Abstract:
To investigate the key characteristics and patterns of embryonic development and early larval stages of farmed hybrid sturgeon (
Acipenser baerii♀×
A. schrenckii♂) and to provide basic data and reference basis for its artificial spawning and nursery breeding, through injecting the exogenous hormone (LHRH-A
2+DOM), we dissected and retrieved the eggs, carried out the artificial insemination, and finally obtained the fertilized eggs by dry fertilization. Then we observed the morphological change characteristics of the hybrid sturgeon embryos and larvae in each period of development, and measured their morphological indexes. The results show that the average catalysis rate of the artificial reproduction was 100%, the fertilization rate was (80.08±8.57)% and the hatching rate was (63.69±10.71)%. The fertilized eggs of the hybrid sturgeon were heavy, grey-black, opaque and rich in yolk, with three layers of egg membranes and an egg diameter of (2.50±0.56) mm. According to the observation and analysis of the morphological characteristics of embryonic development, the embryonic development process of hybrid sturgeon was divided into seven stages, including fertilized egg stage, egg cleavage stage, blastocyst stage, protozoa embryo stage, neuroembryo stage, organ formation stage, and emergence of membranes, which comprised 34 periods. The total cumulative temperature of development was 2 083–2 251 (h· ℃). The total length of the newly hatched larvae was (10.61±0.58) mm. The hatchlings began to feed on the 7
th day and entered the mixed nutritional stage, with the total length being (17.17±0.64) mm. The yolk sac was completely absorbed by 10
th day and entered the exogenous nutrient phase. The mixed nutrient period was only 3 d.