BIBLIOGRAPHY CADATE, REVELYN M. MAY...
BIBLIOGRAPHY
CADATE, REVELYN M. MAY 2012. Effect of Intermittent Lighting Program on
the Growth Performance of Broilers. Benguet State University, La Trinidad, Benguet.
Adviser: Marlene B. Atinyao, PhD.
ABSTRACT
This study was conducted to determine the effect of intermittent lighting program
on the growth performance of broilers. Specifically, the study aimed to find out the effect
of intermittent lighting program on the growth rate, feed intake, feed conversion ratio,
percent abdominal fat and dressing percentage, as well as morbidity and mortality. Finally,
this study aimed to determine the feed cost and return on investment (ROI).
Ninety-six 21 day old Cobb broilers were randomly distributed into three
treatments following the completely randomized design (CRD) with four replications four
times with eight birds per replicate. The treatments were 23-hour light (T0): 1-hour
darkness; 1-hour light: 2-hour darkness at night with normal light during the day (T1) and
1-hour light: 3-hour darkness at night with normal light during the day (T2).
Highly significant differences were observed in the gain in weight, feed intake, feed
conversion ratio, feed cost per kilogram gain in weight, and dressing percentage of birds
exposed to intermittent lighting of 1-hour light: 3-hour darkness. Birds exposed to 1-hour
light: 3-hour darkness at night with normal light during the day had significantly higher
average daily gain in weight of 0.051 kg with a significantly lower FCR of 2.35 as
Effect of Intermittent Lighting Program on the Growth Performance of Broilers
CADATE, REVELYN M. MAY 2012
compared to the birds exposed to 1-hour light: 2-hour darkness with normal light during
the day having an average daily gain of 0.047 with an FCR of 2.82. Birds exposed to
continuous light had the lowest average daily gain in weight of 0.046 with the highest FCR
of 3.46.
Result showed that used of intermittent lighting did not affect the percent abdominal
fat. The average percent abdominal fat obtained in this study was 1.98 %.
Result of the study shows that the return on investment (ROI) of birds exposed to
intermittent lighting of 1-hour light: 3 hour darkness during the night with normal light
during the day resulted to better profit of 2.41% than those birds exposed to 1-hour light:
2 hour darkness during the night with normal light during the day and birds subjected to
continuous light, though it is minimal.
It is concluded that birds subjected to intermittent lighting of 1-hour light and 3-
hour darkness during the night is recommended.
Effect of Intermittent Lighting Program on the Growth Performance of Broilers
CADATE, REVELYN M. MAY 2012
INTRODUCTION
As the broiler industry is expanding, the factors hindering the growth are also taken
in to account by the farmers as well as the scientists. Numerous studies conducted have
shown that among the other managemental practices, different regimens of light to which
the broilers are subjected have significant effect on the weight gain and disease control.
Many light patterns have been applied so far, such as twenty four hours continuous light,
light and dark periods, intermittent lighting programs and different colors of light to rear
broilers. For many years, broiler chickens have usually been reared under continuous or
near continuous (23L: 1D) photoperiods to maximize feed consumption and growth rate.
However, several investigations showed that using continuous light programs induces
sleep deprivation and causes severe physiological stress responses (Campo and Davila,
2002; Kliger et al., 2000).
Dozier (2002) stated that melatonin hormone production in the brain of chicks is
inhibited by light. Melatonin enhances the chick’s immune systems and serves as an
antioxidant, which helps to maintain healthy cells. There were other advantages in applying
lighting program as revealed by previous studies such as reduced leg problems, lesser
incidence of ascites and lesser respiratory lesion and better immunity to respiratory disease.
As a result, mortality is reduced which increases profit for broiler growers.
Most of the recent researches have focused on restricting light regimes to improve
productivity of broiler chickens because the physical activity is very low during darkness
and energy expenditure of activity is considerable (Rahimi et al., 2005).
Both intermittent and non intermittent restricted light regimen improved feed
conversion significantly compared to continuous light regimen. Even though the
Effect of Intermittent Lighting Program on the Growth Performance of Broilers
CADATE, REVELYN M. MAY 2012
intermittent and non intermittent restricted regimens have the same period of darkness, the
intermittent light regimen would be more beneficial than non intermittent restricted light
program (Abbas et al., 2008).
This study intended to find out the effect of intermittent lighting program on the
growth performance of broilers. The result of this study will not only benefit farmers but
can serve as a guide for further studies on better lighting programs.
Generally, this study aimed to determine the effect of lighting programs on the
growth performance of broilers from day 21 to day 40.
Specifically, this study aimed to determine the effect of intermittent lighting
program on the gain in weight, feed intake, feed conversion ratio, abdominal fat, dressing
percentage of broilers; to determine morbidity and mortality rates of broilers subjected to
intermittent lighting program; and to determine the return on investment (ROI).
This study was conducted at Ili, Datakan, Kapangan, Benguet from March to April
2012.
Effect of Intermittent Lighting Program on the Growth Performance of Broilers
CADATE, REVELYN M. MAY 2012
REVIEW OF LITERATURE
Turning the lights off is one best thing that you can do for the young meat-type
chickens. By giving your birds short days and long nights from one week to three weeks
age, you can help them maintain a healthy body and rapid growth rate. Long dark periods
help stimulate melatonin, vitamin D3 and other hormone levels in the blood that improves
the chick’s immune system and tissue development. Limiting the hour of light will slow
growth slightly, allowing the birds to develop strong hearts and bones needed to support
rapid growth later in flocks. Turning the lights off when birds are young produces benefits
that can last in the flocks (Animal Industry Branch, Manitoba Agriculture and Food, 2007).
Classen and Riddell (1989) reported that broiler chicks subjected to intermittent
light had significantly higher body weight and feed efficiency than birds under continuous
illumination.
According to the study of Mahmud et al. 2001, the result showed that the feed
consumption by the birds under intermittent light was not significantly different from
continuous light regimes but the weight gain and feed conversion ratio was significantly
better than the group exposed to continuous light.
