The Preferred Environmental Temperature of Newborn Rabbits

Hull, D; Hull, Jeremy; Vinter, J.

doi:10.1159/000242616

Cited by 23 publications

(9 citation statements)

References 9 publications

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“…To measuire the preferred thermal environment the rabbits were placed on a thermal gradient, the design and construction of which have previously been described (Hull, Hull & Vinter, 1986). The overall (limensions of the apparatus are 122 cm (length).…”

Section: Methodsmentioning

confidence: 99%

“…As the environmental temperature increases beyond the point where extra mechanisms to increase heat loss fail and the body temperature rises, so it is argued will the metabolic rate. This rise in metabolic rate beyond the upper end of the range of thermal control is seen in newborn rabbits (Hull et al 1986). A high body temperature beyond the range of their thermoregulatory control may be stressful to the animal in a non-specific way and this in itself may cause a rise in the rate of oxygen consumption.…”

Section: The Qlo Effectmentioning

confidence: 99%

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The effect of endotoxin‐induced fever on thermoregulation in the newborn rabbit.

Hull

Vinter

McIntyre

1993

The Journal of Physiology

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SUMMARY1. Metabolic responses of endotoxin-injected newborn rabbits were measured in a closed circuit calorimeter at a constant environmental temperature within their thermoneutral range. Oxygen consumption and colonic temperatures were then measured over a range of environmental temperatures from 21-0 to 40 0°C and the responses of endotoxin-injected rabbits compared with non-injected litter mates.2. To measure their preferred thermal environment, endotoxin-injected and noninjected litter mates were allowed to settle on a thermal gradient and their colonic temperatures measured.3. In a constant environmental temperature of 37°C, rises in oxygen consumption and colonic temperature following endotoxin injection were found to be biphasic.Oxygen consumption rose from 21 ml kg-' min-1 to a maximum 35 ml kg-1 minand colonic temperature rose from 39 0 to 39 8 'C.4. The maximal rate of oxygen consumption was the same in both injected and non-injected animals, 53 ml kg-1 min-', being provoked at the same environmental temperature of 24 'C. Minimal rates of oxygen consumption were also similar for the two groups but in the injected animals they were achieved at an environmental temperature of 39°C, 2 'C higher than for non-injected animals.5. We conclude that newborn rabbits challenged with a pyrogen have both behavioural and physiological responses. The thermogenic response is consistent with a change in sensitivity to feedback information rather than a simple shift in the central thermoregulatory set point. We find no evidence to support the view that in the febrile response a higher body temperature necessitates an increase in metabolic rate, the so-called Q1o effect.

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Section: Methodsmentioning

confidence: 99%

Section: The Qlo Effectmentioning

confidence: 99%

The effect of endotoxin‐induced fever on thermoregulation in the newborn rabbit.

Hull

Vinter

McIntyre

1993

The Journal of Physiology

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“…One might speculate, however, that the maternal hypothermic response to infectious stimuli modulates the subsequent generation of proinflammatory cytokines, which may place the fetus at risk for brain injury, particularly when coupled with the asphyxia of parturition (12,28,45). Lastly, Hull et al (24) have provided evidence that newborn rabbits select ambient temperatures that mimic their intrauterine experience and regulate their Tc to a level of ϳ0.8°C above the maternal bodycore temperature on the day prior to delivery (i.e., at a level similar to that which they experienced late in fetal life). Thus, it is also possible that an altered cytokine and maternal febrile response to infection may influence central nervous system thermoregulatory "imprinting" for the newborn.…”

Section: Perspectives and Significancementioning

confidence: 99%

Metyrapone restores the febrile response to Escherichia coli LPS in pregnant rats

