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Ahemeral Photoperiods for Chicken Hens*
Ahemeral Photoperiods for Chicken Hens * J. B . COOPER AND B . D . BARNETT
Poultry Science Department, Clemson University, Clemson, South Carolina 29631 (Received for publication July 3, 1975)
POULTRY SCIENCE 55: 1183-1187, 1976
INTRODUCTION
I
LLUMINATING chicken hens in an attempt to stimulate egg production is not new. Much research has gone into various aspects of lighting and various physiological responses. Grover et al. (1972), Ostrander and Turner (1961), Peterson and Espenshade (1971), Dorminey et al. (1970), and Morris (1967) reported on light intensity research. Another approach has been the duration of the photoperiod and was reported by Rosales et al. (1968), Ryan et al. (1959), and Morris (1961). The photoperiod has been broken up by intervals of darkness during a 24-hour period and results reported by Lanson and Sturkie (1961), Lucas etal. (1967), and Cooper and Barnett (1974). Recommendations given by Lucas et al. (1967) vary the photoperiod from 14 to 16 hours and an increasing increment per week if desired with a minimum of one ft. candle of light intensity at bird level. Research using ahemeral lighting has been reported by Byerly and Moore (1941), Foster (1968, 1969), and Morris (1973). All reports * Published with the approval of the Director of the South Carolina Experiment Station as Technical Contribution No. 1279.
indicate that the length of the light period was constant and that the dark period of the cycle was changed to vary the length of the cycles. Egg production was altered, the advantage being in favor of a cycle which did not exceed 25 or 26 hours, and the light period was 14-16 hours in length. This paper is a report of the results from an experiment in which variations were made in the light portion of the light-dark cycle. PROCEDURES Four light regimes were used with four pens on each treatment. Treatments consisted of light (L) and dark (D) cycles in hours as follows: (1) L14-D10, (2) L16-D10, (3) L18D10, (4) L20-D10. The light intensity ranged from 11-21 lumens/sq. m. within the pen area. Each pen was approximately 6 m. x 3 m. with 2 / 5 of the area having litter and 3/5 having slatted wood flooring. All pens had the same number and size of feeders, waterers, and nests. Both thermostatically and time-controlled fans were used for ventilation. Manually operated blue lights were used when jobs needed to be done during periods of darkness. An all-mash laying ration and water were supplied ad libitum.
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ABSTRACT The effects of ahemeral lighting on egg production, egg quality, egg size, feed efficiency, and mortality were studied. Treatments consisted of light (L) and dark (D) cycles in hours as follows: (1) L14-D10, (2) L16-D10, (3) L18-D10, (4) L20-D10. Light intensity ranged from 11-21 lumens/sq. m. in each pen area. There were four pens of 100 S.C. White Leghorn pullets, 20 weeks old at start, on each treatment. Treatments 3 and 4 resulted in significantly (P < 0.05) lower egg production than treatments 1 and 2. Feed per dozen eggs was lower in treatment 1 than in treatments 2, 3, or 4, but only significantly so over 3 and 4. Haugh units were significantly lower for treatment 4 than 1 and 2. Treatment 3 was significantly lower than 1. Shell thickness for L14-D10 treatment was significantly lower than for any ahemeral treatments. Treatment 2 was significantly lower than treatment 3 but was not significantly lower than treatment 4. Average egg weight was significantly higher for treatments 3 and 4 compared to treatment 1. No differences in mortality were noted.
