Ridgetail white prawn （Exopalaemon carinicauda） are of significant economic importance in China where they are widely cultured. However, there is little information on the basic biology of this species. We evaluated the effect of temperature （16, 19, 22, 25, 28, 31, and 34℃） on the standard metabolic rates （SMRs） of juvenile and adult E. carinicauda in the laboratory under static conditions. The oxygen consumption rate （OCR）, ammonia-N excretion rate （AER）, and atornic ratio of oxygen consumed to nitrogen consumed （O：N ratio） of juvenile and adult E. carinicauda were significantly influenced by temperature （P〈0.05）. Both the OCR and AER of juveniles increased significantly with increasing temperature from 16 to 34℃, but the maximum OCR for adults was at 31℃. Juvenile shrimp exhibited a higher OCR than the adults from 19 to 34℃. There was no significant difference between the AERs of the two life-stages from 16 to 31 ℃ （P〉0.05）. The O：N ratio in juveniles was significantly higher than that in the adults over the entire temperature range （P〈0.05）. The temperature coefficient （Q_10） of OCR and AER ranged from 5.03 to 0.86 and 6,30 to 0.85 for the adults, respectively, and from 6,09-1.03 and 3.66-1.80 for the juveniles, respectively. The optimal temperature range for growth of the juvenile and adult shrimp was from 28 to 31℃, based on Q_10 and SMR values. Results from the present study may be used to guide pond culture production ofE. carinicauda.
As in vertebrates, brains play key roles in rhythmic regulation, neuronal maintenance, diff erentiation and function, and control of the release of hormones in arthropods. But the structure and functional domains of the brain are still not very clear in crustaceans. In the present study, we reveal the structural details of the brain in the redclaw crayfish using hematoxylin-eosin staining and microscopic examination, firstly. The brain of crayfish is consist of three main parts, namely, protocerebrum, deutocerebrum, and tritocerebrum, including some tracts and commissures, briefly. Secondly, at least 9 kinds of brain cells were identified on the basis of topology and cell shapes, as well as antibody labeling. We also provide morphological details of most cell types, which were previously un-described. In general, four types of glia and three types of neurosecretory cells were described except cluster 9/11 and cluster 10 cells. Glia were categorized into another three main kinds:(1) surface glia;(2) cortex glia; and(3) neuropile glia in addition to astrocytes identified by GFAP labelling. And neurosecretory cells were categorized into I, Ⅱ and III types based on morphological observation. Finally, cluster 9/11 and 10 cells derived from the brain of crayfish, could be used for primary culture about 7–9 d under the optimized conditions. There results provide a resource for improving the knowledge of the still incompletely defined neuroendocrinology of this species. Using the crayfish as an animal model, we are easy to carry out further research in manipulating their endocrine system, exploring cellular and synaptic mechanisms so much as larval production on a small scale, such as in a cell or tissue.
