Department of Animal Production, Faculty of Agriculture and Environmental Studies, Université Evangélique en Afrique (UEA), Bukavu, Congo; Department of Public Health, Pharmacology and Toxicology, Faculty of Veterinary Medicine, University of Nairobi, P. O. Box 29053-00625, Nairobi, Kenya.
Department of Veterinary Anatomy and Physiology, Faculty of Veterinary Medicine, University of Nairobi, P.O Box 30197-00100, Nairobi, Kenya.
J Therm Biol. 2021 Jan;95:102780. doi: 10.1016/j.jtherbio.2020.102780. Epub 2020 Nov 25.
The present study investigated the effects of heat stress on oxidative stress status and physiological changes using female New Zealand White rabbits. 24 sexually mature female rabbits weighing 1953.1-2375.4 g were divided into 4 groups of 6 animals each and subjected to ambient temperature (T0: 19-26 °C), 27-28 °C for T1, 31-32 °C for T2 and 35-36 °C for T3 using electrical heaters from 8:00 a.m. to 4:00 p.m. daily for 30 days. Feed intake and body weight gain were recorded daily. Behavioral alterations of anxiety, dizziness, aggression, withdrawal, impaired feed intake were observed. At the end of experimental period animals were sacrificed, blood samples and vital organs such as liver, kidney, heart, ovaries, uterus collected for appropriate analysis. Results revealed that animals of T2 and T3 had an 11% decrease in the final body weights and 62% body weight gain but increase in feed conversion ratio by 64.81%, 24.19% water intake, 3.64% in rectal and 2.42% in skin temperature compared to the control. Dizziness, withdrawal to a corner of the cage and reduced feed intake were observed. The live weight of lungs and kidneys increased by 37.71% and 33.78% while that of ovaries and uterus decreased in the same animals of T2 and T3. Animals from T2 and T3 showed significant decrease (p < 0.05) by 23.64% in hemoglobin concentration, 12.73% in red blood cells, 11.93% in packed cell volume, 12.02% in total protein while mean corpuscular volume, white blood cells, lymphocytes, creatinine, urea and aspartate transaminase increased respectively by 10.73%, 42.37%, 15.53%, 28.98%, 53.2% and 23.31% compared to the control. The kidney level of malondialdehyde was significantly increased in T2 and T3 animals by 74.29%, whereas protein, catalase, superoxide dismutase and glutathione peroxidase activity were significantly lower (p < 0.05) compared with control. It was concluded that long-term exposure of female rabbits to elevated ambient temperatures induces heat stress and accompanying oxidative stress that consequently impairs physiological function.
本研究旨在探讨热应激对雌性新西兰白兔的氧化应激状态和生理变化的影响。将 24 只性成熟雌性新西兰白兔（体重 1953.1-2375.4g）随机分为 4 组，每组 6 只，分别暴露于环境温度（T0：19-26°C）、27-28°C（T1）、31-32°C（T2）和 35-36°C（T3），每天上午 8 点至下午 4 点使用电加热器加热，持续 30 天。记录每日采食量和体重增加情况。观察焦虑、头晕、攻击性、回避、采食量减少等行为改变。实验结束时，处死动物，采集血液样本和重要器官（肝、肾、心、卵巢、子宫）进行适当分析。结果显示，T2 和 T3 组动物的终体重分别下降 11%，体重增加 62%，但饲料转化率增加 64.81%，饮水量增加 24.19%，直肠温度增加 3.64%，皮肤温度增加 2.42%。与对照组相比，观察到头晕、回避到笼子一角和采食量减少。T2 和 T3 组动物的肺和肾脏重量分别增加 37.71%和 33.78%，而卵巢和子宫重量则减少。T2 和 T3 组动物的血红蛋白浓度、红细胞计数、红细胞压积、总蛋白分别显著下降（p<0.05），分别为 23.64%、12.73%、11.93%和 12.02%，而平均红细胞体积、白细胞、淋巴细胞、肌酐、尿素和天冬氨酸转氨酶分别增加 10.73%、42.37%、15.53%、28.98%、53.2%和 23.31%。T2 和 T3 组动物肾脏丙二醛水平显著升高，达 74.29%，而蛋白质、过氧化氢酶、超氧化物歧化酶和谷胱甘肽过氧化物酶活性则显著降低（p<0.05）。综上所述，雌性兔长期暴露于高温环境中会导致热应激和伴随的氧化应激，进而损害生理功能。
