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The Effect of Feeding High Energy Diets Containing Supplemental Fat on Broiler Weight Gain, Feed Efficiency, and Carcass Composition1
The Effect of Feeding High Energy Diets Containing Supplemental Fat on Broiler Weight Gain, Feed Efficiency, and Carcass Composition1 C. N. COON, W. A. BECKER, and J. V. SPENCER Departments of Animal Sciences and Food Sciences, Washington State University, Pullman, Washington 99164 (Received for publication March 24, 1980)
1981 Poultry Science 60:1264-1271 INTRODUCTION A review of t h e literature by S u m m e r s and Leeson ( 1 9 7 9 ) reveals fat deposition in broilers can be influenced b y diet c o m p o s i t i o n , envir o n m e n t and t e m p e r a t u r e , t y p e of housing, age, and sex. N o r d s t r o m et al. ( 1 9 7 8 ) a n d Salleh et al. ( 1 9 7 8 ) have d e m o n s t r a t e d a b d o m i n a l fat deposited in broilers is also related t o strain differences. Broilers containing excessive abd o m i n a l fat are often less desirable for 1) a c o n s u m e r w h e n t h e fat pad comprises part of t h e m a r k e t a b l e p r o d u c t (Bartov et al, 1 9 7 4 ) , 2) a p o u l t r y processing p l a n t because t h e partially removed fat increases waste disposal p r o b l e m s (Kub'ena et al, 1 9 7 4 ) , and 3) a p r o d u c e r because t h e abdominal fat is a nonprofitable conversion of dietary energy (Bartov et al, 1974). Nutrition studies have established widening t h e dietary energy-protein
that ratio
1 Scientific Paper No. 5600. College of Agriculture Research Center, Washington State University, Pullman, WA. Project 0308.
increases fat deposition in broilers and narrowing t h e dietary energy-protein ratio decreases fat deposition (Bartov et al, 1974). Conflicting studies, however, have been r e p o r t e d o n t h e effect of dietary fat on carcass composition. Carew and Hill ( 1 9 6 4 ) and Carew et al. ( 1 9 6 4 ) d e m o n s t r a t e d t h a t t h e isocaloric replacement of c a r b o h y d r a t e s with corn oil increases carcass energy r e t e n t i o n in t h e form of fat. Donaldson et al ( 1 9 5 8 ) r e p o r t e d t h a t t u r k e y s fed diets with comparable energy-protein ratios and increasing levels of dietary fat contained a higher percentage of carcass fat. Edwards and Hart ( 1 9 7 1 ) , Bartov et al ( 1 9 7 4 ) , a n d Griffiths et al. ( 1 9 7 7 ) were unable t o d e m o n s t r a t e any differences in carcass composition resulting from t h e isocaloric s u b s t i t u t i o n of dietary fat for c a r b o h y d r a t e s . Animal fat o r a blend of vegetable and animal fat is c o m m o n l y added to p o u l t r y rations t o reduce dustiness, lubricate pellet dies, increase t h e dietary energy, and improve t h e utilization of metabolizable energy calories and p r o t e i n as suggested by R a n d et al. ( 1 9 5 8 ) . T o u c h b u r n and Naber ( 1 9 6 6 ) and J e n s e n et al. ( 1 9 7 0 ) also observed an " e x t r a caloric" effect
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ABSTRACT We studied the effect of feeding two levels of energy in starter diets [3135 kcal metabolizable energy (ME)/kg low energy and 3410 kcal ME/kg high energy] from 0 to 28 days and finishing diets (3190 kcal ME/kg low energy and 3465 kcal ME/kg high energy) from 28 to 56 days upon broiler weight gain, feed conversion, feed consumption, calorie consumption, and abdominal fat content Feed conversion of male and female broilers fed the high energy starter diet from 0 to 28 days or the high energy finisher diet from 28 to 56 days was superior (P<.05) compared to feed conversion of broilers fed the low energy starter and finisher diet. The weight gain of male and female broilers from 0 to 28 days was not affected (P>.05) by diet; however, weight gain during the 28 to 56 day feeding period demonstrated a sex-diet interaction (P<.05). The males fed the low energy starter and finishing diets gained more weight (P<.05) during the 28 to 56 day period than males fed a high energy finishing diet. The males fed the low energy finishing diet consumed 16 g/day more feed (P<.05) and 18 kcal/day more metabolizable energy than males fed the high energy finishing diet Females fed the low energy finishing diet consumed 9 g additional feed per day (P<.05) but the energy consumption was the same. Male broilers fed the low energy starter and finishing diets and female broilers fed the high energy starter and finishing diets contained slightly increased amounts of abdominal fat compared to the same sex fed different diet combinations; however, differences were nonsignificant (P> .05). A sex-diet interaction was observed (P<.05) for regressed abdominal fat weight on live body weight. (Key words: dietary energy, abdominal fat, sex-diet interaction, broilers, weight gains, feed conversions)
ENERGY AND BROILER CARCASS COMPOSITION for supplemental fat and suggested wider calorie-protein ratios for poultry rations with additional fat can be used for maximum gains and feed efficiency. The objective of the research reported herein was to study the effects of feeding broilers high energy diets containing supplementary fat during starter and finishing periods on broiler weight gain, feed conversion, and abdominal fat content.
watering bowl, hanging tube feeder, infrared 400-W radiant heater, and a 100-W incandescent light bulb providing continuous light. Male and female chicks in 20 pens (10 pens each) were fed the low energy starter diet [3135 kcal metabolizable energy (ME)/kg; 23% crude protein (CP)], and the male and female chicks in the other pens (10 pens each) were fed the high energy starter diet (3410 kcal ME/kg; 25% CP), (Table 1) from 0 to 28 days. Weight gain and feed consumption for each pen of chicks were determined after a 28-day feeding period. One-half the chicks (5 pens of each sex) previously fed the starter diet with the low energy level were fed the low energy finishing diet (3190 kcal ME/kg; 18.9% CP) for an additional 28-day feeding period. The remaining chicks previously fed the low energy starter diet (5 pens of each sex) were fed the high energy finisher diet (3465 kcal ME/kg; 20.5% CP) for
TABLE 1. Experimental starter and finisher diets Finisher (28--56 days)
Starter (0--28 days) Ingredient
Corn, yellow ground Soybean oil meal (47.5% CP)2 Fish meal, anchovy (65% CP)2 Meat and bone meal (50% CP) 2 Limestone Dicalcium phosphate Vitamin premix 3 Trace mineral mix 4 Tallow Amprolium (25% premix) Salt, iodized DL-methionine L-lysine hydrochloride Calculated nutrients Crude protein (%) Metabolizable energy (kcal/kg) Metabolizable energy, (kcal/kg)/crude protein (%) Methionine (g)/Mcal Total sulfur amino acids (g)/Mcal Lysine (g)/McaI
LE
1
HE
LE
HE
58.80 28.65 2.50 5.00 .40 .20 .25 .05 3.65 .05 .25 .15 .05
43.35 34.00 3.50 5.50 .50 .25 .30 .06 12.00 .06 .30 .18
70.47 19.50 2.00 4.00 .45 .25 .25 .05 2.50 .05 .25 .15 .08
57.20 23.40 3.00 4.50 .50 .25 .30 .06 10.25 .06 .26 .18 .04
23.0
25.0
18.9
20.5
3135
3410
3190
3465
136.3 1.72
136.4 1.75
168.8 1.52
169.0 1.55
2.76 3.92
2.77 3.96
2.37 3.04
2.38 3.07
1
Low energy (LE) and High energy (HE).
