Repeated thermal conditioning during the neonatal period affects behavioral and physiological responses to acute heat stress in chicks
Repeated thermal conditioning during the neonatal period affects behavioral and physiological responses to acute heat stress in chicks
复制标题
新生儿期的反复热调节会影响雏鸡对急性热应激的行为和生理反应
DOI：
10.1016/j.jtherbio.2020.102759
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发表时间：
2020
影响因子：
2.7
通讯作者：
Bungo Takashi
中科院分区：
文献类型：
--
作者：
Ouchi Yoshimitsu;Tanizawa Hiroshi;Shiraishi Jun-ichi;Cockrem John F.;Chowdhury Vishwajit S.;Bungo Takashi
本研究的目的是探讨重复热处理（RTC）在早期对鸡的生理和行为responses.MethodsBirds的影响被分配到四个处理之一，其中RTC暴露于40 °C，每天15分钟。处理为1）无热调节（对照）; 2）早期暴露组（EE; 2 - 4日龄RTC）; 3）晚期暴露组（LE; 5 - 7日龄RTC）;或4）早期和晚期暴露（BE; 2 - 7日龄RTC）。所有组的小鸡被挑战与高环境温度（40 °C，15分钟）在两周龄。ResultsDuring热挑战，消散行为（喘气和翅膀下垂）的起始时间进行了测量。分别于热应激前后测定直肠温度和呼吸频率。在热激发结束时收集下丘脑样品和血液。消散行为的起始时间和直肠温度不受处理的影响。早期RTC处理抑制了对热激发反应的呼吸速率增加。没有明确的模式，葡萄糖水平与热调节，而血浆皮质酮水平下降，早期治疗（EE和BE组）。下丘脑促甲状腺激素释放激素基因的表达受到抑制的早期和后期的热调节和抑制进一步的早期和后期曝光。神经肽Y基因的表达在BE组低于其他组，与促肾上腺皮质激素释放激素expression.ConclusionOur研究结果表明，反复热调节对中枢温度调节系统的影响取决于小鸡经历了空调的次数。此外，反复热调节有更大的影响时，空调发生在小鸡的2至4日龄的耐热性收购相比，小鸡的5至7日龄。
ObjectiveThe aim of the present study was to investigate the effects of repeated thermal conditioning (RTC) at an early age on physiological and behavioral responses in chicks.MethodsBirds were assigned to one of the four treatments in which the RTC was exposure to 40 °C for 15 min daily. The treatments were 1) no thermal conditioning (control); 2) early exposure group (EE; RTC from 2 to 4 days of age); 3) later exposure group (LE; RTC from 5 to 7 days of age); or 4) both early and later exposure (BE; RTC from 2 to 7 days of age). All groups of chicks were challenged with high ambient temperature (40 °C for 15 min) at two weeks of age.ResultsDuring heat challenge, initiation times of dissipation behaviors (panting and wing-drooping) were measured. Rectal temperature and respiration rate were measured after and before heat challenge. Hypothalamic samples and blood were collected at the end of heat challenges. Initiation times of dissipation behaviors and rectal temperature were not affected by the treatments. Increases in respiration rate in response to heat challenge were suppressed by early RTC treatment. There was no clear pattern of glucose levels in relation to thermal conditioning, whereas plasma corticosterone levels were decreased by early treatment (EE and BE groups). Hypothalamic thyrotropin releasing hormone gene expression was suppressed by early and later thermal conditioning and suppressed further by both early and later exposure. Neuropeptide Y gene expression in the BE group was lower than in the other groups, with a similar trend for corticotropin releasing hormone expression.ConclusionOur results suggest that the effect of repeated thermal conditioning on the central thermoregulatory system depends on the number of times that chicks experienced conditioning. In addition, repeated thermal conditioning has greater effects on the acquisition of thermotolerance when conditioning occurs in chicks of two to four days of age in comparison with chicks of five to seven days of age.