.46
2.60 2.46 2.49
82.6 84.0 83.3
172.5 186.4 194.5
1.31 1.40 1.49
2,680 2,770 2,715
20.49 20.76 20.88
24.80 24.72 25.05
Body weight
Fat pad
Breast mieat
iDiets 93P contained NRC (1984) recommended essential amino acid concentrations and Diets 107B were supplied with sufficient methionine to achieve the same proportional increase as the increase in dietary protein. 2 M and H indicate the diets containing 102 and 108%, respectively, of the ME n concentrations listed by NRC (1984) for comparable ages.
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93P 100P 107P 107B 93P 100P 107P 107B 93P 100P 107P 107B
(kg per torn)
Carcass yield
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TABLE 12. Influence of dietary protein, amino acid balance, and sequence of dietary MEn proximate composition of eviscerated torn carcasses, Experiment 2
Dietary protf sin1
Eviscerated carcass Water
Protein
Fat
Ash
- (%\ M M M M M-H M-H M-H M-H M-H-M M-H-M M-H-M M-H-M
19.13 18.87 18.35 18.79 18.60 19.24 18.98 19.04 18.46 18.78 18.89 18.73 .27
12.58 13.56 13.74 13.03 14.02 12.56 14.41 12.67 14.51 13.01 13.01 12.43 .69 Probabilities .69 .27 .92 .45 .37 .38
65.36 65.12 64.99 65.57 64.79 66.10 64.42 66.17 64.23 65.22 65.46 65.84 .50 .17 .89 .38
3.55 3.18 3.35 3.40 3.48 3.36 3.44 3.39 3.42 3.42 3.71 3.27 .16 .50 .79 .76
! Diets 93P contained NRC (1984) recommended essential amino acid concentrations and Diets 107B were supplied with sufficient methionine to achieve the same proportional increase as the increase in dietary protein. 2 M and H indicate the diets containing 102 and 108%, respectively, of the ME n concentrations listed by NRC (1984) for comparable ages.
Neither protein nor ash content of eviscerated carcasses was changed bydietary treatments in either experiment. In Experiment 1, carcass water was inversely related to dietary effects on fat. One instance of dietary protein by ME n feeding sequence interaction was observed in Experiment 1 and none occurred in Experiment 2. In Experiment 1, the effects of dietary protein concentration within each ME n feeding sequence on carcass yields were inconsistent, resulting in an interaction that was not interpretable. Similar inconsistencies with respect to BW in Experiment 1 resulted in an indication of interaction (P < .08). Otherwise, all significant treatment effects detected were protein concentration or ME n feeding sequence main effects. These data support the findings that, within reasonable ranges of dietary protein and ME n , each of these independent variables tends to exert independent effects on turkey torn performance and carcass traits (Sell and Owings, 1981; Sell et ah, 1985, 1989; Blair et al, 1989a,b).
TABLE 13. Main effect means showing effects of dietary protein and sequence of dietary MEn on proximate composition of eviscerated torn carcasses, Experiment 2 Eviscerated carcass Main effect
Water
Protein „..
Dietary protein 1 93P 100P 107P 107B Dietary ME n sequence 2 M M-H M-H-M
Fat
Ash
0
f "
64.84 65.50 64.91 65.86
18.75 18.98 18.73 18.86
13.63 13.04 13.78 12.73
3.49 3.31 3.48 3.36
65.26 65.37 65.18
18.78 18.96 18.71
13.23 13.41 13.24
3.37 3.42 3.45
x Diets 93P contained NRC (1984) recommended essential amino acid concentrations and Diets 107B were supplied with sufficient methionine to achieve the same proportional increase as the increase in dietary protein. 2 M and H indicate the diets containing 102 and 108%, respectively, of the ME n concentrations listed by NRC (1984) for comparable ages.
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(% of NRC, 198^ 93P 100P 107P 107B 93P 100P 107P 107B 93P 100P 107P 107B SEM Source of variation Protein (P) ME n sequence (S) P x S
Dietary ME feeding sequence 2
METABOLIZABLE ENERGY FEEDING SEQUENCE AND PROTEIN FOR TOMS
ACKNOWLEDGMENTS
The research reported here was supported, in part, by grants from the Iowa Turkey Marketing Council, Ames, LA 50010, Fats and Protein Research Foundation, Ft. Myers Beach, FL 33931, and Nutri-Quest, Inc., Chesterfield, MO 63017. Nutri-Quest, Inc., supplied the lysine used in this study and provided for the amino acid analyses. Feed Energy, Inc., Des Moines, LA 50318, contributed the animalvegetable fat. The assistance of M. Jeffrey, J. Piquer, P. Palo, M. Soto-Salanova, K. Turner, E. Mallarino, D. Barker, L. Vilaseca, and the staff of the Poultry Science Farm, Iowa State University, is gratefully acknowledged.
REFERENCES Abebe, S., and T. R. Morris, 1990. Note on the effect of protein concentration on the responses to dietary lysine by chicks. Br. Poult. Sci. 31: 255-260. Almquist, H. J., 1952. Amino acid requirements of chickens and turkeys—a review. Poultry Sci. 31: 966-981. Blair, M. E., and L. M. Potter, 1988. Effects of varying fat and protein in diets of growing large white turkeys. 1. Body weights and feed efficiencies. Poultry Sci. 67:1281-1289. Blair, M. E., L. M. Potter, and R. M. Hulet, 1989a. Effects of dietary protein and added fat on turkey varying in strain, sex and age. 1. Live characteristics. Poultry Sci. 68:278-286. Blair, M. E., L. M. Potter, and R. M. Hulet, 1989b. Effects of dietary protein and added fat on turkeys varying in strain, sex and age. 2. Carcass characteristics. Poultry Sci. 68:287-296. Boomgaardt, J., and D. H. Baker, 1971. Tryptophan requirement of growing chicks as affected by dietary protein level. J. Anim. Sci. 33:595-599. Boomgaardt, J. and D. H. Baker, 1973. Lysine requirement of growing chicks fed sesame mealgelatin diets at 3 protein levels. Poultry Sci. 52: 586-591. Emmans, G. C, 1987. Growth, body composition and feed intake. World's Poult. Sci. J. 43:208-227. Ferket, P. R., and J. L. Sell, 1990. Effect of early protein and energy restriction on large turkey toms fed high-fat or low-fat realimentation diets. 2. Carcass characteristics. Poultry Sci. 69: 1982-1990. Hurwitz, S., I. Plavnik, I. Bengal, and I. Bartov, 1988. Response of growing turkeys to dietary fat. Poultry Sci. 67:420-426. Jensen, L. S., G. W. Schumaier, and J. D. Latshaw, 1970. Extra-caloric effect of dietary fat for developing turkeys as influenced by calorie: protein ratio. Poultry Sci. 49:1697-1704. Kagan, A., 1982. Supplemental fats for growing turkeys: A review. World's Poult. Sci. J. 37: 203-210. Moran, E. T., L. M. Poste, P. R. Ferket, and V. Agar, 1984. Response of large turkeys differing in growth characteristics to divergent feeding systems: performance, carcass quality, and sensory evaluation. Poultry Sci. 63:1778-1792. Morris, T. R., K. Al-Azzawi, R. M. Gous, and G. L. Simpson, 1987. Effects of protein concentration on responses to dietary lysine by chicks. Br. Poult. Sci. 28:185-195. National Research Council, 1977. Nutrient Requirements of Poultry. 7th rev. ed. National Academy Press, Washington, DC. National Research Council, 1984. Nutrient Requirements of Poultry. 8th rev. ed. National Academy Press, Washington, DC. Potter, L. M., J. R. Shelton, and L. G. Melton, 1974. Zinc bacitracin and added fat in diets of growing turkeys. Poultry Sci. 53:2072-2081. Robbins, K. R., 1987. Threonine requirement of the broiler chick as affected by protein level and source. Poultry Sci. 66:1531-1534. Salmon, R. E., 1974. Effect of dietary fat concentration
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The results of these two experiments showed that the use of relatively highprotein diets did not favorably influence performance or carcass traits of heavy toms as compared with using protein concentrations recommended by the NRC. This was also true when diets containing relatively high protein concentrations were adjusted to contain a greater concentration of a potentially limiting EAA. Variations between experiments in responses to dietary protein concentrations and MEn feeding sequences also were illustrated. In one experiment, feeding a relatively low-protein diet resulted in reduced breast meat yields, whereas this effect was not observed in another trial. Similarly, a MEn stepdown feeding sequence during the last 14 days of the finishing period reduced body fat of toms in one trial, but was ineffective in doing so in a second experiment. The primary difference between the experiments was ambient temperature during late growth of toms, and this difference ostensibly influenced rates of gain, final BW, and certain responses to dietary treatments. These disparate data between experiments emphasize the need to use caution in drawing general conclusions on the basis of results obtained from single experiments or from experiments for which the environmental conditions are not fully described.
