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Effect of Light, Feeding Space, Stocking Density, and Dietary Energy on Broiler Performance1
Effect of Light, Feeding Space, Stocking Density, and Dietary Energy on Broiler Performance1 W. D. WEAVER, JR., W. L. BEANE, and J. A. CHERRY Poultry Science Department, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061 (Received for publication April 21,1981)
1982 Poultry Science 6 1 : 3 3 - 3 7 lighting regimens when stocking density, feeding space, and diet were varied. It was felt t h a t various m a n a g e m e n t conditions m a y have c o n t r i b u t e d t o the inconsistent results u n d e r b o t h experimental and field conditions.
INTRODUCTION A n u m b e r of investigators have r e p o r t e d improved performances w h e n broilers are provided i n t e r m i t t e n t light (IL) in comparison with c o n t i n u o u s illumination (CL) (Quarles and Kling, 1 9 7 4 ; B u c k l a n d et al, 1 9 7 6 ; McDaniel et al, 1 9 7 7 ; D e a t o n et al, 1978, 1 9 8 0 ; Goodman, 1978; Beane et al, 1 9 7 9 ; Cherry et al, 1980). F u r t h e r m o r e , Buckland et al. ( 1 9 7 1 ) found t h a t increased dietary p r o t e i n improved broiler performance u n d e r IL m o r e t h a n u n d e r CL. T h e y concluded t h a t this was caused by reduced feeding t i m e and reduced total n u t r i e n t intake of birds u n d e r IL. However, Cherry et al. ( 1 9 7 8 ) found t h a t broilers u n d e r CL had significantly heavier b o d y weights t h a n p e n m a t e s on t w o different IL regimens when fed diets increased in b o t h protein and energy. Weights were similar for broilers u n d e r all these lighting regimens when t h e y were fed lower levels of these n u t r i e n t s . Field results have been inconsistent when the performance of broilers grown u n d e r CL and IL regimens were c o m p a r e d . The objective of this investigation was to c o m p a r e IL and CL
'This study was supported in part by the John Lee Pratt Animal Nutrition Program.
METHODS AND MATERIALS Three e x p e r i m e n t s were c o n d u c t e d using either 2 0 0 0 ( E x p e r i m e n t 1) or 2 4 0 0 (Exp e r i m e n t s 2 and 3) male broiler chicks ( H u b bard X H u b b a r d ) o b t a i n e d from commercial hatcheries. T h e chicks in each e x p e r i m e n t were vaccinated for Marek's disease and r a n d o m l y divided into 16 groups of 50 and 16 groups of 75 chicks each in E x p e r i m e n t 1, and 32 groups of 75 chicks each in E x p e r i m e n t s 2 and 3, respectively, and placed in replicated lightcontrolled floor pens measuring 1.52 X 3.66 m. Experiment 1. Two lighting regimens, t w o feeding space levels, and t w o stocking densities were provided in a factorial arrangement. Each t r e a t m e n t was replicated four times. T h e CL at an intensity of approximately 6 5 lx m e a s u r e d 15 cm above t h e litter was provided for all groups until 7 days of age, at which time t h e light t r e a t m e n t s were imposed. T h e light regimens were: 1) CL with low intensity, and 2) IL with 1 hr on and 2 hr off. Light intensity for
33
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on March 26, 2015
ABSTRACT The influence of various light regimens, dietary energy levels, feeding space levels, and stocking densities on male broiler body weight, feed efficiency, and percentage abdominal fat was studied in a series of three experiments. Broilers subjected to intermittent light (1 hr on, 2 hr off) in combination with increased feeding space (2.94 or 4.40 cm/bd) had significantly higher 49 day body weights and feed efficiency (one experiment) than did birds under continuous illumination. However, when feeding space was reduced to 1.47 or 2.20 cm/bd, body weights and feed efficiencies of broilers in intermittently lighted pens were similar to or lower dian those of broilers under continuous illumination. Broilers given more floor space were significantly heavier than, and had similar feed efficiencies to, birds provided a more restricted floor regimen. Furthermore, body weight (one experiment) and feed efficiencies were higher for broilers fed rations containing higher versus lower levels of dietary energy. However, no significant interactions were observed between the lighting regimens and these variables. No differences were noted among treatments in any of the experiments for percentage abdominal fat. (Key words: broiler, lighting regimens, stocking density, feeding space, dietary energy levels, abdominal fat)
WEAVER, JR., ETAL.