2
Crude protein (CP).
3 Vitamin premix at .25% of the diet supplies the following per kilogram of the diet: vitamin A, 5,500 IU; vitamin D 3 , 1,650 ICU; vitamin E, 4.4 IU; riboflavin, 3.3 mg; calcium pantothenate, 4.4 mg; niacin, 22 mg; choline chloride, 577mg; vitamin B 1 2 , .011 mg;and ethoxyquin, 62.2 mg. 4 Mineral premix at .05% of the diet supplies the following per kilogram of the diet: Mn, 50 mg; Fe, 50 mg; Cu, 5 mg; Zn, 50 mg; I, 1.5 mg; Ca, 60 mg; and Co, .5 mg.
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MATERIALS AND METHODS
Five hundred male and 500 female day-old Hubbard broiler chicks were randomly distributed by sex into 40 floor pens with each pen containing 25 chicks. Twenty pens contained male chicks and 20 pens contained female chicks. Each pen measured 2.13 X 2.13 M and contained wood shavings litter, automatic
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COON ET AL.
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for each broiler were weighed to the nearest one-tenth gram. Statistical analyses for weight gain, feed conversion, and carcass composition were determined by analysis of variance and Duncan's new multiple range test (Steel and Torrie, 1960).
RESULTS AND DISCUSSION Starter Feeding Period (0-28 days). The chick weight gain for 0 to 28 days was not (P>.05) different for chicks fed high energy starter diets (3410 kcal ME/kg) or low energy starter diets (3135 kcal ME/kg) (Table 2). The feed conversion (g feed consumed/g weight gain) of male chicks fed the high energy diet (1.40) was superior (P<.05) to the male chicks fed the low energy diet (1.51), female chicks fed the low energy diet (1.58), and female chicks fed the high energy diet (1.49), respectively. Female chicks fed the low energy starter
TABLE 2. The weight gain and feed conversion of each sex and combined sexes of broilers fed diets with two levels of metabolizable energy during the 0 to 28 day and 28 to 56 day feeding period 2 8 - 5 6 Days
0 - 2 8 ; Days'
0 - 5 6 Days
Feed conversion3
Weight gain (g)
Feed conversion
Weight gain (g)
Feed conversion
Sex
Diet 2
Weight gain (g)
Male Female Comb. sexes Male Female Comb. sexes Male Female Comb. sexes Male Female Comb. sexes
HE HE
900* ± 1 0 826 b + 6
1.51 b ± .01 1.58c ± .02
1607 b ± 2 9 1348c ± 1 6
2.10 a ± .06 2.26 b ± .02
2515a ±43 2179b±31
1.85* + .04 1.97 b ± .01
HE LE LE
863 e ± 1 0
1.54f ± .01
1477 e ± 4 8 1640* b ± 3 6 1312C ± 1 4
2.18 e ± .04 2.29 b ± .02 2.48 c ± .03
2347 e ± 64 2572* ± 44 2122 b ± 21
1.918 ± .03 1.96 b ± .01 2.10C ± .03
1476 e ± 3 6 1618 b ± 2 6 1343 c ± 12
2.38 f ± .04 2.13 a ± .02 2.31b±.02
2347 e ± 74 2529* ± 34 2176 b ± 1 3
2.03 e ± .03 1.90* ± .02 2.02 b ± .01
LE HE HE HE LE LE
920* ± 1 4 820 b ± 1 0
1.40a ± .01 1.49 b ± .02
1481 e ± 4 5 1694* ± 16 1311 c ± 2 0
2.22 e ± .03 2.26 b + .02 2.52= ± .02
2352C ± 58 2584* ± 29 2130 b ± 23
1.96 f ± .02 2 . 0 1 b ± .02 2.17 d ± .02
LE
87ie ±14
1.44e ± .01
1502C
2.39 f ± .05
2357C + 82
2.09 e ± .03
±68
' ' ' Means within a column for male or female broilers containing a common superscript are not significantly different (P>.05). ' '•'Means within a column for combined sexes containing a common superscript are not significantly different (P>.05). ' T h e mean values ± SEM represent five replicates of 25 broilers for the 28—56 day and 0—56 day feeding period whereas mean values ± SEM for the 0—28 day period represent 10 replicates. 2 HE and LE represent the high and low energy diets, respectively, listed in Table 1 for 0—28 day and 28—56 day feeding period. 3
Feed conversion is the g feed consumed divided by g weight gain.
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the same length of time. The 28-day-old broiler chicks previously fed the high energy starter diet were fed the two finishing diets by the same method as described. The broilers were weighed and feed consumption recorded at 56 days of age. Protein levels were increased in the high energy diets to keep the calorie-protein ratios equivalent to control diets. DL-methionine and L-lysine hydrochloride were added to the test diets to keep constant the sulfur amino acid-energy ratio and lysine-energy ratio for both starter and finisher diets. Six broilers randomly selected from each pen were wing banded, placed in crates, and held without food or water for 20 hr. The birds were individually weighed prior to being slaughtered in the Washington State University Meats Laboratory. The method of evisceration and removal of abdominal fat was the same as described by Becker et al. (1979). Giblets (gizzard, heart, liver, and neck with connecting skin), abdominal fat, and the eviscerated carcass
148.9 e ± 1.4 127«
±3
407e ±11
Means within a column for combined sexes containing a common superscript are not significantly different (P>.0
Means within a column for male or female broilers containing a common superscript are not significantly differ
47.5 ± .4
± 2
3
2
Kilocalories metaboUzable energy consumed/day.
Same as Table 2.
1 The mean values ± SEM represent five replicates of 25 broilers each for the 2 8 - 5 6 day and 0 - 5 6 day feeding pe period represent 10 replicates.
B
a,b,c,d
LE
f
±2 ±2
405e ± 9 436a± 8 377b ± 8
117 f g 13 7^ 118bc
151.8b: 2.2 146.0b : 1.3
48.4 a ± .7 4 6 . 6 b ± .4
± 2
±3 ±2
HE LE LE
4 1 8 a ±11 378b ± 2
399 e 10 426a ± 8 384b± 6
±3 ±2
125
HE LE LE
12lb 109 d
LE HE HE
152.8 e +1.8
4 4 . 8 e ±.5
HE HE
Male Female Comb. sexes Male Female Comb. sexes Male Female Comb. sexes Male Female Comb. sexes
ME consumed/ day (kcal)
398 e ± 9 4 2 7 a ±10 37lb± 3
157.5a +2.2 148.2b ±2.1
4 6 . 2 b + .6 43.5 C +.6
Diet 2
Sex
2 8 - 5 6 Days Feed consumed/ day (g)
1158 ±3 134 a ±3 116bcd ± 1
ME consumed/ day 3 (kcal)
Feed consumed/ day (g)
0 - 2 8 Days 1
TABLE 3. The daily feed and energy consumption of each sex and combined sexes of broilers f of metaboUzable energy during the 0—28 day and 28—56 day feeding per
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COON ET AL.