1184
J. B. COOPER AND B. D. BARNETT
TABLE 2.—-Feed
Treatment 1 2 3 4 1
TABLE 1.—-Percent
Treatment
Mean range
Average
1 2 3 4
71.0-75.0 64.1-72.2 61.6-66.7 64.9-66.7
72.8a 69.7a 64.1b 65.8b
1 Figures within a column with different letters are significantly (P < 0.05) different.
mine differences due to treatment. Duncan's multiple range test was used to differentiate significance, if any, among treatments (Steel and Torrie, 1960). RESULTS Egg production is shown in Table 1. There was significantly (P < 0.05) lower hen-day egg production in treatments 3 (18L-10D) and 4 (20L-10D) than in treatments 1 (14L-10D) and 2 (16L-10D). Feed consumed per dozen eggs is shown in Table 2. There was significantly less feed used per dozen eggs in treatment 1 than in treatments 3 and 4. There was also significantly less feed used per dozen eggs in treatment 2 than in treatment 3. There were variations in mortality among pens and among treatments, but there were no significant differences among treatments. Mortality varied from 0-8% among pens with an average of 5% for all pens. Percent mortality among treatments varied from 3.3 to 6.0. Eggs from treatments 3 and 4 were significantly (P < 0.05) lower in Haugh units than eggs from treatment 1. Eggs from treatment
efficiency and consumption'
Feed/dozen eggs (kg.) Average Mean range 1.79-1.85 1.85-2.04 1.96-2.09 1.93-2,00
hen-day egg j.traduction1
1.81a 1.90ac 2.03b 1.96bc
Feed/hen-day (g-) Mean range Average 109-113 109-113 104-109 104-109
Figures within a column with different letters are significantly (P < 0.05) different.
111 111 107 107
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There were 16 pens, each containing 100 S.C. White Leghorn pullets, which were housed at 20 weeks of age on March 4, 1974. Records of egg production, feed consumption, and mortality were kept by 28-day periods. Eggs were gathered three times each day. U.S.D.A. egg size classification was determined on all eggs gathered in one day. Six determinations were made at intervals of eight weeks beginning four weeks after housing. Weighings were made with an Egomatic Egg Candler grader, Model D6V-L. Since total egg weight was reported by Morris (1973), mass egg weights were taken and average egg weights were determined for each pen. Mass weights were taken at seven equally spaced time intervals. The first weighing was made 16 weeks after the experiment started. Because of the variable daily gathering of eggs in certain pens as the light periods moved through the 24-hour day, weighings were made on 13 consecutive days for each of the seven times. By doing this, all the 24-hour variations in any one ahemeral lighting program were included. The average mass weight of these 13-day weighings was considered as one weighing in this report. Egg quality studies involving shell thickness and Haugh units were made six times at equally spaced intervals throughout the experiment. All eggs laid in one 24-hour period were used for each study. Eggs were kept in an egg cooler after gathering until the time of weighing and measuring which was not more than 24 hours after oviposition. An analysis of variance was used to deter-
1185
AHEMERAL PHOTOPERIODS
length of the total cycle decreased from 30 to 28 to 26 to 24 hours, the mean mass egg weight increased but not significantly so. When average egg weight is considered in each treatment, there were significantly (P < 0.05) larger eggs in treatments 3 and 4 than in treatments 1 and 2. There was no significant difference between treatments of eggs produced in the 24- and 26-hour cycle regimes. Table 5 also shows the percentage of eggs in the U.S. size classification based on individual egg weights. There was a significantly (P < 0.05) larger percentage of large or better produced under the 28- and 30-hour cycles than under the 24- and 26-hour cycles. There was no significant difference in large or better and medium size eggs produced on the 24and 26-hour cycles. However, these cycles
TABLE 3.—Haugh units and shell thickness-—6 breakings' Units
1
Mm. thickness
Treatment
Mean range
Average
Mean range
Average
1 2 3 4
75.2-89.7. 75.6-88.1 74.6-88.1 72.9-86.7
81.8a 81.0ab 79.8bc 79.5c
J23-.345 .337-.348 .344-.355 .330-.356
.333a .344b .351c .346bc
Figures within a column with different letters are significantly (P < 0.05) different. TABLE 4.—Percent U.S.D.A. grades of eggs based on Haugh units'
1
B
A
AA Treat.