34
TABLE 1. The effect of light on body weight and feed efficiency at 28 and 49 days of age Feed efficiency1
Body weight (g) Light regimens
49 days
28 days
49 days
925 a 918 a
2206 a 2228 b
67ia 690 a
.543 a .546 a
941a a
946
2265 a 2261 a
654 a 662a
.508 b .500 a
1011 b 992 a
2180 a 2172 a
699^ 704 a
.541 a .541 a
ab ' Means within an emperiment followed by the same superscript are not significantly different (P<.05). 1
Body weight/feed consumed.
both light regimens was gradually decreased from 65 to 3 lx by the time the broilers were 28 days of age. This intensity was maintained for the final three weeks of the experiment. Commercial starter and grower diets were fed ad libitum in crumble form to 28 and 49 days of age, respectively. One half of the groups was furnished two tube feeders with the remaining groups having one tube feeder. Pans on all feeders were 35 cm in diameter. Chicks were housed at either .074 or .111 m 2 , resulting in either 75 or 50 birds per group and providing either 1.47, 2.20, 2.94, or 4.40 cm of feeding space per bird. Experiments 2 and 3. Starter diets containing either 3080 or 3410 kcal ME/kg and 24 or 26.5% protein, respectively, were fed ad libitum in crumble form from 1 to 28 days of age. Finisher diets containing either 3134 or 3465 kcal ME/kg and 21 or 23.2% protein, respectively, were pelleted and fed ad libitum for the final 3 weeks of the experiment. Lighting and feeding space regimens were the same as those provided in Experiment 1 and each diet-light-feeding space treatment was replicated four times. Seventy-five chicks were placed in each group to achieve a stocking density of .074 m 2 and a feeding space of either 1.47 or 2.94 cm per bird. Traits Measured and Analysis. The chicks were individually weighed to the nearest 5 g at 28 and 49 days of age and die data were analyzed by analysis of variance. Feed efficiency was also calculated at 28 and 49 days of age with consumption adjusted to reflect daily mor-
tality. Following the experimental period, 5 broilers from each of the 32 groups in Experiment 1 and from 16 of the groups in Experiment 2 were randomly selected and sacrificed. Abdominal fat (gizzard fat not included) was removed, immediately weighed to the nearest .1 g, and expressed as a percentage of total live body weight. These percentages were transformed to arc sin \J% prior to analysis. An analysis of variance was used to
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22002175215021251
I .47 or 2 . 2 0 cm/bd
I
2.94 or 4 . 4 0 cm/bd
FEEDING SPACE FIG. 1. Effect of light and feeding space on body weight at 49 days of age. CL - continuous light, IL - intermittent light; Experiment 1, — — — Experiment 2, . . . . Experiment 3.
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on March 26, 2015
Experiment 1 Continuous (CL) Intermittent (IL) Experiment 2 CL IL Experiment 3 CL IL
28 days
PRODUCTION EFFECTS ON PERFORMANCE
35
TABLE 2. The effect of stocking density on body weight and feed efficiency at 28 and 49 days of age (Experiment 1)
.546y»iL
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.543-
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28 days
49 days
28 days
49 days
.074 .111
902* 950 b
2184 a 2266 b
.690 a .667 a
.546 a .543 a
1
1
1
1.47 cm/bd
2 . 9 4 cm/bd SPACF
FIG. 2. Effect of light and feeding space on feed efficiency at 49 days of age (Experiment 3). CL continuous light, IL - intermittent light.
determine the differences in treatment means for feed efficiency and abdominal fat.
RESULTS AND DISCUSSION
Light Regimen. Broilers under IL were significantly heavier at 49 days of age than birds under continuous light in Experiment 1 but not in Experiments 2 and 3 (Table 1). A significant interaction was consistently observed between lighting regimen and feeding space for body weight (Fig. 1). Broilers under IL were consistently heavier than birds under CL when they were provided two feeders (1.47 or 2.20 cm/bird). However, when only one feeder (2.94 or 4.40 cm/bird) was used, the broilers actually performed better under CL. Furthermore, a similar interaction for feed efficiency was observed in Experiment 3 (Fig. 2). Several studies (Buckland et al, 1973; Deaton et al, 1976, 1978; Beane et al., 1979; Cherry et al, 1980) have shown improved performance under IL but were conducted with ample feeding space (approximately 2.75 to 3.15 cm per bird). Industry standards usually provide approximately one-half this amount of pan space per bird, which could account for many of the failures of IL programs commercially. Proudfoot (1973) reported a significant feed space X lighting regimen (IL vs.
