Abstract:
In order to better rescue and breed
Leuciscus merzbacheri, a unique and vulnerable species in China.The artificial egg collection and insemination technology was used to obtain the larvae of
L.merzbacheri for the starvation trial and the definition of the point of no return(PNR) in the condition of water temperature(21.0±1.5)℃.The effects of feeding on the growth, development and behavior were studied.The results showed that:1) the larvae of
L.merzbacheri began to feed at 3 days old, and came into the stage of nutrition outside, while the yolk-sac and oil globes were exhausted at 5 days old, and the period of mixed nutrition lasted only 2 days, indicating that
L.merzbacheri was vulnerable to starvation;2) the initial feeding rate of
L.merzbacheri larvae reached 36.0%, but the tiptop initial feeding rate of the larvae occurred at 7 days old, while the initial larval feeding rate reached 96.6%.Highly significant difference of starvation on the yolk absorption rate of larvae was observed after 3 days(
P<0.01).The feeding capacity of larvae was only 6 to 7 days.After reaching the PNR, all the starvation groups died in about 3 days, indicating their abilities to tolerate starvation was poor;3) Absorption of yolk sac in larvae was slower than that in normal control group under starvation stress.Starvation have significant effect on larval body length after 5 days(
P<0.05).The growth and development of larvae showed negative growth at 6 days in the hungry group.At the age of 7 days, the larvae began to appear chordate curvature, abdominal depression as well as thorax angle, and there was a negative correlation between clustering, initial feeding ability and hunger time.It also showed a series of obvious morphological and behavioral characteristics caused by starvation.