Mean range
Average
Mean range
Average
Mean range
Average
1 2 3 4
76.7-99.7 72.5-99.7 72.3-100.0 58.3-98.9
88.6a 88.8a 86.5ac 82.3bc
0.2-22.4 0.3-27.5 0.0-25.2 1.1-40.4
10.9a 10.9a 13.0ac 16.8bc
0.00-1.4 0.00-1.0 0.00-2.4 0.00-3.2
0.5ab 0.3a 0.5ab 0.9bc
Figures within a column with different letters are significantly (P < 0.05) different. TABLE 5.-—Mass
Treatment 1 2 3 4
Average wt. 2 g58,171.7a 56,288.3a 55,474.6a 54,105.1a
egg weight and
Average wt. 3 g60.8a 60.7a 62.2b 62.8b
U.S.D.A. classification1
Large up
Medium
Small
%
%
%
75.7a 76.7a 86.3b 85.7b
21.7a 21.6a 12.3b 13.4b
2.5a 1.5b 1.3b 0.9b
'Figures within a column with different letters are significantly (P < 0.05) different. Average weight of seven 13 consecutive days of mass weighings. 'Average individual egg weight for all weighings. 2
Peewee % 0.1a 0.2a 0.1a 0.0a
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4 were significantly (P < 0.05) lower in Haugh units than eggs from treatment 2 (Table 3). Eggs from treatment 3 (18L-10D) were significantly higher (P < 0.05) in shell thickness than eggs from treatments 1 and 2, with treatment 1 being significantly lower than any of the ahemeral treatments. The percentages of U.S.D.A. grades of eggs are shown in Table 4. Hens in treatment 4 produced eggs with the lowest percentage of grade AA, which was significantly (P < 0.05) below the percentage for eggs produced in treatments 1 and 2. This was reflected in treatment 4, which produced a significantly (P < 0.05) higher percentage of eggs in grade A than treatments 1 and 2. There was a tendency for a heavier mass weight in those treatments having the shortest cycle of light and darkness (Table 5). As the
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J. B. COOPER AND B. D. BARNETT
did have a significantly (P < 0,05) higher percentage of medium-size eggs than did the 28- and 30-hour cycles. Treatment 1 (24-hour cycle) had a significantly (P < 0.05) higher percentage of small eggs than did treatments 2, 3, and 4.
percentage of eggs that were grades AA and A combined. Therefore, a poultry producer needing grade A and an improvement of egg size and shell thickness might find help with ahemeral lighting. ACKNOWLEDGMENTS
DISCUSSION
REFERENCES Byerly, T. C , and 0. K. Moore, 1941. Clutch length in relation to period of illumination in the domestic fowl. Poultry Sci. 20: 387-390. Cooper J. B., and B. D. Barnett, 1974. Photoperiods for layers. World's Poultry Congress Proc: 423-425. Dorminey, R. W., J. E. Parker and W. H. McCluskey, 1970. Effects of light intensity on Leghorn pullets during the development and laying periods. Poultry Sci. 49: 1657-1661. Foster, W. H., 1968. The effect of light-dark cycles of abnormal lengths upon egg production. Brit. Poultry Sci. 9: 273-284. Foster, W. H., 1969. Egg production under 24, 26, and 28 hour light-dark cycles. Brit. Poultry Sci. 10: 273-279. Grover, R. M., D. L. Anderson, R. A. Damon, Jr. and L. H. Ruggles, 1972. The effects of bird density, dietary energy, light intensity, and cage level on the reproductive performance of heavy type chickens in wire cages. Poultry Sci. 51: 565-575. Lanson, R. K., and P. D. Sturkie, 1961. The influence of light and darkness upon the reproductive performance of the fowl. Poultry Sci. 40: 1751-1756. Lucas, L. M., L. E. Campbell and H. L. Marks, 1967. Lighting poultry houses. Farmers' Bull. No. 2229. Morris, J. A., 1961. The effect of continuous light and continuous noise on pullets held in sealed chambers. Poultry Sci. 40: 995-1000. Morris, T. R., 1967. The effect of light intensity on growing and laying pullets. World Poultry Sci. J. 23: 246-252. Morris, T. R., 1973. The effects of ahemeral light and dark cycles on egg production in the fowl. Poultry Sci. 52: 423-445. Ostrander, C. E., and C. N. Turner, 1961. Effect of various intensities of light on egg production of Single Comb White Leghorn pullets. Poultry Sci. 40: 1440.
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Ahemeral lighting as used in this experiment varied from other reports, Byerly and Moore (1941), Foster (1968,1969), and Morris (1973), in that the cycle was changed by increasing the light phase rather than the dark phase. The results were similar to earlier reports in that ahemeral lighting and normal lighting produced about the same total egg weight even though there were fewer eggs produced with ahemeral lighting. Individual egg size was larger in the treatments on longer cycles. In this experiment the eggs were gathered at times convenient to labor, but not always close to laying time. This may account for lower average Haugh units found in eggs from treatments 3 and 4, which had the longer cycles, and more time for the eggs that had to be left in the house. No accurate record could be made of broken eggs, but more dirty eggs were observed coming from the ahemeral pens when the light cycle was in the night. Ahemeral lighting created considerable labor problems of work in the houses when the dark cycle came during the daylight hours. The main benefit found was the increase in egg size, which was at the expense of production. Further work is desirable with birds in cages to determine a desirable cycle to produce larger eggs, if needed, at little if any loss in production. By using cages there might be fewer broken eggs as well as fewer dirty eggs. The loss in Haugh units with ahemeral lighting was not great enough to affect the
The authors are indebted to Dr. Walter E. Johnston of the Experimental Statistical Service of Clemson University for the statistical analysis.