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the low energy finishing diet and female broilers fed either of the two finishing diets. There was no significant difference in feed conversion during the 28 to 56 day feeding period for males fed the low energy finishing diet or females fed the high energy finishing diets. The two groups of female broilers fed the low energy finishing diet from 28 to 56 days demonstrated a poorer (P<.05) feed conversion compared to all groups of broilers. Male and female broilers previously fed the high energy starter diet improved their feed conversion by .069 and .079, respectively, during the 28 to 56 day finishing period with each additional 100 kcal ME in the high energy finisher diet compared to broilers fed the low energy finishing diet. However, male broilers previously fed the low energy starter diet only improved their feed conversion by .047 during the 28 to 56 day finishing period with each additional 100 kcal ME in the high energy finishing diet. The males fed both low energy starter and finishing diets gained the largest weight during the 28 to 56 day feeding period and the high weight gain decreased the feed conversion improvement produced with the high energy finishing diet. Female broilers previously fed the low energy starter diet improved their feed conversion .076 during the 28 to 56 day feeding period with each additional 100 kcal ME in the high energy finishing diet. Male broilers fed the low energy finishing diet consumed more (P< .05) feed during the 28 to 56 day period than males fed the high energy finishing diet or females fed the high or low energy finishing diets. Males fed the low energy finishing diet also tended to consume 18 kcal/ day more metabolizable energy because of the 16.2 g/day increase in feed intake compared to males fed high energy diets although the energy
TABLE 4. Analysis of variance for broiler weight gain and regressed abdominal fat Source of variation
Weight gain 28—56 Days df MS
Diet Sex Sex X diet Error
3 1 3 32
•Significant at P<.05. * 'Significant at P<.001.
7782* 952879** 7288* 2537
Regressed abdominal fat on live weight df MS 3 1 3 200
18.8 1674.3** 270.7* 90.3
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diet during the 0 to 28 day feeding period demonstrated a poorer (P<.05) feed efficiency compared to all chick groups. The feed conversion was improved .033 for females and .040 fo,r males with each additional 100 kcal ME in the high energy starter diet compared to the low energy starter diet. The male chicks fed the low energy starter diet from 0 to 28 days consumed more (P<.05) feed per day compared to other male or female groups; however, the male chicks fed the high energy diet during the same feeding period consumed more (P<.05) ME per day (Table 3). Female chicks fed the high energy starter diet consumed (P<.05) less feed per day compared to all broiler groups, but the daily caloric consumption was equivalent to males or females fed the low energy starter diet. Finisher Feeding Period (28—56 days). The largest weight gain of male broilers for the 28 to 56 day feeding period was 1694 g for males fed the low energy starter diet prior to being fed the low energy finishing diet. The 1694 g weight gain was larger (P<.05) than 1618.5 g and 1606.6 g weight gain for males fed low energy and high energy starter diets, respectively, prior to feeding the high energy finishing diet. A sex-diet interaction (P<.05) for weight gain during the 28 to 56 day feeding period was demonstrated (Table 4). The two groups of males fed the low energy finishing diet gained more weight (1667 g combined average) from 28 to 56 days than the two groups of male broilers fed the high energy finishing diet (1613 g combined average), whereas females fed the same two diets demonstrated an opposite weight gain response (1311 g and 1346 g combined average, respectively). Male broilers fed the high energy finishing diet during the 28 to 56 day feeding period had an improved (P<.05) feed conversion compared to males fed
ENERGY AND BROILER CARCASS COMPOSITION
The average feed consumption per day during the total 0 to 56 day period for male broilers fed the low energy starter and finishing diet was larger (P<.05) and females fed high energy diets for the 56 day period consumed less (P<.05) than all broiler groups. Male broilers consumed increased (P<.05) amounts
of calories per day during the 0 to 56 day period compared to females; however, the caloric consumption was not different (P>.05) among treatments for either sex. The weight gain of combined sexes for the 0 to 28 day, 28 to 56 day, and 56 day period was not significantly (P>.05) different for the dietary energy combinations. The average feed conversion for combined sexes fed a high energy starter diet from 0 to 28 days and the feed conversion for both sexes fed a high energy finishing diet from 28 to 56 days, regardless of starter diet fed during the 0 to 28 day period, was superior (P<.05) to the average feed conversion of both sexes of broilers fed a low energy diet during the two separate feeding periods. The total 56 day feed conversion was improved (P<.05) for combined sexes of broilers fed the high energy starter and high energy finishing diet compared to all groups. Carcass Composition. The live weight, regressed abdominal fat on live weight, giblet weight, consumer carcass weight (carcass weight + giblet weight), percent yield, percent abdominal fat of live weight, and percent abdominal fat of consumer carcass weight were different (P<.05) for male and female broilers (Table 5). The regressed abdominal fat weight on live weight was determined because a correlation (P<.01) between live body weight and abdominal fat weight for males (r = .44) and females (r = .42) was observed. Becker et al. (1979) suggested regressed abdominal fat weight is relatively independent of body weight and is a superior comparison for abdominal fat measurements. A sex-diet interaction was significant at the 5% level for regressed abdominal fat (Table 4); however, giblet weight, carcass weight, and consumer carcass weight for females were the only carcass measurements for either sex significantly (P<.05) affected by diet. The female broilers fed the high energy starter and finishing diet had a larger (P<.05) giblet weight, carcass weight, consumer carcass weight, and the regressed abdominal fat weight approached a significant increase (P=.067) compared to females fed the high energy starter and low energy finishing diet. The abdominal fat weight for male and female broilers was not significantly different (P>.05). Male broilers fed the low energy starter and finishing diet and female broilers fed the high energy starter and finishing diet contained slightly increased amounts of abdominal fat compared to the same sex fed different diet combinations;
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difference was not significant (P>.05). Female broilers previously fed the low energy starter diet for the first 28 days and then fed the low energy finisher diet from 28 to 56 days consumed significantly (P<.05) more feed during the finishing period compared to females fed high energy starter and finishing diets. The 8 g/day increase in feed intake for female broilers fed the low energy finishing diet was sufficient to equal the energy consumption of female broilers fed the high energy finishing diet. The feeding of low or high energy starter diets for the 0 to 28 day period had no effect (P>.05) upon the 28 to 56 day broiler weight gain, feed conversion, and feed consumption. Combined Starter and Finishing Feeding Period (0—56 days). The total weight gain (0 to 56 days) for each male broiler group was larger (P<.05) than the weight gain of each female broiler group. The diets containing various energy levels had no effect upon total 56 day weight gain for either sex. The increased gain of male broilers fed the low energy finishing diet during the 28 to 56 day period was not enough to compensate for the slight reduction (P<,05) in weight gain from 0 to 28 days produced by feeding the low energy starter diet. The small increase (P>.05) in gain of females fed the high energy finishing diet from 28 to 56 days was also eliminated by an opposite trend in weight gain for the starter period. The feed conversion for the total 56 day feeding period was 1.85 and 1.90 for male broilers fed high energy starter and finishing diets and males fed low energy starter and high energy finishing diets, respectively. The feed conversion of the males fed the high energy finishing diet was improved (P<.05) compared to the two male groups fed low energy finishing diets and all female groups. The feed conversion for the total 56 day period of the two male broiler groups fed the low energy finishing diet was no different (P>.05) than the feed conversion for females fed the high energy finishing diet. The feed conversion for females fed low energy starter and finishing diets for the 56 day period was 2.17 and significantly different compared to all broiler groups.
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35 4.2 1.8 4 30 33 1.2 .16
.20
± ± ± ± + ± ± ±
4.70 ±
37 5.1 1.8 3 27 29 .3 .20
.30
5.61 ±
4.50 ± 2105 + 80.9 ± 81.9 ± 170ab + 1357ab ± 1527ab + 72.5 ± 3.82 ± 5.28 ±
+ 37 ± 3.8 ± 1.9 ± 4 + 23 ± 24 ± 1.0 ± .18
.22
5.70 ±
2077 83.9 80.5 164* 1304 a 146 ?a 70.9 4.05
Females
.20
LE-HE 2591 ± 85.0 ± 89.3 ± 204 ± 1679 ± 1883 ± 72.7 ± 3.27 +
- Males
Diet 2
± 30 ± 3.9 ± 1.5 + 4 ± 22 ± 23 ± .3 ± .14
4.62 ±
2592 87.3 89.3 208 1684 1892 73.0 3.36
—
.20
27 3.5 1.3 2 19 20 .2 .14
.20
39 4.0 2.0 3 25 30 .4 .14
Mean ± SEM for the carcass composition for each dietary treatment represent 24 broilers. The mean value ± SEM fo
' Means containing a common superscript within a row are not significantly different (PX05).
