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British Poultry Science Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/cbps20
Effect of diurnal or nocturnal heat stress on egg formation a
a
a
D. Wolfenson , Yael F. Frei , N. Snapir & A. Berman
a
a
Department of Animal Science, Faculty of Agriculture , The Hebrew University of Jerusalem , Rehovot, Israel Published online: 08 Nov 2007.
To cite this article: D. Wolfenson , Yael F. Frei , N. Snapir & A. Berman (1979) Effect of diurnal or nocturnal heat stress on egg formation, British Poultry Science, 20:2, 167-174, DOI: 10.1080/00071667908416565 To link to this article: http://dx.doi.org/10.1080/00071667908416565
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://www.tandfonline.com/page/termsand-conditions
Br. Poult. Set., 20: 167-174. 1979
Longman: printed in Great Britain
EFFECT OF DIURNAL OR NOCTURNAL HEAT STRESS ON EGG FORMATION D. WOLFENSON, YAEL F. FREI, N. SNAPIR AND A. BERMAN Department of Animal Science, Faculty of Agriculture, The Hebrew University of Jerusalem, Rehovot, Israel
Downloaded by [] at 08:09 30 December 2014
Received for publication 25th April 1978
1. Mature laying hens were subjected to ambient temperatures sufficient to maintain body temperature of 43 °C for periods of 6 to 7 h during the day (eight periods) or the night (five periods). This did not reduce total daily food consumption. 2. The effect of heat stress during the day was mostly on egg-shell quality, being adverse and significant. During the night heat stress caused a significant decrease in egg production, its effect during the day was less marked in this respect. 3. Heat stress thus seems mostly to affect the early stages of shell formation, while its effect on egg production seems to depend on the time at which it occurs in relation to ovulation. 4. These results suggest that egg production is directly affected by heat stress; prolonged heat stress probably also acts indirectly, by suppression of food intake. INTRODUCTION
The relationship between ambient temperature and egg formation and production has been much studied. Decreased egg production and weight and shell thickness have been reported to result from natural and experimentally-produced high temperatures (e.g. Bennion and Warren, 1933; Payne, 1966; Wilson et al., 1972). These changes were generally accompanied by decreased food intake. It has thus been supposed that the decrease in food intake is the primary response. In some studies increasing the nutrient concentration of the food diet did partially counteract the effect of high temperature on egg production and shell thickness (Mowbray and Sykes, 1971; de Andrade et al., 1976), although it has been claimed that there is a direct effect of high temperature on egg production, which cannot be reversed by concentrating the diet (Mueller, 1967). A method of distinguishing between a direct effect of heat on egg production and an indirect effect due to decreased food intake is to use periods of heat stress too short to allow expression of effects of decreased food intake. Such short exposures would also prevent the complication of acclimation. A distinction between direct and indirect effects would be unlikely in studies in which the lower air temperature coincided with the dark period, during which little if any food is ingested (Miller and Sunde, 1975; de Andrade et al., 1977). Studies in 167
1 68
D. WOLFENSON, YAEL F. FREI, N. SNAPIR AND A. BERMAN
which birds were exposed to heat stress for 24 to 36 h would be more likely to indicate a direct effect of heat on egg production. Exposure of fowls to 38 °C for about 24 h resulted in decreased egg production and weight and egg-shell quality and food intake for 1 to 2 d (Campos et al., 1960). Similar effects have been noted during the 1st day after transfer to high temperature whether cyclic or constant (Harrison and Biellier, 1969; Miller and Sunde, 1975). Yolk formation is essentially a continuous process, while oviposition, ovulation and formation of other egg components are discrete events within the cycle. It is thus possible that the latter events are more susceptible to temperature extremes within the 24-h cycle. It was the aim of this study to examine the effects of high ambient temperature imposed at different times during the 24-h cycle on egg formation and production. MATERIALS AND METHODS
Downloaded by [] at 08:09 30 December 2014
Animals
Twenty-four White Leghorn x Rhode Island Red cross-bred hens, 10 months of age at the start were used for a period of 5 months. The birds were individually caged in a small insulated light-proof poultry house, artificial light was provided for 15 h/d (04.00 to 19.00 h). They were fed on a proprietary breeder mash ad libitum. Oviposition times were determined using an event recorder (Rustrak 4392) activated via microswitches by a ruler located in the path of a rolling egg. The experiments started in February 1977 and ended in July 1977. During this period ambient temperatures in the poultry house ranged from 13 to 27 °C. Treatments