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and energy to protein ratio on performance, yield of carcass components, and composition of skin and meat of turkeys as related to age. Br. Poult. Sri. 15:543-560. SAS Institute, 1985. SAS® User's Guide. Statistics. Version 5 Edition. SAS Institute Inc., Cary, NC. Sell, J. L., P. R. Ferket, C. R. Angel, S. E. Scheideler, F. Escribano, and I. Zatari, 1989. Performance and carcass characteristics of turkey toms as influenced by dietary protein and metabolizable energy. Nutr. Rep. Int. 40:979-992. Sell, J. L., R. J. Hasiak, W. J. Owings, 1985. Independent effects of dietary ME and protein concentrations on performance and carcass
characteristics of torn turkey. Poultry Sci. 64: 1527-1533. Sell, J. L., and W. J. Owings, 1981. Supplemental fat and metabolizable-to-nutrient ratios for growing turkeys. Poultry Sci. 60:2293-2305. Spencer, G. K., 1984. Minimum Protein Requirements of Turkeys fed Adequate Levels of Lysine and Methionine. Ph.D. Dissertation, University of Arkansas, Fayetteville, AR. Touchburn, S. P., and E. C. Naber, 1966. The energy value of fats for growing turkeys. Pages 190-195 in: Proceedings 13th World's Poultry Congress. Kiev, Ukraine. Downloaded from http://ps.oxfordjournals.org/ at UNIVERSITY OF ARIZONA on May 27, 2015
1993 Poultry Science 72:521-534
Because the relative improvements in feed efficiency resulting from increasing dieThe favorable effects on productive tary ME are greatest during the latter performance of growing turkeys by using portion nof the rearing period, greater supplemental fat to increase dietary MEn concentration are well documented concentrations of MEn are commonly used (Touchburn and Naber, 1966; Jensen et al., in growing and finishing diets. Young 1970; Potter et al, 1974; Sell and Owings, animals grow to attain their lipid-free, 1981; Kagan, 1982; Blair and Potter, 1988). mature body mass and then to achieve their inherent fatness (Emmans, 1987). During early periods of growth, priority is given to growth of lipid-free tissue. SubseReceived for publication July 27, 1992. quently, deposition of body fat accelerates. Accepted for publication November 17, 1992. The degree of this acceleration in growing journal Paper Number 1-14987 of the Iowa Agriculture and Home Economics Experiment Station, turkeys depends to a great extent on the MEn concentration of the diet (Salmon, Ames, IA 50011. Project Number 2887. INTRODUCTION
521
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ABSTRACT Two identically designed experiments were done to determine the effects of reducing dietary MEn concentration during late growth and of dietary protein concentration on performance and selected carcass traits of turkey toms. A complete factorial arrangement of three MEn feeding sequences and four dietary protein concentrations was used. The MEn feeding sequences were 102% of MEn concentrations listed by NRC (1984), from 1 to 119 days of age (M), 102% MEn for 1 to 42 days followed by 108% MEn from 42 to 119 days (M-H), and the same as the M-H sequence except the 102% MEn diets were fed from 105 to 119 days (M-H-M). The four dietary protein concentrations were 93, 100, and 107%, of NRC recommended protein concentrations, in which essential amino acid (EAA) levels met or exceeded NRC recommendations, and 107% of NRC, in which the EAA concentrations were at least 107% of NRC recommendations. Feeding diets of the M-H and M-H-M MEn sequence improved feed efficiency (P < .01) in both experiments as compared with the M sequence. Toms fed the M-H or M-H-M sequences in Experiment 1, but not in Experiment 2, were heavier at the finish than those fed the M sequence. Body fat of toms was increased (P < .05) by feeding the M-H MEn sequence, compared with feeding the M or M-H-M sequences in Experiment 1. No dietary MEn effects on body fat were observed in Experiment 2. Dietary protein concentration did not modify the effects of MEn feeding sequence and there were no effects of protein concentration on BW or feed efficiency in either experiment. Fat pad and breast meat weights were affected differently by dietary treatments in the two experiments, possibly because of differences in ambient temperature during the last 3 to 4 wk of the experiments. {Key words: nitrogen-corrected metabolizable energy, dietary protein, turkey toms, performance, carcass composition)
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to improve performance and decrease body fat of heavy turkeys may be related to inappropriate amino acid balance. The research reported herein was done to determine whether a reduction in MEn of diets fed during the last 2 wk of the finishing period and selective amino acid supplementation of diets of relatively low or high protein content would reduce body fat of heavy toms without adversely affecting performance and certain carcass traits. MATERIALS AND METHODS In each of two identically designed experiments, 1,320,1-day-old male turkeys were allotted randomly to 44 floor pens, 30 toms per pen. Each pen provided .095 m2 per torn. The toms were reared to 117 days in Experiment 1 and to 119 days in Experiment 2 under continuous lighting with feed and water provided for ad libitum consumption. Twelve treatments were used, consisting of a complete factorial arrangement of four dietary protein-amino acid concentrations and three MEn feeding sequences, as outlined in Table 1. Three of the protein levels were 93, 100, and 107% of the protein concentration recommended by NRC (Diets 93P, 100P, and 107P, respectively). In all instances, these diets were formulated to at least meet NRC recommended EAA concentrations. A fourth protein-amino acid test diet series (Diet 107B) was obtained by formulating Diet 107P to contain at least 107% of the EAA concentrations recommended by NRC. Achieving this goal involved supplementing the Diet 107P with additional DL-Met. On a calculated basis, the concentrations of all other essential amino acids were present in the 107B diet at 107% or more of NRC recommended levels. The three MEn feeding sequences consisted of 1) feeding a diet of moderate MEn content [102% of that listed by NRC from 1 to 119 days of age (Sequence M)]; 2) feeding the moderate-MEn diets from 1 to 42 days of age followed by feeding high-MEn diets [108% of the MEn listed by NRC from 43 to 119 days (Sequence M-H)]; or 3) feeding the moderate-MEn diets from 1 to 42 days, the high-MEn diets from 43 to 105 days,
