风速和偏热处理对肉仔鸡生理、内分泌和免疫指标的影响

Effects of Air Velocity and Moderate Ambient Temperatures on Physiological,Endocrine and Immune Indices of Broilers

本试验旨在研究不同风速和偏热处理对肉仔鸡生理、内分泌和免疫指标的影响。选取42日龄体重相近、健康的爱拔益加肉仔公鸡150羽,随机分成15个处理,每个处理10羽,每羽鸡作为1个重复。试验动物放在环控舱中(温度21℃,相对湿度60%),每次试验处理前从中随机挑选10羽,放置在另一个由本实验室研发的纵向通风试验环控舱中。每次处理分6 h适应期(自由采食与饮水)和6 h试验期(禁食禁水),适应期温湿度与试验前一致。试验期将环控舱的温湿度调至试验要求(相对湿度保持不变),风速由纵向通风实现。试验采用3×5因子设计,试验温度分3个水平:26、29和32℃;风速分为5个水平:0、0.5、1.0、1.5和2.0 m/s。各试验处理条件在第1小时内实现,第2~6小时分别采集数据。结果表明:1)风速和偏热处理的交互作用显著影响肉仔鸡体核温度(Tc)、呼吸频率(Fr)、皮肤温度(Ts)以及血清三碘甲腺原氨酸(T3)和皮质酮含量(P<0.05)。与0风速相比,在26℃偏热温度下,1.0 m/s及以上风速显著降低肉仔鸡Tc(P<0.05),2.0 m/s风速显著降低肉仔鸡Fr(P<0.05),1.5 m/s及以上风速显著降低肉仔鸡耳叶皮温(Tes)(P<0.05),1.0 m/s及以上风速显著降低肉仔鸡鸡冠皮温(Tcs)和小腿皮温(Tss)(P<0.05);29℃偏热温度下,1.0 m/s及以上风速显著降低肉仔鸡Tc、Tes、Tcs和Tss(P<0.05);32℃偏热温度下,1.0 m/s及以上风速显著降低肉仔鸡Tc和Fr(P<0.05),0.5 m/s及以上风速显著降低肉仔鸡Tes、Tcs和Tss(P<0.05);较高偏热和无风(32℃+0风速)或较高偏热和低风(32℃+0.5 m/s风速)下肉仔鸡Tc、Ts、Fr较高,血清T3含量较低,应激程度较大。2)偏热处理下,低风速(0.5 m/s)会加重肉仔鸡热负荷,风速对肉仔鸡免疫指标影响较小,最适风速为1.5 m/s。总之,偏热处理下风速不同程度影响肉仔鸡生理、内分泌和免疫指标。

This experiment was conducted to investigate the effects of air velocity and moderate ambient temperatures on physiological,endocrine and immune indices of broiler chickens. One hundred and fifty 42-day-old Arbor Acres male broilers were assigned randomly to fifteen treatments,each treatment contained ten birds and each bird as a replicate. These birds were raised in environment chamber [21 ℃ ＋ 60% relative humidity（ RH） ]. Before each treatment,ten selected birds were placed into another environment chamber with tunnel ventilation which made by our laboratory. Each treatment contained 6 h adaptive period（ ad libitum） and 6 h test period（ no feed or water）. Adaptive period and reserved chamber both were 21 ℃ ＋ 60% RH. Environment chamber set temperature and humidity（ 60% RH）,air velocity was controlled by tunnel ventilation chamber.The 3 × 5 two factorial design was used,and temperature had three levels as 26,29 and 31 ℃,while air velocity had five levels as 0,0.5,1.0,1.5 and 2.0 m/s. Each treatment was achieved within 1 h,and the data was collected from 2 to 6 h. The results showed as follows： 1） interaction of air velocity and temperature significantly affected core body temperature（ Tc）,respiratory frequency（ Fr）,skin temperature（ Ts）,and serum contents of 3,5,3’-triiodothyronine（ T3） and cortisol of broilers（ P〈0.05）. Compared with 0 air velocity,under 26 ℃ condition,1.0 m/s or higher air velocity significantly reduced Tc（ P〈 0.05）,2.0 m/s air velocity significantly reduced Fr（ P〈 0.05）,1.5 m/s or higher air velocity significantly reduced earlobe skin temperature（ Tes）,and 1.0 m/s or higher air velocity significantly reduced comb skin temperature（ Tcs） and shank skin temperature（ Tss）（ P〈 0.05） of broilers; under 29 ℃ condition,1.0 m/s or higher air velocity significantly reduced Tc,Tes,Tcs and Tss（ P〈 0.05） of broilers; under 32 ℃ condition,1.0 m/s or higher air velocity significantly reduced Tc and Fr（ P〈 0.05）,and 0.5 m/s or higher air velocity significantly reduced Tes,Tcs and Tss（ P〈 0.05） of broilers; 32 ℃ ＋ 0 air velocity and 32 ℃ ＋ 0.5 m/s air velocity increased Tc,Ts,Fr and reduced T3 deeply,which meant broilers were under stress heavily. 2） Under acute moderate temperatures,lowair velocity（ 0. 5 m/s） exacerbated heat load,air velocity had no effect on immune indices of broilers,and the best air velocity was 1.5 m/s. In conclusion,air velocity at moderate temperatures affects physiological,endocrine and immune indices of broilers in some degrees.