2200 88.8 86.7 177b 1403 b 1580 b 71.8 4.02
± ± ± ± ± ± ± ±
2525 88.2 85.8 204 1666 1870 74.2 3.49
HE-LE
Abdominal fat.
Consumer carcass weight is the carcass weight plus giblet weight.
Minus leaf fat.
Regressed abdominal fat on live weight.
* "Means are not significantly different (P>.05) for sexes.
*Means are significantly different (P<.01) for sexes.
6
5
4
3
The first and second group of letters of HE-HE, HE-LE, LE-HE, and LE-LE represent the type of starter diet (H days and finisher diet fed from 28—56 days, respectively.
2
1
a
Live weight (g) Abdominal fat 3 (g) Regressed abdominal fat 4 (g) Giblet weight (g) Carcass weight5 (g) Consumer carcass weight 5 ' 6 (g) % Yield5 % Abdominal fat 3 /live weight % Abdominal fat 3 /consumer carcass weight 5 ' 6
Live weight (g) Abdominal fat 3 (g) Regressed abdominal fat4 (g) Giblet weight (g) Carcass weight 5 (g) Consumer carcass weight 5 ' 6 (g) % Yield5 % Abdominal fat 3 /live weight % Abdominal fat 3 /consumer carcass weight 5 ' 6
HE-HE
TABLE 5. Fifty-six day carcass composition of male and female broilers fed varying levels of energy for the 0
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ENERGY AND BROILER CARCASS COMPOSITION
Although t h e high energy diets fed t o broilers significantly ( P < . 0 5 ) improved feed conversion a n d did n o t increase t h e a b d o m i n a l fat c o n t e n t of broilers, t h e t o t a l feed cost a t t h e time of t h e e x p e r i m e n t (WSU F e e d Mill prices) for t h e 5 6 d a y feeding period was 5i m o r e p e r bird c o m p a r e d t o t h e cost of feeding l o w energy diets. T h e additional cost of t h e e x t r a tallow a n d p r o t e i n c o n t e n t in t h e high energy starter a n d finishing diets eliminated t h e benefits of less feed c o n s u m p t i o n . REFERENCES Bartov, I., S. Bornstein, and B. Iipstein, 1974. Effect of calorie to protein ratio on the degree of fatness in broilers fed on practical diets. Brit Poultry Sci. 15:107-117.
Becker, W. A., J. V. Spencer, L. W. Mirosh, and J. A. Veistrate, 1979. Prediction of fat and fat free live weight in broiler chickens using backskin fat, abdominal fat, and live body weight Poultry Sci. 58:83 5-842. Carew, L. B., Jr., and F. W. Hill, 1964. Effect of corn oil on metabolic efficiency of energy utilization by chicks. J. Nutr. 83:293-299. Carew, L. B., Jr., D. T. Hopkins, and M. C. Nesheim, 1964. Influence of amount and type of fat on metabolic efficiency of energy utilization by the chick. J. Nutr. 83:300-306. Donaldson, W. E,, G. F. Combs, and G. L. Romoser, 1958. Studies on energy levels in poultry rations. 3. Effect of calorie-protein ratio of the ration on growth, nutrient utilization and body composition of poults. Poultry Sci. 37:614-619. Edwards, H. M., and P. Hart, 1971. Carcass composition of chickens fed carbohydrate-free diets containing various lipid energy sources. J. Nutr. 101:989— 996. Griffiths, L., S. Leeson, and J. D. Summers, 1977. Influence of energy system and level of various fat sources on performance and carcass composition of broilers. Poultry Sci. 56:1018-1026. Jensen, L. S., G. W. Schumaier, and J. D. Latshaw, 1970. "Extra caloric" effect of dietary fat for developing turkeys as influenced by calorieprotein ratio. Poultry Sci. 49:1697—1704. Kubena, L. F., J. W. Deaton, T. C. Chen, and F. N. Reece, 1974. Factors influencing the quantity of abdominal fat in broilers. 1. Rearing temperature, sex, age or weight and dietary choline chloride and inositol supplementation. Poultry Sci. 53:211-214. National Research Council, 1977. Nutrient requirements of poultry. Nat Acad. ScL, Washington, DC. Nordstrom, J. O., R. H, Towner, G. B. Havenstein, and G. L. Walker, 1978. Influence of genetic strain, sex and dietary energy level on abdominal fat deposition in broilers. Poultry Sci. 57:1176. (Abstr.) Rand, N. T., H. M. Scott, and F. A. Kummerow, 1958. Dietary fat in the nutrition of the growing chick Poultry Sci. 37:1075-1085. Salleh, M. S., N. L. Kamus, and A. J. Farr, 1978. Ration and strain effects on broiler growth performance and processing parameters. Poultry Sci. 57:1186. (Abstr.) Scheibel, M. S., C. N. Coon, and K. W. Kelley, 1979. The heat increment of feed used in poultry diets. Nutr. Rep. I n t 20:871-881. Steel, R.G.D., and J. H. Torrie, 1960. Principles and procedures of statistics. McGraw-Hill Book Company, Inc., New York, NY. Summers, J. D., and S. Leeson, 1979. Composition of poultry meat as affected by nutritional factors. Poultry Sci. 58:536-542. Touchburn, S. P., and E. C. Naber, 1966. The energy value of fats for growing turkeys. Pages 190—195 in Proc. 13th World's Poultry Congr.
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however, differences were nonsignificant ( P > . 0 5 ) . T h e nonsignificant ( P > . 0 5 ) sex o r diet difference for a b d o m i n a l fat weight m a y have been a t t r i b u t e d t o a 2 3 % coefficient of variation (CV) for males a n d 24.6% CV for females. T h e significant sex-diet interaction for regressed a b d o m i n a l fat was because t h e regressed abdominal fat weight was observed to have a 1 1 % CV for males a n d 1 1 . 1 % CV for females. T h e sex-diet interaction for weight gain during t h e 2 8 t o 56 day feeding period d e m o n strated an advantage of feeding sexes separately. T h e increased weight gain of females fed t h e high energy finishing diet c o m p a r e d t o males gaining m o r e weight o n t h e low energy finishing diet was cancelled w h e n weight gain for b o t h sexes fed t h e same diet was c o m b i n e d . T h e l o w energy finishing d i e t c o n t a i n e d t h e same a m o u n t of m e t a b o l i z a b l e energy as recomm e n d e d b y t h e National Research Council ( 1 9 7 7 ) . T h e large a m o u n t of tallow in t h e high energy starter a n d finishing diets w o u l d increase t h e n e t energy c o n t e n t of t h e diets (Scheibel et «/., 1 9 7 9 ) and c o n s e q u e n t l y increase t h e n e t e n e r g y / p r o t e i n ratio of high energy diets c o m p a r e d t o l o w energy diets. T h e slight increase in daily calorie ( 1 8 kcal) and p r o t e i n ( 1 g) c o n s u m p t i o n of males consuming 16 g m o r e feed/day of t h e l o w energy finishing diet suggests t h e high energy finishing diet limited n u t r i e n t intake t o o severely. Females only c o n s u m e d 8 g/day m o r e of t h e low energy finishing diet; therefore, t h e calorie and protein c o n s u m p t i o n t e n d e d t o be higher for females fed t h e high energy finishing diet.