Weaver et al. (1982) used different photoperiod regimens in raising broiler chicks
and reported that changing the photoperiod length from short to long during broiler growth
improves bird’s health while maintaining equal or slightly superior performance
characteristics compared with effect of a long constant day length.
Deaton et al. (1978) indicated that total light intensity control is required within the
broiler house for the entire twenty-four hours period to obtain maximum feed saving when
broilers are maintained reared under intermittent lighting program.
Effect of Intermittent Lighting Program on the Growth Performance of Broilers
CADATE, REVELYN M. MAY 2012
Recent research has indicated that light source may affect body weight, immune
response, livability and health status. Broiler behavior is strongly affected by light sources
(Ghuffar et al., 2009).
Dozier (2002) observed that intermittent lighting program decreased leg
abnormalities and total mortality was also significantly reduced, less respiratory lesion and
better immunity to respiratory diseases than in poultry that was exposed to constant light.
The health of the bird was improved due to melatonin hormone produced during the dark
periods. Dozier (2002) further stated that broiler growers should consider not only
controlling the number of hours but as well as light intensity. He also added that lighting
system and program that is best for a particular company or producer depends on the type
of housing, the type of birds grown, climate and electricity.
Effect of Intermittent Lighting Program on the Growth Performance of Broilers
CADATE, REVELYN M. MAY 2012
MATERIALS AND METHODS
The materials and equipment used in the study were ninety heads of broiler,
commercial feeds, antibiotics, disinfectants, feeding troughs, drinkers, weighing scale,
stick broom, 100-watt bulbs, old newspapers, brooding-rearing cages, record book and
marking pen.
Pre-experimental phase. A week before the arrival of the chicks, all materials used
in the study were cleaned and disinfected. The brooding rearing cages were divided to
accommodate the three treatments having four replicates. The floor was covered with
newspaper to serve as a trap for the feeds that are being wasted, provide heat during
brooding and protect the chicks from falling. The cages were provided with proper lighting.
From day old to 21 days of the birds, antibiotics were added to the drinking water
following the prescribed dosage for the first one week of the chicks. Chick booster was
given to the chicks for the first up to two weeks of age and then was gradually shifted to to
grower ration. Shifting of feeds was done by mixing 25% of the new feed ration on the first
day, 50% on the second day and 75% on the third day so that on the fourth day, the birds
were fed with 100% new feed ration. Feeders and drinkers were provided inside the cages.
Continuous lighting and adlibitum feeding were employed.
Experimental phase. On the 21st day of age, the chicks were randomly distributed
into three treatments which were replicated four times with 10 birds per replicate, following
the Completely Randomized Design (CRD). The chicks were weighed individually to
obtain their initial weight. The treatments were as follows:
Effect of Intermittent Lighting Program on the Growth Performance of Broilers
CADATE, REVELYN M. MAY 2012
T0 - Continuous lighting (23L: 1D)
T1 – 1 hour light and 2 hours darkness with normal light during the day (cycle)
T2 – 1 hour light and 3 hours darkness with normal light during the day (cycle)
For T0, 23-hour light: 1-hour darkness (23hL: 1hD) was maintained. For T1,
intermittent lighting schedule of 1-hour light: 2 hrs dark was imposed at night starting when
it gets dark, with normal light during the day. For T2, intermittent lighting schedule of 1-
hour light: 3 hour dark was imposed at night starting when it gets dark, with normal light
during the day. This was the cycle implemented throughout the study.
Adlibitum feeding was employed from the start until the end of the study. Purely
commercial feeds were fed to the birds throughout the study with available fresh water all
the time.
Data Gathered
1. Initial weight of the broilers (kg). This was obtained by weighing the chicks
individually at 21 days of age.
2. Final weight of the broilers (kg). This was taken by weighing the chicks
individually at 35 days of age.
3. Number of dead birds. This was obtained from the number of birds that died
during the experimental period.
4. Number of sick birds. This was obtained from the number of sick birds during
the experimental period.
5. Feed left over (kg). This was the amount of feed which is left by the birds from
the feed offered each day during the experimental period.
Effect of Intermittent Lighting Program on the Growth Performance of Broilers
CADATE, REVELYN M. MAY 2012
6. Feed offered (kg). This refers to the amount of feeds given to the experimental
birds per day.
7. Feed cost. This was the purchase cost of feeds incurred in the study.
8. Abdominal fat (kg). This was obtained by weighing the fat contained by the
abdomen.
9. Slaughter weight (kg). This was obtained by taking the weight of the broiler
prior to slaughter.
10. Carcass weight (kg). This was obtained by taking the weight of the carcass
without the entrails, head and feet.
Data Computed
1.
Average daily gain in weight (kg). This was obtained by dividing
total gain in weight with the number of days on trial.
2.
Average feed intake of broilers (kg). This was obtained by taking
the difference between the feed offered and feed refuse divided by the number of
days on trial.
3.
Feed conversion ratio. This was obtained by dividing the total feed
consumption by total gain in weight of the experimental birds.
4.
Feed cost per kilogram gain in weight of broilers (Php). This was
obtained by multiplying the FCR with the average feed cost per kg.
5.
Percent mortality of broilers (%). This was obtained by dividing the
number of experimental birds died over the total number of experimental birds
multiplied by 100.
Effect of Intermittent Lighting Program on the Growth Performance of Broilers
CADATE, REVELYN M. MAY 2012
6.
Percent morbidity of broilers (%). This was obtained by dividing the
number of sick birds in the experiment by the total number of experimental birds
multiplied by 100.
7.
Dressing percentage (%). This was computed by dividing the
dressed weight by the live weight multiplied by 100.
8.
Percent abdominal fat (%). This was computed by dividing the
weight of the abdominal fat over the carcass weight of broiler multiplied by 100.
9.
Return on investment (ROI) (%). This was computed by dividing
the net income by the total cost of production multiplied by 100.
10.
Gross income. This was obtained by multiplying the final weight of
the birds by the price per kilogram of live weight.
11.
Net income. This was obtained by subtracting the gross income from
the total cost of production.
Data Analysis
The data was analyzed using the analysis of variance (ANOVA) appropriate for
completely randomized design (CRD).