Body weight/feed consumed.
CL) interaction for both body weight and feed conversion, but the directions of these relationships were not reported. Furthermore, Malone et al. (1980b) found no feeder space X light regimen interaction with broilers at 54 days of age when feeder spaces of 1.8, 2.3, or 2.7 cm/bird were compared under CL and IL. However, the feeder spaces provided in their study were intermediate to the two regimens used in ours (1.47 and 2.94 cm/bird), and possibly were too similar to induce a significant response. The interaction between dietary energy and lighting regimen for body weight was not significant in either Experiment 2 or 3. It was hypothesized that the effect of reduced feeding space on body weight of broilers under IL could be at least partially compensated by increasing the nutrient density of the ration. However, contrary to the results reported by
2275 2250 -
o
2225
LU
*
2200
>Q
o
2175
00
2150 .III m * STOCKING
.074 m2 DENSITY
FIG. 3. Effect of light and stocking density on body weight at 49 days of age (Experiment 1). CL continuous light, IL - intermittent light.
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on March 26, 2015
N CL
FEEDING
Feed efficiency1
a ' b Means followed by the same superscript are not significantly different (P<.05).
\
.537-
Body weight (g)
Stocking density (m 2 )
WEAVER, JR., ET AL.
36
TABLE 3. The effect of feeding space on body weight and feed efficiency at 28 and 49 days of age Feed efficiency1
Body weight (g) Feeding space
28 days
49 days
Experiment 1 l2 23 Experiment 2 l4 2s Experiment 3 l4 25
896 a 947b
2202 a 2248 b
.671a .690a
.543a .546a
933 a 954b
2239 a 2288 b
,658a .658a
.503a .505a
1001 a 1002 a
2161 a 2190 b
.704a .699a
.541a .541a
ab ' Means within an experiment followed by the same superscript are not significantly different (P<.05). 1
Body weight/feed consumed.
2
1.47 or 2.20 cm/bird.
3
2.94 or 4.40 cm/bird.
4
1.47 cm/bird.
5
2.94 cm/bird.
Buckland et al. (1971), no interrelationship was found between these two variables for body weight in these experiments. Other first or second order interactions involving these traits were inconsistent and did not appear as biologically meaningful. Floor Space. Increasing stocking density significantly depressed body weight at 28 and 49 days of age (Table 2). Furthermore, an interaction involving this variable and the two light regimens on body weight (Fig. 3) appro-
ached significance (P<.10), suggesting that increased stocking density was more detrimental to birds under CL. Broilers under CL regimens appeared to be more docile than those provided IL. Possibly, the increased activity in the intermittent pens when the lights were on enabled these broilers to find the feeders more easily when grown under more crowded conditions. Feeding Space. Increased feeding space improved body weight in all experiments (Table
TABLE 4. The effect of dietary energy on body weight and feed efficiency at 28 and 49 days of age Feed efficiency1
Body weight (g) Diet
28 days
Experiment 2 l2
2
3
Experiment 3 l2 23
950 b " 937 a 978 a 1025 b
49 days
28 days
49 days
2284 b 2243 a
.645 a .671°
.495 a .513 b
2137 a 2214 b
.680 a .725 b
.526 a .559 b
a ' b Means within an experiment followed by the same superscript are not significantly different (P<.05). 1
Body weight/feed consumed.
2
Diet 1, 3080 kcal/kg from 0 to 28 days and 3134 kcal/kg from 29 to 49 days of age.
3
Diet 2, 3410 kcal/kg from 0 to 28 days and 3465 kcal/kg from 29 to 49 days of age.
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on March 26, 2015
49 days
28 days
PRODUCTION EFFECTS ON PERFORMANCE TABLE 5. The effect of light regimen on abdominal fat at 49 days of age Light regimen Experiment 1 Continuous .(CL) Intermittent (IL) Experiment 2 CL IL
Abdominal fat (%)'
2.22 a 2.38 a 1.88 a 1.95a
1
Expressed as percentage of live weight.
