Department of Animal Science, Faculty of Agriculture,University of Van Yüzüncü Yıl,65080 Van,Turkey.
Animal. 2018 Aug;12(8):1584-1593. doi: 10.1017/S1751731118000344. Epub 2018 Mar 6.
Hypoxia strongly affects embryonic development during the pre-hatch period. This study was conducted to investigate the effects of oxygen supplementation (O) and a 38.5°C high temperature (HT) at high altitude (HA, 1720 m) on morphological traits during a pre-hatch period and on relative fluctuating asymmetry (relative FA) and allometric growth during an early post-hatch period in broilers. A total of 720 eggs were obtained from a 45-week-old Ross 308 broiler breeder flock raised at sea level (2 m). The eggs were divided into six incubation condition (IC) groups and were incubated at HA. O groups were exposed to 23.5% O2 for 1 h daily from either days 0 to 11 (O0-11), days 12 to 21 (O12-21) or days 18 to 21 (O18-21) of incubation. HT groups were exposed to 38.5°C daily from either days 12 to 21 (HT12-21) or days 18 to 21 (HT18-21) of incubation. A control was maintained at 37.8°C and 21% O2. The hatched chicks were raised for 6 days at HA. Embryo/chick and beak lengths and head diameter were measured during pre- and post-hatch periods. The face, middle toe and shank lengths were measured for each chick. The relative asymmetry (RA), mean RA (MRA) and allometric growth of the lengths were computed and the existence of FA was demonstrated. The IC significantly affected the embryo length, with embryos of the O0-11 group shorter than embryos of the other O groups. Chicks were longer in the O and HT groups than those in the control, except for the O0-11. We found significant interactions between the IC and each development period for beak length. During the post-hatch period, the head diameter of the O0-11 was significantly smaller than that of the other groups, but not in O12-21. The interactions among IC, age and sex were significant for the RA of the face and middle toe lengths and for MRA. All the examined bilateral traits were evaluated as allometric growth. The FA for bilateral traits was determined in both sexes. The right (R) - left (L) and IR-Ll were the lowest in females for face length and in males for shank length from the O18-21 and in males for middle toe length from the O0-11 and HT18-21 groups. Therefore, the effects of factors such as HT and O2 could mitigate the adverse effects of HA-induced hypoxia on optimal developmental stability of bilateral traits of broiler.
缺氧强烈影响孵化前期的胚胎发育。本研究旨在探讨高海拔（1720 米）孵化期间氧补充（O）和 38.5°C 高温（HT）对肉鸡孵化前期形态特征的影响，以及孵化后期相对波动不对称（relative FA）和异速生长的影响。总共从一个 45 周龄罗斯 308 肉鸡种鸡群获得 720 个鸡蛋，在海平面（2 米）饲养。鸡蛋被分为六个孵化条件（IC）组，并在高海拔地区孵化。O 组在孵化的第 0 天至第 11 天（O0-11）、第 12 天至第 21 天（O12-21）或第 18 天至第 21 天（O18-21）每天暴露于 23.5%的 O2 1 小时。HT 组在孵化的第 12 天至第 21 天（HT12-21）或第 18 天至第 21 天（HT18-21）每天暴露于 38.5°C。对照组保持在 37.8°C 和 21%的 O2。孵化后，小鸡在高海拔地区饲养 6 天。在孵化前和孵化后期间测量胚胎/小鸡和喙的长度以及头部直径。为每个小鸡测量面部、中趾和小腿长度。计算相对不对称（RA）、平均 RA（MRA）和长度的异速生长，并证明 FA 的存在。IC 显著影响胚胎长度，O0-11 组的胚胎比其他 O 组的胚胎短。O 和 HT 组的小鸡比对照组的小鸡长，除了 O0-11 组。我们发现喙长在 IC 和每个发育阶段之间存在显著的相互作用。在孵化后期，O0-11 的头部直径明显小于其他组，但在 O12-21 中则不然。IC、年龄和性别的相互作用对面部和中趾长度的 RA 和 MRA 有显著影响。所有检查的双侧特征均被评估为异速生长。在两性中均确定了双侧特征的 FA。O18-21 组的雌性和 O0-11 和 HT18-21 组的雄性中，面部长度的右（R）-左（L）和 IR-Ll 最低，中趾长度的雄性最低。因此，HT 和 O2 等因素的影响可以减轻高海拔引起的缺氧对肉鸡双侧特征最佳发育稳定性的不利影响。