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1974; Moran et al, 1984; Sell et al, 1985, 1989; Hurwitz et al, 1988). Thus, the common use in the commercial industry of growing and finishing diets of high MEn content generally results in market turkeys that are deemed excessively fat. Because the economics of feeding highMEn diets through the finishing period have usually been favorable, little consideration has been given to using diets of relatively low MEn content during the final phases of growth as a means of reducing body fat while maintaining turkey performance. Research has shown that manipulation of dietary protein and amino acid concentrations within practical limits has little influence on the effect of high dietary MEn concentrations, whereby fat content of turkeys is increased. For example, toms fed high-MEn, high-protein diets during the growing and finishing periods deposited body fat to essentially the same extent as those fed high-MEn, low-protein diets (Sell et al, 1985, 1989; Blair et al, 1989a; Ferket and Sell, 1990). In these earlier studies, however, diets of ample or excess protein content were formulated to meet NRC (1984) recommendations for the essential amino acids (EAA). Consequently, the concentrations of most EAA in high-protein diets exceeded those recommended by a substantial margin but, simultaneously, one or two EAA often just met the recommended concentration. In the study of Sell et al (1989), the relative concentrations of some EAA in diets containing 109% of NRC recommended protein levels exceeded NRC requirements by up to 40%, but, in the same diets, the Lys and Met concentrations only met or slightly exceeded the NRC recommendations. Almquist (1952) stated that amino acid requirements of chicks, as percentages of the diet, increased as the concentration of dietary protein increased. Since that time, additional evidence indicates that requirements of certain EAA, stated as a percentage of the diet, increased as dietary protein concentration increased (Boomgaardt and Baker, 1971,1973; Morris et al, 1987; Robbins, 1987; Abebe and Morris, 1990). Thus, the question arises whether the failure of relatively high-protein diets
523
METABOLIZABLE ENERGY FEEDING SEQUENCE AND PROTEIN FOR TOMS TABLE 1. Outline of relative dietary concentrations of protein and MEn used in Experiments 1 and 2 Relative MEn by days of age Dietary ME,, feeding sequence2
1 to 42
(% of NRC, 1984) 93P1 100P 107P 107B 93P 100P 107P 107B 93P 100P 107P 107B
M M M M M-H M-H M-H M-H M-H-M M-H-M M-H-M M-H-M
102 102 102 102 102 102 102 102 102 102 102 102
43 to 105 (% of ME„ NRC, 1984) — 102 102 102 102 108 108 108 108 108 108 108 108
106 to 119 102 102 102 102 108 108 108 108 102 102 102 102
Numerical values indicate the percentages of the dietary protein concentrations recommended by NRC (1984); 107B indicates that concentrations of protein and essential amino acids equaled at least 107% of NRC (1984) recommendations. 2 M and H correspond to 102 and 108%, respectively, of the NRC (1984) guidelines for dietary MEj, concentrations.
values and those determined by laboratory analysis are shown. Crude protein content of the diets was determined by the macro-Kjeldahl procedure and amino acid analyses were done at a commercial laboratory.2 Composition of diets used in Experiment 2 were nearly the same as those of Experiment 1. All diets were fed in mash form. A pen of toms represented an experimental unit, and each of the eight treatments of MEn Sequences M and M-H was assigned to four pens. Because only 44 pens were available for the experiment, each of the four treatments of MEn Sequence M-H-M was assigned to three pens. Body weight and feed consumption data were recorded when toms were 21, 42, 63, 84, 105, and 119 days old. Immediately after the toms were weighed at 119 days of age (117 days of age in Experiment 1), two toms representing average pen weight were selected from each pen. Feed was withdrawn from these toms, but water was provided for approximately 16 h before the toms were processed at the Meat Laboratory, Iowa State University. Experiment Station Chemical Laboratories, Toms were weighed individually, stunned Columbia, MO 65211.
and then the moderate-MEn diets from 106 to 119 days (Sequence M-H-M). Adjustments in nutrient and MEn concentrations of the diets were made according to six age categories: 1 to 21, 22 to 42, 43 to 63, 64 to 84, 85 to 105, and 106 to 119 days. In instances of the age categories of 21 to 42, 43 to 63, and 64 to 84 days, which did not correspond to age categories listed by NRC, protein, amino acid, and MEn values used to determine dietary concentration for the current study were obtained by extrapolation. National Research Council requirements given for the periods of 1 to 4 wk and 16 to 20 wk were used in formulating diets for the age periods of 1 to 21 and 106 to 117 days, respectively. The ingredient composition and MEn, CP, and amino acid contents of the starter diets (1 to 21 days) of Experiment 1 are presented in Tables 2 and 3, respectively, and the analogous data for the finisher diets (106 to 119 days) are presented in Tables 4 and 5, respectively. In the instances of CP and amino acids, calculated
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Dietary protein1
524
SELL TABLE 2. Ingredient composition of turkey starter diets, Experiment 1 Relative concentration of dietary protein1
Ingredients
93 M
100 M
107 M
107B M
Corn (7.71% CP) Soybean meal (47.7% CP) Dehydrated alfalfa meal (17% CP) Feather meal (78% CP) Animal-vegetable fat2 Dicalcium phosphate Limestone Salt-mineral premix 3 Vitamin premix 4 L-lysineHCl DL-methionine Stafac®5
45.77 41.79 3.00 2.00 2.41 2.36 1.67 .30 .30 .15 .21 .05
39.75 47.08 3.00 2.00 3.39 2.32 1.66 .30 .30
33.92 52.09 3.00 2.00 4.32 2.29 1.64 .30 .30
33.96 52.00 3.00 2.00 4.30 2.29 1.64 .30 .30
.15 .05
.09 .05
.16 .05
(%)
TABLE 3. Concentrations of MEn, protein, and amino acids in turkey starter diets, Experiment 1 Relative concentration of dietary protein1 93 M
100 M 2
Concentration
CaP
ME„, kcal/kg
2,850
2,850
Protein TSSA Met Lys Arg His He Leu Phe + Tyr Thr Trp Val
26.06 26.51 1.05 1.04 .56 .60 1.60 1.61 1.87 1.83 .71 .65 1.30 1.22 2.19 2.27 2.29 2.27 1.04 1.05 .33 .33 1.47 1.40
28.00 28.15 1.05 1.02 .57 .58 1.64 1.64 2.03 1.98 .71 .75 1.42 1.31 2.33 2.37 2.46 2.44 1.12 1.13 .37 .37 1.59 1.46
Det
Cal
107 M Cal
Det
Det
107B M Cal
Det
2,850
2,850 . . .
29.96 29.99 1.05 1.05 .54 .52 1.79 1.76 2.19 2.13 .77 .80 1.53 1.44 2.47 2.53 2.62 2.61 1.20 1.18 .39 .40 1.70 1.64
29.96 29.62 1.12 1.13 .61 .59 1.78 1.74 2.19 2.10 .77 .79 1.53 1.38 2.47 2.49 2.69 2.57 1.20 1.19 .39 .41 1.69 1.56
\ju)
'Numerical values indicate percentage of the dietary protein concentration recommended by NRC (1984); 107B indicates that concentrations of protein and essential amino acids equaled at least 107% of NRC (1984) recommendations; M indicates 102% of MEn concentration listed by NRC (1984). 2 Cal = calculated values; Det = values determined by laboratory analysis.
