摘要
运用实时荧光定量PCR技术,研究禁食对体质量为(100±1)g的1龄大口黑鲈(Micropterus salmoides)的生长和肝脏中类胰岛素生长因子-Ⅰ(IGF-Ⅰ)mRNA表达丰度的影响。在为期6周的实验期间,对照组每天表观饱食投喂2次;禁食组禁食3周后恢复投喂3周。实验期间对照组鱼体质量和体长逐渐增加。6周后,对照组鱼体增重率为10.99%,体长增加率为3.07%。禁食组禁食3周期间,鱼体质量下降了5.08%、体长减少了1.79%。同时肝组织IGF-ⅠmRNA表达水平呈下降趋势,禁食结束时仅为对照组的29.93%。恢复投喂2周后肝组织IGF-ⅠmRNA的表达量仍显著低于对照组(P<0.05),鱼体质量为实验初始水平的98.54%,体长为实验初始水平的99.03%;恢复投喂3周后,禁食组鱼体质量、体长恢复到实验初始时水平(P>0.05),但仍与对照组有显著差异(P<0.01);肝组织IGF-ⅠmRNA的表达丰度与对照组无显著性差异(P>0.05)。结果显示,禁食使大口黑鲈体质量、体长下降,同时肝组织IGF-ⅠmRNA表达丰度也随之降低;而恢复投饲后,其生长、肝脏IGF-ⅠmRNA的表达丰度也逐渐恢复。研究表明,鱼类的营养状况、生长和与IGF-ⅠmRNA的表达之间存有正相关关系。
The endocrine axis of growth hormone-insulin-like growth factorⅠ plays a critical role in adjusting fish growth. Meanwhile,nutritional status exerts a complicated effect on the axis. In this study,real-time fluorogentic quantitative RT-PCR（ rfqRT-PCR） was used and the effects of fasting on growth and hepatic insulin-like growth factor（ IGF-Ⅰ） mRNA expression abundance in 1-year aged largemouth bass,body weight（ 100±1）g,were evaluated. During a 6 weeks’ trial,control fish（ Control group） were fed to apparent satiation twice daily,while test fish（ Fasted group） were fasted over the first 3 weeks and re-fed over the later 3 weeks. At the end of the trial,the body weight and body length of the control fish gradually increased by 10.99% and 3.07%,respectively. Those of the fish fasted for the first 3 weeks reduced by 5.08% and 1.79%,respectively. During fasting,IGF-ⅠmRNA expression abundance in liver came to downtrend ending in 29.93%,significantly lower compared to that of the control fish （P 〈0.01）. After 2 weeks of re-feeding,the hepatic IGF-ⅠmRNA level was still significantly lower（P〈 0.05）and the body weight and body length restored to 96.54% and 99.03% of the initial values,respectively. After 3 weeks of re-feeding,the expression of hepatic IGF-1 mRNA did not show significant difference compared to that of the control fish（P 〉0.05）. But the fish restored only to the initial levels in body weight and body length. These results showed that fasting caused body weight and length losing with reduction of hepatic IGF-ⅠmRNA expression in largemouth bass and that re-feeding resulted in restoration in body growth and expression of hepatic IGF-ⅠmRNA. It was conducted that there was a positive correlation between nutritional status,growth and hepatic IGF-ⅠmRNA level. In most juvenile vertebrates,plasma GH is increased rather than decreased under conditions of nutritional restriction. Current evidence suggests that the biosynthesis of IGF-Ⅰis a key control point for nutritional regulation of growth. Plasma IGF-Ⅰpeptide levels and hepatic IGF-ⅠmRNA abundance are correlated with growth velocity and are consistently decreased when growth is arrested by nutritional deprivation. As for fish,many important questions need to be answered to fully understand the nutritional roles of IGF-Ⅰand the underlying molecular basis. The effect of nutritional status on the autocrine or paracrine of IGF-Ⅰin fish remains unclear. In addition,it is essential to investigate whether individual nutrients,such as amino acids,energy,minerals and vitamins,regulate IGF-Ⅰgene expression and biological activity in fish as in mammals. These pending findings will contribute to completely understanding information on fish IGF-Ⅰphysiology.
出处
《中国水产科学》
CAS
CSCD
北大核心
2010年第4期713-720,共8页
Journal of Fishery Sciences of China
基金
上海市科技兴农重点攻关项目(沪农攻字2006第6-4号)
