Physiology of Animal and Poultry Department, Animal and Poultry Production Division, Desert Research Center, Cairo, Egypt.
Botany Department, Faculty of Science, Damanhour University, Damanhour, Egypt.
J Therm Biol. 2020 Apr;89:102561. doi: 10.1016/j.jtherbio.2020.102561. Epub 2020 Feb 27.
Heat stress (HS) is the most potent environmental stressors for livestock in tropical and subtropical regions. HS induced splanchnic tissue hypoxia and intestinal oxidative damage, leading to endotoxemia and systemic inflammation. The present study evaluated and compared the modulatory effects of feeding Barki male sheep (Ovis aries) on a standard concentrated diet containing 2% or 4% of the brown seaweed (Sargassum latifolium) followed by roughage for 40 consecutive days on the toxicity-induced by exposure to severe environmental HS (temperature-humidity index = 28.55 ± 1.62). The present study showed that the diet containing Sargassum latifolium (especially 4%) modulated significantly (P < 0.05-0.001) almost all changes shown in the HS-exposed sheep including the increase in the thermo-respiratory responses (skin and rectal temperatures, and respiration rate) and the resulted dyslipidemia, anemia, and systemic inflammation (blood leukocytosis, the elevation in the erythrocyte sedimentation rate, and the increase in serum proinflammatory cytokines and heat shock protein-70 concentrations). In addition, Sargassum latifolium improved significantly (P < 0.05-0.001) the body-weight gain, kidney functions (especially at the high dose), and blood antioxidant defense system (total antioxidant capacity, and the activities of catalase and superoxide dismutase) in the HS-exposed sheep, as well as protected the animals from oxidative tissue damage and the risk of atherosclerosis. In conclusion, feeding sheep with the diet containing 4% of Sargassum latifolium was safe and suitable for animal nutrition, as well as efficiently alleviated the harmful effects of the environmental HS in Barki sheep through improving the animal antioxidant defense system, and regulating the thermo-respiratory and inflammatory responses.
热应激（HS）是热带和亚热带地区家畜最强烈的环境胁迫因素。HS 导致内脏组织缺氧和肠道氧化损伤，导致内毒素血症和全身炎症。本研究评估并比较了在连续 40 天内给雄性巴克里羊（Ovis aries）喂食标准浓缩饲料（含 2%或 4%的褐藻（Sargassum latifolium）），然后再喂粗饲料对暴露于严重环境 HS（温湿度指数=28.55±1.62）引起的毒性的调节作用。本研究表明，含 Sargassum latifolium（尤其是 4%）的饮食显著调节（P<0.05-0.001）了 HS 暴露羊的几乎所有变化，包括热呼吸反应（皮肤和直肠温度、呼吸率）的增加以及由此导致的血脂异常、贫血和全身炎症（白细胞增多、红细胞沉降率升高以及促炎细胞因子和热休克蛋白-70 浓度增加）。此外，Sargassum latifolium 显著改善（P<0.05-0.001）了 HS 暴露羊的体重增加、肾功能（尤其是高剂量）和血液抗氧化防御系统（总抗氧化能力以及过氧化氢酶和超氧化物歧化酶的活性），并保护动物免受氧化组织损伤和动脉粥样硬化的风险。总之，给羊喂食含 4% Sargassum latifolium 的饮食是安全且适合动物营养的，并且通过改善动物抗氧化防御系统以及调节热呼吸和炎症反应，有效地缓解了 Barki 羊环境 HS 的有害影响。