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'Numerical values indicate percentages of the dietary concentration recommended by NRC (1984); 107B indicates that concentrations of protein and essential amino acids equaled at least 107% of NRC (1984) recommendations; M indicates 102% of ME n concentration listed by NRC (1984). 2 Fatty acid composition, as percentage methyl esters: Cjgo, 17.64; Cig.j, 1.47; Cjgo, 9.61; Cjgi, 31.3; Cjg^, 33.89; C18:3, 3.63; others, 2.46. 3 Supplied per kilogram of diet: Mn, 70 mg; Zn, 40 mg; Fe, 37 mg; Cu, 6 mg; Se, .15 mg; NaCl(I), 2.60 g. 4 Supplied per kilogram of diet: vitamin A, 5,000 IU; cholecalciferol, 1,500 IU; vitamin E, 15 IU; vitamin B12, 11 /ig; menadione sodium bisulfite, 1.8 mg; riboflavin, 2.7 mg; pantothenic acid, 7 mg; niacin, 75 mg; choline, 509 mg; folic acid, 550 \t%; biotin 75 ^g; ethoxyquin, .0045%. 5 Contains 44 g virginiamycin/kg; SmithKline Beecham, Exton, PA 19341.
METABOLIZABLE ENERGY FEEDING SEQUENCE AND PROTEIN FOR TOMS
525
TABLE 4. Ingredient composition of turkey finisher diets, Experiment 1 Relative concentration of dietary protein1 Ingredients
93 M
100 M 107 M 107B M
Corn (6.98% CP) Soybean meal (48.8% CP) Meat and bone meal (50.1% CP) Feather meal (78% CP) Animal-vegetable fat2 Dicalcium phosphate Limestone Salt-mineral premix 3 Vitamin premix 4 L-lysineHCl DL-methionine Stafac®5
75.46 11.65 4.00 3.00 3.60 .75 .70 .30 .30 .17 .045 .025
71.88 14.81 4.00 3.00 4.19 .73 .69 .30 .30 .05 .025 .025
93 H
100 H 107 H 107B H
(%)
.01 .025
68.42 17.79 4.00 3.00 4.74 .71 .68 .30 .30 .18 .03 .025
70.59 12.39 4.00 3.00 7.76 .77 .69 .30 .30 .16 .045 .025
67.01 15.55 4.00 3.00 8.34 .75 .68 .30 .30 .04 .027 .025
63.57 18.52 4.00 3.00 8.89 .73 .67 .30 .30
63.55 18.52 4.00 3.00 8.89 .73 .67 .30 .30
.01 .025
.03 .025
Numerical values indicate percentages of the dietary protein concentration recommended by NRC (1984); 107B indicates that concentrations of protein and essential amino acids equaled at least 107% of NRC (1984) recommendations; M indicates 102% and H indicates 108% of MEn concentration listed by NRC (1984). 2 Fatty acid composition, as percentage methyl esters: C\(,Q, \7.(A; C\&\, 1A7; CJS-O' 9.61; Cjgi, 31.3; Cj8-2/ 33.89; C18:3, 3.63; others, 2.46. ^Supplied per kilogram of diet: Mn, 70 mg; Zn, 40 mg; Fe, 37 mg; Cu, 6 mg; Se, .15 mg; NaCl(I), 2.60 g. Supplied per kilogram of diet: vitamin A, 5,000 IU; cholecalciferol, 1,500 IU; vitamin E, 15 IU; vitamin B^, 11 ng; menadione sodium bisulfite, 1.8 mg; riboflavin, 2.7 mg; pantothenic acid, 7 mg; niacin, 75 mg; choline, 509 mg; folic acid, 550 pg; biotin, 75 tig; ethoxyquin, .0045%. 5 Contains 44 g virginiamycin/kg; SmithKline Beecham, Exton, PA 19341.
TABLE 5. Concentrations of MEn, protein, and amino acids in moderate MEn turkey finisher diets, Experiment 1 Relative concentration of dietary protein1 93 M1 Det 2
100 M
107 M Det
107B M Cal
Det
Nutrient
CaP
MEn, kcal/kg
3,264
3,264
3,264
3,264 . . .
Protein TSSA Met Lys Arg His lie Leu Phe + Tyr Thr Trp Val
15.34 15.62 .60 .73 .30 .28 .80 .90 .95 1.03 .33 .38 .66 .61 1.39 1.41 1.38 1.19 .63 .62 .14 .16 .76 .86
16.50 16.64 .62 .73 .28 .28 .80 .81 .99 1.13 .41 .37 .68 .73 1.48 1.51 1.48 1.30 .68 .66 .15 .18 .83 .93
17.67 18.05 .64 .76 .28 .29 .85 .87 1.22 1.16 .40 .45 .80 .73 1.56 1.58 1.58 1.40 .72 .73 .17 .19 1.00 .87
17.67 18.27 .66 .78 .30 .36 .86 .94 1.22 1.29 .40 .48 .80 .77 1.56 1.59 1.58 1.43 .72 .72 .19 .18 .99 .88
Cal
Det
Cal
Numerical values indicate percentages of the dietary protein concentration recommended by NRC (1984); 107B indicates that levels of protein and essential amino acids equaled at least 107% of NRC (1984) recommendations; M indicates 102% of ME„ concentration listed by NRC (1984). 2 Cal = calculated values; Det = values determined by laboratory analysis.
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68.38 17.85 4.00 3.00 4.75 .71 .68 .30 .30
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RESULTS Experiment 1
Because of a conflict of dates to process toms of Experiment 1, terminal body weight and feed consumption data were recorded at 117 days instead of 119 days of age, and the toms were processed at 118 days of age. Body weight, feed efficiency (feed:gain), and carcass trait data are presented according to treatment means in Table 6 and as main effect means in Table 7. There were no significant effects (P > .05) of dietary protein concentration on
3 Hobart Manufacturing Co., Des Moines, IA 50318.
117-day BW, feed efficiency, or carcass traits measured. There were favorable effects (P < .05) of MEn feeding sequence, whereby MEn sequences M-H and M-H-M improved BW and feed efficiency (P < .05) compared with the continuous M feeding sequence. Reducing the dietary MEn concentration for the age interval of 106 to 117 days (Sequence M-H-M) did not significantly affect performance of toms as compared with Sequence M-H. An interaction between protein concentration and MEn sequence was indicated (P = .081) for BW. However, there were no consistent patterns observed that could be related causally to this interaction. Mortality totaled 8.8% and was distributed among the treatment groups. Carcass yield, stated as percentage of live weight, was not affected by protein concentration or MEn feeding sequence. Statistical analysis revealed a protein concentration by MEn feeding sequence interaction effect on carcass yield. A perusal of these data, however, showed that the interaction occurred because of inconsistencies among the treatments. These inconsistencies had no meaningful pattern. In comparison with toms fed Sequence M, toms fed Sequence M-H had heavier fat pads (P < .01). Fat pad weight and percentage of live weight of toms fed Sequence M-H-M were slightly greater than those of toms fed Sequence M, but were less than those of toms fed Sequence M-H. Protein concentration did not affect fat pad of the toms, and no interaction was observed between protein concentration and MEn feeding sequence. Also, no treatment effects were observed for weight or percentage yields of breast meat. Data obtained from chemical analysis of the carcasses (Tables 8 and 9) show that only the percentages of water and fat were affected (P < .05) by treatments. Carcasses of toms fed the MEn Sequence M-H contained less water and more fat than those of toms fed either Sequences M or M-H-M. In the instance of carcass fat, the main effect means of Sequence M and M-H-M treatment groups were similar. Protein concentration did not affect carcass composition, and there were no effects of MEn feeding sequence on carcass protein or ash.
