Lordelo M M, Davis A J, Calhoun M C, Dowd M K, Dale N M
Department of Poultry Science, University of Georgia, Athens, Georgia 30602-2772, USA.
Poult Sci. 2005 Sep;84(9):1376-82. doi: 10.1093/ps/84.9.1376.
Use of cottonseed meal in poultry diets has been avoided in large part because of fear of gossypol toxicity. Gossypol exists naturally as a mixture of 2 enantiomers that exhibit different biological activities. Two experiments were conducted to determine the relative toxicity of gossypol enantiomers on broilers. In the first experiment, 3-d-old broilers were fed a standard diet containing 0, 100, 200, 300, or 400 mg of gossypol from gossypol acetic acid per kilogram of diet from 3 to 42 d of age. This form of gossypol contains both enantiomers in an equimolar ratio. Each dietary treatment consisted of 6 replicate pens of 4 birds. In the second experiment, 3-d-old broilers were divided into 15 pens of 4 birds each and fed a standard diet supplemented with either no gossypol or one of the gossypol enantiomers at 200 or 400 mg/kg of diet from 3 to 21 d of age. In both experiments, feed intake and BW gain were measured. In addition, several organ and tissue samples were collected at 21 d (experiments 1 and 2) and 42 d (experiment 1) of age and analyzed for gossypol. In experiment 1, feed consumption and BW gain were reduced (P < 0.05) at 21 and 42 d for the birds fed the highest level of gossypol. The concentration of gossypol in the heart, kidney, and plasma were equivalent at 21 and 42 d of age. In experiment 2, total feed consumption was reduced only in birds consuming (-)-gossypol, but BW gains were lower for birds fed either enantiomer. However, (-)-gossypol was more detrimental to growth than (+)-gossypol. The liver had the highest tissue concentration of both enantiomers, and accumulation of (+)-gossypol was higher than (-)-gossypol in all tissues examined. No racemization of the enantiomers was apparent in the tissues analyzed. Our results indicated that both gossypol enantiomers were toxic to broilers but that (-)-gossypol was more harmful to efficient broiler production than (+)-gossypol.
在很大程度上，家禽日粮中一直避免使用棉籽粕，因为担心棉酚毒性。棉酚天然存在为两种对映体的混合物，它们具有不同的生物活性。进行了两项实验以确定棉酚对映体对肉鸡的相对毒性。在第一个实验中，3日龄的肉鸡从3日龄到42日龄饲喂含有每千克日粮0、100、200、300或400毫克来自醋酸棉酚的棉酚的标准日粮。这种形式的棉酚含有等摩尔比的两种对映体。每个日粮处理由6个重复栏组成，每个栏有4只鸡。在第二个实验中，3日龄的肉鸡被分成15个栏，每个栏4只鸡，并从3日龄到21日龄饲喂补充了0毫克/千克日粮或两种棉酚对映体之一（200或400毫克/千克日粮）的标准日粮。在两个实验中，均测量了采食量和体重增加。此外，在21日龄（实验1和2）和42日龄（实验1）采集了几个器官和组织样本，并分析了棉酚含量。在实验1中，饲喂最高水平棉酚的鸡在21日龄和42日龄时采食量和体重增加降低（P<0.05）。在21日龄和42日龄时，心脏、肾脏和血浆中的棉酚浓度相当。在实验2中，仅在采食（-）-棉酚的鸡中总采食量降低，但饲喂任何一种对映体的鸡体重增加均较低。然而，（-）-棉酚对生长的危害大于（+）-棉酚。肝脏中两种对映体的组织浓度最高，在所检查的所有组织中，（+）-棉酚的积累高于（-）-棉酚。在所分析的组织中，对映体没有明显的外消旋作用。我们的结果表明，两种棉酚对映体对肉鸡均有毒性，但（-）-棉酚比（+）-棉酚对高效肉鸡生产更有害。
