Performance of growing pigs subjected to lighting programs in climate-controlled environments

ABSTRACT The objective of this research was to evaluate the thermal comfort, physiological responses and performance of pigs in the growth phase, subjected to supplemental lighting programs in air-conditioned environments, in semiarid region of Pernambuco state, Brazil. Twenty-seven pigs (3/4 Duroc, ¼ Pietrain) were subjected to pens with no climate control, pens with forced ventilation and pens with adiabatic evaporative cooling, associated with 12 h of natural light, 12 h of natural light + 4 h of artificial light and 12 h of natural light + 6 h of artificial light. The experimental design was completely randomized, in a 3 x 3 factorial arrangement with three repetitions. Meteorological responses, physiological responses and performance variables of the animals were recorded. The evaporative cooling system attenuated the action of the stressors and ensured adequate thermal conditions for the animals. Respiratory rate and rectal temperature indicated that evaporative cooling ensured the maintenance of homeothermy. Weight gain and feed conversion were positively influenced for the animals exposed to evaporative cooling, but without significant effect of lighting programs.

摘要
本研究旨在评估巴西伯南布哥州半干旱地区内，不同圈舍环境调控模式配合补充光照方案对生长阶段肉猪的热舒适度、生理反应及生产性能的影响。试验选取27头（3/4杜洛克（Duroc）、1/4皮特兰（Pietrain））杂交肉猪，将其随机分配至三类圈舍：无气候调控圈舍、强制通风圈舍、绝热蒸发冷却（adiabatic evaporative cooling）圈舍，并分别搭配三种光照方案：12小时自然光、12小时自然光+4小时人工光照、12小时自然光+6小时人工光照。本试验采用完全随机设计，设置3×3因子排列，共3次重复。记录受试动物的气象指标、生理反应及生产性能相关变量。结果表明，绝热蒸发冷却系统可缓解应激源的不利影响，为受试动物提供了适宜的热环境条件；呼吸频率与直肠温度指标显示，绝热蒸发冷却可维持受试动物的体温恒定（homeothermy）。暴露于绝热蒸发冷却环境的肉猪，其增重与饲料转化效率得到显著正向改善，但光照方案未对上述指标产生显著影响。