Alexander

Fewell

2011

American Journal of Physiology-Regulatory, Integrative and Comp

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Alexander BN, Fewell JE. Metyrapone restores the febrile response to Escherichia coli LPS in pregnant rats. Am J Physiol Regul Integr Comp Physiol 300: R1588 -R1595, 2011. First published April 13, 2011 doi:10.1152 doi:10. /ajpregu.00785.2010 an important component of the host's defense response to immune challenge, is absent or attenuated in rats near the term of pregnancy. The present experiments were carried out to determine the role of endogenous glucocorticoids in mediating the altered core temperature (Tc) response to exogenous pyrogen (i.e., Escherichia coli LPS). For the experiments, metyrapone-a glucocorticoid synthesis inhibitor-was administered to near-term pregnant rats prior to an EC100 dose of E. coli LPS. Administration of LPS following vehicle elicited a significant corticosterone response and resulted in a decrease in Tc (i.e., hypothermia). Prior administration of metyrapone, however, which abolished the corticosterone response and altered the pyrogenic/ cryogenic cytokine response to LPS, eliminated hypothermia and restored the febrile response. Our results provide evidence that endogenous glucocorticoids play a role in mediating the altered febrile response to immune stimuli observed in rats near the term of pregnancy.glucocorticoids; hypothermia; infection NUMEROUS PHYSIOLOGICAL CHANGES accompany the maternal adaptation to pregnancy in rats, including reversible changes in blood hormone concentrations (e.g., corticosterone) and basal thermoregulatory control, as well as the cytokine, prostanoid, and Tc responses to immune challenge (4,17,19,21,34). For example, Fofie and Fewell (21) observed that Tc responses to intraperitoneal administration of 160 g/kg Escherichia coli LPS (EC 100 in nonpregnant rats) are different in pregnant rats as early as day 10 of the 21-day gestational period compared with nonpregnant oophorectomized rats. In nonpregnant rats, 160 g/kg E. coli LPS elicits an increase in Tc (i.e., a fever) with a latency, magnitude, and duration of 1.5 h, 1.9°C, and at least 4.5 h, respectively (21). Accompanying the febrile response are significant increases in plasma IL-1␤, IL-6, TNF-␣, and IL-1ra (22). In pregnant rats, however, 160 g/kg E. coli LPS elicits a "regulated" decrease in Tc (i.e., hypothermia)-the magnitude and duration of which increase with increasing LPS dose and gestation-before a modest increase in Tc above baseline is recorded (21, 52); accompanying the hypothermia are significant increases in plasma TNF-␣, and IL-ra, but not IL-1␤ and IL-6 (22). The mechanism and consequences for the mother and fetus of this altered thermoregulatory component of the acute phase response remain largely unknown.It has long been known that glucocorticoids have an antipyretic action on natural fevers in man (27), and Coelho et al.(13) and Morrow et al. (38) have shown that endogenous glucocorticoids modulate bacterial pyrogen-induced fever in male rats. Furthermore, Moore and Fewell (36) have recently shown that oral administration of mifepristone (RU38486)-a progesterone and gl...

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“…The effect of high ambient temperature on kits is different from the adult rabbits, because they born hairless, so their optimal ambient temperature is higher, around 38°C at birth and 30°C at 14 days of age (Hull et al, 1986). This is why 23 °C could be warm for does, but at the same time it could be cold for kits.…”

Section: Kits' Performancementioning

confidence: 99%

Effect of ambient temperature and restricted feeding on the production of rabbit does and their kits

Szendrő

Papp

Kustos

2018

AAK

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Thirty-six lactating New Zealand White rabbit does were divided into 6 groups according to ambient temperature and feed intake. The does were kept at 20 °C during pregnancy and at kindling, then they were put into climatic chambers at temperatures of 5, 15, 23 or 30 °C. One part of the does were fed ad libitum (5A, 15A, 23A and 30A), two other groups were housed at 15 °C, but they received the same amount of pellet as the does' intake at 23 °C or 30 °C (15/23R and 15/30R). The litter sizes were equalized to seven. The weight of does, milk production, feed intake and water intake were recorded daily. Heat stress reduced milk yield (148, 152, 150 and 106 g/day), feed intake (287, 279, 260 and 179 g/day) and water intake (497, 512, 526 and 428 g/day), but increased the water/feed ratio (1.73, 1.84, 2.02 and 2.39) in the groups of 5A, 15A, 23A and 30A, respectively. Body weight of does decreased at 23 °C and 30 °C by 5.6% and 8.5%, respectively, compared to 15 °C. Comparing the groups of rabbits kept at 23 °C and 30 °C fed ad libitum (23A and 30A) and the data obtained for groups of 15/23R and 15/30R it was observed that the milk yield decreased by 8.0% and 2.5%, water intake increased by 8.6 and 13.3%, and the feed/water ratio was higher by 0.18 and 0.18, respectively. The effect of heat stress was less significant on kits than on does. It can be concluded that the high ambient temperature mainly affected the milk production through the reduction of feed intake.

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The Preferred Environmental Temperature of Newborn Rabbits

Cited by 23 publications

References 9 publications

The effect of endotoxin‐induced fever on thermoregulation in the newborn rabbit.

The effect of endotoxin‐induced fever on thermoregulation in the newborn rabbit.

Metyrapone restores the febrile response to Escherichia coli LPS in pregnant rats

Effect of ambient temperature and restricted feeding on the production of rabbit does and their kits

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