3); however, as previously stated, most of this improvement can be attributed to the increased body weight of the broilers under IL rather than the CL regimens (Fig. 1). Dietary Energy. A significant increase in body weight (Experiment 3 only) and a significant improvement in feed efficiency were found when broilers were fed a ration containing a higher versus a lower level of dietary energy (Table 4). An unexplained increase in body weight among broilers on the ration containing a low level of dietary energy was observed in Experiment 2. The combined effects of this variable and lighting regimens did not produce a significant interaction, indicating that a mere change in the density of the ration will not compensate for reduced feeding space when broilers are under intermittent light. These results are consistent with those of Cherry et al. (1978) and Malone et al. (1980a), who observed a failure of diets with higher energy to increase the body weights of broilers subjected to intermittent light. Abdominal Fat. No statistical differences were noted between light regimens for percentage abdominal fat (Table 5). This is consistent with the findings of Beane et al. (1979), who reported no differences between IL and CL regimens for abdominal fat from broiler males. However, they did find a significant increase in this tissue from females reared under IL regimens. Cave (1980) reported contrasting results. He found that broilers under IL had less abdominal fat than did birds provided CL.
REFERENCES Beane, W. L., J. A. Cherry, and W. D. Weaver, Jr., 1979. Intermittent light and restricted feeding of broiler chickens. Poultry Sci. 58:567—571. Buckland, R. B., D. E. Bernon, and A. Goldrosen, 1976. Effect of four lighting regimens on broiler performance, leg abnormalities and plasma corticoid levels. Poultry Sci. 55:1072— 1076. Buckland, R. B., H. C. Gasperdone, and D. B. Bfagg, 1971. Interaction of strain, density and ration with two light systems on broiler performance. Can. J. Anim. Sci. 51:613-619. Buckland, R. B., A. T. Hill and D. E. Bernon, 1973. Effects of four lighting regimens on the performance of broilers and roasters. Can. J. Anim. Sci. 53:21-24. Cave, N. A., 1980. Effect of intermittent lighting on feed efficiency and broiler carcass fat. Poultry Sci. 59:1590. (Abstr.) Cherry, J. A., W. L. Beane, and W. D. Weaver, Jr. 1978. The influence of dietary energy on the performance of broilers reared under different lighting regimens. Poultry Sci. 57:998-1001. Cherry, J. A., W. L. Beane and W. D. Weaver, Jr. 1980. Continuous versus intermittent photoperiod under low intensity illumination. Poultry Sci. 59:1550-1551. Deaton, J. W., F. N. Reese, L. F. Kubena, and J. D. May, 1976. Effect of varying light intensity on broiler performance. Poultry Sci. 55:515— 519. Deaton, J. W., F. N. Reese, and J. L. McNaughton, 1978. Effect of intermittent light on broilers reared under moderate temperature conditions. Poultry Sci. 57:785-788. Deaton, J. W., F. N. Reese, and J. L. McNaughton, 1980. Effect of differing intermittent lighting regimens on broiler feed conversion. Poultry Sci. 59:1342-1344. Goodman, B. L., 1978. The influence of intermittent light on growth of broilers. Poultry Sci. 57: 1423-1428. Malone, G. W., G. W. Chaloupka, E. W. Walpole, and L. H. Littlefield, 1980a. The effect of dietary energy and light treatment on broiler performance. Poultry Sci. 59:576-581. Malone, G. W., G. W. Chaloupka, J. W. Merkley, and L. H.. Littlefield, 1980b. The effect of feeder space and light treatment on broiler performance. Poultry Sci. 59:2697-2702. McDaniel, G. R., J. L. Koon, and C. A. Flood, 1977. The effect of intermittent light on broiler performance, dust production and litter moisture. Poultry Sci. 56:1381-1383. Proudfoot, F. G., 1973. Response of broilers to variations in waterer, feeder, and floor space under continuous and intermittent photoperiods. Can. J. Anim. Sci. 53:349-354. Quarles, C. L., and H. F. Kling, 1974. The effect of three lighting regimens on broiler performance. Poultry Sci. 53:1435-1438.