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1981 Poultry Science 60:1264-1271 INTRODUCTION A review of t h e literature by S u m m e r s and Leeson ( 1 9 7 9 ) reveals fat deposition in broilers can be influenced b y diet c o m p o s i t i o n , envir o n m e n t and t e m p e r a t u r e , t y p e of housing, age, and sex. N o r d s t r o m et al. ( 1 9 7 8 ) a n d Salleh et al. ( 1 9 7 8 ) have d e m o n s t r a t e d a b d o m i n a l fat deposited in broilers is also related t o strain differences. Broilers containing excessive abd o m i n a l fat are often less desirable for 1) a c o n s u m e r w h e n t h e fat pad comprises part of t h e m a r k e t a b l e p r o d u c t (Bartov et al, 1 9 7 4 ) , 2) a p o u l t r y processing p l a n t because t h e partially removed fat increases waste disposal p r o b l e m s (Kub'ena et al, 1 9 7 4 ) , and 3) a p r o d u c e r because t h e abdominal fat is a nonprofitable conversion of dietary energy (Bartov et al, 1974). Nutrition studies have established widening t h e dietary energy-protein
that ratio
1 Scientific Paper No. 5600. College of Agriculture Research Center, Washington State University, Pullman, WA. Project 0308.
increases fat deposition in broilers and narrowing t h e dietary energy-protein ratio decreases fat deposition (Bartov et al, 1974). Conflicting studies, however, have been r e p o r t e d o n t h e effect of dietary fat on carcass composition. Carew and Hill ( 1 9 6 4 ) and Carew et al. ( 1 9 6 4 ) d e m o n s t r a t e d t h a t t h e isocaloric replacement of c a r b o h y d r a t e s with corn oil increases carcass energy r e t e n t i o n in t h e form of fat. Donaldson et al ( 1 9 5 8 ) r e p o r t e d t h a t t u r k e y s fed diets with comparable energy-protein ratios and increasing levels of dietary fat contained a higher percentage of carcass fat. Edwards and Hart ( 1 9 7 1 ) , Bartov et al ( 1 9 7 4 ) , a n d Griffiths et al. ( 1 9 7 7 ) were unable t o d e m o n s t r a t e any differences in carcass composition resulting from t h e isocaloric s u b s t i t u t i o n of dietary fat for c a r b o h y d r a t e s . Animal fat o r a blend of vegetable and animal fat is c o m m o n l y added to p o u l t r y rations t o reduce dustiness, lubricate pellet dies, increase t h e dietary energy, and improve t h e utilization of metabolizable energy calories and p r o t e i n as suggested by R a n d et al. ( 1 9 5 8 ) . T o u c h b u r n and Naber ( 1 9 6 6 ) and J e n s e n et al. ( 1 9 7 0 ) also observed an " e x t r a caloric" effect
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ABSTRACT We studied the effect of feeding two levels of energy in starter diets [3135 kcal metabolizable energy (ME)/kg low energy and 3410 kcal ME/kg high energy] from 0 to 28 days and finishing diets (3190 kcal ME/kg low energy and 3465 kcal ME/kg high energy) from 28 to 56 days upon broiler weight gain, feed conversion, feed consumption, calorie consumption, and abdominal fat content Feed conversion of male and female broilers fed the high energy starter diet from 0 to 28 days or the high energy finisher diet from 28 to 56 days was superior (P<.05) compared to feed conversion of broilers fed the low energy starter and finisher diet. The weight gain of male and female broilers from 0 to 28 days was not affected (P>.05) by diet; however, weight gain during the 28 to 56 day feeding period demonstrated a sex-diet interaction (P<.05). The males fed the low energy starter and finishing diets gained more weight (P<.05) during the 28 to 56 day period than males fed a high energy finishing diet. The males fed the low energy finishing diet consumed 16 g/day more feed (P<.05) and 18 kcal/day more metabolizable energy than males fed the high energy finishing diet Females fed the low energy finishing diet consumed 9 g additional feed per day (P<.05) but the energy consumption was the same. Male broilers fed the low energy starter and finishing diets and female broilers fed the high energy starter and finishing diets contained slightly increased amounts of abdominal fat compared to the same sex fed different diet combinations; however, differences were nonsignificant (P> .05). A sex-diet interaction was observed (P<.05) for regressed abdominal fat weight on live body weight. (Key words: dietary energy, abdominal fat, sex-diet interaction, broilers, weight gains, feed conversions)
ENERGY AND BROILER CARCASS COMPOSITION for supplemental fat and suggested wider calorie-protein ratios for poultry rations with additional fat can be used for maximum gains and feed efficiency. The objective of the research reported herein was to study the effects of feeding broilers high energy diets containing supplementary fat during starter and finishing periods on broiler weight gain, feed conversion, and abdominal fat content.
watering bowl, hanging tube feeder, infrared 400-W radiant heater, and a 100-W incandescent light bulb providing continuous light. Male and female chicks in 20 pens (10 pens each) were fed the low energy starter diet [3135 kcal metabolizable energy (ME)/kg; 23% crude protein (CP)], and the male and female chicks in the other pens (10 pens each) were fed the high energy starter diet (3410 kcal ME/kg; 25% CP), (Table 1) from 0 to 28 days. Weight gain and feed consumption for each pen of chicks were determined after a 28-day feeding period. One-half the chicks (5 pens of each sex) previously fed the starter diet with the low energy level were fed the low energy finishing diet (3190 kcal ME/kg; 18.9% CP) for an additional 28-day feeding period. The remaining chicks previously fed the low energy starter diet (5 pens of each sex) were fed the high energy finisher diet (3465 kcal ME/kg; 20.5% CP) for
TABLE 1. Experimental starter and finisher diets Finisher (28--56 days)
Starter (0--28 days) Ingredient
Corn, yellow ground Soybean oil meal (47.5% CP)2 Fish meal, anchovy (65% CP)2 Meat and bone meal (50% CP) 2 Limestone Dicalcium phosphate Vitamin premix 3 Trace mineral mix 4 Tallow Amprolium (25% premix) Salt, iodized DL-methionine L-lysine hydrochloride Calculated nutrients Crude protein (%) Metabolizable energy (kcal/kg) Metabolizable energy, (kcal/kg)/crude protein (%) Methionine (g)/Mcal Total sulfur amino acids (g)/Mcal Lysine (g)/McaI
LE
1
HE
LE
HE
58.80 28.65 2.50 5.00 .40 .20 .25 .05 3.65 .05 .25 .15 .05
43.35 34.00 3.50 5.50 .50 .25 .30 .06 12.00 .06 .30 .18
70.47 19.50 2.00 4.00 .45 .25 .25 .05 2.50 .05 .25 .15 .08
57.20 23.40 3.00 4.50 .50 .25 .30 .06 10.25 .06 .26 .18 .04
23.0
25.0
18.9
20.5
3135
3410
3190
3465
136.3 1.72
136.4 1.75
168.8 1.52
169.0 1.55
2.76 3.92
2.77 3.96
2.37 3.04
2.38 3.07
1
Low energy (LE) and High energy (HE).
2
Crude protein (CP).
