日粮高碘对獭兔生长轴相关激素基因mRNA表达的影响

Effects of high iodine dietary on the gene mRNA expression of the related hormones in growth axis of Rex rabbits

微量元素碘是动物生长及发育的必需元素,其缺乏或过量都将影响动物的健康与生产。为了探讨高碘对家兔生长轴相关激素的影响,本试验选取120只4月龄、体重相近(2235.4 g±13.04 g)的青年獭兔,随机分为对照组(0 mg/kg)、低碘水平组(0.2 mg/kg)、中碘水平组(2 mg/kg)、高碘水平组(4 mg/kg)。试验期35 d时,每组随机抽取体重相近獭兔5只,空腹24 h后进行屠宰,采集垂体、肝脏组织,采用实时荧光定量PCR方法,检测了獭兔垂体生长激素(GH)、肝脏IGF-1、IGFBP1基因m RNA表达水平。采用2-△△Ct方法计算垂体GH、肝脏IGF-1、IGFBP1基因m RNA相对表达量。结果显示:与对照组相比,中水平组、高水平组垂体GH表达量分别下降3.8%、8.6%,IGF-1表达量分别下降25.8%、19.6%,但无显著差异(P>0.05)。此外,高水平组肝脏IGFBP1基因m RNA表达量比对照组高14.2%,但也无显著影响(P>0.05)。综上所述,试验期内,日粮添加高碘对獭兔生长轴激素表达无显著影响,高水平组碘添加量未达到獭兔采食安全上限。

Iodine（I）is the essential trace elements for animal growth and development,which can impact animal health and productivity.In this test,the effects of dietary high iodine on the related hormones of growth axis in rex rabbits were in- vestigated.The mRNA expression of growth hormone （GH）in pituitary,insulin-like growth factor-I （IGF-1）and insulin-like growth factor binding protein-1 （IGFBP1）in liver were measured using real-time quantitative PCR.One hundred and twenty 4-month-old rabbits with （2235.4＋13.04）g body weight were divided into 4 groups and their diets were supplemented with different levels of I （0,0.2,2,4 mg/kg）.The four treatment groups were：control group, low level group, middle level group, and high level group.The trial lasted 35 days.At the end of trail,five rabbits of each group with 24 h limosis was slaughtered in order to collect the pituitary and liver.The samples were frozen in liquid nitrogen and would be used to carry out real-time quantitative PCR analysis.The mRNA expression of GH ,IGF-1 and IGFBP1 was calculated using 2-~~~.The results showed that the mRNA expression of pituitary GH and liver IGF-1 was 3.8% ,8.6% and 2：5.8% ,19.6% lower than control group,but there was no statistical difference （P 〉 0.05 ）.Otherwise, compared with control group, the mRNA expression of the liver IGF- BP1 increased by 14.2% in high level group,there was also no significant difference（P 〉 0.05）.In conclusion,the growth axis wasn＇t influenced by feeding high iodine dietary, and the iodine intake wasn＇t up to upper limit.