短期饥饿和再投喂对岩原鲤仔鱼生存生长以及RNA/DNA和RNA/蛋白质比率的影响(英文)

研究通过对岩原鲤仔鱼在饥饿和再投喂条件下其生存、生长率、RNA/DNA和RNA/蛋白质比率的测定,评估了仔鱼对饥饿的耐受能力和恢复能力。在(19.5±0.5)℃水温下,将岀膜后第16天的岩原鲤仔鱼随机分成6个组:1个持续投饲对照组,实验组分别禁食1、2、3、4、5d后再投喂,实验共进行10d。每天分别从各组取9尾鱼测定体重、体长、RNA、DNA、蛋白质含量。实验结果显示,饥饿处理组仔鱼存活率和以上各项生长指标均随饥饿时间的增加而下降,在恢复投喂后均表现不同程度的补偿生长,其中饥饿1、2、3d的仔鱼在恢复投喂后显示出完全补偿生长,几乎弥补了饥饿所产生的影响,平均终体重与对照组比较无显著差异。饥饿4、5d的仔鱼显示部分补偿生长,恢复投喂只少量减轻了饥饿的影响,平均终体重与对照组相比存在显著差异。饥饿1、2、3d的仔鱼和4、5d的仔鱼在恢复投喂后分别需要1—2d和4d时间才能达到与对照组无显著差异水平。仔鱼生长率变动范围从0.59%到8.00%WW/day,仔鱼RNA/DNA比率、RNA/蛋白质比率与生长率的回归方程为:GR=3.63RNA/DNA 1.74(R2=0.80)和GR=120.14RNA/Protein 2.33(R2=0.31),两种比率均与生长率呈显著线性相关,RNA/DNA比率对生长变化的拟合度更好。结果表明,仔鱼阶段食物缺乏很可能是影响岩原鲤仔鱼存活、生长的主要因素。RNA/DNA更适合作为评定岩原鲤仔鱼营养条件和生长的指标。

EFFECTS OF SHORT-TERM STARVATION AND REFEEDING ON THE SURVIVAL,GROWTH,AND RNA/DNA AND RNA/ PROTEIN RATIOS IN ROCK CARP (PROCYPRIS RABAUDI) LARVAE

The ability of rock carp(Procypris rabaudi) larvae to resist and recover from starvation was examined by measuring their survival,growth rate,RNA/DNA and RNA/protein ratios during starvation and refeeding.At water temperature of(19.5±0.5)℃,sixteen days after hatching the larvae were randomly separated into six feeding treatments: a control treatment(food was always available) and treatments starved for 1,2,3,4,and 5 days,and then refed.Whole experiment lasted for 10 days.Wet weight(WW),body length,and contents of RNA,DNA and protein were measured in 9 Larvae from each treatment everyday.The results,in general,showed that survival and growth indicators above decreased as the starvation period increased.Larvae in all starvation treatments exhibited different extents of compensatory growth after refeeding.Larvae starved for 1,2,and 3 days showed full compensatory growth that almost counteracted the effects of starvation and attained mean final WW similar to the control treatment.Larvae starved for 4 and 5 days showed partial compensatory growth that slightly abated the effects of starvation and their final WW was significantly different from the control.For larvae starved for 1–3 days and 4–5 days,it took 1–2 days and 4 days respectively,after refeeding to attain RNA/DNA ratios not significantly different from the control.Growth rates ranged from 0.59% to 8.00% WW/d and the regression equations between RNA/DNA and RNA/protein ratio and GR of larvae were GR=3.63RNA/DNA 1.74(R 2 =0.80) and GR=120.14RNA/protein 2.33(R 2 =0.31) respectively.The two ratios were significantly correlated with GR and RNA/DNA ratio fitted the growth variability better.Findings from the present study indicate that available food shortage is likely major factor to impair survival and growth during larval stage.The rock carp larvae were able to recover from less than 5 days of starvation.The RNA/DNA ratio was a more reliable indicator nutritional condition and growth in rock carp larvae.