Early age thermal conditioning and a dual feeding program for male broilers challenged by heat stress
Early age thermal conditioning and a dual feeding program for male broilers challenged by heat stress
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DOI：
10.1093/ps/80.1.29
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发表时间：
2001-01-01
期刊：
影响因子：
4.4
通讯作者：
Picard, M
中科院分区：
文献类型：
--
作者：
De Basilio, V;Vilariño, M;Picard, M
本文报道了早期热适应(TC)和双重饲养对34日龄雄性肉鸡热刺激反应的影响。将300只雏鸡随机分为两组。其中一组在5d龄时暴露于38℃、42%相对湿度的热适应24 h，另一组不暴露。11~41日龄，温度为26℃(1600~0900h)和30℃(0900~1600h)。从第19天开始，进行析因(2×2，TC×日粮)试验，每个处理用8个栏，每组6只肉鸡。日粮为对照日粮，高蛋白组分(1600~0900h)和高能组分(0900~1600h)混合饲喂。热处理可使仔鱼的生长和饲料效率略有提高(+4%)，而双重饲养则略有降低(-4%)。热刺激期间的死亡率因这两个因素而降低。[在非条件饲养鸡(N)中，31只饲喂对照饲粮(NG)，12只饲喂双重饲喂(NDF)；在热条件雏鸡(T)中，18只饲喂对照饲粮(TG)，11只饲喂双重饲喂(TDF)死亡。]在热激期间，体温(T-b)持续降低。在热激期间，通过热适应和双重摄食降低了体温。在32日龄时测量T-b，可以估计鸡在2天后应对热应激的能力。TDF和NDF组大鼠的胸肌重量明显增加，而肝脏和肌胃的重量显著增加。这些结果表明，5日龄的热适应可以诱导雄性肉鸡发生一致的代谢变化。在热应激过程中，双重摄食可能对产热产生了短暂的影响。
The effects of early age thermal conditioning (TC) and dual feeding on responses of male broilers to a thermal challenge at 34 d of age are reported. Three hundred chicks were randomly divided into two equal groups. One group was exposed to thermal conditioning (38 C, 42% relative humidity for 24 h) at the age of 5 d, and the other group was not exposed. From 11 to 41 d of age, temperature was diurnally cyclic: 26 C (1600 to 0900 h) and 30 C (0900 to 1600 h). From Day 19, a factorial (2 x 2, TC x diet) experiment was conducted using eight pens of six broilers per treatment. Diets were control diet and dual feeding of a high protein fraction (1600 to 0900 h) and an energy-rich fraction (0900 to 1600 h). Growth and feed efficiency were slightly enhanced (+4%) by thermal conditioning and slightly reduced (-4%) by dual feeding. Mortality during thermal challenge was reduced by both factors. [In not conditioned chicks (N), 31 fed a control grower diet (NG) and 12 on a dual feeding program (NDF) died; in thermal conditioned chicks (T), 18 fed a control grower diet (TG) and 11 on a dual feeding program (TDF) died.] Before the thermal challenge period, body temperature (T-b) was consistently reduced in T. During the thermal challenge period, T-b was reduced by thermal conditioning and dual feeding. Measured at the age of 32 d, T-b gave an estimation of the ability of the chickens to cope with heat stress 2 d later. Pectoral mass was increased in TG, whereas the liver and the gizzard were significantly heavier in TDF and NDF. These results suggest that thermal conditioning at 5 d of age induces a consistent metabolic change in broiler males. The dual feeding program might have induced transitory effects on heat production during the heat stress.