饥饿对方斑东风螺形态和组织生化成分的影响

Effects of fasting on the morphology and biochemical composition of tissues of juvenile spotted babylon,Babylonia areolata

以室内实验测定了方斑东风螺(Babylonia areolata)在饥饿120d过程中形态、组织生化成分及RNA/DNA比值的连续变化.结果显示,饥饿前期幼螺体重变幅较小,肝体比与体壳比下降迅速,三者分别于饥饿80、40、20d时显著地低于对照组,至饥饿120d时其降幅分别为22.33%、44.02%、30.39%.方斑东风螺在饥饿过程中,螺足肌与肝胰脏的水分含量分别从80.19%、48.44%上升至89.68%、63.97%;灰分含量分别从11.35%、8.92%增加至22.80%、16.52%;肝胰脏蛋白质含量从53.18%上升至56.65%.饥饿40d时,其足肌、肝胰脏脂肪含量均显著低于对照组,糖原含量在其饥饿20、40d时也显著地下降.饥饿120d时,其足肌的脂肪和糖原含量相应降幅分别为32.22%、44.64%,而肝胰脏的脂肪和糖原含量相应降幅则分别为26.87%、47.17%.足肌蛋白质含量在其饥饿80d前较稳定,后期迅速下降,实验结束时降幅为8.61%.这2种组织的RNA/DNA比值也呈逐渐下降趋势.上述结果表明,在饥饿状态下幼螺主要消耗这2种组织中脂肪与糖原的供能,当禁食长达80d后则加大对足肌蛋白质的动用,而相对保留肝胰脏蛋白质.组织含水量、RNA/DNA比值均可作为方斑东风螺饥饿状态下的营养预测指标.

An experiment was conducted to determine the continuous effects of fasting for 120d on morphological parameters,biochemical composition and RNA/DNA ratio of Babylonia areolata juveniles.The results indicated significant differences in total body weight,HSI and Sb/S for fasting times longer than 80d,40d and 20d,respectively.Decreases in total body weight,HSI and Sb/S of 22.33%,44.02% and 30.39%,respectively,were recorded after the snails had been deprived of food for 120d when compared with the control group.During the course of the experiment,the water contents in the foot muscle and hepatopancreas increased from 80.19% to 89.68% and 48.44% to 63.97%,respectively.The ash contents of the foot muscle and hepatopancreas increased from 11.35% to 22.80% and 8.92% to 16.52%,respectively,while the protein content in hepatopancreas also increased from 53.18% to 56.65%.The lipid content of the foot muscle and hepatopancreas both decreased significantly after 40d of starvation,the glycogen contents of the foot muscle and hepatopancreas decreased markedly after fasting periods of 20d and 40d respectively.Decreases of these four parameters were 32.22%,26.87%,44.64% and 47.17%,respectively,when compared with the control group at the end of the experiment.On the other hand the protein content of the foot muscle only decreased markedly once the snails were starved for longer than 80d.The ratios of RNA/DNA in the two tissues decreased gradually during the experiment.In conclusion,lipid and glycogen from the foot muscle and hepatopancreas were mobilized to provide energy during food deprivation,the protein content of the muscle was only used notably after 80d of starvation,while the protein in the hepatopancreas was relatively maintained.The water content and the RNA/DNA ratio of either tissue could be used as a good index to estimate the nutritional status of the snails under starvation.