Pak J Biol Sci. 2021 Jan;24(2):268-273. doi: 10.3923/pjbs.2021.268.273.
Exposure of breeder hens to hyperthermia causes disturbances in the breeder's eggs due to insufficient nutrient deposition from heat-stressed hen into the egg. Therefore, this experiment was conducted to test the hypothesis that the adverse effects of heat stress on hatchability, embryonic growth and hatchling health status could be ameliorated by in ovo injection of certain vitamins.
A total of 270 fertile eggs from Fayoumi breeders (45 weeks) were randomly assigned to 6 groups (45 eggs/group). During the egg collection period in the summer season, birds were maintained at 9-13°C above the standard thermo-neutral temperature. The experimental groups were: negative control (eggs not injected either with vitamins or Sterile Deionized Water (SDW)), positive control (eggs injected with 0.1 mL of SDW/egg) and four other treatments in which vitamins A, E, D3 and folic acid were injected (1 mg of each vitamin dissolved in 0.1 mL of SDW/egg). The eggs were incubated at 37.7°C and 65% relative humidity in an automatic incubator.
The residual yolk, embryo length and weight and hatchability% were improved (p<0.01) in all vitamins in ovo injected groups compared with both controls. Hatchling weight and the assessed health status indices were increased (p<0.01) in all vitamins in ovo injected groups compared with both controls.
It is concluded that direct injection of vitamins into eggs laid by heat-stressed breeders is an effective way of reducing the disturbance in eggs resulting from inadequate nutrient deposition from hen to egg.
种母鸡暴露在高温下会导致种蛋出现问题，这是因为热应激母鸡向蛋中沉积的营养不足。因此，本实验旨在验证以下假设，即在种蛋中注射某些维生素可以减轻热应激对孵化率、胚胎生长和雏鸡健康状况的不利影响。
本研究共选用 270 枚法尤米种母鸡（45 周龄）的受精蛋，随机分为 6 组（每组 45 枚）。在夏季种蛋收集期间，鸡舍温度比标准热中性温度高 9-13°C。实验组包括：阴性对照组（未注射维生素或无菌去离子水的蛋）、阳性对照组（注射 0.1 mL 无菌去离子水/枚的蛋）和另外 4 个处理组，分别在蛋中注射维生素 A、E、D3 和叶酸（每种维生素 1mg 溶解在 0.1 mL 无菌去离子水中）。鸡蛋在自动孵化器中以 37.7°C 和 65%的相对湿度孵化。
与对照组相比，所有注射维生素的实验组的蛋黄残留量、胚胎长度和重量以及孵化率均有显著提高（p<0.01）。与对照组相比，所有注射维生素的实验组的雏鸡体重和评估的健康状况指标均有显著提高（p<0.01）。
综上所述，直接向热应激母鸡所产蛋中注射维生素是一种减少因母鸡向蛋中沉积的营养不足而导致蛋内问题的有效方法。