AHEMERAL PHOTOPERIODS
Peterson, R. A., and J. Espenshade, 1971. Performance of laying hens maintained in colony cages under low intensity "panelescent tape-lites." Poultry Sci. 50: 291-293. Rosales, A. A., H. V. Biellier and A. B. Stephenson, 1968. Effect of light cycles on ovipositions and egg production. Poultry Sci. 47: 586-591.
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Ryan, F. A., E. P. Singsen, J. R. Carson, L. M. Potter and W. A. Junnila, 1959. Fourteen hour day versus all-night lights in poultry laying houses. Poultry Sci. 38: 1243. Steel, R. G. D., and J. H. Torrie, 1960. Principles and Procedures of Statistics. McGraw-Hill, New York.
Mineral Metabolism in Chicks on High Dietary Pyridoxine and Magnesium! (Received for publication July 16, 1975)
ABSTRACT The effect of high dietary pyridoxine and magnesium on tissue electrolytes was studied in day-old broiler-type male chicks. There were 15 treatments of 875, 1375 and 1875 mg. magnesium/kg. diet and pyridoxine at 1, 4, 31, 301, 3001 mg./kg. diet in a 3 x 5 factorial block design. The sodium concentration of the liver decreased linearly with increasing dietary magnesium concentration expressed as log10. In the kidney, no such effect was observed. The response of sodium concentration in these two tissues to increasing dietary pyridoxine, also expressed as log,0, was curvilinear, decreasing to minimum concentrations at pyridoxine intakes estimated to be equal to 40 mg./kg. of diet for the liver and 50 for the kidney and thereafter increasing. Potassium concentration of the liver exhibited opposite trends to those for sodium concentration but the responses to dietary magnesium were not consistent at each dietary pyridoxine concentration. Kidney potassium content followed essentially opposite trends to those of sodium. Kidney calcium decreased with increases in either dietary magnesium or pyridoxine, but the decreases were not consistent. The magnesium content of the kidney tended to increase with increases in dietary magnesium. Dietary pyridoxine resulted in a curvilinear response only in those chicks fed the 1875 mg. diet, decreasing to a minimum value at a pyridoxine intake of 26 mg., and increasing at higher pyridoxine dietary concentrations. No significant effects on sodium, potassium, calcium and magnesium concentrations in the heart were observed. It was speculated that the maximum potassium retention estimated to occur in the livers of birds consuming a diet containing 48 mg. pyridoxine/kg. diet might be due to increased glycogen turnover or increased phosphorylase activity. POULTRY SCIENCE 55: 1187-1194, 1976
INTRODUCTION HERE appears to be a belief among proponents of megavitamin therapy and some nutritionists that massive doses of the B-vitaminsare safe. Rimland(1973)has stated that "it is widely accepted that with the exception of vitamins A and D, fat soluble vitamins that are not readily excreted, there is no serious toxicity problem even when vitamins are taken in very large quantities."
T
1. Scientific contribution no. 621, Storrs Agricultural Experiment Station, The University of Connecticut, Storrs, Conn. 06268.