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electrically, and the jugular veins were severed. Carcasses were deplumed after a 2-min scald at 60 C and were eviscerated. During evisceration, abdominal fat pads, including adipose tissue around the gizzard, were removed and weighed. After evisceration, carcasses without neck and giblets were placed in ice water and chilled for 21 to 22 h. Chilled carcasses were removed from ice water, drained, and weighed. Breast meat without skin was removed from each carcass and weighed. The carcasses and breasts of the two toms from each pen were placed in a plastic bag and frozen at -20 C. In preparation for chemical analysis, an electric meat saw (Model 50-12)3 was used to cut the frozen carcasses into pieces that would pass down the throat of a Buffalo N066BX, worm-gear meat grinder. After four passages through the grinder, the ground turkey was blended (Model VCM40 Blender)3 for 2 min. Subsamples of this blend were taken for determination of carcass protein, fat, water, and ash. Because many responses to dietary treatments differed between Experiments 1 and 2, data of each experiment were analyzed separately. Two-way analyses of variance were done to determine main effects and interactions of dietary proteinamino acid concentration and MEn feeding sequence by using the General Linear Models program (SAS Institute, 1985).
METABOLIZABLE ENERGY FEEDING SEQUENCE AND PROTEIN FOR TOMS
527
TABLE 6. Influence of dietary protein, amino acid balance, and sequence of dietary MEn on performance and selected carcass traits of toms, Experiment 1
Dietary protein 1
M2 M M M M-H M-H M-H M-H M-H-M M-H-M M-H-M M-H-M
Source of variation Protein level (P) ME sequence (S) P x S
Carcass yield
(kg per torn)
11.59 11.81 12.24 11.70 12.33 12.12 11.74 12.19 11.91 12.29 12.37 12.13 .19
2.59 2.56 2.54 2.59 2.42 2.44 2.44 2.38 2.48 2.49 2.46 2.45 .022
(% of live weight) 79.8 78.8 80.8 80.4 78.7 78.5 78.8 80.8 79.4 80.1 79.0 79.5 .5
.54 .001 .33
.23 .15 .042
.86 .043 .081
Breast meal
Fal: pad (g per torn)
(% of live weight) .87 1.03 1.10 1.05 1.48 1.55 1.31 1.14 1.08 1.37 1.17 1.08 .12
(g per torn)
96.9 118.8 127.9 118.5 181.6 181.4 144.6 134.2 127.2 163.3 138.6 126.0 15.6 Probabilities — .24 .23 .002 .003 .29 .42
2,151 2,091 2,306 2,120 2,340 2,171 2,014 2,188 2,298 2,194 2,255 2,247 82
(% of live weight) 19.37 18.15 19.88 18.78 19.08 18.49 18.14 18.58 19.46 18.33 19.17 19.38 .47
.47 .45 .22
.13 .37 .57
(% of carcass) 24.29 23.04 24.62 23.38 24.24 23.58 23.01 23.25 24.50 22.88 24.28 24.37 .60 .15 .59 .61
!Diet 93P contained NRC (1984) recommended essential amino acid concentrations and Diets 107B were supplied with sufficient methionine to achieve the same proportional increase as the increase in dietary protein. 2 M and H indicate the diets containing 102 and 108%, respectively, of the ME n concentrations listed by NRC (1984) for comparable ages.
Experiment 2 Dietary protein concentration had no effect on 119-day BW or feed efficiencies in Experiment 2 (Tables 10 and 11). Body weights also were not affected by ME n feeding sequence. Feed efficiencies, however, were improved (P < .001) by Sequences M-H and M-H-M, compared with the Sequence M, irrespective of dietary protein concentration. No significant protein concentration by ME n feeding sequence interaction was observed for 119-day BW and feed efficiencies. Mortality was not affected by dietary treatments and totalled 12.6% during the 119-day experiment. Both dietary protein concentration and ME n sequence affected (P < .01) eviscerated carcass yield (Tables 10 and 11). In the instance of protein, feeding diets containing 100% or more of the concentrations recommended by NRC (Diets 100P, 107P, and 107B) increased percentage carcass yield as compared with the Diet 93P. Carcass yield
also was increased for toms fed Sequence M-H, especially compared with the carcass yields of toms fed Sequence M. Neither weight of fat pad per torn nor fat pad as a percentage of body weight was affected by protein concentration or ME n feeding sequence. However, weight and percentage yield of breast meat and eviscerated carcass yield were affected by dietary protein. Feeding Diets 100P, 107P, or 107B increased breast meat weight and percentage yield, compared with feeding the Diet 93P, and this protein concentration effect occurred irrespective of ME n feeding sequence. The ME n feeding sequence did not affect breast meat yield. Proximate analyses of the eviscerated carcasses showed that dietary treatments did not influence water, protein, fat, or ash content (Tables 12 and 13). DISCUSSION Although many responses to dietary treatments were the same in Experiments
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93P 100P 107P 107B 93P 100P 107P 107B 93P 100P 107P 107B SEM
Dietary 117-•day ME„ lvlE, n Feed: feeding 2 Body sequence weight gain
528
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TABLE 7. Main effect means showing effects of dietary protein and sequence of dietary MEn on performance and selected carcass traits of toms, Experiment 1 117- day Body weight
Feed: gain
Carcass yield
(kg per torn)
(8=8)
(% of live weight)
(g per torn)
(% of live weight)
(g per torn)
(% of live weight)
(% of carcass weight)
Dietary protein 1 93P 100P 107P 107B
11.94 12.05 12.07 11.99
2.50 2.50 2.48 2.48
79.3 79.1 79.4 80.0
136.0 153.7 137.8 126.2
1.15 1.31 1.20 1.09
2,260 2,149 2,174 2,180
19.29 18.33 18.97 18.88
24.33 23.19 23.87 23.60
Dietary ME n sequence 2 M M-H M-H-M
11.80 12.09 12.16
2.57 2.42 2.46
79.9 79.1 79.4
114.7 161.6 139.1
1.01 1.38 1.18
2,158 2,179 2,243
19.00 18.59 19.03
23.78 23.52 23.94
Main effect
Fat : pad
Breast mieat
1 and 2, there were several instances in which treatment responses differed. The latter phase of Experiment 1 occurred during late June and, at this time, ambient temperature and relative humidity were high. Average daily high temperature was 31.7 C during the last 3 wk of the Experiment 1. In contrast, daily high temperatures during the last 3 wk of Experiment 2, which was completed in February, averaged 14.4 C. Ostensibly, these dissimilar ambient conditions resulted in differences between the two experiments in some performance and carcass characteristics of the same strain of toms fed identically formulated diets. For example, toms of Experiment 1 averaged 12.0 kg each at 117 days of age as compared with 13.4 kg each at 119 days for toms of Experiment 2. Accompanying the differences in BW were differences in carcass traits, whereby the heavier toms of Experiment 2 had greater carcass and breast meat yields and more body fat. Notwithstanding the differences b e tween experiments, no main effects of feeding diets containing protein concentrations ranging from 93 to 107% of those recommended by NRC were observed for BW, feed efficiency, or fat content of the body in either experiment. Proportional supplementation of the Diet 107P with
Met also had no discernible influence on these response criteria. The lack of effect of protein concentration on BW and feed efficiency of heavy toms agrees with results obtained by others. Spencer (1984) reported that turkeys fed diets containing 90% of NRC (1977) recommended protein concentrations and supplemented with Met and Lys grew as rapidly and efficiently as those fed diets with recommended protein concentrations. Sell et al. (1989) found that diets containing 90% of NRC (1984) recommended protein concentrations and supplemented with EAA to meet NRC requirements supported rate and efficiency of growth of toms comparable to those obtained with diets of greater protein content. Sell et al (1989) also observed no effect of diets containing 90% or more of the NRC recommended protein concentrations on proximate composition of carcasses of 20-wk-old toms. Increasing the potentially limiting EAA (Met plus Cys) content of diets containing 107% of the protein concentration recommended by NRC proportional to the exira
piuieiii y/ /o) (LSICI
J.U, U) U.1G n o t
influence performance of toms, compared with Diets 100P or 107P. Compared with Diet 107P, relatively small additions of Met were required in Diet 107B (.05% in the starter, .02% in the finisher) to achieve
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!Diets 93P contained NRC (1984) recommended essential amino acid concentrations and Diets 107B were supplied with sufficient methionine to achieve the same proportional increase as the increase in dietary protein. 2 M and H indicate the diets containing 102 and 108%, respectively, of the ME n concentrations listed by NRC (1984) for comparable ages.