3 Vitamin premix at .25% of the diet supplies the following per kilogram of the diet: vitamin A, 5,500 IU; vitamin D 3 , 1,650 ICU; vitamin E, 4.4 IU; riboflavin, 3.3 mg; calcium pantothenate, 4.4 mg; niacin, 22 mg; choline chloride, 577mg; vitamin B 1 2 , .011 mg;and ethoxyquin, 62.2 mg. 4 Mineral premix at .05% of the diet supplies the following per kilogram of the diet: Mn, 50 mg; Fe, 50 mg; Cu, 5 mg; Zn, 50 mg; I, 1.5 mg; Ca, 60 mg; and Co, .5 mg.
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MATERIALS AND METHODS
Five hundred male and 500 female day-old Hubbard broiler chicks were randomly distributed by sex into 40 floor pens with each pen containing 25 chicks. Twenty pens contained male chicks and 20 pens contained female chicks. Each pen measured 2.13 X 2.13 M and contained wood shavings litter, automatic
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for each broiler were weighed to the nearest one-tenth gram. Statistical analyses for weight gain, feed conversion, and carcass composition were determined by analysis of variance and Duncan's new multiple range test (Steel and Torrie, 1960).
RESULTS AND DISCUSSION Starter Feeding Period (0-28 days). The chick weight gain for 0 to 28 days was not (P>.05) different for chicks fed high energy starter diets (3410 kcal ME/kg) or low energy starter diets (3135 kcal ME/kg) (Table 2). The feed conversion (g feed consumed/g weight gain) of male chicks fed the high energy diet (1.40) was superior (P<.05) to the male chicks fed the low energy diet (1.51), female chicks fed the low energy diet (1.58), and female chicks fed the high energy diet (1.49), respectively. Female chicks fed the low energy starter
TABLE 2. The weight gain and feed conversion of each sex and combined sexes of broilers fed diets with two levels of metabolizable energy during the 0 to 28 day and 28 to 56 day feeding period 2 8 - 5 6 Days
0 - 2 8 ; Days'
0 - 5 6 Days
Feed conversion3
Weight gain (g)
Feed conversion
Weight gain (g)
Feed conversion
Sex
Diet 2
Weight gain (g)
Male Female Comb. sexes Male Female Comb. sexes Male Female Comb. sexes Male Female Comb. sexes
HE HE
900* ± 1 0 826 b + 6
1.51 b ± .01 1.58c ± .02
1607 b ± 2 9 1348c ± 1 6
2.10 a ± .06 2.26 b ± .02
2515a ±43 2179b±31
1.85* + .04 1.97 b ± .01
HE LE LE
863 e ± 1 0
1.54f ± .01
1477 e ± 4 8 1640* b ± 3 6 1312C ± 1 4
2.18 e ± .04 2.29 b ± .02 2.48 c ± .03
2347 e ± 64 2572* ± 44 2122 b ± 21
1.918 ± .03 1.96 b ± .01 2.10C ± .03
1476 e ± 3 6 1618 b ± 2 6 1343 c ± 12
2.38 f ± .04 2.13 a ± .02 2.31b±.02
2347 e ± 74 2529* ± 34 2176 b ± 1 3
2.03 e ± .03 1.90* ± .02 2.02 b ± .01
LE HE HE HE LE LE
920* ± 1 4 820 b ± 1 0
1.40a ± .01 1.49 b ± .02
1481 e ± 4 5 1694* ± 16 1311 c ± 2 0
2.22 e ± .03 2.26 b + .02 2.52= ± .02
2352C ± 58 2584* ± 29 2130 b ± 23
1.96 f ± .02 2 . 0 1 b ± .02 2.17 d ± .02
LE
87ie ±14
1.44e ± .01
1502C
2.39 f ± .05
2357C + 82
2.09 e ± .03
±68
' ' ' Means within a column for male or female broilers containing a common superscript are not significantly different (P>.05). ' '•'Means within a column for combined sexes containing a common superscript are not significantly different (P>.05). ' T h e mean values ± SEM represent five replicates of 25 broilers for the 28—56 day and 0—56 day feeding period whereas mean values ± SEM for the 0—28 day period represent 10 replicates. 2 HE and LE represent the high and low energy diets, respectively, listed in Table 1 for 0—28 day and 28—56 day feeding period. 3
Feed conversion is the g feed consumed divided by g weight gain.
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the same length of time. The 28-day-old broiler chicks previously fed the high energy starter diet were fed the two finishing diets by the same method as described. The broilers were weighed and feed consumption recorded at 56 days of age. Protein levels were increased in the high energy diets to keep the calorie-protein ratios equivalent to control diets. DL-methionine and L-lysine hydrochloride were added to the test diets to keep constant the sulfur amino acid-energy ratio and lysine-energy ratio for both starter and finisher diets. Six broilers randomly selected from each pen were wing banded, placed in crates, and held without food or water for 20 hr. The birds were individually weighed prior to being slaughtered in the Washington State University Meats Laboratory. The method of evisceration and removal of abdominal fat was the same as described by Becker et al. (1979). Giblets (gizzard, heart, liver, and neck with connecting skin), abdominal fat, and the eviscerated carcass
148.9 e ± 1.4 127«
±3
407e ±11
Means within a column for combined sexes containing a common superscript are not significantly different (P>.0
Means within a column for male or female broilers containing a common superscript are not significantly differ
47.5 ± .4
± 2
3
2
Kilocalories metaboUzable energy consumed/day.
Same as Table 2.
1 The mean values ± SEM represent five replicates of 25 broilers each for the 2 8 - 5 6 day and 0 - 5 6 day feeding pe period represent 10 replicates.
B
a,b,c,d
LE
f
±2 ±2
405e ± 9 436a± 8 377b ± 8
117 f g 13 7^ 118bc
151.8b: 2.2 146.0b : 1.3
48.4 a ± .7 4 6 . 6 b ± .4
± 2
±3 ±2
HE LE LE
4 1 8 a ±11 378b ± 2
399 e 10 426a ± 8 384b± 6
±3 ±2
125
HE LE LE
12lb 109 d
LE HE HE
152.8 e +1.8
4 4 . 8 e ±.5
HE HE
Male Female Comb. sexes Male Female Comb. sexes Male Female Comb. sexes Male Female Comb. sexes
ME consumed/ day (kcal)
398 e ± 9 4 2 7 a ±10 37lb± 3
157.5a +2.2 148.2b ±2.1
4 6 . 2 b + .6 43.5 C +.6
Diet 2
Sex
2 8 - 5 6 Days Feed consumed/ day (g)
1158 ±3 134 a ±3 116bcd ± 1
ME consumed/ day 3 (kcal)
Feed consumed/ day (g)
0 - 2 8 Days 1
TABLE 3. The daily feed and energy consumption of each sex and combined sexes of broilers f of metaboUzable energy during the 0—28 day and 28—56 day feeding per
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COON ET AL.
1268
the low energy finishing diet and female broilers fed either of the two finishing diets. There was no significant difference in feed conversion during the 28 to 56 day feeding period for males fed the low energy finishing diet or females fed the high energy finishing diets. The two groups of female broilers fed the low energy finishing diet from 28 to 56 days demonstrated a poorer (P<.05) feed conversion compared to all groups of broilers. Male and female broilers previously fed the high energy starter diet improved their feed conversion by .069 and .079, respectively, during the 28 to 56 day finishing period with each additional 100 kcal ME in the high energy finisher diet compared to broilers fed the low energy finishing diet. However, male broilers previously fed the low energy starter diet only improved their feed conversion by .047 during the 28 to 56 day finishing period with each additional 100 kcal ME in the high energy finishing diet. The males fed both low energy starter and finishing diets gained the largest weight during the 28 to 56 day feeding period and the high weight gain decreased the feed conversion improvement produced with the high energy finishing diet. Female broilers previously fed the low energy starter diet improved their feed conversion .076 during the 28 to 56 day feeding period with each additional 100 kcal ME in the high energy finishing diet. Male broilers fed the low energy finishing diet consumed more (P< .05) feed during the 28 to 56 day period than males fed the high energy finishing diet or females fed the high or low energy finishing diets. Males fed the low energy finishing diet also tended to consume 18 kcal/ day more metabolizable energy because of the 16.2 g/day increase in feed intake compared to males fed high energy diets although the energy
TABLE 4. Analysis of variance for broiler weight gain and regressed abdominal fat Source of variation
Weight gain 28—56 Days df MS
Diet Sex Sex X diet Error
3 1 3 32
•Significant at P<.05. * 'Significant at P<.001.
