Tona K, Malheiros R D, Bamelis F, Careghi C, Moraes V M B, Onagbesan O, Decuypere E, Bruggeman V
Laboratory for Physiology and Immunology of Domestic Animals, Department of Animal Production, Faculty of Agricultural and Applied Biological Sciences, K.U. Leuven Kasteelpark Arenberg 30, B-3001 Leuven, Belgium.
Poult Sci. 2003 May;82(5):840-5. doi: 10.1093/ps/82.5.840.
Incubating eggs (1,800 total) produced by a commercial flock of Cobb broiler breeders were used to determine the effects of storage duration (3 and 18 d) on gas partial pressure, thyroid hormones, and hatching parameters. Partial pressure of oxygen (pO2) and carbon dioxide (pCO2) were measured on d 18 and at internal pipping (IP) during incubation. Blood samples were collected for determination of triiodothyronine (T3), thyroxine (T4), and corticosterone concentrations in the embryos at IP and in newly hatched chicks. From 464 to 510 h of incubation, eggs were checked individually every 2 h to determine the timing and duration of IP, external pipping (EP), and total hatching time. At 18 d of incubation and at IP, pCO2 was greater in air cell of eggs stored for 3 d compared to those stored for 18 d (P < 0.05), but pO2 was greater in eggs stored for 18 d. At IP, T3 and corticosterone levels were higher in plasma of the embryos of eggs stored for 3 d compared to those stored for 18 d, but it was the reverse in newly hatched chicks (P < 0.05). Embryos from eggs stored for 18 d required more time to complete IP compared to embryos of eggs stored for only 3 d (P < 0.05), whereas the duration of EP was not affected by storage. The overall longer incubation was, however, not only due to prolonged IP but also to later occurrence of IP. It was concluded that prolonged IP as a result of long storage may be related to the late increase in corticosterone level, which may be a necessary stimulus for higher T3/T4 ratio, late increase in pCO2 level, and decrease in pO2. The effect of long storage was a delay in hatching and a continuous increase in T3 due to higher corticosterone levels between IP and hatching, which may be an indication of the more stressful event of hatching of embryos from eggs stored longer. Differences in pCO2, pO2, T3, T4, and corticosterone levels in the incubating eggs may be manifestations of these changes culminating in altered hatching parameters and consequently differences in chick quality and growth potentials.
使用科宝肉鸡育种商用鸡群生产的1800枚种蛋来确定储存时间（3天和18天）对气体分压、甲状腺激素和孵化参数的影响。在孵化第18天和内部啄壳（IP）时测量氧气（pO2）和二氧化碳（pCO2）的分压。采集血液样本以测定胚胎在IP时以及新孵出雏鸡体内三碘甲状腺原氨酸（T3）、甲状腺素（T4）和皮质酮的浓度。在孵化464至510小时期间，每2小时对种蛋进行单独检查，以确定IP、外部啄壳（EP）的时间和持续时间以及总孵化时间。在孵化第18天和IP时，储存3天的种蛋气室内的pCO2高于储存18天的种蛋（P < 0.05），但储存18天的种蛋中pO2更高。在IP时，储存3天的种蛋胚胎血浆中的T3和皮质酮水平高于储存18天的种蛋，但新孵出雏鸡的情况则相反（P < 0.05）。与仅储存3天的种蛋胚胎相比，储存18天的种蛋胚胎完成IP所需时间更长（P < 0.05），而EP的持续时间不受储存影响。然而，总体孵化时间延长不仅是由于IP时间延长，还由于IP出现较晚。得出的结论是，长时间储存导致的IP延长可能与皮质酮水平后期升高有关，这可能是T3/T4比值升高、pCO2水平后期升高和pO2降低的必要刺激因素。长时间储存的影响是孵化延迟，并且由于IP和孵化之间皮质酮水平较高，T3持续升高，这可能表明从储存时间较长的种蛋中孵化出的胚胎面临更具压力的事件。孵化种蛋中pCO2、pO2、T3、T4和皮质酮水平的差异可能是这些变化的表现，最终导致孵化参数改变，进而导致雏鸡质量和生长潜力的差异。