Boger et al. (1973) have mentioned that "with water-soluble vitamins, overdoses are wasteful but not harmful because the excess is excreted in the urine." Ellis and Presley (1973) have concluded that "one may safely give 50 to 450 mg. of pyridoxine daily and up to 1000 mg. daily for short intervals for 3 to 5 days during hospital confinement for delivery." However, Cohen et al. (1973) have warned that since striking changes in metabolism resulted from megadoses of pyridoxine, further studies are needed before assuming that massive doses of water-soluble vitamins can be used with impunity. A relationship has been established be-
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GBASAY ROGERSON AND E . P. SINGSEN
Department of Nutritional Sciences, University of Connecticut, Storrs, Connecticut 06268
Poultry Science Department, Clemson University, Clemson, South Carolina 29631 (Received for publication July 3, 1975)
POULTRY SCIENCE 55: 1183-1187, 1976
INTRODUCTION
I
LLUMINATING chicken hens in an attempt to stimulate egg production is not new. Much research has gone into various aspects of lighting and various physiological responses. Grover et al. (1972), Ostrander and Turner (1961), Peterson and Espenshade (1971), Dorminey et al. (1970), and Morris (1967) reported on light intensity research. Another approach has been the duration of the photoperiod and was reported by Rosales et al. (1968), Ryan et al. (1959), and Morris (1961). The photoperiod has been broken up by intervals of darkness during a 24-hour period and results reported by Lanson and Sturkie (1961), Lucas etal. (1967), and Cooper and Barnett (1974). Recommendations given by Lucas et al. (1967) vary the photoperiod from 14 to 16 hours and an increasing increment per week if desired with a minimum of one ft. candle of light intensity at bird level. Research using ahemeral lighting has been reported by Byerly and Moore (1941), Foster (1968, 1969), and Morris (1973). All reports * Published with the approval of the Director of the South Carolina Experiment Station as Technical Contribution No. 1279.
indicate that the length of the light period was constant and that the dark period of the cycle was changed to vary the length of the cycles. Egg production was altered, the advantage being in favor of a cycle which did not exceed 25 or 26 hours, and the light period was 14-16 hours in length. This paper is a report of the results from an experiment in which variations were made in the light portion of the light-dark cycle. PROCEDURES Four light regimes were used with four pens on each treatment. Treatments consisted of light (L) and dark (D) cycles in hours as follows: (1) L14-D10, (2) L16-D10, (3) L18D10, (4) L20-D10. The light intensity ranged from 11-21 lumens/sq. m. within the pen area. Each pen was approximately 6 m. x 3 m. with 2 / 5 of the area having litter and 3/5 having slatted wood flooring. All pens had the same number and size of feeders, waterers, and nests. Both thermostatically and time-controlled fans were used for ventilation. Manually operated blue lights were used when jobs needed to be done during periods of darkness. An all-mash laying ration and water were supplied ad libitum.
1183
Downloaded from http://ps.oxfordjournals.org/ at New York University on May 10, 2015
ABSTRACT The effects of ahemeral lighting on egg production, egg quality, egg size, feed efficiency, and mortality were studied. Treatments consisted of light (L) and dark (D) cycles in hours as follows: (1) L14-D10, (2) L16-D10, (3) L18-D10, (4) L20-D10. Light intensity ranged from 11-21 lumens/sq. m. in each pen area. There were four pens of 100 S.C. White Leghorn pullets, 20 weeks old at start, on each treatment. Treatments 3 and 4 resulted in significantly (P < 0.05) lower egg production than treatments 1 and 2. Feed per dozen eggs was lower in treatment 1 than in treatments 2, 3, or 4, but only significantly so over 3 and 4. Haugh units were significantly lower for treatment 4 than 1 and 2. Treatment 3 was significantly lower than 1. Shell thickness for L14-D10 treatment was significantly lower than for any ahemeral treatments. Treatment 2 was significantly lower than treatment 3 but was not significantly lower than treatment 4. Average egg weight was significantly higher for treatments 3 and 4 compared to treatment 1. No differences in mortality were noted.
