摘要
通过室外喂养观察 3种营养状况对幼年鲤鱼生长、血清生长激素 (GH)水平和组织胰岛素样生长因子 Ⅰ (IGF Ⅰ )mRNA表达的影响。一组鱼喂含 40 %酪蛋白的饵料 (H组 ) ,一组鱼喂含 2 0 %酪蛋白的饵料 (L组 ) ,饵料的总能量相同 ;另一组鱼先饥饿 32天再投喂含 40 %酪蛋白的饵料。禁食后饥饿组鲤鱼体重和体长的生长受阻 ,在第 16天饥饿组鱼血清GH水平明显升高 ,到第 32天达到H组的 4倍 ;而肝组织IGF ⅠmRNA水平在第 16天无明显下降 ,但是到第 32天已降到不到H组的一半。鲤鱼其它组织饥饿 32天未发现IGF ⅠmRNA表达有明显变化。饥饿 32天后开始投喂含 40 %酪蛋白的饵料 ,鲤鱼生长、肝组织IGF ⅠmRNA的表达水平逐渐恢复 ,再投喂 16天皆与H组无明显差异。再投喂过程中 ,GH水平也逐渐下降 ,第 16天恢复正常。实验结果提示鲤鱼营养对肝组织IGF ⅠmRNA的表达有调节作用。营养缺乏将导致鲤鱼肝组织IGF ⅠmRNA的表达水平也相应恢复正常 ,从而导致鲤鱼生长恢复。同时 ,实验结果也提示 ,鲤鱼肝以外的组织IGF ⅠmRNA表达不受营养调节。L组鲤鱼在喂养过程中 ,体重和体长的增长比H组低 ,但即使喂养 40天 ,两组鱼体重和体长并无显著差异。两组鱼血清生长激素水平和各组织IGF ⅠmRNA的表达水平到实验第 32天也未发现有明显?
Effects of three kinds of nutritional status on tissue IGF Ⅰ mRNA expression in juvenile Common carp ( Cyprinus carpio ) were studied by prolonged outdoor feeding. One group of fish was fed with food containing 40% Casein (H group); another group was fed with food containing 20% Casein (L group). Two kinds of food contain the same amount of energy. The last group of fish was fasted until the 32th day, then fed with food containing 40% Casein (Starvation group). During the experiment, the growth of starved fish was less than half of that of the L group fish on the 32th day, though no significant change of IGF Ⅰ mRNA amount in other tissues was observed. Growth and hepatic IGF Ⅰ mRNA level in fasted fish began to gradually be restored after being fed again with food containing 40% Casein. Like previous studies by other researchers, during starvation the serum growth hormone level increased significantly and two week refeeding restored it to normal. Even though the growth rate in L group fish was lower than that of H group fish, no statistically significant difference was found between the two group fish after 40 day's feeding. Also, no obvious differences in the serum growth hormone level and hepatic IGF Ⅰ mRNA amount between the two group was discovered even on the 32th day. The results suggest that in juvenile Common carp, live in other fishes and mammals, nutrition should be also a regulator of the hepatic IGF Ⅰ mRNA expression. Lack of nutrition depresses the hepatic IGF Ⅰ mRNA expression, which was most likely to lead to the decrease of serum IGF Ⅰ level, and the latter in turn retard growth in juvenile Common carp. When the nutrition was restored, the hepatic IGF Ⅰ mRNA was also restored, which would probably lead to the restoration of growth. The results suggest the non hepatic IGF Ⅰ mRNA expression should be independent of the nutritional status as in other reported fishes. In addition, because no differences in growth status and hepatic IGF Ⅰ mRNA expression were observed between H group and L group on the 32th day, it is conceivable that the total energy of food may be an important factor in modulate hepatic IGF Ⅰ mRNA expression as reported in mammals, and the food containing normal energy and 20% Casein already can maintain a high level of hepatic IGF Ⅰ expression. Alternatively, 32 days perhaps is not long enough for the two nutritional status to show fully the different effects on hepatic IGF Ⅰ mRNA expression of the two group of fishes.
出处
《动物学报》
SCIE
CAS
CSCD
北大核心
2001年第1期94-100,共7页
ACTA ZOOLOGICA SINICA
基金
中山大学基础性研究前沿项目! (1995~ 1998)