Effect of Intermittent Lighting Program on the Growth Performance of Broilers
CADATE, REVELYN M. MAY 2012
RESULTS AND DISCUSSION
Mean Weight of Birds
Table 1 shows the initial and final weights of birds in the different treatments.
Statistical analysis showed that there were no significant differences in the initial weights
of birds between treatments. This implies that the birds at the start of the study were
relatively uniform in terms of weight. The average initial weight of birds was 0.43 kg at 21
days of age.
Statistical analysis revealed highly significant differences in final weight of broilers
at 40 days of age among treatments. The final weight of birds exposed to 1-hour light: 3-
hour darkness was 1.44 kg, birds with 1-hour L: 2-hour darkness at night with normal light
during the day of 1.44 kg was higher than the final weight of birds exposed to 1-hour light:
2-hour darkness at night with normal light during the day of 1.368 kg. Birds exposed to 23-
hours continuous light with 1-hour darkness daily had the lowest final weight of 1.335 kg.
Table 1. Initial and final weights of birds at day 21 and 40, respectively
INITIAL WEIGHT FINAL WEIGHT
AT 21 DAYS OLD
AT 40 DAYS OLD
TREATMENT
(kg)
(kg)
________________________________________________________________________
23 h L: 1h D
0.425a
1.335c
1h L: 2h D with normal
light during the day
0.426a
1.368b
1h L: 3h D with normal
light during the day
1.426a
1.440a
Means with common letter(s) are not significantly different at 0.05 % by DMRT
Effect of Intermittent Lighting Program on the Growth Performance of Broilers
CADATE, REVELYN M. MAY 2012
Mean Gain in Weight of Birds
from 21to 40 Days of Age
Table 2 shows the total and average gain in weight of the birds from 21 days old to
40 days in the different treatments. Statistical analysis revealed highly significant
differences in the total and average daily gain (ADG) of birds. The ADG of birds subjected
to intermittent lighting of 1-hour light: 3 hour darkness at night with normal light during
the day was significantly higher than those birds subjected to 1-hour light:2 hours darkness
at night with normal light during the day and continuous light having an average daily gain
in weight of 0.047 kg and 0.046 kg, respectively.
This study supports the observation of Mahmud et al. (2011), that intermittent
lighting program significantly affect gain in weight than on continuous light, and the
physical activity of birds is very low during darkness and energy expenditure of activity is
considerable (Rahimi et al., 2005). Studies have shown however, that although birds
subjected to continuous light consumed more feeds; it does not necessarily mean that they
would weigh more than those birds subjected on shorter light periods.
Table 2. Total and daily gain in weight of birds from 21 to 40 days of age
TOTAL GAIN AVERAGE DAILY
IN WEIGHT GAIN IN WEIGHT
TREATMENT
(kg)
(kg)
________________________________________________________________________
23 h L: 1h D
0.910c
0.046c
1h L: 2h D with normal
light during the day
0.942b
0.047b
1h L: 3h D with normal
light during the day
1.014a
0.051a
Means with common letter(s) are not significantly different at 0.05 % by DMRT
Effect of Intermittent Lighting Program on the Growth Performance of Broilers
CADATE, REVELYN M. MAY 2012
Mean Feed Intake of Birdss
Table 3 shows the feed consumption of birds from day 21 to day 40. Statistical
analysis revealed highly significant differences in the feed intake of birds. Birds subjected
to 1-hour light: 3-hour darkness at night with normal light during the day had a total feed
intake of 2.39 kg with an average daily feed of 0.12 kg was significantly lower than the
total and average feed intake of birds exposed to 1-hour light: 2-hour darkness at night with
normal light during the day of 2.69 kg and 0.14 kg respectively. Birds exposed to 23-hour
light with 1-hour darkness had the highest feed intake of 3.15 kg and average daily feed
intake of 0.16 kg.
Feed Conversion Ratio (FCR) from 21 to 40 Days of Age
Statistical analysis revealed highly significant differences in the feed conversion
ratio of birds. Birds subjected to 1-hour light: 3-hour darkness at night with normal light
during the day of 2.35 was significantly lower than the FCR of birds exposed to 1-hour
light: 2-hour darkness with normal light during the day of 2.85. Birds subjected to 23-hour
light with 1-hour darkness had the highest FCR of 3.46.
Table 3. Total and average feed intake of birds from 21 to 40 days of age
TOTAL FEED AVERAGE DAILY
INTAKE FEED INTAKE
TREATMENT
(kg)
(kg)
________________________________________________________________________
23 h L: 1h D
3.15a
0.16a
1h L: 2h D with normal
light during the day
2.69b
0.14b
1h L: 3h D with normal
light during the day
2.39c
0.12c
Means with common letter(s) are not significantly different at 0.05 % by DMRT
Effect of Intermittent Lighting Program on the Growth Performance of Broilers
CADATE, REVELYN M. MAY 2012
Feed Cost to Produce a Kilogram of Broiler
Table 4 shows the feed cost to produce a kilogram gain in body weight of broilers.
Statistical analysis revealed highly significant differences in the feed cost to produce a
kilogram of broilers. Birds subjected to 1-hour light: 3-hour darkness at night with normal
light during the day of Php54.76 was significantly lower than the feed cost to produce a kg
gain in weight 0of broilers of birds exposed to 1-hour light: 2-hour darkness at night with
normal light during the day of Php61.28. Birds subjected to continuous light had the highest
feed cost to produce a kilogram gain in weight of broilers of Php70.48.
Morbidity and Mortality
Mortality and morbidity of birds were not observed from day 21 to 40. The
incidence of leg abnormalities observed during the pre- experimental period from day 14
to day 18 was no longer encountered. This may be attributed to the reduced feed
consumption of the birds when the lighting regimens were imposed. This may be due to
their fast muscle growth but their leg bones were not growing as fast as the muscle.