1184
J. B. COOPER AND B. D. BARNETT
TABLE 2.—-Feed
Treatment 1 2 3 4 1
TABLE 1.—-Percent
Treatment
Mean range
Average
1 2 3 4
71.0-75.0 64.1-72.2 61.6-66.7 64.9-66.7
72.8a 69.7a 64.1b 65.8b
1 Figures within a column with different letters are significantly (P < 0.05) different.
mine differences due to treatment. Duncan's multiple range test was used to differentiate significance, if any, among treatments (Steel and Torrie, 1960). RESULTS Egg production is shown in Table 1. There was significantly (P < 0.05) lower hen-day egg production in treatments 3 (18L-10D) and 4 (20L-10D) than in treatments 1 (14L-10D) and 2 (16L-10D). Feed consumed per dozen eggs is shown in Table 2. There was significantly less feed used per dozen eggs in treatment 1 than in treatments 3 and 4. There was also significantly less feed used per dozen eggs in treatment 2 than in treatment 3. There were variations in mortality among pens and among treatments, but there were no significant differences among treatments. Mortality varied from 0-8% among pens with an average of 5% for all pens. Percent mortality among treatments varied from 3.3 to 6.0. Eggs from treatments 3 and 4 were significantly (P < 0.05) lower in Haugh units than eggs from treatment 1. Eggs from treatment
efficiency and consumption'
Feed/dozen eggs (kg.) Average Mean range 1.79-1.85 1.85-2.04 1.96-2.09 1.93-2,00
hen-day egg j.traduction1
1.81a 1.90ac 2.03b 1.96bc
Feed/hen-day (g-) Mean range Average 109-113 109-113 104-109 104-109
Figures within a column with different letters are significantly (P < 0.05) different.
111 111 107 107
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There were 16 pens, each containing 100 S.C. White Leghorn pullets, which were housed at 20 weeks of age on March 4, 1974. Records of egg production, feed consumption, and mortality were kept by 28-day periods. Eggs were gathered three times each day. U.S.D.A. egg size classification was determined on all eggs gathered in one day. Six determinations were made at intervals of eight weeks beginning four weeks after housing. Weighings were made with an Egomatic Egg Candler grader, Model D6V-L. Since total egg weight was reported by Morris (1973), mass egg weights were taken and average egg weights were determined for each pen. Mass weights were taken at seven equally spaced time intervals. The first weighing was made 16 weeks after the experiment started. Because of the variable daily gathering of eggs in certain pens as the light periods moved through the 24-hour day, weighings were made on 13 consecutive days for each of the seven times. By doing this, all the 24-hour variations in any one ahemeral lighting program were included. The average mass weight of these 13-day weighings was considered as one weighing in this report. Egg quality studies involving shell thickness and Haugh units were made six times at equally spaced intervals throughout the experiment. All eggs laid in one 24-hour period were used for each study. Eggs were kept in an egg cooler after gathering until the time of weighing and measuring which was not more than 24 hours after oviposition. An analysis of variance was used to deter-
1185
AHEMERAL PHOTOPERIODS
length of the total cycle decreased from 30 to 28 to 26 to 24 hours, the mean mass egg weight increased but not significantly so. When average egg weight is considered in each treatment, there were significantly (P < 0.05) larger eggs in treatments 3 and 4 than in treatments 1 and 2. There was no significant difference between treatments of eggs produced in the 24- and 26-hour cycle regimes. Table 5 also shows the percentage of eggs in the U.S. size classification based on individual egg weights. There was a significantly (P < 0.05) larger percentage of large or better produced under the 28- and 30-hour cycles than under the 24- and 26-hour cycles. There was no significant difference in large or better and medium size eggs produced on the 24and 26-hour cycles. However, these cycles
TABLE 3.—Haugh units and shell thickness-—6 breakings' Units
1
Mm. thickness
Treatment
Mean range
Average
Mean range
Average
1 2 3 4
75.2-89.7. 75.6-88.1 74.6-88.1 72.9-86.7
81.8a 81.0ab 79.8bc 79.5c
J23-.345 .337-.348 .344-.355 .330-.356
.333a .344b .351c .346bc
Figures within a column with different letters are significantly (P < 0.05) different. TABLE 4.—Percent U.S.D.A. grades of eggs based on Haugh units'
1
B
A
AA Treat.