All the experimental birds were exposed to high temperature during either the day or the night. During the day high temperature was imposed from 10.00 to 16.00 h, during the night from 20.00 to 03.00 h. In total there were eight periods of heat exposure during the day and five during the night. The shortest time between two consecutive high temperature exposures was 1 week; which allowed for recovery from high temperature exposure, as indicated by return to normal egg production. The insulated chamber was heated by thermostatically-controlled fan heaters. Ambient temperature is often used to define heat load; it does not account, however, for the nychthemeral fluctuation in metabolic rate (Berman and Meltzer, 1978) nor for the modifying effect of acclimation (Whittow, 1976). For these reasons we used, as an index of heat load, the body temperature at which continuous rapid first stage panting as defined by Frankel et al. (1962) occurred. This was found to be about 43 °C in preliminary tests and was similar during the day and night. This approach, in which the output of the thermoregulatory system represents the deviation from the regulated temperature, is consistent with current concepts of thermoregulation (Bligh, 1973). Room temperature was therefore increased rapidly until the birds spread their wings and started panting, which occurred at ambient temperatures between 34 and 40 °C, and the temperature was then set to maintain continuous panting. If a colonic temperature of more than 44 °C was found, which occurred in 11 cases of the 312 tests made, the fowls were removed from the heated
HEAT STRESS AND EGG FORMATION
169
chamber and were returned to it after body temperature had decreased to less than 43 °C The mean (±SD) colonic temperature during heat exposures was 43-01 + 0-70 °C. Mean relative humidity during the heat exposures was 35 ± 9%. At night observations were made using a small torch lit for a few seconds at a time. Body temperature measurements were therefore limited to five or six birds every 1 to 2 h. After completion of a high temperature period, ambient temperature returned to normal within 30 min. The birds usually fed normally during the first 3 h of high temperature exposure during the day. When panting became continuous, the birds stopped eating. Feeding resumed within 1 h of cessation of heating.
Downloaded by [] at 08:09 30 December 2014
Measurements
Egg production was measured throughout the 5-month period. More detailed observations were carried out during each experimental period. These observations started 1 d prior to the high temperature exposure and were continued for 5 d. Exposure to high temperature was carried out on day 2 or on the night between days 2 and 3. Egg, shell and albumen weights were measured on all eggs laid during experimental periods. Before weighing the eggs were stored at 20 CG. Egg shells (including membranes) were weighed after drying at 105 °C for 2 h. Shell quality was assessed by weight per unit surface area (Mueller and Scott, 1940). Blood samples were drawn from the brachial vein in control and heated birds (within minutes of completion of heating), after which the fowls were killed to determine the position of the egg in the oviduct. Birds were also bled and killed in two subsequent experiments to determine the effect of heat exposure at night (one trial, 10 birds) and day (two trials, 10 fowls each) on food consumption. Total calcium in plasma was determined (Diehl and Ellingboe, 1956). Data analysis
Statistical analysis was carried out by the Duncan's multiple range test (Snedecor and Cochran, 1971).
RESULTS
Egg production
Mean egg productions for exposure to heat during the day and the night are shown in the Fig. The 4 days before heat was applied and the day on which heat was applied served as control periods. Egg production was not significantly affected by heat exposure during the day, most of the eggs having been laid before the start of the treatment (10.00 h). Production was 82*6 eggs/100 bird-d during the control period and decreased to 74-0 eggs/100 bird-d 2 days (day 4) after heat exposure. Egg production reverted to normal 2 days later. Two days after exposure to heat in the night (d 4) egg production decreased from 83-6 (control period) to 68-0 eggs/ 100 bird'd. The difference between d 3 and d 4 was statistically significant (P
British Poultry Science Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/cbps20
Effect of diurnal or nocturnal heat stress on egg formation a
a
a
D. Wolfenson , Yael F. Frei , N. Snapir & A. Berman
a
a
Department of Animal Science, Faculty of Agriculture , The Hebrew University of Jerusalem , Rehovot, Israel Published online: 08 Nov 2007.
