The evaluation of ammonia tolerance in introduced and local Pacific white shrimp, Litopenaeus vannamei, populations in China

The white shrimp, Litopenaeus vannamei, is one of the most valuable commodities in the global seafood trade. Affected by high-density farming environments, ammonia accumulates in shrimp cultures and has a strong toxic effect, resulting in poor shrimp survival and poor immune function and metabolism. We selected six different populations of L. vannamei from Xing Hai No.1 (A and B), CHAI, Sy Aqua, PRIMO, and a second-generation Sy Aqua-PRIMO hybrid population (SP). The shrimps (3.24 +/- 0.71 cm body length) were exposed to ammonia (24 h, 48 h), followed by recovery (R48 h, R96 h) to assess the tolerance of different populations. The survival rate (SR), immune-related enzymes (superoxide dismutase SOD, catalase CAT, and Glutathione peroxidase GSH-PX), Malondialdehyde (MDA), and metabolism (glutamate dehydrogenase GDH, glutamine synthetase GS, and aspartic acid transaminase GOT) and were measured at different populations under acute ammonia stress. Multiple comparisons of the ammonia resistance index from six populations showed that the expression of these indicators varied among the populations. The degree of lipid peroxidation in the Sy Aqua and PRIMO was significantly higher than in the other populations (P < 0.05), and the ammonia metabolism index was poor. The GDH and GOT genes for the Xing Hai No.1 (A) were higher than for the other populations. Mortality and physiological indicators recovered to varying degrees for all experimental populations following 96 h of ammonia relief, whereas the Sy Aqua and PRIMO showed a noticeable lag. These results indicated that the immunity and metabolic capacity of Xing Hai No.1 (A) might be higher than those of Sy Aqua and PRIMO. These data could have value in developing future scientific breeding schemes and in the sustainability of shrimp farming.