Mean range
Average
Mean range
Average
Mean range
Average
1 2 3 4
76.7-99.7 72.5-99.7 72.3-100.0 58.3-98.9
88.6a 88.8a 86.5ac 82.3bc
0.2-22.4 0.3-27.5 0.0-25.2 1.1-40.4
10.9a 10.9a 13.0ac 16.8bc
0.00-1.4 0.00-1.0 0.00-2.4 0.00-3.2
0.5ab 0.3a 0.5ab 0.9bc
Figures within a column with different letters are significantly (P < 0.05) different. TABLE 5.-—Mass
Treatment 1 2 3 4
Average wt. 2 g58,171.7a 56,288.3a 55,474.6a 54,105.1a
egg weight and
Average wt. 3 g60.8a 60.7a 62.2b 62.8b
U.S.D.A. classification1
Large up
Medium
Small
%
%
%
75.7a 76.7a 86.3b 85.7b
21.7a 21.6a 12.3b 13.4b
2.5a 1.5b 1.3b 0.9b
'Figures within a column with different letters are significantly (P < 0.05) different. Average weight of seven 13 consecutive days of mass weighings. 'Average individual egg weight for all weighings. 2
Peewee % 0.1a 0.2a 0.1a 0.0a
Downloaded from http://ps.oxfordjournals.org/ at New York University on May 10, 2015
4 were significantly (P < 0.05) lower in Haugh units than eggs from treatment 2 (Table 3). Eggs from treatment 3 (18L-10D) were significantly higher (P < 0.05) in shell thickness than eggs from treatments 1 and 2, with treatment 1 being significantly lower than any of the ahemeral treatments. The percentages of U.S.D.A. grades of eggs are shown in Table 4. Hens in treatment 4 produced eggs with the lowest percentage of grade AA, which was significantly (P < 0.05) below the percentage for eggs produced in treatments 1 and 2. This was reflected in treatment 4, which produced a significantly (P < 0.05) higher percentage of eggs in grade A than treatments 1 and 2. There was a tendency for a heavier mass weight in those treatments having the shortest cycle of light and darkness (Table 5). As the
1186
J. B. COOPER AND B. D. BARNETT
did have a significantly (P < 0,05) higher percentage of medium-size eggs than did the 28- and 30-hour cycles. Treatment 1 (24-hour cycle) had a significantly (P < 0.05) higher percentage of small eggs than did treatments 2, 3, and 4.
percentage of eggs that were grades AA and A combined. Therefore, a poultry producer needing grade A and an improvement of egg size and shell thickness might find help with ahemeral lighting. ACKNOWLEDGMENTS
DISCUSSION
REFERENCES Byerly, T. C , and 0. K. Moore, 1941. Clutch length in relation to period of illumination in the domestic fowl. Poultry Sci. 20: 387-390. Cooper J. B., and B. D. Barnett, 1974. Photoperiods for layers. World's Poultry Congress Proc: 423-425. Dorminey, R. W., J. E. Parker and W. H. McCluskey, 1970. Effects of light intensity on Leghorn pullets during the development and laying periods. Poultry Sci. 49: 1657-1661. Foster, W. H., 1968. The effect of light-dark cycles of abnormal lengths upon egg production. Brit. Poultry Sci. 9: 273-284. Foster, W. H., 1969. Egg production under 24, 26, and 28 hour light-dark cycles. Brit. Poultry Sci. 10: 273-279. Grover, R. M., D. L. Anderson, R. A. Damon, Jr. and L. H. Ruggles, 1972. The effects of bird density, dietary energy, light intensity, and cage level on the reproductive performance of heavy type chickens in wire cages. Poultry Sci. 51: 565-575. Lanson, R. K., and P. D. Sturkie, 1961. The influence of light and darkness upon the reproductive performance of the fowl. Poultry Sci. 40: 1751-1756. Lucas, L. M., L. E. Campbell and H. L. Marks, 1967. Lighting poultry houses. Farmers' Bull. No. 2229. Morris, J. A., 1961. The effect of continuous light and continuous noise on pullets held in sealed chambers. Poultry Sci. 40: 995-1000. Morris, T. R., 1967. The effect of light intensity on growing and laying pullets. World Poultry Sci. J. 23: 246-252. Morris, T. R., 1973. The effects of ahemeral light and dark cycles on egg production in the fowl. Poultry Sci. 52: 423-445. Ostrander, C. E., and C. N. Turner, 1961. Effect of various intensities of light on egg production of Single Comb White Leghorn pullets. Poultry Sci. 40: 1440.
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Ahemeral lighting as used in this experiment varied from other reports, Byerly and Moore (1941), Foster (1968,1969), and Morris (1973), in that the cycle was changed by increasing the light phase rather than the dark phase. The results were similar to earlier reports in that ahemeral lighting and normal lighting produced about the same total egg weight even though there were fewer eggs produced with ahemeral lighting. Individual egg size was larger in the treatments on longer cycles. In this experiment the eggs were gathered at times convenient to labor, but not always close to laying time. This may account for lower average Haugh units found in eggs from treatments 3 and 4, which had the longer cycles, and more time for the eggs that had to be left in the house. No accurate record could be made of broken eggs, but more dirty eggs were observed coming from the ahemeral pens when the light cycle was in the night. Ahemeral lighting created considerable labor problems of work in the houses when the dark cycle came during the daylight hours. The main benefit found was the increase in egg size, which was at the expense of production. Further work is desirable with birds in cages to determine a desirable cycle to produce larger eggs, if needed, at little if any loss in production. By using cages there might be fewer broken eggs as well as fewer dirty eggs. The loss in Haugh units with ahemeral lighting was not great enough to affect the
The authors are indebted to Dr. Walter E. Johnston of the Experimental Statistical Service of Clemson University for the statistical analysis.