Table 4. Feed conversion ratio and feed cost to produced a kg of broiler within 20 days
FEED CONVERSION FEED COST TO PRODUCED
RATIO
A KG OF BROILER
TREATMENT
(Php)
________________________________________________________________________
23 h L: 1h D
3.46a
70.48a
1h L: 2h D with normal
light during the day
2.85b
61.28b
1h L: 3h D with normal
light during the day
2.35c
54.76c
Means with common letter(s) are not significantly different at 0.05% by DMRT
Effect of Intermittent Lighting Program on the Growth Performance of Broilers
CADATE, REVELYN M. MAY 2012
Dressing Percentage
Table 5 shows the dressing percentage of the birds. Statistical analysis revealed a
highly significant difference among the dressing percentages of broilers. Birds subjected
to intermittent lighting of 1-hour light: 3-hour darkness at night with normal light during
the day had the highest dressing percentage of 71% as compared to the dressing percentage
of birds exposed to 1-hour light: 2-hour darkness with normal light during the day of
67.34%. Birds subjected to 23 hours continuous light with 1-hour darkness had the lowest
dressing percentage of 59.67%. This implies that the differences that occur among
treatments were caused by the variation of feathers and fats.
Percent Abdominal Fat
Table 6 shows the percent abdominal fat of birds in the different treatments.
Statistical analysis showed that there were no significant differences among treatments.
Thus, it implies that percent abdominal fat of broilers was not significantly affected by
intermittent light. The average percent abdominal fat of broiler is 1.98%.
Table 5. Dressing percentage of birds at 40 days of age
DRESSING PERCENTAGE
TREATMENT
(%)
________________________________________________________________________
23 h L: 1h D
59.67c
1h L: 2h D with normal
light during the day
67.34b
1h L: 3h D with normal
light during the day
71.00a
Means with common letter(s) are not significantly different at 0.05% by DMRT
Effect of Intermittent Lighting Program on the Growth Performance of Broilers
CADATE, REVELYN M. MAY 2012
Table 6. Percent abdominal fat of birds at 40 days of age
ABDOMINAL FAT
TREATMENT
(%)
________________________________________________________________________
23 h L: 1h D
2.0925a
1h L: 2h D with normal
light during the day
1.8560a
1h L: 3h D with normal
light during the day
1.9940a
Means with common letter(s) are not significantly different at 0.05% by DMRT
Return on Investment
The returns on investment in the different treatments are shown in Table 7. Data
shows that higher profit was obtained from the birds exposed to intermittent light of 1-hour
light: 3-hour darkness during the night with normal light during the day. This implies that
subjecting the birds under intermittent lighting program having 1-hour light: 3-hour
darkness resulted to better profit, though it is minimal.
Table 7. Net returns and return on investment
TOTAL TOTAL NET
ROI
SALES COST INCOME (%)
TREATMENT
(Php)
(Php) (Php)
________________________________________________________________________
Continuous light
(23h L: 1h D)
5,130.00 5,721.48 -591.48
-10.34
1h L: 2h D with
normal light during the day 5,244.00 6,174.60 -930.60
-15.07
1h L: 2h D with
normal light during the day 5,532.00 5,401.81 130.19 2.41
Effect of Intermittent Lighting Program on the Growth Performance of Broilers
CADATE, REVELYN M. MAY 2012
SUMMARY, CONCLUSION AND RECOMMENDATION
Summary
This study was conducted to determine the effect of intermittent lighting program
on the growth performance of broilers. Specifically, growth rate, feed conversion ratio,
feed consumption and gain in weight. This was conducted at Ili, Datakan, Kapangan,
Benguet from March 11, 2012 to April 20, 2012.
A total of ninety-six, 21-day-old broiler chicks were used in the study. Following
the completely randomized design (CRD), the birds were randomly distributed into four
treatments. Each treatment was replicated four times with eight birds per replication. The
different treatments were as follows: T0 (Control or continuous light); T1 (1h L: 2h D at
night with normal light during the day) and T2 (1h L: 3h D at night with normal light during
the day).
Highly significant differences were observed in gain in weight, feed intake, feed
conversion ratio, feed cost per kilogram gain in weight and dressing percentage of birds
subjected to 1-hour light: 3-hour darkness during the night with normal light during the
day. The average daily gain in weight of birds was 0.05 kg with an average daily feed
intake of 0.14 kg. The average FCR of birds was 2.89 with an average feed cost to produce
a kg gain in weight of birds of 62.17. The average dressing percentage of birds was 66%.
Results of the study revealed that intermittent light did not affect the percent abdominal
fat. The average percent abdominal fat was 1.98 %.
Although the net profit returns on investment (ROI) were not subjected to statistical
analysis, results showed that better ROI was obtained from the group of birds having 1-
hour light: 3-hour darkness at night with normal light during the day, though it is minimal.
Effect of Intermittent Lighting Program on the Growth Performance of Broilers
CADATE, REVELYN M. MAY 2012
Conclusion
Based on the observation and result of the study, it is therefore concluded that
subjecting birds on intermittent lighting having 1-hour light: 3-hour darkness at night with
normal light during the day can be imposed to broilers.
Recommendation
Based on the results of the study, the researcher therefore recommends that
intermittent lighting program having 1h L: 3h D can be imposed to broilers. However,
further studies should be done using intermittent lighting program with longer number of
hours of darkness.
Effect of Intermittent Lighting Program on the Growth Performance of Broilers
CADATE, REVELYN M. MAY 2012
LITERATURE CITED
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ANIMAL INDUSTRY BRANCH, MANNITOBA AGRICULTURE and FOOD. 2007.
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CAMPO, J. L., and S.G. DAVILA. 2002. Effect of photoperiod on heterophil to
lymphocyte ratio and tonic immobility duration of chickens. Poult. Sci., 81:1637-
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CLASSEN, H. L. and C. RIDDELL. 1989. Photoperiod effects on performance and leg
abnormalities in broiler chickens. Poult. Sci. 68:873-879. Retrieved 13 February
2012 from www.ncbi.nih.gov/pubmed/2780476.
DEATON, J.W., F. N. REECE and J.L.M. NAUGHTON. 1978. Effect of intermittent light
on broilers reared under moderate temperature conditions. Poult. Science, 57:785-
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DOZIER, M.C.B. 2002. Poultry housing tips, Broiler lighting program. The University of
Georgia Cooperative Extension Service.Vol.14(2). Retrieved 03 February 2012
from www.poultryventilation.com/sites/default files/tips/2002/vol142.pdf.