7782* 952879** 7288* 2537
Regressed abdominal fat on live weight df MS 3 1 3 200
18.8 1674.3** 270.7* 90.3
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diet during the 0 to 28 day feeding period demonstrated a poorer (P<.05) feed efficiency compared to all chick groups. The feed conversion was improved .033 for females and .040 fo,r males with each additional 100 kcal ME in the high energy starter diet compared to the low energy starter diet. The male chicks fed the low energy starter diet from 0 to 28 days consumed more (P<.05) feed per day compared to other male or female groups; however, the male chicks fed the high energy diet during the same feeding period consumed more (P<.05) ME per day (Table 3). Female chicks fed the high energy starter diet consumed (P<.05) less feed per day compared to all broiler groups, but the daily caloric consumption was equivalent to males or females fed the low energy starter diet. Finisher Feeding Period (28—56 days). The largest weight gain of male broilers for the 28 to 56 day feeding period was 1694 g for males fed the low energy starter diet prior to being fed the low energy finishing diet. The 1694 g weight gain was larger (P<.05) than 1618.5 g and 1606.6 g weight gain for males fed low energy and high energy starter diets, respectively, prior to feeding the high energy finishing diet. A sex-diet interaction (P<.05) for weight gain during the 28 to 56 day feeding period was demonstrated (Table 4). The two groups of males fed the low energy finishing diet gained more weight (1667 g combined average) from 28 to 56 days than the two groups of male broilers fed the high energy finishing diet (1613 g combined average), whereas females fed the same two diets demonstrated an opposite weight gain response (1311 g and 1346 g combined average, respectively). Male broilers fed the high energy finishing diet during the 28 to 56 day feeding period had an improved (P<.05) feed conversion compared to males fed
ENERGY AND BROILER CARCASS COMPOSITION
The average feed consumption per day during the total 0 to 56 day period for male broilers fed the low energy starter and finishing diet was larger (P<.05) and females fed high energy diets for the 56 day period consumed less (P<.05) than all broiler groups. Male broilers consumed increased (P<.05) amounts
of calories per day during the 0 to 56 day period compared to females; however, the caloric consumption was not different (P>.05) among treatments for either sex. The weight gain of combined sexes for the 0 to 28 day, 28 to 56 day, and 56 day period was not significantly (P>.05) different for the dietary energy combinations. The average feed conversion for combined sexes fed a high energy starter diet from 0 to 28 days and the feed conversion for both sexes fed a high energy finishing diet from 28 to 56 days, regardless of starter diet fed during the 0 to 28 day period, was superior (P<.05) to the average feed conversion of both sexes of broilers fed a low energy diet during the two separate feeding periods. The total 56 day feed conversion was improved (P<.05) for combined sexes of broilers fed the high energy starter and high energy finishing diet compared to all groups. Carcass Composition. The live weight, regressed abdominal fat on live weight, giblet weight, consumer carcass weight (carcass weight + giblet weight), percent yield, percent abdominal fat of live weight, and percent abdominal fat of consumer carcass weight were different (P<.05) for male and female broilers (Table 5). The regressed abdominal fat weight on live weight was determined because a correlation (P<.01) between live body weight and abdominal fat weight for males (r = .44) and females (r = .42) was observed. Becker et al. (1979) suggested regressed abdominal fat weight is relatively independent of body weight and is a superior comparison for abdominal fat measurements. A sex-diet interaction was significant at the 5% level for regressed abdominal fat (Table 4); however, giblet weight, carcass weight, and consumer carcass weight for females were the only carcass measurements for either sex significantly (P<.05) affected by diet. The female broilers fed the high energy starter and finishing diet had a larger (P<.05) giblet weight, carcass weight, consumer carcass weight, and the regressed abdominal fat weight approached a significant increase (P=.067) compared to females fed the high energy starter and low energy finishing diet. The abdominal fat weight for male and female broilers was not significantly different (P>.05). Male broilers fed the low energy starter and finishing diet and female broilers fed the high energy starter and finishing diet contained slightly increased amounts of abdominal fat compared to the same sex fed different diet combinations;
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difference was not significant (P>.05). Female broilers previously fed the low energy starter diet for the first 28 days and then fed the low energy finisher diet from 28 to 56 days consumed significantly (P<.05) more feed during the finishing period compared to females fed high energy starter and finishing diets. The 8 g/day increase in feed intake for female broilers fed the low energy finishing diet was sufficient to equal the energy consumption of female broilers fed the high energy finishing diet. The feeding of low or high energy starter diets for the 0 to 28 day period had no effect (P>.05) upon the 28 to 56 day broiler weight gain, feed conversion, and feed consumption. Combined Starter and Finishing Feeding Period (0—56 days). The total weight gain (0 to 56 days) for each male broiler group was larger (P<.05) than the weight gain of each female broiler group. The diets containing various energy levels had no effect upon total 56 day weight gain for either sex. The increased gain of male broilers fed the low energy finishing diet during the 28 to 56 day period was not enough to compensate for the slight reduction (P<,05) in weight gain from 0 to 28 days produced by feeding the low energy starter diet. The small increase (P>.05) in gain of females fed the high energy finishing diet from 28 to 56 days was also eliminated by an opposite trend in weight gain for the starter period. The feed conversion for the total 56 day feeding period was 1.85 and 1.90 for male broilers fed high energy starter and finishing diets and males fed low energy starter and high energy finishing diets, respectively. The feed conversion of the males fed the high energy finishing diet was improved (P<.05) compared to the two male groups fed low energy finishing diets and all female groups. The feed conversion for the total 56 day period of the two male broiler groups fed the low energy finishing diet was no different (P>.05) than the feed conversion for females fed the high energy finishing diet. The feed conversion for females fed low energy starter and finishing diets for the 56 day period was 2.17 and significantly different compared to all broiler groups.
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35 4.2 1.8 4 30 33 1.2 .16
.20
± ± ± ± + ± ± ±
4.70 ±
37 5.1 1.8 3 27 29 .3 .20
.30
5.61 ±
4.50 ± 2105 + 80.9 ± 81.9 ± 170ab + 1357ab ± 1527ab + 72.5 ± 3.82 ± 5.28 ±
+ 37 ± 3.8 ± 1.9 ± 4 + 23 ± 24 ± 1.0 ± .18
.22
5.70 ±
2077 83.9 80.5 164* 1304 a 146 ?a 70.9 4.05
Females
.20
LE-HE 2591 ± 85.0 ± 89.3 ± 204 ± 1679 ± 1883 ± 72.7 ± 3.27 +
- Males
Diet 2
± 30 ± 3.9 ± 1.5 + 4 ± 22 ± 23 ± .3 ± .14
4.62 ±
2592 87.3 89.3 208 1684 1892 73.0 3.36
—
.20
27 3.5 1.3 2 19 20 .2 .14
.20
39 4.0 2.0 3 25 30 .4 .14
Mean ± SEM for the carcass composition for each dietary treatment represent 24 broilers. The mean value ± SEM fo
' Means containing a common superscript within a row are not significantly different (PX05).
