Journal of Tropical Oceanography ›› 2022, Vol. 41 ›› Issue (3): 156-163.doi: 10.11978/2021106CSTR: 32234.14.2021106

• Marine Biology • Previous Articles     Next Articles

Effects of salinity on growth, molting, Na+-K+-ATP enzyme activities, immune index, and antioxidantion of juvenile Chinese horseshoe crab, Tachypleus tridentatus

DONG Lanfang(), XU Mingzhu, LIU Haijuan, ZENG Mengqing, CHEN Ruifang(), LI Shicai   

  1. Guangxi Engineering Technology Research Center of Breeding of New Mariculture Varieties (Guangxi Institute of Oceanology Co., Ltd.), Beihai 536000, China
  • Received:2021-08-20 Revised:2021-10-20 Published:2021-10-25
  • Contact: CHEN Ruifang E-mail:0xiao0dong0@163.com;ttrfchen@foxmail.com
  • Supported by:
    Guangxi Natural Science Foundation(2018GXNSFBA281071);Start-up Fund for Innovation Team of Guangxi Academy of Sciences(CQ-D-2410)

Abstract:

Artificial proliferation and release is the most effective and rapid method to restore Limulus resources. Understanding and grasping the influence of environmental factors on the growth of juvenile Chinese horseshoe crab (Tachypleus tridentatus), and then choosing a suitable time and sea area for release are the key steps to ensure the success of manual release. Under laboratory conditions, we studied the effects of different salinity (5‰, 10‰, 15‰, 20‰, 25‰, 30‰, 35‰, and 40‰) on the survival rate, molting rate, molting weight gain rate, Na+-K+-ATPase activity, immune enzyme activity, and antioxidant enzyme activity of juvenile Chinese horseshoe crab. The changes of growth, molting, osmotic adjustment, immunity, and antioxidation of the juvenile horseshoe crab at different salinity levels were recorded. The culture experiment lasted for 56 days. The results showed that different salinity levels significantly affected the survival rate, molting rate, average weight of the 2nd instar horseshoe crabs, and molting weight gain rate of the juvenile horseshoe crab (P< 0.05), which increased at first and then decreased with increasing salinity. Regression analysis of molting rate, molting weight gain rate and salinity showed that the optimum salinity for molting and growth of young horseshoe crab were 24.10‰ and 24.94‰, respectively. The Na+-K+-ATPase activities of the 1st and 2nd instar horseshoe crabs increased at first and then decreased significantly with the increase of salinity (P< 0.05). The acid phosphatase (ACP) activities of the 1st instar larvae in the 35‰ and 40‰ test groups were significantly higher than those in the other test groups, while the alkaline phosphatase (AKP) activities of the 5‰ test group were significantly lower than those in the 25‰ test group (P< 0.05). The activities of ACP, AKP and lysozyme (LZM) of the 2nd instar larvae did not change significantly under different salinity conditions (P> 0.05). The catalase (CAT) activities of the 1st instar larvae in 35‰ and 40‰ test groups were significantly higher than those of low-salinity test groups (P< 0.05). And the glutathione peroxidase (GSH-Px) activities of the 2nd WHAT tended to increase with the increase of salinity, and those in 10‰ test group were significantly lower than those in 35‰ and 40‰ test groups (P< 0.05). We show that salinity had a significant effect on growth, molting, Na+-K+-ATPase activity, immune index, and antioxidation of the juvenile horseshoe crab. The optimum salinity for molting was between 24‰ and 25‰. Too high or too low salinity will cause the growth rate, survival rate of juvenile silver carp, the osmotic adjustment ability, immunity, and antioxidation of the juvenile horseshoe crab to decrease significantly.

Key words: salinity, juvenile Tachypleus tridentatus, molting, Na+-K+-ATPase, immune enzyme, antioxidation

CLC Number: 

  • S917.4