To cite this article: D. Wolfenson , Yael F. Frei , N. Snapir & A. Berman (1979) Effect of diurnal or nocturnal heat stress on egg formation, British Poultry Science, 20:2, 167-174, DOI: 10.1080/00071667908416565 To link to this article: http://dx.doi.org/10.1080/00071667908416565
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://www.tandfonline.com/page/termsand-conditions
Br. Poult. Set., 20: 167-174. 1979
Longman: printed in Great Britain
EFFECT OF DIURNAL OR NOCTURNAL HEAT STRESS ON EGG FORMATION D. WOLFENSON, YAEL F. FREI, N. SNAPIR AND A. BERMAN Department of Animal Science, Faculty of Agriculture, The Hebrew University of Jerusalem, Rehovot, Israel
Downloaded by [] at 08:09 30 December 2014
Received for publication 25th April 1978
1. Mature laying hens were subjected to ambient temperatures sufficient to maintain body temperature of 43 °C for periods of 6 to 7 h during the day (eight periods) or the night (five periods). This did not reduce total daily food consumption. 2. The effect of heat stress during the day was mostly on egg-shell quality, being adverse and significant. During the night heat stress caused a significant decrease in egg production, its effect during the day was less marked in this respect. 3. Heat stress thus seems mostly to affect the early stages of shell formation, while its effect on egg production seems to depend on the time at which it occurs in relation to ovulation. 4. These results suggest that egg production is directly affected by heat stress; prolonged heat stress probably also acts indirectly, by suppression of food intake. INTRODUCTION
The relationship between ambient temperature and egg formation and production has been much studied. Decreased egg production and weight and shell thickness have been reported to result from natural and experimentally-produced high temperatures (e.g. Bennion and Warren, 1933; Payne, 1966; Wilson et al., 1972). These changes were generally accompanied by decreased food intake. It has thus been supposed that the decrease in food intake is the primary response. In some studies increasing the nutrient concentration of the food diet did partially counteract the effect of high temperature on egg production and shell thickness (Mowbray and Sykes, 1971; de Andrade et al., 1976), although it has been claimed that there is a direct effect of high temperature on egg production, which cannot be reversed by concentrating the diet (Mueller, 1967). A method of distinguishing between a direct effect of heat on egg production and an indirect effect due to decreased food intake is to use periods of heat stress too short to allow expression of effects of decreased food intake. Such short exposures would also prevent the complication of acclimation. A distinction between direct and indirect effects would be unlikely in studies in which the lower air temperature coincided with the dark period, during which little if any food is ingested (Miller and Sunde, 1975; de Andrade et al., 1977). Studies in 167
1 68
D. WOLFENSON, YAEL F. FREI, N. SNAPIR AND A. BERMAN
which birds were exposed to heat stress for 24 to 36 h would be more likely to indicate a direct effect of heat on egg production. Exposure of fowls to 38 °C for about 24 h resulted in decreased egg production and weight and egg-shell quality and food intake for 1 to 2 d (Campos et al., 1960). Similar effects have been noted during the 1st day after transfer to high temperature whether cyclic or constant (Harrison and Biellier, 1969; Miller and Sunde, 1975). Yolk formation is essentially a continuous process, while oviposition, ovulation and formation of other egg components are discrete events within the cycle. It is thus possible that the latter events are more susceptible to temperature extremes within the 24-h cycle. It was the aim of this study to examine the effects of high ambient temperature imposed at different times during the 24-h cycle on egg formation and production. MATERIALS AND METHODS
Downloaded by [] at 08:09 30 December 2014
Animals
Twenty-four White Leghorn x Rhode Island Red cross-bred hens, 10 months of age at the start were used for a period of 5 months. The birds were individually caged in a small insulated light-proof poultry house, artificial light was provided for 15 h/d (04.00 to 19.00 h). They were fed on a proprietary breeder mash ad libitum. Oviposition times were determined using an event recorder (Rustrak 4392) activated via microswitches by a ruler located in the path of a rolling egg. The experiments started in February 1977 and ended in July 1977. During this period ambient temperatures in the poultry house ranged from 13 to 27 °C. Treatments
