Abstract:
The proportion of sulfate ions in saline-alkali waters and fresh water in northwest China is usually high. In order to investigate the adaptability of
Litopenaeus vannamei to high sulfate content saline water, taking the juvenile shrimps Average body mass of (0.9±0.2) g as objects, we conducted a 5-week aquaculture experiment in a controlled indoor environment. The experimental water was prepared with customized artificial sea salts and the salinity was 5‰, the sulfate ion concentrations were 0.385 (Control), 1.175, 1.735 and 2.300 g·L
−1, corresponding to \mathrmSO_4^2- /Cl
− (mg/mg) ratios of 0.140, 0.577, 1.127 and 2.225 (Labeled as Group A, B, C and D). The results show that the survival rate of
L. vannamei in all the groups were above 70%, and there were no significant differences in the survival rate, wet mass, weight gain rate and specific growth rate among all the groups (
p>0.05). The SOD activity in hepatopancreas and gills of
L. vannamei increased first and then decreased as the water sulfate concentration increased. The SOD activity in hepatopancreas of Group D was significantly lower than that of the other groups (
p<0.05), while the SOD activity in gills of Group A and D was significantly lower than that of the other groups (
p<0.05). There were no significant differences in the GSH-P
X, sodium-potassium ATPase activity and MDA content among all the groups (
p>0.05). There were no significant differences in the hepatopancreas ACP and AKP and tyrosinase activity among all the groups (
p>0.05), but the ACP activity in gills of all the groups decreased as the sulfate concentration increased. The ACP activity in gills of Group D was the lowest, and its AKP and TYR activities were significantly lower than those of Group A (
p<0.05). No obvious changes were observed in the structure of gill tissues under HE staining in any group. In Group D, the lumen of hepatopancreas was deformed and enlarged, and some B cells were broken. In summary,
L. vannamei has tolerance to certain sulfate content in low salinity water, but high sulfate stress may cause changes in the immune and antioxidant enzyme activity of gills and hepatopancreas, as well as damage to hepatopancreas tissue. The suitable range of \mathrmSO_4^2- /Cl
− for
L. vannamei is 0.140 to 1.127 under salinity 5‰. The findings provide a scientific reference for promoting
L. vannamei aquaculture with high sulfate content waters in the northwest inland areas in China.