GHUFFAR, A., K. RAHMAN, M. SIDDQUE, F. AHMAD and M. A KHAN. 2009.
Impact of various lighting source incandescent, Flourescent, metal halide and high
pressure sodium on the production performance of chicken broilers. Pakistan. J.
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pakjas.com.pk/upload/48131.pdf.
KLIGER, C.A., A.E. GEHAD, R.M. HULET, W.B. ROUSH, H.S. LILLEHOJ and M.M.
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Effect of Intermittent Lighting Program on the Growth Performance of Broilers
CADATE, REVELYN M. MAY 2012
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Effect of Intermittent Lighting Program on the Growth Performance of Broilers
CADATE, REVELYN M. MAY 2012
CADATE, REVELYN M. MAY 2012. Effect of Intermittent Lighting Program on
the Growth Performance of Broilers. Benguet State University, La Trinidad, Benguet.
Adviser: Marlene B. Atinyao, PhD.
ABSTRACT
This study was conducted to determine the effect of intermittent lighting program
on the growth performance of broilers. Specifically, the study aimed to find out the effect
of intermittent lighting program on the growth rate, feed intake, feed conversion ratio,
percent abdominal fat and dressing percentage, as well as morbidity and mortality. Finally,
this study aimed to determine the feed cost and return on investment (ROI).
Ninety-six 21 day old Cobb broilers were randomly distributed into three
treatments following the completely randomized design (CRD) with four replications four
times with eight birds per replicate. The treatments were 23-hour light (T0): 1-hour
darkness; 1-hour light: 2-hour darkness at night with normal light during the day (T1) and
1-hour light: 3-hour darkness at night with normal light during the day (T2).
Highly significant differences were observed in the gain in weight, feed intake, feed
conversion ratio, feed cost per kilogram gain in weight, and dressing percentage of birds
exposed to intermittent lighting of 1-hour light: 3-hour darkness. Birds exposed to 1-hour
light: 3-hour darkness at night with normal light during the day had significantly higher
average daily gain in weight of 0.051 kg with a significantly lower FCR of 2.35 as
Effect of Intermittent Lighting Program on the Growth Performance of Broilers
CADATE, REVELYN M. MAY 2012
compared to the birds exposed to 1-hour light: 2-hour darkness with normal light during
the day having an average daily gain of 0.047 with an FCR of 2.82. Birds exposed to
continuous light had the lowest average daily gain in weight of 0.046 with the highest FCR
of 3.46.
Result showed that used of intermittent lighting did not affect the percent abdominal
fat. The average percent abdominal fat obtained in this study was 1.98 %.
Result of the study shows that the return on investment (ROI) of birds exposed to
intermittent lighting of 1-hour light: 3 hour darkness during the night with normal light
during the day resulted to better profit of 2.41% than those birds exposed to 1-hour light:
2 hour darkness during the night with normal light during the day and birds subjected to
continuous light, though it is minimal.
It is concluded that birds subjected to intermittent lighting of 1-hour light and 3-
hour darkness during the night is recommended.
Effect of Intermittent Lighting Program on the Growth Performance of Broilers
CADATE, REVELYN M. MAY 2012
INTRODUCTION
As the broiler industry is expanding, the factors hindering the growth are also taken
in to account by the farmers as well as the scientists. Numerous studies conducted have
shown that among the other managemental practices, different regimens of light to which
the broilers are subjected have significant effect on the weight gain and disease control.
Many light patterns have been applied so far, such as twenty four hours continuous light,
light and dark periods, intermittent lighting programs and different colors of light to rear
broilers. For many years, broiler chickens have usually been reared under continuous or
near continuous (23L: 1D) photoperiods to maximize feed consumption and growth rate.
However, several investigations showed that using continuous light programs induces
sleep deprivation and causes severe physiological stress responses (Campo and Davila,
2002; Kliger et al., 2000).
Dozier (2002) stated that melatonin hormone production in the brain of chicks is
inhibited by light. Melatonin enhances the chick’s immune systems and serves as an
antioxidant, which helps to maintain healthy cells. There were other advantages in applying
lighting program as revealed by previous studies such as reduced leg problems, lesser
incidence of ascites and lesser respiratory lesion and better immunity to respiratory disease.
As a result, mortality is reduced which increases profit for broiler growers.
Most of the recent researches have focused on restricting light regimes to improve
productivity of broiler chickens because the physical activity is very low during darkness
and energy expenditure of activity is considerable (Rahimi et al., 2005).
Both intermittent and non intermittent restricted light regimen improved feed
conversion significantly compared to continuous light regimen. Even though the
Effect of Intermittent Lighting Program on the Growth Performance of Broilers
CADATE, REVELYN M. MAY 2012
intermittent and non intermittent restricted regimens have the same period of darkness, the
intermittent light regimen would be more beneficial than non intermittent restricted light
program (Abbas et al., 2008).
This study intended to find out the effect of intermittent lighting program on the
growth performance of broilers. The result of this study will not only benefit farmers but
can serve as a guide for further studies on better lighting programs.
Generally, this study aimed to determine the effect of lighting programs on the
growth performance of broilers from day 21 to day 40.
Specifically, this study aimed to determine the effect of intermittent lighting
program on the gain in weight, feed intake, feed conversion ratio, abdominal fat, dressing
percentage of broilers; to determine morbidity and mortality rates of broilers subjected to
intermittent lighting program; and to determine the return on investment (ROI).
This study was conducted at Ili, Datakan, Kapangan, Benguet from March to April
2012.
Effect of Intermittent Lighting Program on the Growth Performance of Broilers
CADATE, REVELYN M. MAY 2012
REVIEW OF LITERATURE
Turning the lights off is one best thing that you can do for the young meat-type
chickens. By giving your birds short days and long nights from one week to three weeks
age, you can help them maintain a healthy body and rapid growth rate. Long dark periods
help stimulate melatonin, vitamin D3 and other hormone levels in the blood that improves
the chick’s immune system and tissue development. Limiting the hour of light will slow
growth slightly, allowing the birds to develop strong hearts and bones needed to support
rapid growth later in flocks. Turning the lights off when birds are young produces benefits
that can last in the flocks (Animal Industry Branch, Manitoba Agriculture and Food, 2007).