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on March 26, 2015
' Means within an experiment followed by the same superscript are not significantly different (P<.05).
37
1982 Poultry Science 6 1 : 3 3 - 3 7 lighting regimens when stocking density, feeding space, and diet were varied. It was felt t h a t various m a n a g e m e n t conditions m a y have c o n t r i b u t e d t o the inconsistent results u n d e r b o t h experimental and field conditions.
INTRODUCTION A n u m b e r of investigators have r e p o r t e d improved performances w h e n broilers are provided i n t e r m i t t e n t light (IL) in comparison with c o n t i n u o u s illumination (CL) (Quarles and Kling, 1 9 7 4 ; B u c k l a n d et al, 1 9 7 6 ; McDaniel et al, 1 9 7 7 ; D e a t o n et al, 1978, 1 9 8 0 ; Goodman, 1978; Beane et al, 1 9 7 9 ; Cherry et al, 1980). F u r t h e r m o r e , Buckland et al. ( 1 9 7 1 ) found t h a t increased dietary p r o t e i n improved broiler performance u n d e r IL m o r e t h a n u n d e r CL. T h e y concluded t h a t this was caused by reduced feeding t i m e and reduced total n u t r i e n t intake of birds u n d e r IL. However, Cherry et al. ( 1 9 7 8 ) found t h a t broilers u n d e r CL had significantly heavier b o d y weights t h a n p e n m a t e s on t w o different IL regimens when fed diets increased in b o t h protein and energy. Weights were similar for broilers u n d e r all these lighting regimens when t h e y were fed lower levels of these n u t r i e n t s . Field results have been inconsistent when the performance of broilers grown u n d e r CL and IL regimens were c o m p a r e d . The objective of this investigation was to c o m p a r e IL and CL
'This study was supported in part by the John Lee Pratt Animal Nutrition Program.
METHODS AND MATERIALS Three e x p e r i m e n t s were c o n d u c t e d using either 2 0 0 0 ( E x p e r i m e n t 1) or 2 4 0 0 (Exp e r i m e n t s 2 and 3) male broiler chicks ( H u b bard X H u b b a r d ) o b t a i n e d from commercial hatcheries. T h e chicks in each e x p e r i m e n t were vaccinated for Marek's disease and r a n d o m l y divided into 16 groups of 50 and 16 groups of 75 chicks each in E x p e r i m e n t 1, and 32 groups of 75 chicks each in E x p e r i m e n t s 2 and 3, respectively, and placed in replicated lightcontrolled floor pens measuring 1.52 X 3.66 m. Experiment 1. Two lighting regimens, t w o feeding space levels, and t w o stocking densities were provided in a factorial arrangement. Each t r e a t m e n t was replicated four times. T h e CL at an intensity of approximately 6 5 lx m e a s u r e d 15 cm above t h e litter was provided for all groups until 7 days of age, at which time t h e light t r e a t m e n t s were imposed. T h e light regimens were: 1) CL with low intensity, and 2) IL with 1 hr on and 2 hr off. Light intensity for
33
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on March 26, 2015
ABSTRACT The influence of various light regimens, dietary energy levels, feeding space levels, and stocking densities on male broiler body weight, feed efficiency, and percentage abdominal fat was studied in a series of three experiments. Broilers subjected to intermittent light (1 hr on, 2 hr off) in combination with increased feeding space (2.94 or 4.40 cm/bd) had significantly higher 49 day body weights and feed efficiency (one experiment) than did birds under continuous illumination. However, when feeding space was reduced to 1.47 or 2.20 cm/bd, body weights and feed efficiencies of broilers in intermittently lighted pens were similar to or lower dian those of broilers under continuous illumination. Broilers given more floor space were significantly heavier than, and had similar feed efficiencies to, birds provided a more restricted floor regimen. Furthermore, body weight (one experiment) and feed efficiencies were higher for broilers fed rations containing higher versus lower levels of dietary energy. However, no significant interactions were observed between the lighting regimens and these variables. No differences were noted among treatments in any of the experiments for percentage abdominal fat. (Key words: broiler, lighting regimens, stocking density, feeding space, dietary energy levels, abdominal fat)
WEAVER, JR., ETAL.