All the experimental birds were exposed to high temperature during either the day or the night. During the day high temperature was imposed from 10.00 to 16.00 h, during the night from 20.00 to 03.00 h. In total there were eight periods of heat exposure during the day and five during the night. The shortest time between two consecutive high temperature exposures was 1 week; which allowed for recovery from high temperature exposure, as indicated by return to normal egg production. The insulated chamber was heated by thermostatically-controlled fan heaters. Ambient temperature is often used to define heat load; it does not account, however, for the nychthemeral fluctuation in metabolic rate (Berman and Meltzer, 1978) nor for the modifying effect of acclimation (Whittow, 1976). For these reasons we used, as an index of heat load, the body temperature at which continuous rapid first stage panting as defined by Frankel et al. (1962) occurred. This was found to be about 43 °C in preliminary tests and was similar during the day and night. This approach, in which the output of the thermoregulatory system represents the deviation from the regulated temperature, is consistent with current concepts of thermoregulation (Bligh, 1973). Room temperature was therefore increased rapidly until the birds spread their wings and started panting, which occurred at ambient temperatures between 34 and 40 °C, and the temperature was then set to maintain continuous panting. If a colonic temperature of more than 44 °C was found, which occurred in 11 cases of the 312 tests made, the fowls were removed from the heated
HEAT STRESS AND EGG FORMATION
169
chamber and were returned to it after body temperature had decreased to less than 43 °C The mean (±SD) colonic temperature during heat exposures was 43-01 + 0-70 °C. Mean relative humidity during the heat exposures was 35 ± 9%. At night observations were made using a small torch lit for a few seconds at a time. Body temperature measurements were therefore limited to five or six birds every 1 to 2 h. After completion of a high temperature period, ambient temperature returned to normal within 30 min. The birds usually fed normally during the first 3 h of high temperature exposure during the day. When panting became continuous, the birds stopped eating. Feeding resumed within 1 h of cessation of heating.
Downloaded by [] at 08:09 30 December 2014
Measurements
Egg production was measured throughout the 5-month period. More detailed observations were carried out during each experimental period. These observations started 1 d prior to the high temperature exposure and were continued for 5 d. Exposure to high temperature was carried out on day 2 or on the night between days 2 and 3. Egg, shell and albumen weights were measured on all eggs laid during experimental periods. Before weighing the eggs were stored at 20 CG. Egg shells (including membranes) were weighed after drying at 105 °C for 2 h. Shell quality was assessed by weight per unit surface area (Mueller and Scott, 1940). Blood samples were drawn from the brachial vein in control and heated birds (within minutes of completion of heating), after which the fowls were killed to determine the position of the egg in the oviduct. Birds were also bled and killed in two subsequent experiments to determine the effect of heat exposure at night (one trial, 10 birds) and day (two trials, 10 fowls each) on food consumption. Total calcium in plasma was determined (Diehl and Ellingboe, 1956). Data analysis
Statistical analysis was carried out by the Duncan's multiple range test (Snedecor and Cochran, 1971).
RESULTS
Egg production
Mean egg productions for exposure to heat during the day and the night are shown in the Fig. The 4 days before heat was applied and the day on which heat was applied served as control periods. Egg production was not significantly affected by heat exposure during the day, most of the eggs having been laid before the start of the treatment (10.00 h). Production was 82*6 eggs/100 bird-d during the control period and decreased to 74-0 eggs/100 bird-d 2 days (day 4) after heat exposure. Egg production reverted to normal 2 days later. Two days after exposure to heat in the night (d 4) egg production decreased from 83-6 (control period) to 68-0 eggs/ 100 bird'd. The difference between d 3 and d 4 was statistically significant (P
