不同养殖密度下革胡子鲶幼鱼的生长和垂体GH基因mRNA表达分析

Analysis of daily weight gain and GH mRNA expression in juvenile Clarias gariepinu reared at different stocking densities

革胡子鲶（Clarias gariepinus）幼鱼在35 kg·m-3、65 kg·m-3、95 kg·m-3和125 kg·m-3的密度下养殖60 d,第30和第60天时分析鱼的日增质量并应用半定量RT-PCR法分析垂体生长激素（GH）基因mRNA的相对表达量。0~30 d养殖期内,35 kg·m-3和65 kg·m-3密度组间及95 kg·m-3和125 kg·m-3密度组间的鱼日增质量差异不显著,但前2个密度组的鱼日增质量显著高于后2个密度组;而养殖第30天时各养殖密度组间GH基因mRNA相对表达量差异均不显著。30~60 d养殖期内,35 kg·m-3和65 kg·m-3密度组的日增质量显著高于125 kg·m-3密度组,但其余各密度组间差异不显著;养殖第60天时,35 kg·m-3和65 kg·m-3密度组GH基因mRNA相对表达量显著高于95 kg·m-3和125 kg·m-3密度组。结果表明革胡子鲶幼鱼的日增质量与垂体GH基因mRNA相对表达量不存在紧密的相关性。

Juvenile Clarias gariepinus were reared at densities of 35 kg.m-3, 65 kg m-3, 95 kg.m-3and 125 kg.m-3for 60 d. On 30＇h and 60th day, we measured the daily weight gain （DWG） and assayed the mRNA level of GH in pituitary by semi-quantitative RT-PCR. During 0 - 30 d breeding, the DWGs showed no significant difference between 35 kg＇m-3and 65 kg m-3 treatments as well as between 95 kg m-3and 125 kg m-3treatments, but the DWGs were significantly higher at 35 kg-m-3and 65 kg.m-3treatments than those at 95 kg m-3 and 125 kgm-3 treatments. While on 30th day, significant difference was not found in the GH mRNA level of pituitary between any two stocking densities. During 30 -60 d breeding, the DWGs of 35 kg.m-3 and 65 kg-m-3 treatments were significantly higher than that of 125 kg-m-3treatment, there was no significant difference in DWG between the other two treatments. On 60th day, the expressions of GH gene were significantly higher in 35 kg m-3and 65 kg.m -3treatments than those in 95 kg m -3and 125 kg-m-3treatments. The results indicate that there was no close correlation between DWG and mRNA level of GH in pituitary of juvenile C. gariepinus.