Classen and Riddell (1989) reported that broiler chicks subjected to intermittent
light had significantly higher body weight and feed efficiency than birds under continuous
illumination.
According to the study of Mahmud et al. 2001, the result showed that the feed
consumption by the birds under intermittent light was not significantly different from
continuous light regimes but the weight gain and feed conversion ratio was significantly
better than the group exposed to continuous light.
Weaver et al. (1982) used different photoperiod regimens in raising broiler chicks
and reported that changing the photoperiod length from short to long during broiler growth
improves bird’s health while maintaining equal or slightly superior performance
characteristics compared with effect of a long constant day length.
Deaton et al. (1978) indicated that total light intensity control is required within the
broiler house for the entire twenty-four hours period to obtain maximum feed saving when
broilers are maintained reared under intermittent lighting program.
Effect of Intermittent Lighting Program on the Growth Performance of Broilers
CADATE, REVELYN M. MAY 2012
Recent research has indicated that light source may affect body weight, immune
response, livability and health status. Broiler behavior is strongly affected by light sources
(Ghuffar et al., 2009).
Dozier (2002) observed that intermittent lighting program decreased leg
abnormalities and total mortality was also significantly reduced, less respiratory lesion and
better immunity to respiratory diseases than in poultry that was exposed to constant light.
The health of the bird was improved due to melatonin hormone produced during the dark
periods. Dozier (2002) further stated that broiler growers should consider not only
controlling the number of hours but as well as light intensity. He also added that lighting
system and program that is best for a particular company or producer depends on the type
of housing, the type of birds grown, climate and electricity.
Effect of Intermittent Lighting Program on the Growth Performance of Broilers
CADATE, REVELYN M. MAY 2012
MATERIALS AND METHODS
The materials and equipment used in the study were ninety heads of broiler,
commercial feeds, antibiotics, disinfectants, feeding troughs, drinkers, weighing scale,
stick broom, 100-watt bulbs, old newspapers, brooding-rearing cages, record book and
marking pen.
Pre-experimental phase. A week before the arrival of the chicks, all materials used
in the study were cleaned and disinfected. The brooding rearing cages were divided to
accommodate the three treatments having four replicates. The floor was covered with
newspaper to serve as a trap for the feeds that are being wasted, provide heat during
brooding and protect the chicks from falling. The cages were provided with proper lighting.
From day old to 21 days of the birds, antibiotics were added to the drinking water
following the prescribed dosage for the first one week of the chicks. Chick booster was
given to the chicks for the first up to two weeks of age and then was gradually shifted to to
grower ration. Shifting of feeds was done by mixing 25% of the new feed ration on the first
day, 50% on the second day and 75% on the third day so that on the fourth day, the birds
were fed with 100% new feed ration. Feeders and drinkers were provided inside the cages.
Continuous lighting and adlibitum feeding were employed.
Experimental phase. On the 21st day of age, the chicks were randomly distributed
into three treatments which were replicated four times with 10 birds per replicate, following
the Completely Randomized Design (CRD). The chicks were weighed individually to
obtain their initial weight. The treatments were as follows:
Effect of Intermittent Lighting Program on the Growth Performance of Broilers
CADATE, REVELYN M. MAY 2012
T0 - Continuous lighting (23L: 1D)
T1 – 1 hour light and 2 hours darkness with normal light during the day (cycle)
T2 – 1 hour light and 3 hours darkness with normal light during the day (cycle)
For T0, 23-hour light: 1-hour darkness (23hL: 1hD) was maintained. For T1,
intermittent lighting schedule of 1-hour light: 2 hrs dark was imposed at night starting when
it gets dark, with normal light during the day. For T2, intermittent lighting schedule of 1-
hour light: 3 hour dark was imposed at night starting when it gets dark, with normal light
during the day. This was the cycle implemented throughout the study.
Adlibitum feeding was employed from the start until the end of the study. Purely
commercial feeds were fed to the birds throughout the study with available fresh water all
the time.
Data Gathered
1. Initial weight of the broilers (kg). This was obtained by weighing the chicks
individually at 21 days of age.
2. Final weight of the broilers (kg). This was taken by weighing the chicks
individually at 35 days of age.
3. Number of dead birds. This was obtained from the number of birds that died
during the experimental period.
4. Number of sick birds. This was obtained from the number of sick birds during
the experimental period.
5. Feed left over (kg). This was the amount of feed which is left by the birds from
the feed offered each day during the experimental period.
Effect of Intermittent Lighting Program on the Growth Performance of Broilers
CADATE, REVELYN M. MAY 2012
6. Feed offered (kg). This refers to the amount of feeds given to the experimental
birds per day.
7. Feed cost. This was the purchase cost of feeds incurred in the study.
8. Abdominal fat (kg). This was obtained by weighing the fat contained by the
abdomen.
9. Slaughter weight (kg). This was obtained by taking the weight of the broiler
prior to slaughter.
10. Carcass weight (kg). This was obtained by taking the weight of the carcass
without the entrails, head and feet.
Data Computed
1.
Average daily gain in weight (kg). This was obtained by dividing
total gain in weight with the number of days on trial.
2.
Average feed intake of broilers (kg). This was obtained by taking
the difference between the feed offered and feed refuse divided by the number of
days on trial.
3.
Feed conversion ratio. This was obtained by dividing the total feed
consumption by total gain in weight of the experimental birds.
4.
Feed cost per kilogram gain in weight of broilers (Php). This was
obtained by multiplying the FCR with the average feed cost per kg.
5.
Percent mortality of broilers (%). This was obtained by dividing the
number of experimental birds died over the total number of experimental birds
multiplied by 100.
Effect of Intermittent Lighting Program on the Growth Performance of Broilers
CADATE, REVELYN M. MAY 2012
6.