34
TABLE 1. The effect of light on body weight and feed efficiency at 28 and 49 days of age Feed efficiency1
Body weight (g) Light regimens
49 days
28 days
49 days
925 a 918 a
2206 a 2228 b
67ia 690 a
.543 a .546 a
941a a
946
2265 a 2261 a
654 a 662a
.508 b .500 a
1011 b 992 a
2180 a 2172 a
699^ 704 a
.541 a .541 a
ab ' Means within an emperiment followed by the same superscript are not significantly different (P<.05). 1
Body weight/feed consumed.
both light regimens was gradually decreased from 65 to 3 lx by the time the broilers were 28 days of age. This intensity was maintained for the final three weeks of the experiment. Commercial starter and grower diets were fed ad libitum in crumble form to 28 and 49 days of age, respectively. One half of the groups was furnished two tube feeders with the remaining groups having one tube feeder. Pans on all feeders were 35 cm in diameter. Chicks were housed at either .074 or .111 m 2 , resulting in either 75 or 50 birds per group and providing either 1.47, 2.20, 2.94, or 4.40 cm of feeding space per bird. Experiments 2 and 3. Starter diets containing either 3080 or 3410 kcal ME/kg and 24 or 26.5% protein, respectively, were fed ad libitum in crumble form from 1 to 28 days of age. Finisher diets containing either 3134 or 3465 kcal ME/kg and 21 or 23.2% protein, respectively, were pelleted and fed ad libitum for the final 3 weeks of the experiment. Lighting and feeding space regimens were the same as those provided in Experiment 1 and each diet-light-feeding space treatment was replicated four times. Seventy-five chicks were placed in each group to achieve a stocking density of .074 m 2 and a feeding space of either 1.47 or 2.94 cm per bird. Traits Measured and Analysis. The chicks were individually weighed to the nearest 5 g at 28 and 49 days of age and die data were analyzed by analysis of variance. Feed efficiency was also calculated at 28 and 49 days of age with consumption adjusted to reflect daily mor-
tality. Following the experimental period, 5 broilers from each of the 32 groups in Experiment 1 and from 16 of the groups in Experiment 2 were randomly selected and sacrificed. Abdominal fat (gizzard fat not included) was removed, immediately weighed to the nearest .1 g, and expressed as a percentage of total live body weight. These percentages were transformed to arc sin \J% prior to analysis. An analysis of variance was used to
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I .47 or 2 . 2 0 cm/bd
I
2.94 or 4 . 4 0 cm/bd
FEEDING SPACE FIG. 1. Effect of light and feeding space on body weight at 49 days of age. CL - continuous light, IL - intermittent light; Experiment 1, — — — Experiment 2, . . . . Experiment 3.
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on March 26, 2015
Experiment 1 Continuous (CL) Intermittent (IL) Experiment 2 CL IL Experiment 3 CL IL
28 days
PRODUCTION EFFECTS ON PERFORMANCE
35
TABLE 2. The effect of stocking density on body weight and feed efficiency at 28 and 49 days of age (Experiment 1)
.546y»iL
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UJ O
.543-
\^ / \. / ^\ N / /
u.
ULLl Q UJ 1x1 U.
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K
/
/
.540" /
/ \ / \^^ v
/
28 days
49 days
28 days
49 days
.074 .111
902* 950 b
2184 a 2266 b
.690 a .667 a
.546 a .543 a
1
1
1
1.47 cm/bd
2 . 9 4 cm/bd SPACF
FIG. 2. Effect of light and feeding space on feed efficiency at 49 days of age (Experiment 3). CL continuous light, IL - intermittent light.
determine the differences in treatment means for feed efficiency and abdominal fat.
RESULTS AND DISCUSSION
Light Regimen. Broilers under IL were significantly heavier at 49 days of age than birds under continuous light in Experiment 1 but not in Experiments 2 and 3 (Table 1). A significant interaction was consistently observed between lighting regimen and feeding space for body weight (Fig. 1). Broilers under IL were consistently heavier than birds under CL when they were provided two feeders (1.47 or 2.20 cm/bird). However, when only one feeder (2.94 or 4.40 cm/bird) was used, the broilers actually performed better under CL. Furthermore, a similar interaction for feed efficiency was observed in Experiment 3 (Fig. 2). Several studies (Buckland et al, 1973; Deaton et al, 1976, 1978; Beane et al., 1979; Cherry et al, 1980) have shown improved performance under IL but were conducted with ample feeding space (approximately 2.75 to 3.15 cm per bird). Industry standards usually provide approximately one-half this amount of pan space per bird, which could account for many of the failures of IL programs commercially. Proudfoot (1973) reported a significant feed space X lighting regimen (IL vs.
