Sahin Nurhan, Onderci Muhittin, Sahin Kazim, Smith Michael O
Veterinary Control and Research Institute, Firat University, 23119 Elazig, Turkey.
Biol Trace Elem Res. 2003 Winter;96(1-3):169-77. doi: 10.1385/BTER:96:1-3:169.
Melatonin, the major pineal hormone, modulates growth in poultry by influencing hormones involved in growth. We investigated the effects of dietary melatonin supplementation on performance, carcass characteristics, and excretion of nitrogen and some minerals in broiler Japanese quails (Coturnix coturnix japonica) exposed to high-ambient-temperature stress (34 degrees C). One hundred twenty Japanese quails (10 d old) were randomly assigned to 4 treatment groups, 3 replicates of 10 birds each. The birds were kept in either an environment-controlled room at a constant 22 degrees C or were kept at 22 degrees C for 16 h/d and at 34 degrees C for 8 h/d (9:00 AM to 5:00 PM). At both temperatures birds were fed either a basal diet or the basal diet supplemented with 40 mg of melatonin per kilogram of diet. The experiment lasted for 32 d. Melatonin improved feed efficiency in both temperatures groups compared with their corresponding controls. Although feed intake was similar in all groups, the improvement in feed efficiency was more noticeable in melatonin-fed quails kept at high temperature (p< 0.01). Supplemental melatonin significantly increased live weight gain and carcass characteristics under stress conditions (p < 0.01) but did not show the same effect at thermoneutral conditions (p > 0.05). Heat exposure increased excretion of N, Ca, P, Zn, Fe, and Cr and decreased retention rates for them. Dietary melatonin supplementation returned these values to normal (p < 0.01). No interactions between melatonin and temperature were found in the parameters measured. The results of the study show that melatonin supplementation attenuated the retardation in performance as well as the excretion of minerals caused by heat stress in broiler quails. Our data suggest that melatonin might offer protection against heat-stress-related depression in the performance of broiler quails.
褪黑素是松果体分泌的主要激素，通过影响与生长相关的激素来调节家禽的生长。我们研究了在暴露于高温环境（34摄氏度）的日本肉鹌鹑（Coturnix coturnix japonica）日粮中添加褪黑素对其生产性能、胴体特性以及氮和一些矿物质排泄的影响。120只10日龄的日本鹌鹑被随机分为4个处理组，每组10只，重复3次。这些鹌鹑要么饲养在温度恒定为22摄氏度的环境控制室内，要么每天在22摄氏度环境中饲养16小时，在34摄氏度环境中饲养8小时（上午9点至下午5点）。在这两种温度条件下，鹌鹑分别饲喂基础日粮或每千克日粮添加40毫克褪黑素的基础日粮。实验持续32天。与相应对照组相比，褪黑素提高了两个温度组的饲料效率。尽管所有组的采食量相似，但在高温环境下饲喂褪黑素的鹌鹑中，饲料效率的提高更为显著（p<0.01）。在应激条件下，补充褪黑素显著增加了体重增加和胴体特性（p<0.01），但在热中性条件下未显示出相同效果（p>0.05）。热暴露增加了氮、钙、磷、锌、铁和铬的排泄，并降低了它们的保留率。日粮中添加褪黑素使这些值恢复正常（p<0.01）。在所测参数中未发现褪黑素与温度之间的相互作用。研究结果表明，添加褪黑素减轻了热应激导致的日本肉鹌鹑生产性能下降以及矿物质排泄增加的情况。我们的数据表明，褪黑素可能为日本肉鹌鹑抵御与热应激相关的生产性能下降提供保护。
