Effects of Incubator Carbon Dioxide and Oxygen Levels, and Egg Weight on Broilers’ Hatchability of Fertile Eggs

ABSTRACT This study investigated the effects of incubator carbon dioxide (CO2) and oxygen (O2) levels, and egg weight (EW) on embryo mortality (EM) and hatchability of fertile eggs (HFE). A total of 1920 hatching eggs were obtained from a middle-aged (41 weeks) ROSS 308 broiler breeder flock. The eggs were classified according to EW as heavy (69.63 ± 0.09 g), medium (65.20 ± 0.04 g) and light (61.11 ± 0.08 g) and randomly allocated to four separate identical incubators. To these incubators, four different incubator ventilation programmes (IVP) classified as control (C; 0.7% CO2 and 20.9% O2), high CO2 (HC; 1.1% CO2 and 20.3% O2), high O2 (HO; 0.6% CO2 and 22.0% O2), and high CO2 + O2 (HCO; 0.9% CO2 21.0% O2) were applied, and EM and HFE were examined. IVP affected EM and HFE; a higher rate of early EM and a lower rate of HFE were obtained from the HO group compared to the HCO group, and a lower rate of HFE was observed in the HO group than to the C group (p<0.05). An association was found between EW and IVP (p<0.05), being more evident in early EM for light eggs. Consequently, IVP; i.e., different CO2 and O2 levels in the incubator affected the hatching results. This is considered to be due to the altitude of the experiment (724m) and the uniform eggs being obtained from the same middle-aged flock, and incubator O2 levels should be taken into consideration, as well as CO2.

摘要 本研究探讨了孵化器二氧化碳（carbon dioxide, CO₂）与氧气（oxygen, O₂）浓度、蛋重（egg weight, EW）对胚胎死亡率（embryo mortality, EM）及受精蛋孵化率（hatchability of fertile eggs, HFE）的影响。共计从41周龄的罗斯308（ROSS 308）肉种鸡群中获取1920枚种蛋，随后按照蛋重将其分为重型（69.63±0.09 g）、中型（65.20±0.04 g）与轻型（61.11±0.08 g）三组，并随机分配至4台规格一致的独立孵化器中。为上述孵化器设置4种不同的孵化器通风程序（Incubator Ventilation Programme, IVP），分别为对照组（C；0.7% CO₂、20.9% O₂）、高CO₂组（HC；1.1% CO₂、20.3% O₂）、高O₂组（HO；0.6% CO₂、22.0% O₂）及高CO₂+O₂组（HCO；0.9% CO₂、21.0% O₂），并对胚胎死亡率与受精蛋孵化率进行检测分析。结果表明，孵化器通风程序对胚胎死亡率与受精蛋孵化率均存在显著影响：与高CO₂+O₂组相比，高O₂组的早期胚胎死亡率更高，受精蛋孵化率更低；且高O₂组受精蛋孵化率显著低于对照组（p<0.05）。研究发现蛋重与孵化器通风程序存在显著交互效应（p<0.05），其中轻型蛋的早期胚胎死亡率所呈现的差异更为明显。综上，孵化器通风程序，即孵化器内不同的CO₂与O₂浓度，会显著影响孵化效果。本研究结果推测与试验所处海拔（724米）及所用种蛋均来自同一中年种鸡群、种蛋均一性良好有关，因此在孵化管理中，除二氧化碳浓度外，也应重视孵化器氧气浓度的调控。