Benson E R, Alphin R L, Rankin M K, Caputo M P, Johnson A L
Department of Animal and Food Sciences, University of Delaware, 242 Townsend Hall, Newark, DE 19716, USA.
Avian Dis. 2012 Dec;56(4 Suppl):884-90. doi: 10.1637/10163-040912-Reg.1.
When an avian influenza or virulent Newcastle disease outbreak occurs within commercial poultry, key steps involved in managing a fast-moving poultry disease can include: education; biosecurity; diagnostics and surveillance; quarantine; elimination of infected poultry through depopulation or culling, disposal, and disinfection; and decreasing host susceptibility. Available mass emergency depopulation procedures include whole-house gassing, partial-house gassing, containerized gassing, and water-based foam. To evaluate potential depopulation methods, it is often necessary to determine the time to the loss of consciousness (LOC) in poultry. Many current approaches to evaluating LOC are qualitative and require visual observation of the birds. This study outlines an electroencephalogram (EEG) frequency domain-based approach for determining the point at which a bird loses consciousness. In this study, commercial broilers were used to develop the methodology, and the methodology was validated with layer hens. In total, 42 data sets from 13 broilers aged 5-10 wk and 12 data sets from four spent hens (age greater than 1 yr) were collected and analyzed. A wireless EEG transmitter was surgically implanted, and each bird was monitored during individual treatment with isoflurane anesthesia. EEG data were evaluated using a frequency-based approach. The alpha/delta (A/D, alpha: 8-12 Hz, delta: 0.5-4 Hz) ratio and loss of posture (LOP) were used to determine the point at which the birds became unconscious. Unconsciousness, regardless of the method of induction, causes suppression in alpha and a rise in the delta frequency component, and this change is used to determine unconsciousness. There was no statistically significant difference between time to unconsciousness as measured by A/D ratio or LOP, and the A/D values were correlated at the times of unconsciousness. The correlation between LOP and A/D ratio indicates that the methodology is appropriate for determining unconsciousness. The A/D ratio approach is suitable for monitoring during anesthesia, during depopulation, and in situations where birds cannot be readily viewed.
当商业家禽群中发生禽流感或强毒新城疫疫情时，应对快速传播的家禽疾病所涉及的关键步骤可包括：开展教育；实施生物安全措施；进行诊断和监测；实施隔离；通过扑杀或淘汰、处置和消毒来清除感染家禽；以及降低宿主易感性。现有的大规模紧急扑杀程序包括整舍气体熏蒸、部分舍气体熏蒸、集装箱式气体熏蒸和水基泡沫法。为评估潜在的扑杀方法，通常有必要确定家禽失去意识（LOC）的时间。当前许多评估LOC的方法都是定性的，需要对家禽进行视觉观察。本研究概述了一种基于脑电图（EEG）频域的方法来确定家禽失去意识的时间点。在本研究中，使用商品肉鸡来开发该方法，并使用蛋鸡对该方法进行了验证。总共收集并分析了来自13只5至10周龄肉鸡的42个数据集以及来自4只产蛋后期母鸡（年龄大于1岁）的12个数据集。通过手术植入了无线EEG发射器，并在每只鸡接受异氟烷麻醉的个体治疗过程中对其进行监测。使用基于频率的方法评估EEG数据。使用α/δ（A/D，α：8 - 12Hz，δ：0.5 - 4Hz）比值和姿势丧失（LOP）来确定家禽失去意识的时间点。无论诱导方法如何，意识丧失都会导致α波抑制和δ频率成分增加，这种变化用于确定意识丧失。通过A/D比值或LOP测量的意识丧失时间之间没有统计学上的显著差异，并且在意识丧失时A/D值具有相关性。LOP与A/D比值之间的相关性表明该方法适用于确定意识丧失。A/D比值方法适用于麻醉期间、扑杀期间以及难以直接观察到家禽的情况的监测。