Percent morbidity of broilers (%). This was obtained by dividing the
number of sick birds in the experiment by the total number of experimental birds
multiplied by 100.
7.
Dressing percentage (%). This was computed by dividing the
dressed weight by the live weight multiplied by 100.
8.
Percent abdominal fat (%). This was computed by dividing the
weight of the abdominal fat over the carcass weight of broiler multiplied by 100.
9.
Return on investment (ROI) (%). This was computed by dividing
the net income by the total cost of production multiplied by 100.
10.
Gross income. This was obtained by multiplying the final weight of
the birds by the price per kilogram of live weight.
11.
Net income. This was obtained by subtracting the gross income from
the total cost of production.
Data Analysis
The data was analyzed using the analysis of variance (ANOVA) appropriate for
completely randomized design (CRD).
Effect of Intermittent Lighting Program on the Growth Performance of Broilers
CADATE, REVELYN M. MAY 2012
RESULTS AND DISCUSSION
Mean Weight of Birds
Table 1 shows the initial and final weights of birds in the different treatments.
Statistical analysis showed that there were no significant differences in the initial weights
of birds between treatments. This implies that the birds at the start of the study were
relatively uniform in terms of weight. The average initial weight of birds was 0.43 kg at 21
days of age.
Statistical analysis revealed highly significant differences in final weight of broilers
at 40 days of age among treatments. The final weight of birds exposed to 1-hour light: 3-
hour darkness was 1.44 kg, birds with 1-hour L: 2-hour darkness at night with normal light
during the day of 1.44 kg was higher than the final weight of birds exposed to 1-hour light:
2-hour darkness at night with normal light during the day of 1.368 kg. Birds exposed to 23-
hours continuous light with 1-hour darkness daily had the lowest final weight of 1.335 kg.
Table 1. Initial and final weights of birds at day 21 and 40, respectively
INITIAL WEIGHT FINAL WEIGHT
AT 21 DAYS OLD
AT 40 DAYS OLD
TREATMENT
(kg)
(kg)
________________________________________________________________________
23 h L: 1h D
0.425a
1.335c
1h L: 2h D with normal
light during the day
0.426a
1.368b
1h L: 3h D with normal
light during the day
1.426a
1.440a
Means with common letter(s) are not significantly different at 0.05 % by DMRT
Effect of Intermittent Lighting Program on the Growth Performance of Broilers
CADATE, REVELYN M. MAY 2012
Mean Gain in Weight of Birds
from 21to 40 Days of Age
Table 2 shows the total and average gain in weight of the birds from 21 days old to
40 days in the different treatments. Statistical analysis revealed highly significant
differences in the total and average daily gain (ADG) of birds. The ADG of birds subjected
to intermittent lighting of 1-hour light: 3 hour darkness at night with normal light during
the day was significantly higher than those birds subjected to 1-hour light:2 hours darkness
at night with normal light during the day and continuous light having an average daily gain
in weight of 0.047 kg and 0.046 kg, respectively.
This study supports the observation of Mahmud et al. (2011), that intermittent
lighting program significantly affect gain in weight than on continuous light, and the
physical activity of birds is very low during darkness and energy expenditure of activity is
considerable (Rahimi et al., 2005). Studies have shown however, that although birds
subjected to continuous light consumed more feeds; it does not necessarily mean that they
would weigh more than those birds subjected on shorter light periods.
Table 2. Total and daily gain in weight of birds from 21 to 40 days of age
TOTAL GAIN AVERAGE DAILY
IN WEIGHT GAIN IN WEIGHT
TREATMENT
(kg)
(kg)
________________________________________________________________________
23 h L: 1h D
0.910c
0.046c
1h L: 2h D with normal
light during the day
0.942b
0.047b
1h L: 3h D with normal
light during the day
1.014a
0.051a
Means with common letter(s) are not significantly different at 0.05 % by DMRT
Effect of Intermittent Lighting Program on the Growth Performance of Broilers
CADATE, REVELYN M. MAY 2012
Mean Feed Intake of Birdss
Table 3 shows the feed consumption of birds from day 21 to day 40. Statistical
analysis revealed highly significant differences in the feed intake of birds. Birds subjected
to 1-hour light: 3-hour darkness at night with normal light during the day had a total feed
intake of 2.39 kg with an average daily feed of 0.12 kg was significantly lower than the
total and average feed intake of birds exposed to 1-hour light: 2-hour darkness at night with
normal light during the day of 2.69 kg and 0.14 kg respectively. Birds exposed to 23-hour
light with 1-hour darkness had the highest feed intake of 3.15 kg and average daily feed
intake of 0.16 kg.
Feed Conversion Ratio (FCR) from 21 to 40 Days of Age
Statistical analysis revealed highly significant differences in the feed conversion
ratio of birds. Birds subjected to 1-hour light: 3-hour darkness at night with normal light
during the day of 2.35 was significantly lower than the FCR of birds exposed to 1-hour
light: 2-hour darkness with normal light during the day of 2.85. Birds subjected to 23-hour
light with 1-hour darkness had the highest FCR of 3.46.
Table 3. Total and average feed intake of birds from 21 to 40 days of age
TOTAL FEED AVERAGE DAILY
INTAKE FEED INTAKE
TREATMENT
(kg)
(kg)
________________________________________________________________________
23 h L: 1h D
3.15a
0.16a
1h L: 2h D with normal
light during the day
2.69b
0.14b
1h L: 3h D with normal
light during the day
2.39c
0.12c
Means with common letter(s) are not significantly different at 0.05 % by DMRT
Effect of Intermittent Lighting Program on the Growth Performance of Broilers
CADATE, REVELYN M. MAY 2012
Feed Cost to Produce a Kilogram of Broiler
Table 4 shows the feed cost to produce a kilogram gain in body weight of broilers.
Statistical analysis revealed highly significant differences in the feed cost to produce a
kilogram of broilers. Birds subjected to 1-hour light: 3-hour darkness at night with normal
light during the day of Php54.76 was significantly lower than the feed cost to produce a kg
gain in weight 0of broilers of birds exposed to 1-hour light: 2-hour darkness at night with
normal light during the day of Php61.28. Birds subjected to continuous light had the highest
feed cost to produce a kilogram gain in weight of broilers of Php70.48.