Body weight/feed consumed.
CL) interaction for both body weight and feed conversion, but the directions of these relationships were not reported. Furthermore, Malone et al. (1980b) found no feeder space X light regimen interaction with broilers at 54 days of age when feeder spaces of 1.8, 2.3, or 2.7 cm/bird were compared under CL and IL. However, the feeder spaces provided in their study were intermediate to the two regimens used in ours (1.47 and 2.94 cm/bird), and possibly were too similar to induce a significant response. The interaction between dietary energy and lighting regimen for body weight was not significant in either Experiment 2 or 3. It was hypothesized that the effect of reduced feeding space on body weight of broilers under IL could be at least partially compensated by increasing the nutrient density of the ration. However, contrary to the results reported by
2275 2250 -
o
2225
LU
*
2200
>Q
o
2175
00
2150 .III m * STOCKING
.074 m2 DENSITY
FIG. 3. Effect of light and stocking density on body weight at 49 days of age (Experiment 1). CL continuous light, IL - intermittent light.
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on March 26, 2015
N CL
FEEDING
Feed efficiency1
a ' b Means followed by the same superscript are not significantly different (P<.05).
\
.537-
Body weight (g)
Stocking density (m 2 )
WEAVER, JR., ET AL.
36
TABLE 3. The effect of feeding space on body weight and feed efficiency at 28 and 49 days of age Feed efficiency1
Body weight (g) Feeding space
28 days
49 days
Experiment 1 l2 23 Experiment 2 l4 2s Experiment 3 l4 25
896 a 947b
2202 a 2248 b
.671a .690a
.543a .546a
933 a 954b
2239 a 2288 b
,658a .658a
.503a .505a
1001 a 1002 a
2161 a 2190 b
.704a .699a
.541a .541a
ab ' Means within an experiment followed by the same superscript are not significantly different (P<.05). 1
Body weight/feed consumed.
2
1.47 or 2.20 cm/bird.
3
2.94 or 4.40 cm/bird.
4
1.47 cm/bird.
5
2.94 cm/bird.
Buckland et al. (1971), no interrelationship was found between these two variables for body weight in these experiments. Other first or second order interactions involving these traits were inconsistent and did not appear as biologically meaningful. Floor Space. Increasing stocking density significantly depressed body weight at 28 and 49 days of age (Table 2). Furthermore, an interaction involving this variable and the two light regimens on body weight (Fig. 3) appro-
ached significance (P<.10), suggesting that increased stocking density was more detrimental to birds under CL. Broilers under CL regimens appeared to be more docile than those provided IL. Possibly, the increased activity in the intermittent pens when the lights were on enabled these broilers to find the feeders more easily when grown under more crowded conditions. Feeding Space. Increased feeding space improved body weight in all experiments (Table
TABLE 4. The effect of dietary energy on body weight and feed efficiency at 28 and 49 days of age Feed efficiency1
Body weight (g) Diet
28 days
Experiment 2 l2
2
3
Experiment 3 l2 23
950 b " 937 a 978 a 1025 b
49 days
28 days
49 days
2284 b 2243 a
.645 a .671°
.495 a .513 b
2137 a 2214 b
.680 a .725 b
.526 a .559 b
a ' b Means within an experiment followed by the same superscript are not significantly different (P<.05). 1
Body weight/feed consumed.
2
Diet 1, 3080 kcal/kg from 0 to 28 days and 3134 kcal/kg from 29 to 49 days of age.
3
Diet 2, 3410 kcal/kg from 0 to 28 days and 3465 kcal/kg from 29 to 49 days of age.
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49 days
28 days
PRODUCTION EFFECTS ON PERFORMANCE TABLE 5. The effect of light regimen on abdominal fat at 49 days of age Light regimen Experiment 1 Continuous .(CL) Intermittent (IL) Experiment 2 CL IL
Abdominal fat (%)'
2.22 a 2.38 a 1.88 a 1.95a
1
Expressed as percentage of live weight.