METABOLIZABLE ENERGY FEEDING SEQUENCE AND PROTEIN FOR TOMS
529
TABLE 8. Influence of dietary protein, amino acid balance, and sequence of dietary MEn on proximate composition of eviscerated torn carcasses, Experiment 1
Dietary protein 1
Eviscerated carcass Water
Protein
66.65 66.32 65.74 65.48 64.48 64.59 64.65 65.32 66.05 64.83 65.97 65.72 .51
18.82 18.56 18.35 18.37 18.28 18.42 18.34 18.38 18.74 18.35 18.90 18.53 .26
Fat •
M M M M M-H M-H M-H M-H M-H-M M-H-M M-H-M M-H-M
Protein (P) ME sequence (S) P x S
.75 .006 .42
Ash
(%)
10.75 11.08 11.99 12.26 12.93 12.74 13.33 13.35 10.86 12.96 10.92 12.21 .78 Probabilities .77 .46 .31 .026 .66 .68
3.01 3.33 3.38 3.59 3.55 3.35 3.17 3.14 3.29 3.32 3.57 3.28 .17 .94 .90 .15
1 Diets 93P contained NRC (1984) recommended essential amino acid concentrations and Diets 107B were supplied with sufficient methionine to achieve the same proportional increase as the increase in dietary protein. 2 M and H indicate the diets containing 102 and 108%, respectively, of the ME n concentrations listed by NRC (1984) for comparable ages.
the desired proportional increases in TSAA of the diet. These small additions, however, translated into greater differences when expressed as a percentage of dietary protein. In the instance of the starter diet, the added Met increased the TSAA content of the Diet 107B to 3.73% of the protein as compared with 3.50% TSAA in Diet 107F. Corresponding values for the finisher diets were 1.70 and 1.58% of the protein, respectively. The percentages of TSAA in the protein recommended by NRC for starter and finisher diets are 3.75 and 1.70% respectively. The concentrations of all other EAA in the protein of Diets 107P and 107B met or exceeded those recommended by NRC for comparable ages. The data obtained herein show that striving for a proportional balance of EAA in the 107% protein diet did not affect torn performance. In this sense, the data do not support the concept that EAA requirements for growing turkeys should be increased proportionally with dietary protein, at least with respect to protein concentrations that exceed those recommended by NRC and the use of extra Met
to achieve the proportional increase in the potentially most limiting EAA. Research with chickens suggested that requirements of EAA should be expressed as a percentage of protein (Almquist, 1952; Morris et al., 1987; Abebe and Morris, 1990). The majority of the diets evaluated in these earlier studies, however, contained protein concentrations that were less than those recommended by NRC and extrapolation of the findings to high-protein diets may not be appropriate. A main effect of dietary protein was observed with carcass yield and breast meat yield of toms in Experiment 2. Yields of eviscerated carcass and breast meat of toms fed Diets 100P, 107P, and 107B were greater than those of toms fed Diet 93P. This effect of dietary protein was not observed in Experiment 1. Toms of Experiment 2, however, gained weight more rapidly during the late stages of growth, ostensibly because of comparatively low ambient temperatures. Because of this rapid late growth, rate of breast meat development and associated needs for dietary protein and EAA would be greater
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(% of NRC, 1984) 93P 100P 107P 107B 93P 100P 107P 107B 93P 100P 107P 107B SEM Source of variation
Dietary ME feeding sequence 2
530
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TABLE 9. Main effect means showing effects of dietary protein and sequence of dietary MEn on proximate composition of eviscerated torn carcasses. Experiment 1 Eviscerated carcass Main effect
Protein Fat
Ash
(%) 65.70 65.29 65.37 65.52
18.60 18.45 18.52 18.43
11.57 12.20 12.21 12.54
3.28 3.34 3.36 3.35
66.07 64.72 65.65
18.54 18.36 18.62
11.49 13.07 11.77
3.32 3.31 3.36
JDiets 93P contained NRC (1984) recommended essential amino acid concentrations and Diets 107B were supplied with sufficient methionine to achieve the same proportional increase as the increase in dietary protein. 2 M and H indicate the diets containing 102 and 108%, respectively, of the ME n concentrations listed by NRC (1984) for comparable ages.
for toms of Experiment 2 than for toms of Experiment 1. Toms fed Diet 93P in Experiment 2 consumed the same amount of feed per kilogram of weight gain as those fed Diets 100P, 107P, or 107B. Consequently, the intake of protein and EAA of toms fed Diet 93P in Experiment 2 may have been inadequate to support optimum development of breast muscle. It is noteworthy that the main effect mean BW of toms fed Diets 93P and 100P in Experiment 2 differed by .25 kg per torn (P < .15) and mean breast meat weight of the same treatment groups differed by about .27 kg per torn (P < .001). Thus, breast meat development, in this instance, was a more sensitive criterion for adequacy of Diet 93P than was BW. The influence of MEn feeding sequence on BW differed between the two experiments. In Experiment 1, feeding high MEn concentrations from 43 to 105 (Sequence M-H-M) or from 43 to 117 days (Sequence M-K) increased 117-day BW, whereas the same MEn regimens did not significantly alter 119-day BW in Experiment 2. Again, differences in ambient temperatures during the last 3 wk of the experiments probably influenced the outcome by alter-
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Dietary protein1 93P 100P 107P 107B Dietary MEn sequence2 M M-H M-H-M
Water
ing rate of gain and final BW. It is noteworthy that the effects of MEn feeding sequence were similar in the two experiments when torn BW were similar. For example, feeding high-MEn diets after 42 days of age resulted in a favorable effect (P < .05) in Experiment 1 when 117-day-old toms weighed an average of 12.0 kg each and in Experiment 2 when 105-day-old toms averaged 11.4 kg each (data not shown). In the latter instance, however, the relative differences in BW among MEn feeding sequence treatment groups decreased during the last 14 days of the experiment and, as a result, the main effect of ME n sequence on 119-day BW was not significant. Feeding sequences involving high MEn after 42 days of age improved feed efficiency by about the same magnitude in both experiments, compared with feeding moderate MEn throughout (Sequence M). Also, there was no significant effect on feed efficiency when MEn was reduced (Sequence M-H-M) during the last 12 and 14 days of Experiments 1 and 2, respectively. This decrease in dietary MEn during late growth, however, was effective in reducing the amount of fat pad and percentage of carcass fat in Experiment 1 but not in Experiment 2. In fact, fat pad development and percentage of fat in the carcasses of toms fed moderate MEn (Sequence M) throughout in Experiment 2 were not different from those observed for toms fed Sequences M-H-M or M-H. These results indicate that ambient temperature, growth rate, or stage of body development, or a combination of these factors, influenced the response of toms to MEn feeding sequence in terms of body fat. Toms of Experiment 1, finished under high-temperature conditions, not only were approximately 1.4 kg per torn lighter at the finish than those of Experiment 2, but had, on the average, smaller fat pads (1.19 versus 1.40% of BW) and less carcass fat (12.11 versus 13.29%). The relative importance of stage of development (BW) and the possible impact of ambient temperature on the energy intake and metabolic use of energy in determining body fatness and its responsiveness to dietary MEn manipulation cannot be determined from this study.