Morbidity and Mortality
Mortality and morbidity of birds were not observed from day 21 to 40. The
incidence of leg abnormalities observed during the pre- experimental period from day 14
to day 18 was no longer encountered. This may be attributed to the reduced feed
consumption of the birds when the lighting regimens were imposed. This may be due to
their fast muscle growth but their leg bones were not growing as fast as the muscle.
Table 4. Feed conversion ratio and feed cost to produced a kg of broiler within 20 days
FEED CONVERSION FEED COST TO PRODUCED
RATIO
A KG OF BROILER
TREATMENT
(Php)
________________________________________________________________________
23 h L: 1h D
3.46a
70.48a
1h L: 2h D with normal
light during the day
2.85b
61.28b
1h L: 3h D with normal
light during the day
2.35c
54.76c
Means with common letter(s) are not significantly different at 0.05% by DMRT
Effect of Intermittent Lighting Program on the Growth Performance of Broilers
CADATE, REVELYN M. MAY 2012
Dressing Percentage
Table 5 shows the dressing percentage of the birds. Statistical analysis revealed a
highly significant difference among the dressing percentages of broilers. Birds subjected
to intermittent lighting of 1-hour light: 3-hour darkness at night with normal light during
the day had the highest dressing percentage of 71% as compared to the dressing percentage
of birds exposed to 1-hour light: 2-hour darkness with normal light during the day of
67.34%. Birds subjected to 23 hours continuous light with 1-hour darkness had the lowest
dressing percentage of 59.67%. This implies that the differences that occur among
treatments were caused by the variation of feathers and fats.
Percent Abdominal Fat
Table 6 shows the percent abdominal fat of birds in the different treatments.
Statistical analysis showed that there were no significant differences among treatments.
Thus, it implies that percent abdominal fat of broilers was not significantly affected by
intermittent light. The average percent abdominal fat of broiler is 1.98%.
Table 5. Dressing percentage of birds at 40 days of age
DRESSING PERCENTAGE
TREATMENT
(%)
________________________________________________________________________
23 h L: 1h D
59.67c
1h L: 2h D with normal
light during the day
67.34b
1h L: 3h D with normal
light during the day
71.00a
Means with common letter(s) are not significantly different at 0.05% by DMRT
Effect of Intermittent Lighting Program on the Growth Performance of Broilers
CADATE, REVELYN M. MAY 2012
Table 6. Percent abdominal fat of birds at 40 days of age
ABDOMINAL FAT
TREATMENT
(%)
________________________________________________________________________
23 h L: 1h D
2.0925a
1h L: 2h D with normal
light during the day
1.8560a
1h L: 3h D with normal
light during the day
1.9940a
Means with common letter(s) are not significantly different at 0.05% by DMRT
Return on Investment
The returns on investment in the different treatments are shown in Table 7. Data
shows that higher profit was obtained from the birds exposed to intermittent light of 1-hour
light: 3-hour darkness during the night with normal light during the day. This implies that
subjecting the birds under intermittent lighting program having 1-hour light: 3-hour
darkness resulted to better profit, though it is minimal.
Table 7. Net returns and return on investment
TOTAL TOTAL NET
ROI
SALES COST INCOME (%)
TREATMENT
(Php)
(Php) (Php)
________________________________________________________________________
Continuous light
(23h L: 1h D)
5,130.00 5,721.48 -591.48
-10.34
1h L: 2h D with
normal light during the day 5,244.00 6,174.60 -930.60
-15.07
1h L: 2h D with
normal light during the day 5,532.00 5,401.81 130.19 2.41
Effect of Intermittent Lighting Program on the Growth Performance of Broilers
CADATE, REVELYN M. MAY 2012
SUMMARY, CONCLUSION AND RECOMMENDATION
Summary
This study was conducted to determine the effect of intermittent lighting program
on the growth performance of broilers. Specifically, growth rate, feed conversion ratio,
feed consumption and gain in weight. This was conducted at Ili, Datakan, Kapangan,
Benguet from March 11, 2012 to April 20, 2012.
A total of ninety-six, 21-day-old broiler chicks were used in the study. Following
the completely randomized design (CRD), the birds were randomly distributed into four
treatments. Each treatment was replicated four times with eight birds per replication. The
different treatments were as follows: T0 (Control or continuous light); T1 (1h L: 2h D at
night with normal light during the day) and T2 (1h L: 3h D at night with normal light during
the day).
Highly significant differences were observed in gain in weight, feed intake, feed
conversion ratio, feed cost per kilogram gain in weight and dressing percentage of birds
subjected to 1-hour light: 3-hour darkness during the night with normal light during the
day. The average daily gain in weight of birds was 0.05 kg with an average daily feed
intake of 0.14 kg. The average FCR of birds was 2.89 with an average feed cost to produce
a kg gain in weight of birds of 62.17. The average dressing percentage of birds was 66%.
Results of the study revealed that intermittent light did not affect the percent abdominal
fat. The average percent abdominal fat was 1.98 %.
Although the net profit returns on investment (ROI) were not subjected to statistical
analysis, results showed that better ROI was obtained from the group of birds having 1-
hour light: 3-hour darkness at night with normal light during the day, though it is minimal.
Effect of Intermittent Lighting Program on the Growth Performance of Broilers
CADATE, REVELYN M. MAY 2012
Conclusion
Based on the observation and result of the study, it is therefore concluded that
subjecting birds on intermittent lighting having 1-hour light: 3-hour darkness at night with
normal light during the day can be imposed to broilers.
Recommendation
Based on the results of the study, the researcher therefore recommends that
intermittent lighting program having 1h L: 3h D can be imposed to broilers. However,
further studies should be done using intermittent lighting program with longer number of
hours of darkness.
Effect of Intermittent Lighting Program on the Growth Performance of Broilers
CADATE, REVELYN M. MAY 2012
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CADATE, REVELYN M. MAY 2012