AHEMERAL PHOTOPERIODS
Peterson, R. A., and J. Espenshade, 1971. Performance of laying hens maintained in colony cages under low intensity "panelescent tape-lites." Poultry Sci. 50: 291-293. Rosales, A. A., H. V. Biellier and A. B. Stephenson, 1968. Effect of light cycles on ovipositions and egg production. Poultry Sci. 47: 586-591.
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Ryan, F. A., E. P. Singsen, J. R. Carson, L. M. Potter and W. A. Junnila, 1959. Fourteen hour day versus all-night lights in poultry laying houses. Poultry Sci. 38: 1243. Steel, R. G. D., and J. H. Torrie, 1960. Principles and Procedures of Statistics. McGraw-Hill, New York.
Mineral Metabolism in Chicks on High Dietary Pyridoxine and Magnesium! (Received for publication July 16, 1975)
ABSTRACT The effect of high dietary pyridoxine and magnesium on tissue electrolytes was studied in day-old broiler-type male chicks. There were 15 treatments of 875, 1375 and 1875 mg. magnesium/kg. diet and pyridoxine at 1, 4, 31, 301, 3001 mg./kg. diet in a 3 x 5 factorial block design. The sodium concentration of the liver decreased linearly with increasing dietary magnesium concentration expressed as log10. In the kidney, no such effect was observed. The response of sodium concentration in these two tissues to increasing dietary pyridoxine, also expressed as log,0, was curvilinear, decreasing to minimum concentrations at pyridoxine intakes estimated to be equal to 40 mg./kg. of diet for the liver and 50 for the kidney and thereafter increasing. Potassium concentration of the liver exhibited opposite trends to those for sodium concentration but the responses to dietary magnesium were not consistent at each dietary pyridoxine concentration. Kidney potassium content followed essentially opposite trends to those of sodium. Kidney calcium decreased with increases in either dietary magnesium or pyridoxine, but the decreases were not consistent. The magnesium content of the kidney tended to increase with increases in dietary magnesium. Dietary pyridoxine resulted in a curvilinear response only in those chicks fed the 1875 mg. diet, decreasing to a minimum value at a pyridoxine intake of 26 mg., and increasing at higher pyridoxine dietary concentrations. No significant effects on sodium, potassium, calcium and magnesium concentrations in the heart were observed. It was speculated that the maximum potassium retention estimated to occur in the livers of birds consuming a diet containing 48 mg. pyridoxine/kg. diet might be due to increased glycogen turnover or increased phosphorylase activity. POULTRY SCIENCE 55: 1187-1194, 1976
INTRODUCTION HERE appears to be a belief among proponents of megavitamin therapy and some nutritionists that massive doses of the B-vitaminsare safe. Rimland(1973)has stated that "it is widely accepted that with the exception of vitamins A and D, fat soluble vitamins that are not readily excreted, there is no serious toxicity problem even when vitamins are taken in very large quantities."
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1. Scientific contribution no. 621, Storrs Agricultural Experiment Station, The University of Connecticut, Storrs, Conn. 06268.
Boger et al. (1973) have mentioned that "with water-soluble vitamins, overdoses are wasteful but not harmful because the excess is excreted in the urine." Ellis and Presley (1973) have concluded that "one may safely give 50 to 450 mg. of pyridoxine daily and up to 1000 mg. daily for short intervals for 3 to 5 days during hospital confinement for delivery." However, Cohen et al. (1973) have warned that since striking changes in metabolism resulted from megadoses of pyridoxine, further studies are needed before assuming that massive doses of water-soluble vitamins can be used with impunity. A relationship has been established be-
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GBASAY ROGERSON AND E . P. SINGSEN
Department of Nutritional Sciences, University of Connecticut, Storrs, Connecticut 06268