METABOLIZABLE ENERGY FEEDING SEQUENCE AND PROTEIN FOR TOMS
531
TABLE 10. Influence of dietary protein, amino acid balance, and sequence of dietary MEn on performance and selected carcass traits of toms, Experiment 2
Dietary protein 1
Dietary 119-•day ME„ feeding Body Feed: sequence 2 weight gam
(% of NRC, 1984) M M M M M-H M-H M-H M-H M-H-M M-H-M M-H-M M-H-M
SEM Source of variation Protein level (P) ME n sequence (S) P x S
fe:R)
13.03 13.54 13.31 13.46 13.34 13.52 13.63 13.54 13.32 13.31 13.69 13.53 .17
2.58 2.58 2.65 2.60 2.46 2.48 2.45 2.44 2.56 2.49 2.43 2.52 .03
.15 .35 .76
.94 .001 .11
(% of live weight) 81.8 82.9 82.1 83.8 82.6 84.6 83.6 85.0 82.5 83.6 83.7 83.5 .49 .001 .004 .45
Breast meat
Fat: pad (% of live weight) 1.23 157.5 1.31 173.2 200.2 1.50 1.22 159.2 1.45 190.8 1.28 173.0 1.57 213.0 1.28 169.0 1.81 235.0 1.48 191.3 1.43 186.0 1.25 165.6 .13 18.3 Probabilities .13 .16 .27 .28 .38 .41 (g per torn)
(g per torn) 2,412 2,695 2,874 2,740 2,584 2,853 2,777 2,866 2,591 2,725 2,697 2,848 63 .001 .14 .16
(% of live weight) 19.10 20.36 21.57 20.95 19.62 21.21 20.47 21.75 20.02 21.09 20.86 21.54 .40
(% of carcass weight) 23.36 24.56 26.25 25.02 23.75 25.06 24.51 25.57 24.26 25.24 24.93 25.79 .48
.011 .42 .21
.001 .58 .13
^iets 93P contained NRC (1984) recommended essential amino acid concentrations and Diets 107B were supplied with sufficient methionine to achieve the same proportional increase as the increase in dietary protein. 2 M and H indicate the diets containing 102 and 108%, respectively, of the MEn concentrations listed by NRC (1984) for comparable ages.
TABLE 11. Main effect means showing effects of dietary protein and sequence of dietary MEn on performance and selected carcass traits of toms, Experiment 2 119-day Main effect
Dietary protein 1 93P 100P 107P 107B Dietary MEj, sequence 2 M M-H M-H-M
Feed: gain
Carcass yield
(kg per (g=g) torn)
(% of live weight)
(g per torn)
(% of live weight)
(g per torn)
(% of live weight)
(% of carcass weight)
13.22 13.47 13.53 13.51
2.53 2.52 2.52 2.52
82.3 83.7 83.1 84.2
194.4 179.2 199.7 164.6
1.47 1.34 1.51 1.25
2,523 2,760 2,790 2,815
19.54 20.87 20.98 21.40
23.75 24.93 25.57 25.43
13.33 13.51 13.46
2.60 2.46 2.49
82.6 84.0 83.3
172.5 186.4 194.5
1.31 1.40 1.49
2,680 2,770 2,715
20.49 20.76 20.88
24.80 24.72 25.05
Body weight
Fat pad
Breast mieat
iDiets 93P contained NRC (1984) recommended essential amino acid concentrations and Diets 107B were supplied with sufficient methionine to achieve the same proportional increase as the increase in dietary protein. 2 M and H indicate the diets containing 102 and 108%, respectively, of the ME n concentrations listed by NRC (1984) for comparable ages.
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93P 100P 107P 107B 93P 100P 107P 107B 93P 100P 107P 107B
(kg per torn)
Carcass yield
532
SELL
TABLE 12. Influence of dietary protein, amino acid balance, and sequence of dietary MEn proximate composition of eviscerated torn carcasses, Experiment 2
Dietary protf sin1
Eviscerated carcass Water
Protein
Fat
Ash
- (%\ M M M M M-H M-H M-H M-H M-H-M M-H-M M-H-M M-H-M
19.13 18.87 18.35 18.79 18.60 19.24 18.98 19.04 18.46 18.78 18.89 18.73 .27
12.58 13.56 13.74 13.03 14.02 12.56 14.41 12.67 14.51 13.01 13.01 12.43 .69 Probabilities .69 .27 .92 .45 .37 .38
65.36 65.12 64.99 65.57 64.79 66.10 64.42 66.17 64.23 65.22 65.46 65.84 .50 .17 .89 .38
3.55 3.18 3.35 3.40 3.48 3.36 3.44 3.39 3.42 3.42 3.71 3.27 .16 .50 .79 .76
! Diets 93P contained NRC (1984) recommended essential amino acid concentrations and Diets 107B were supplied with sufficient methionine to achieve the same proportional increase as the increase in dietary protein. 2 M and H indicate the diets containing 102 and 108%, respectively, of the ME n concentrations listed by NRC (1984) for comparable ages.
Neither protein nor ash content of eviscerated carcasses was changed bydietary treatments in either experiment. In Experiment 1, carcass water was inversely related to dietary effects on fat. One instance of dietary protein by ME n feeding sequence interaction was observed in Experiment 1 and none occurred in Experiment 2. In Experiment 1, the effects of dietary protein concentration within each ME n feeding sequence on carcass yields were inconsistent, resulting in an interaction that was not interpretable. Similar inconsistencies with respect to BW in Experiment 1 resulted in an indication of interaction (P < .08). Otherwise, all significant treatment effects detected were protein concentration or ME n feeding sequence main effects. These data support the findings that, within reasonable ranges of dietary protein and ME n , each of these independent variables tends to exert independent effects on turkey torn performance and carcass traits (Sell and Owings, 1981; Sell et ah, 1985, 1989; Blair et al, 1989a,b).
TABLE 13. Main effect means showing effects of dietary protein and sequence of dietary MEn on proximate composition of eviscerated torn carcasses, Experiment 2 Eviscerated carcass Main effect
Water
Protein „..
