**5. Conclusions**

In this research, the full-length *PmNHE* gene was cloned, the structure of the *PmNHE* gene was analyzed by bioinformatics, the expression changes of *PmNHE* in various tissues and in the gill and intestine of *P. monodon* under acute ammonia nitrogen stress were investigated, and the death curve under high levels of ammonia nitrogen stress was explored by RNAi technology. The results provide a basis for further exploring the role of the sodium/hydrogen ion transporter in *P. monodon* under ammonia nitrogen stress.

**Author Contributions:** S.J. (Shigui Jiang) and F.Z. conceived and designed the experiments. Y.L. performed the bioinformatics analysis and prepared the manuscript, the table, and the figures. H.F., J.H. and W.Z. conducted the experiment. L.Y., X.C., S.J. (Song Jiang) and Q.Y. collected the samples and performed sequencing. All authors have read and agreed to the published version of the manuscript.

**Funding:** This study was funded by the National Key R&D Program of China (2022YFD2401900); China Agriculture Research System (CARS-48); Hainan Yazhou Bay Seed Laboratory (Project of B21Y10701 and B21HJ0701); Research and Development Projects in Key Areas of Guangdong Province (2021B0202003); Central Public interest Scientific Institution Basal Research Fund, CAFS (2020TD30); Central Public Interest Scientific Institution Basal Research Fund, South China Sea Fisheries Research Institute, CAFS (2020ZD01,2021SD13); Hainan Provincial Natural Science Foundation of China (320QN359,322RC806,320LH008); Guangdong Basic and Applied Basic Research Foundation (2020A1515110200); Guangzhou Science and Technology Planning Project (202102020208); and Hainan Provincial Association for Science and Technology of Young Science and Technology Talents Innovation Plan Project (QCQTXM202206).

**Institutional Review Board Statement:** The use of all the shrimps in these experiments was approved by the Animal Care and Use Committee at the Chinese Academy of Fishery Sciences (CAFS), and we also applied the national and institutional guidelines for the care and use of laboratory animals at the CAFS.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** Not applicable.

**Conflicts of Interest:** The authors declare no conflict of interest.

### **References**

