水料比作为偏热环境肉鸡热舒适评价指标的研究

Water/Feed: a Thermal Comfort Evaluation Index for Broilers at Moderate Temperatures

本试验旨在研究持续不同温度(21、26和31℃)处理对肉鸡生长性能、生理指标、采食量和饮水量及相关血清激素含量的影响,探讨水料比(W/F)能否作为肉鸡热舒适评价的指标。试验选取144只22日龄爱拔益加(AA)肉鸡转入环境控制舱,随机分成3组,每组6个重复,每个重复8只鸡(公母各4只)。适应期7 d,温度21℃,相对湿度60%。29日龄时,试验温度分别调整到21、26和31℃,相对湿度60%。试验期14 d。结果表明:1)随着环境温度升高,肉鸡平均日增重(ADG)、平均日采食量(ADFI)极显著降低(P<0.01),料重比(F/G)极显著升高(P<0.01),其中21和26℃组肉鸡F/G无显著差异(P>0.05);肉鸡平均日饮水量(ADWC)无显著差异(P>0.05),但随着环境温度升高全期W/F、水重比(W/G)极显著升高(P<0.01)。2)随着环境温度升高,肉鸡体核温度、呼吸频率极显著升高(P<0.01);相比21℃,31℃组肉鸡血清瘦素(LEP)含量显著升高(P<0.05),抗利尿激素(ADH)含量显著降低(P<0.05);26℃组与21、31℃组肉鸡血清LEP、ADH含量无显著差异(P>0.05);各组肉鸡血清胆囊收缩素(CCK)、醛固酮(ALD)含量无显著差异(P>0.05)。3)试验第1天、前3 d、前7 d及全期14 d肉鸡W/F与肉鸡ADG、ADFI呈极显著负相关(P<0.01);第1天、前3 d肉鸡W/F与肉鸡F/G呈极显著正相关(P<0.01),前7 d、全期14 d肉鸡W/F与肉鸡F/G呈显著正相关(P<0.05)。4)肉鸡每日W/F与环境温度、肉鸡体核温度、呼吸频率呈极显著相关(P<0.01)。综上,本试验条件下,肉鸡W/F反映出不同温度下肉鸡的冷热程度,可作为偏热环境下肉鸡热舒适评价的指标。

This experiment was conducted to study the effects of three different constant temperatures （21, 26 and 31 ℃） on the growth performance, physiological reactions, feed intake, water consumption and serum hormonal indices of broilers, in order to investigate the water/food （ W/F） as a new thermal comfort evalua-tion index for broilers. One hundred and forty four 22-day-old Arbor Acres （ AA） broilers were assigned to en-vironment chambers, the broilers were randomly assigned to 3 groups with 6 replicates per group and 8 broilers per replicate （ with four males and four females） . The pre-test period lasted for 7 days and broilers were kept at 21 ℃ and 60% relative humidity. When broilers were 29-day-old, the temperatures of each environmental chamber were gradually regulated to 21, 26 and 31℃, respectively, while maintaining the relative humidity at 60% and both kept constant until the end of the experiment. The trial period lasted for 14 days. The results showed as follows：1） with temperature increasing, the three groups showed significant depression in average daily gain （ ADG ） , average daily feed intake （ ADFI ） , and significant increase in feed/gain （ F/G ） （ P〈0.01） , but no significant difference in F/G was found between 21 and 26 ℃ groups （ P〉0.05） . The average daily water consumption （ ADWC ） was not significantly affected by different constant ambient temperatures （ P〉0.05） , but with significant difference in total W/F and water/gain （ W/G） with temperature increasing （ P〈0.01） . 2） With temperature increasing, the three groups showed significant increase in rectal temperatures and respiratory frequency （ P〈0.01）;serum leptin （ LEP） content in 31 ℃ group was significantly higher and antidiuretic hormone （ ADH） content was significantly lower than that in 21 ℃ group （ P〈0.05） , and no sig-nificant difference of serum LEP and ADH contents in 26 ℃ group than that in 21 and 31 ℃ groups （ P〉0.05）; with no significant difference in serum cholecystokinin （ CCK） and aidosterone （ ALD） contents in all groups （ P〉0.05） . 3） The W/F of the first day, the first three days, the first week and the total period had significant negative correlations with the ADG and ADFI of broilers through 14 days （ P〈0.01）; the W/F of the first day and the first three days had significant positive correlations with the F/G of broilers （P〈0.01）, with the W/F of the first week and the total period had significant positive correlation with the F/G of broilers （ P〈0.05） . 4） The W/F of average day had significant correlations with the ambient temperatures, rectal tem-peratures and respiratory frequency at the same days （ P〈0.01） . In conclusion, under the feeding conditions of this study, the results indicate that the W/F can accurately reflect the thermal comfort station of broiler at dif-ferent temperatures, and it is a new thermal comfort evaluation index for broilers.