半胱胺对高邮鸭增重及相关激素分泌和基因表达的影响

Effect of Cysteamine on Weight Gain and Gene Expression and Secretion of Some Growth Related Hormones in Gaoyou Ducks

随机选取 5日龄体况良好的雄性高邮鸭 2 4只 ,分成对照组和半胱胺 (CS)试验组。试验组每周按体重在日粮中添加 1次 CS(10 0 mg/ kg) ,以观察半胱胺对高邮鸭增重及相关激素分泌和基因表达的影响。结果表明 ,前 3周平均日增重试验组比对照组提高 12 .86 %,料肉比下降 12 .82 %;整个试验期平均日增重提高 4.5 3%,料肉比下降 4.0 3%。血清 IGF- 1水平 ,试验组为 (2 2 9.88± 8.6 9) μg/ L,显著高于对照组 (2 0 2 .31± 7.10 ) μg/ L(P<0 .0 5 ,n=10 ) ;血清 GH水平 ,试验组为 (0 .5 4± 0 .0 3) μg/ L,显著高于对照组 (0 .45± 0 .0 2 ) μg/ L(P<0 .0 5 ,n=10 ) ;垂体 GH m RNA的净灰度(net intensity) ,试验组为 (2 .2 3× 10 5± 0 .19× 10 5) ,显著高于对照组 (1.6 5× 10 5± 0 .12× 10 5) (P<0 .0 5 ,n=9) ,而下丘脑生长抑素 (SS) m RNA的净灰度 ,试验组为 (1.33× 10 5± 0 .10× 10 5) ,比对照组 (2 .14× 10 5± 0 .5 7× 10 5)降低37.85 %(P=0 .0 97,n=8) ,提示半胱胺对 SS基因转录水平可能没有影响。半胱胺促进生长和提高饲料转化率的机制 ,可能与 GH基因表达的上调和血清 IGF- 1水平的提高有关。

Twenty-four 5-day-old male Gaoyou ducks were divided into control and CS treated gourps.CS was added to the commercial diet at the dosage of 100 mg/kg body weight once per week.Birds were kept in poultry house,free access to food and water.At 33 days of age,they were sacrificed and plasma and tissue samples were taken for further analysis.Results showed that daily weight gain of ducks in experiment group improved by 12.86%(P<0.05,n=12) in the end of the third week and 4.53% in the end of research.No difference was found in feed consumption,thus the feed efficiency increased by 12.82% and 4.03% respectively.CS also significantly increased the serum levels of GH and IGF-1(P<0.05,n=10).Northern blot analysis indicated that the net intensity of GH mRNA was significantly higher in CS treated group than that in control group(P<0.05,n=9),but no significant difference in the SS mRNA expression was found between control and CS treated ducks(P=0.097,n=8).The results suggest that CS may not affect the transcription of SS gene.The increased level of pituitary GH mRNA expression as well as elevated IGF-1 secretion are involved in the mechanism of growth promoting effect of CS.