Dietary protein 1 93P 100P 107P 107B Dietary ME n sequence 2 M M-H M-H-M
Fat
Ash
0
f "
64.84 65.50 64.91 65.86
18.75 18.98 18.73 18.86
13.63 13.04 13.78 12.73
3.49 3.31 3.48 3.36
65.26 65.37 65.18
18.78 18.96 18.71
13.23 13.41 13.24
3.37 3.42 3.45
x Diets 93P contained NRC (1984) recommended essential amino acid concentrations and Diets 107B were supplied with sufficient methionine to achieve the same proportional increase as the increase in dietary protein. 2 M and H indicate the diets containing 102 and 108%, respectively, of the ME n concentrations listed by NRC (1984) for comparable ages.
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(% of NRC, 198^ 93P 100P 107P 107B 93P 100P 107P 107B 93P 100P 107P 107B SEM Source of variation Protein (P) ME n sequence (S) P x S
Dietary ME feeding sequence 2
METABOLIZABLE ENERGY FEEDING SEQUENCE AND PROTEIN FOR TOMS
ACKNOWLEDGMENTS
The research reported here was supported, in part, by grants from the Iowa Turkey Marketing Council, Ames, LA 50010, Fats and Protein Research Foundation, Ft. Myers Beach, FL 33931, and Nutri-Quest, Inc., Chesterfield, MO 63017. Nutri-Quest, Inc., supplied the lysine used in this study and provided for the amino acid analyses. Feed Energy, Inc., Des Moines, LA 50318, contributed the animalvegetable fat. The assistance of M. Jeffrey, J. Piquer, P. Palo, M. Soto-Salanova, K. Turner, E. Mallarino, D. Barker, L. Vilaseca, and the staff of the Poultry Science Farm, Iowa State University, is gratefully acknowledged.
REFERENCES Abebe, S., and T. R. Morris, 1990. Note on the effect of protein concentration on the responses to dietary lysine by chicks. Br. Poult. Sci. 31: 255-260. Almquist, H. J., 1952. Amino acid requirements of chickens and turkeys—a review. Poultry Sci. 31: 966-981. Blair, M. E., and L. M. Potter, 1988. Effects of varying fat and protein in diets of growing large white turkeys. 1. Body weights and feed efficiencies. Poultry Sci. 67:1281-1289. Blair, M. E., L. M. Potter, and R. M. Hulet, 1989a. Effects of dietary protein and added fat on turkey varying in strain, sex and age. 1. Live characteristics. Poultry Sci. 68:278-286. Blair, M. E., L. M. Potter, and R. M. Hulet, 1989b. Effects of dietary protein and added fat on turkeys varying in strain, sex and age. 2. Carcass characteristics. Poultry Sci. 68:287-296. Boomgaardt, J., and D. H. Baker, 1971. Tryptophan requirement of growing chicks as affected by dietary protein level. J. Anim. Sci. 33:595-599. Boomgaardt, J. and D. H. Baker, 1973. Lysine requirement of growing chicks fed sesame mealgelatin diets at 3 protein levels. Poultry Sci. 52: 586-591. Emmans, G. C, 1987. Growth, body composition and feed intake. World's Poult. Sci. J. 43:208-227. Ferket, P. R., and J. L. Sell, 1990. Effect of early protein and energy restriction on large turkey toms fed high-fat or low-fat realimentation diets. 2. Carcass characteristics. Poultry Sci. 69: 1982-1990. Hurwitz, S., I. Plavnik, I. Bengal, and I. Bartov, 1988. Response of growing turkeys to dietary fat. Poultry Sci. 67:420-426. Jensen, L. S., G. W. Schumaier, and J. D. Latshaw, 1970. Extra-caloric effect of dietary fat for developing turkeys as influenced by calorie: protein ratio. Poultry Sci. 49:1697-1704. Kagan, A., 1982. Supplemental fats for growing turkeys: A review. World's Poult. Sci. J. 37: 203-210. Moran, E. T., L. M. Poste, P. R. Ferket, and V. Agar, 1984. Response of large turkeys differing in growth characteristics to divergent feeding systems: performance, carcass quality, and sensory evaluation. Poultry Sci. 63:1778-1792. Morris, T. R., K. Al-Azzawi, R. M. Gous, and G. L. Simpson, 1987. Effects of protein concentration on responses to dietary lysine by chicks. Br. Poult. Sci. 28:185-195. National Research Council, 1977. Nutrient Requirements of Poultry. 7th rev. ed. National Academy Press, Washington, DC. National Research Council, 1984. Nutrient Requirements of Poultry. 8th rev. ed. National Academy Press, Washington, DC. Potter, L. M., J. R. Shelton, and L. G. Melton, 1974. Zinc bacitracin and added fat in diets of growing turkeys. Poultry Sci. 53:2072-2081. Robbins, K. R., 1987. Threonine requirement of the broiler chick as affected by protein level and source. Poultry Sci. 66:1531-1534. Salmon, R. E., 1974. Effect of dietary fat concentration
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The results of these two experiments showed that the use of relatively highprotein diets did not favorably influence performance or carcass traits of heavy toms as compared with using protein concentrations recommended by the NRC. This was also true when diets containing relatively high protein concentrations were adjusted to contain a greater concentration of a potentially limiting EAA. Variations between experiments in responses to dietary protein concentrations and MEn feeding sequences also were illustrated. In one experiment, feeding a relatively low-protein diet resulted in reduced breast meat yields, whereas this effect was not observed in another trial. Similarly, a MEn stepdown feeding sequence during the last 14 days of the finishing period reduced body fat of toms in one trial, but was ineffective in doing so in a second experiment. The primary difference between the experiments was ambient temperature during late growth of toms, and this difference ostensibly influenced rates of gain, final BW, and certain responses to dietary treatments. These disparate data between experiments emphasize the need to use caution in drawing general conclusions on the basis of results obtained from single experiments or from experiments for which the environmental conditions are not fully described.
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and energy to protein ratio on performance, yield of carcass components, and composition of skin and meat of turkeys as related to age. Br. Poult. Sri. 15:543-560. SAS Institute, 1985. SAS® User's Guide. Statistics. Version 5 Edition. SAS Institute Inc., Cary, NC. Sell, J. L., P. R. Ferket, C. R. Angel, S. E. Scheideler, F. Escribano, and I. Zatari, 1989. Performance and carcass characteristics of turkey toms as influenced by dietary protein and metabolizable energy. Nutr. Rep. Int. 40:979-992. Sell, J. L., R. J. Hasiak, W. J. Owings, 1985. Independent effects of dietary ME and protein concentrations on performance and carcass
characteristics of torn turkey. Poultry Sci. 64: 1527-1533. Sell, J. L., and W. J. Owings, 1981. Supplemental fat and metabolizable-to-nutrient ratios for growing turkeys. Poultry Sci. 60:2293-2305. Spencer, G. K., 1984. Minimum Protein Requirements of Turkeys fed Adequate Levels of Lysine and Methionine. Ph.D. Dissertation, University of Arkansas, Fayetteville, AR. Touchburn, S. P., and E. C. Naber, 1966. The energy value of fats for growing turkeys. Pages 190-195 in: Proceedings 13th World's Poultry Congress. Kiev, Ukraine. Downloaded from http://ps.oxfordjournals.org/ at UNIVERSITY OF ARIZONA on May 27, 2015