2200 88.8 86.7 177b 1403 b 1580 b 71.8 4.02
± ± ± ± ± ± ± ±
2525 88.2 85.8 204 1666 1870 74.2 3.49
HE-LE
Abdominal fat.
Consumer carcass weight is the carcass weight plus giblet weight.
Minus leaf fat.
Regressed abdominal fat on live weight.
* "Means are not significantly different (P>.05) for sexes.
*Means are significantly different (P<.01) for sexes.
6
5
4
3
The first and second group of letters of HE-HE, HE-LE, LE-HE, and LE-LE represent the type of starter diet (H days and finisher diet fed from 28—56 days, respectively.
2
1
a
Live weight (g) Abdominal fat 3 (g) Regressed abdominal fat 4 (g) Giblet weight (g) Carcass weight5 (g) Consumer carcass weight 5 ' 6 (g) % Yield5 % Abdominal fat 3 /live weight % Abdominal fat 3 /consumer carcass weight 5 ' 6
Live weight (g) Abdominal fat 3 (g) Regressed abdominal fat4 (g) Giblet weight (g) Carcass weight 5 (g) Consumer carcass weight 5 ' 6 (g) % Yield5 % Abdominal fat 3 /live weight % Abdominal fat 3 /consumer carcass weight 5 ' 6
HE-HE
TABLE 5. Fifty-six day carcass composition of male and female broilers fed varying levels of energy for the 0
from http://ps.oxfordjournals.org/ at Dartmouth College Library on January 2, 2015
ENERGY AND BROILER CARCASS COMPOSITION
Although t h e high energy diets fed t o broilers significantly ( P < . 0 5 ) improved feed conversion a n d did n o t increase t h e a b d o m i n a l fat c o n t e n t of broilers, t h e t o t a l feed cost a t t h e time of t h e e x p e r i m e n t (WSU F e e d Mill prices) for t h e 5 6 d a y feeding period was 5i m o r e p e r bird c o m p a r e d t o t h e cost of feeding l o w energy diets. T h e additional cost of t h e e x t r a tallow a n d p r o t e i n c o n t e n t in t h e high energy starter a n d finishing diets eliminated t h e benefits of less feed c o n s u m p t i o n . REFERENCES Bartov, I., S. Bornstein, and B. Iipstein, 1974. Effect of calorie to protein ratio on the degree of fatness in broilers fed on practical diets. Brit Poultry Sci. 15:107-117.
Becker, W. A., J. V. Spencer, L. W. Mirosh, and J. A. Veistrate, 1979. Prediction of fat and fat free live weight in broiler chickens using backskin fat, abdominal fat, and live body weight Poultry Sci. 58:83 5-842. Carew, L. B., Jr., and F. W. Hill, 1964. Effect of corn oil on metabolic efficiency of energy utilization by chicks. J. Nutr. 83:293-299. Carew, L. B., Jr., D. T. Hopkins, and M. C. Nesheim, 1964. Influence of amount and type of fat on metabolic efficiency of energy utilization by the chick. J. Nutr. 83:300-306. Donaldson, W. E,, G. F. Combs, and G. L. Romoser, 1958. Studies on energy levels in poultry rations. 3. Effect of calorie-protein ratio of the ration on growth, nutrient utilization and body composition of poults. Poultry Sci. 37:614-619. Edwards, H. M., and P. Hart, 1971. Carcass composition of chickens fed carbohydrate-free diets containing various lipid energy sources. J. Nutr. 101:989— 996. Griffiths, L., S. Leeson, and J. D. Summers, 1977. Influence of energy system and level of various fat sources on performance and carcass composition of broilers. Poultry Sci. 56:1018-1026. Jensen, L. S., G. W. Schumaier, and J. D. Latshaw, 1970. "Extra caloric" effect of dietary fat for developing turkeys as influenced by calorieprotein ratio. Poultry Sci. 49:1697—1704. Kubena, L. F., J. W. Deaton, T. C. Chen, and F. N. Reece, 1974. Factors influencing the quantity of abdominal fat in broilers. 1. Rearing temperature, sex, age or weight and dietary choline chloride and inositol supplementation. Poultry Sci. 53:211-214. National Research Council, 1977. Nutrient requirements of poultry. Nat Acad. ScL, Washington, DC. Nordstrom, J. O., R. H, Towner, G. B. Havenstein, and G. L. Walker, 1978. Influence of genetic strain, sex and dietary energy level on abdominal fat deposition in broilers. Poultry Sci. 57:1176. (Abstr.) Rand, N. T., H. M. Scott, and F. A. Kummerow, 1958. Dietary fat in the nutrition of the growing chick Poultry Sci. 37:1075-1085. Salleh, M. S., N. L. Kamus, and A. J. Farr, 1978. Ration and strain effects on broiler growth performance and processing parameters. Poultry Sci. 57:1186. (Abstr.) Scheibel, M. S., C. N. Coon, and K. W. Kelley, 1979. The heat increment of feed used in poultry diets. Nutr. Rep. I n t 20:871-881. Steel, R.G.D., and J. H. Torrie, 1960. Principles and procedures of statistics. McGraw-Hill Book Company, Inc., New York, NY. Summers, J. D., and S. Leeson, 1979. Composition of poultry meat as affected by nutritional factors. Poultry Sci. 58:536-542. Touchburn, S. P., and E. C. Naber, 1966. The energy value of fats for growing turkeys. Pages 190—195 in Proc. 13th World's Poultry Congr.
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however, differences were nonsignificant ( P > . 0 5 ) . T h e nonsignificant ( P > . 0 5 ) sex o r diet difference for a b d o m i n a l fat weight m a y have been a t t r i b u t e d t o a 2 3 % coefficient of variation (CV) for males a n d 24.6% CV for females. T h e significant sex-diet interaction for regressed a b d o m i n a l fat was because t h e regressed abdominal fat weight was observed to have a 1 1 % CV for males a n d 1 1 . 1 % CV for females. T h e sex-diet interaction for weight gain during t h e 2 8 t o 56 day feeding period d e m o n strated an advantage of feeding sexes separately. T h e increased weight gain of females fed t h e high energy finishing diet c o m p a r e d t o males gaining m o r e weight o n t h e low energy finishing diet was cancelled w h e n weight gain for b o t h sexes fed t h e same diet was c o m b i n e d . T h e l o w energy finishing d i e t c o n t a i n e d t h e same a m o u n t of m e t a b o l i z a b l e energy as recomm e n d e d b y t h e National Research Council ( 1 9 7 7 ) . T h e large a m o u n t of tallow in t h e high energy starter a n d finishing diets w o u l d increase t h e n e t energy c o n t e n t of t h e diets (Scheibel et «/., 1 9 7 9 ) and c o n s e q u e n t l y increase t h e n e t e n e r g y / p r o t e i n ratio of high energy diets c o m p a r e d t o l o w energy diets. T h e slight increase in daily calorie ( 1 8 kcal) and p r o t e i n ( 1 g) c o n s u m p t i o n of males consuming 16 g m o r e feed/day of t h e l o w energy finishing diet suggests t h e high energy finishing diet limited n u t r i e n t intake t o o severely. Females only c o n s u m e d 8 g/day m o r e of t h e low energy finishing diet; therefore, t h e calorie and protein c o n s u m p t i o n t e n d e d t o be higher for females fed t h e high energy finishing diet.
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