3); however, as previously stated, most of this improvement can be attributed to the increased body weight of the broilers under IL rather than the CL regimens (Fig. 1). Dietary Energy. A significant increase in body weight (Experiment 3 only) and a significant improvement in feed efficiency were found when broilers were fed a ration containing a higher versus a lower level of dietary energy (Table 4). An unexplained increase in body weight among broilers on the ration containing a low level of dietary energy was observed in Experiment 2. The combined effects of this variable and lighting regimens did not produce a significant interaction, indicating that a mere change in the density of the ration will not compensate for reduced feeding space when broilers are under intermittent light. These results are consistent with those of Cherry et al. (1978) and Malone et al. (1980a), who observed a failure of diets with higher energy to increase the body weights of broilers subjected to intermittent light. Abdominal Fat. No statistical differences were noted between light regimens for percentage abdominal fat (Table 5). This is consistent with the findings of Beane et al. (1979), who reported no differences between IL and CL regimens for abdominal fat from broiler males. However, they did find a significant increase in this tissue from females reared under IL regimens. Cave (1980) reported contrasting results. He found that broilers under IL had less abdominal fat than did birds provided CL.
REFERENCES Beane, W. L., J. A. Cherry, and W. D. Weaver, Jr., 1979. Intermittent light and restricted feeding of broiler chickens. Poultry Sci. 58:567—571. Buckland, R. B., D. E. Bernon, and A. Goldrosen, 1976. Effect of four lighting regimens on broiler performance, leg abnormalities and plasma corticoid levels. Poultry Sci. 55:1072— 1076. Buckland, R. B., H. C. Gasperdone, and D. B. Bfagg, 1971. Interaction of strain, density and ration with two light systems on broiler performance. Can. J. Anim. Sci. 51:613-619. Buckland, R. B., A. T. Hill and D. E. Bernon, 1973. Effects of four lighting regimens on the performance of broilers and roasters. Can. J. Anim. Sci. 53:21-24. Cave, N. A., 1980. Effect of intermittent lighting on feed efficiency and broiler carcass fat. Poultry Sci. 59:1590. (Abstr.) Cherry, J. A., W. L. Beane, and W. D. Weaver, Jr. 1978. The influence of dietary energy on the performance of broilers reared under different lighting regimens. Poultry Sci. 57:998-1001. Cherry, J. A., W. L. Beane and W. D. Weaver, Jr. 1980. Continuous versus intermittent photoperiod under low intensity illumination. Poultry Sci. 59:1550-1551. Deaton, J. W., F. N. Reese, L. F. Kubena, and J. D. May, 1976. Effect of varying light intensity on broiler performance. Poultry Sci. 55:515— 519. Deaton, J. W., F. N. Reese, and J. L. McNaughton, 1978. Effect of intermittent light on broilers reared under moderate temperature conditions. Poultry Sci. 57:785-788. Deaton, J. W., F. N. Reese, and J. L. McNaughton, 1980. Effect of differing intermittent lighting regimens on broiler feed conversion. Poultry Sci. 59:1342-1344. Goodman, B. L., 1978. The influence of intermittent light on growth of broilers. Poultry Sci. 57: 1423-1428. Malone, G. W., G. W. Chaloupka, E. W. Walpole, and L. H. Littlefield, 1980a. The effect of dietary energy and light treatment on broiler performance. Poultry Sci. 59:576-581. Malone, G. W., G. W. Chaloupka, J. W. Merkley, and L. H.. Littlefield, 1980b. The effect of feeder space and light treatment on broiler performance. Poultry Sci. 59:2697-2702. McDaniel, G. R., J. L. Koon, and C. A. Flood, 1977. The effect of intermittent light on broiler performance, dust production and litter moisture. Poultry Sci. 56:1381-1383. Proudfoot, F. G., 1973. Response of broilers to variations in waterer, feeder, and floor space under continuous and intermittent photoperiods. Can. J. Anim. Sci. 53:349-354. Quarles, C. L., and H. F. Kling, 1974. The effect of three lighting regimens on broiler performance. Poultry Sci. 53:1435-1438.
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on March 26, 2015
' Means within an experiment followed by the same superscript are not significantly different (P<.05).
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