饥饿胁迫对中华绒螯蟹(Eriocheir sinensis)仔蟹的影响

Impacts of starvation on the juveniles of Chinese mitten crab Eriocheir sinensis

在26.2～28.4℃水温条件下,研究了饥饿对中华绒螯蟹(Eriocheirsinensis)仔蟹的形态、行为、存活及体重损失的影响,同时确定了仔Ⅱ的营养饱和储存点(PRS)和不可恢复点(PNR)。结果表明:饥饿胁迫下中华绒螯蟹仔Ⅰ、仔Ⅱ、仔Ⅲ的初次死亡时间(T1)分别为8.0、14.0和20.3d,50%死亡时间(T50)分别为11.4、16.0和25.5d,100%死亡时间(T100)分别为15.0、22.0和32.3d,耐饥饿能力为仔Ⅲ>仔Ⅱ>仔Ⅰ;饥饿期间中华绒螯蟹体内水分含量持续升高,干重量降低显著,干重损失速率也随时间延长逐渐减小;先饱食后饥饿的给饵模式中仔Ⅱ蜕皮率随初始饱食时间延长而升高,50%个体完成蜕皮所需饱食时间(PRS50)为2.10d,各处理组仔Ⅱ的蜕皮周期与持续饱食组均无显著差异(P>0.05),但只有饱食3d以上才能达到持续饱食饲养蟹的增重率;先饥饿后饱食的给饵模式中,仔Ⅱ的蜕皮率随着初始饥饿时间的延长而下降,其中仔Ⅱ50%不能蜕皮的初始饥饿时间(PNR50)和100%不能蜕皮的初始饥饿时间(PNR100)分别为10d和14d,并且蜕皮周期相对延长,延长时间约等于初始饥饿时间,不存在额外的摄食时间来弥补饥饿期间损失的能量,各处理组蜕皮后仔蟹与对照组体重无显著差异(P>0.05)。

This paper studied the impacts of starvation on the morphology, behavior, survival, and physiology of juvenile Eriocheir sinensis at water temperature 26.2-28.4 ℃, and determined the point of reserve saturation （PRS） and the point of no return （PNR）. Under starvation, the time the first death occurred （T1） for the E. sinensis juveniles at stages Ⅰ, Ⅱ, and Ⅲ was 8.0, 14.0, and 20.3 d, the time the 50% mortality occurred （T50） was 11.4, 16.0, and 25.5 d, and the time the 100% mortality occurred （T100） was 15.0, 22.0, and 32.3 d, respectively. The ability of starvation resistance for stage Ⅲ juveniles was the highest, followed by stage Ⅱ, and stage Ⅰ juveniles. During starvation period, the moisture content of E. sinensis increased, dry weight decreased significantly, and the dry weight loss rate decreased gradually with the extension of time. Under the feeding strategy of presatiation, the molting rate of stage Ⅱ juveniles increased with the extension of feeding time, and the PRS50 was 2.10 d. No significant difference was found in the molting duration between different treatment groups and continuous feeding group. However, if continuous feeding lasted less than 3 d, the weight of the juvenile crabs in each treatment couldn＆rsquo;t reach to that of the continuous feeding group. Under the feeding strategy of prestarvation, the molting rate of stage Ⅱ juveniles decreased with the extension of starvation time, the PNR50 was 9.95±0.33 d, and the PNR100 was 14 d. The time of molting cycle extended, and the gap was approximately equal to the initial starvation time. There was no extra feeding time taken to offset the lost energy during the starvation period. No significant difference was observed in the body weight after molting between treatment groups and control group （P〉 0.05）.