[目的]研究新疆裸重唇鱼(Gymnodiptychus dybowskii)仔鱼的饥饿耐受能力及最佳投喂时间,为其仔鱼培育提供理论参考.[方法]采用试验生态学方法,在水温 15.2～16.4℃条件下,研究新疆裸重唇鱼仔鱼在饥饿胁迫下的形态发育、生长及存活率等的变化,通过记录饥饿组仔鱼每日的初次摄食率,测定其不可逆点(Point of no return,PNR).[结果]新疆裸重唇鱼仔鱼 7日龄开口摄食,12～13日龄卵黄囊消失,混合营养期 5～6 d.仔鱼开口时初次摄食率仅为 5%,11日龄达到初次摄食率的最大值 100%;17日龄后下降至 50%,到达PNR,仔鱼具有初次摄食能力的时间为 10 d.9日龄前,两组仔鱼全长无显著差异(P＞0.05),12日龄后饥饿组仔鱼全长与对照组有显著差异(P＜0.05),饥饿组仔鱼负增长并出现生理性萎缩.饥饿组仔鱼进入PNR后,因饥饿出现身体扭曲、畸形,死亡率逐渐升高,至25日龄死亡率达100%.[结论]在水温15.2～16.4℃下,新疆裸重唇鱼具有一定的耐受饥饿能力,其仔鱼最佳投喂时间为11日龄.
Tolerance and PNR of Gymnodiptychus dybowskii Larvae under Artificial Starvations
[Objective]Starvation tolerance of Gymnodiptychus dybowskii larvae was studied to determine the optimal time to start feeding larvae for the aquaculture.[Method]Morphological development,growth,and survival rate of regularly fed G.dybowskii larvae and those under artificially imposed starvation were observed in separate fish tanks with a controlled water temperature at 15.2-16.4℃.The point of no return(PNR)under starvation of the larvae was determined by the percentage of the stressed fish that took daily feed initially.[Result]The normal mixed nutrition for the larvae lasted 5-6 d.In general,on the 7th day after hatching the larvae started natural feeding,and their yolk sac disappeared in 12-13 d.Approximately 5%of the larvae began to feed at the time of feeding initiation stage.The percentage of larvae started feeding reached 100%on the 11th day but was 50%at PNR after 17 d when deprived of food.Normally,it lasted for 10 d for the larva beginning to take the initial morsel of food.There was no significant difference found in the total length of the larvae fed regularly and under the starvation treatment up until the age of 9 d(P＞0.05).However,at 12-day-old,the two groups of larvae began to significantly widen the differentiation in body length(P＜0.05),and the starved fish started to show negative growth with physiological atrophy.After PNR,body distortion and deformities appeared on the starved larvae with the mortality rate gradually rising to 100%25 d after hatching.[Conclusion]In a water of 15.2-16.4℃,G.dybowskii larvae displayed a tolerance to starvation with an apparent PNR.It showed that the optimal start time for feeding the larvae was 11 d after hatching.
Gymnodiptychus dybowskiilarvaestarvationpoint of no return
国家科技期刊平台
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