Belay T, Wiernusz C J, Teeter R G
Oklahoma State University, Animal Science Department, Stillwater 74078.
Poult Sci. 1992 Jun;71(6):1043-7. doi: 10.3382/ps.0711043.
Two experiments were conducted utilizing 4- to 7-wk posthatching Vantress x Arbor Acres male broilers to evaluate heat distress effects on mineral balance partitioned into urinary and fecal loss. In the first study, 8 colostomized and 14 intact birds were allotted to two environmental chambers maintained at either a thermoneutral temperature (24 C) or a cycling temperature heat distress (24 to 35 C) in a switch-back design. Birds were precision-fed 2% of body weight thrice daily to equalize consumption prior to and over each 48-h experimental period. Feces and urine for colostomized birds and total excrement for intact birds were collected and analyzed for mineral content. Averaging across surgical classification, heat distress increased (P less than .05) excretion of K, P, S, Mg, Cu, Mo, and Zn. Despite little heat distress effect on urine production, minerals disproportionately excreted in urine included K, Mg, P, and S; Cu and Mg were lost primarily in feces. In the second study 42 colostomized birds were used to expand the urinary excretion data with the period of heat distress held at 35 C for 36 h. Heat distress increased (P less than .05) urine output from 52.3 +/- 5.3 to 109.9 +/- 4.5 mL/12 h and also increased total urinary K, P, S, Na, Mg, Ca, and Mn excretion. The present data provide evidence that heat distress adversely impacts bird mineral balance and that the excretion route for this effect varies with the specific mineral and possibly, heat distress severity.
进行了两项试验，使用4至7周龄刚孵化的Vantress×Arbor Acres雄性肉鸡，以评估热应激对矿物质平衡的影响，该平衡分为尿流失和粪流失。在第一项研究中，8只做了结肠造口术的鸡和14只未做手术的鸡被分配到两个环境舱中，环境舱采用折返式设计，分别保持在热中性温度（24℃）或循环温度热应激（24至35℃）条件下。在每个48小时的试验期之前和期间，精确地按照鸡体重的2%每日三次投喂，以使采食量均等。收集做了结肠造口术鸡的粪便和尿液以及未做手术鸡的全部排泄物，分析其中的矿物质含量。综合手术分类来看，热应激使钾、磷、硫、镁、铜、钼和锌的排泄量增加（P<0.05）。尽管热应激对尿量影响不大，但尿中排泄比例过高的矿物质包括钾、镁、磷和硫；铜和镁主要通过粪便流失。在第二项研究中，使用42只做了结肠造口术的鸡，在热应激温度保持在35℃持续36小时的条件下，扩展尿液排泄数据。热应激使尿量从52.3±5.3毫升/12小时增加到109.9±4.5毫升/12小时，同时也使尿中钾、磷、硫、钠、镁、钙和锰的总排泄量增加。目前的数据表明，热应激对鸡的矿物质平衡有不利影响，而且这种影响的排泄途径因特定矿物质以及可能因热应激严重程度而异。
