Institute of Animal Science, Agricultural Research Organization (ARO), the Volcani Center, 68 HaMakkabbim Road, Rishon Le Ziyyon P.O.Box 15159, Israel.
Faculty of Agriculture Food and Environment, The Hebrew University, Rehovot 76100, Israel.
Poult Sci. 2018 Jun 1;97(6):1961-1967. doi: 10.3382/ps/pey052.
The prenatal circulatory system is adaptive and capable of plasticity designed for the needs of the growing tissue. When a broiler embryo is faced with hypoxic stress, the process of angiogenesis in tissues begins. Exposure to hypoxic conditions of 17% oxygen during the chorioallantoic membrane (CAM) development (E5 to E12) affected the circulatory system and contributed to an increase in the blood oxygen carrying capacity. The present study aimed to evaluate the effects of hypoxic exposure during CAM development on post-hatch performance of broilers and to examine whether hypoxic exposure improved sustainability of birds exposed to acute heat stress.Two consecutive trials, with male broilers from each of the incubation treatments-optimal conditions and exposure to hypoxia of 15 or 17% oxygen, for 12 h/day, during CAM development-were conducted. In experiment 1, 60 male chicks from each group were raised in individual cages. In experiment 2, 160 male chicks from each group were raised in 40-chick pens until marketing. On d 35, 20 birds from each group were transferred to individual cages kept at a temperature of 23°C for 72 h, and then birds were exposed to 35°C for 5 hours. Body temperatures were measured at 0, 2, and 5 h of the heat exposure. In both experiments BW, feed intake, and FCR were recorded. At marketing, chicks were slaughtered, and relative weights of breast muscle, abdominal fat pad, heart, and liver were calculated.Hypoxia treatment resulted in a FCR advantage. Food intake was similar in all treatments, but groups exposed to hypoxia grew better than controls until the age of 35 days. Hypoxia-treated groups had higher relative breast, heart, and liver weights than controls. Body temperatures of hypoxia-treated chickens remained lower during heat stress exposure, and their mortality rate was lower as well. Intermittent exposure to moderate hypoxia during CAM development confers advantages to broilers in feed utilization efficiency and in coping with heat stress. It may be considered as a mitigating step in incubation to facilitate broilers in achieving their full growth potential.
胎儿循环系统具有适应性和可塑性，旨在满足不断生长的组织的需求。当肉鸡胚胎面临低氧应激时，组织中的血管生成过程开始。在绒毛尿囊膜（CAM）发育期间（E5 至 E12）暴露于 17%氧气的低氧条件下，影响了循环系统，并导致血液携氧能力增加。本研究旨在评估 CAM 发育期间低氧暴露对肉鸡孵化后性能的影响，并研究低氧暴露是否改善了暴露于急性热应激的鸟类的可持续性。进行了两项连续试验，试验鸡来自于孵化处理-最佳条件和在 CAM 发育期间每天 12 小时暴露于 15%或 17%氧气的低氧-的连续孵化处理，每组孵化鸡各 60 只，在单独的笼子中饲养。在试验 2 中，每组孵化鸡各 160 只在 40 只鸡的鸡笼中饲养，直到上市。在第 35 天，每组的 20 只鸡被转移到单独的笼子中，保持在 23°C 的温度下 72 小时，然后暴露于 35°C 5 小时。在热暴露的 0、2 和 5 小时测量体温。在两个试验中都记录了体重、采食量和饲料转化率。上市时，鸡被屠宰，计算胸肌、腹脂垫、心脏和肝脏的相对重量。低氧处理导致饲料转化率优势。所有处理组的采食量相似，但暴露于低氧的组比对照组生长更好，直到 35 日龄。低氧处理组的胸肌、心脏和肝脏的相对重量高于对照组。在热应激暴露期间，低氧处理鸡的体温保持较低，死亡率也较低。CAM 发育期间间歇性暴露于适度低氧可为肉鸡提供饲料利用效率和应对热应激的优势。它可以被认为是孵化中的一种缓解措施，有助于肉鸡充分发挥其生长潜力。
