Toxicological mechanism of ammonia-N on haematopoiesis and apoptosis of haemocytes in Litopenaeus vannamei

Ammonia, as an important pollutant, contributed to the reduction of immunity, disruption of physiology in animals. RNA interference (RNAi) was performed to understand the function of astakine (AST) in haematopoiesis and apoptosis in Litopenaeus vannamei under ammonia-N exposure. Shrimps were exposed to 20 mg/L ammonia-N from 0 to 48 h with injection of 20 mu g AST dsRNA. Further, shrimps were exposed to 0, 2,10 and 20 mg/L ammonia-N also from 0 to 48 h. The results showed that the total haemocytes count (THC) decreased under ammonia-N stress and the knock-down of AST resulted in a further decrease of THC, suggesting that 1) the proliferation was decreased through the re-duction of AST and Hedgehog, the differentiation was interfered by Wnt4, Wnt5 and Notch, and the migration was inhibited by the decrease of VEGF; 2) oxidative stress was induced under ammonia-N stress, leading to the increase of DNA damage with the up-regulated gene expression of death receptor, mitochondrial and endoplasmic reticulum stress pathways; 3) the changes of THC resulted from the decrease of proliferation, differentiation and migration of haematopoiesis cells and the increase of apoptosis of haemocytes. This study helps to deepen our understanding of risk management in shrimp aquaculture.

Automated summary

In this study, RNA interference was used to investigate the effects of ammonia exposure on haematopoiesis and apoptosis in Litopenaeus vannamei. The results showed that ammonia stress reduced the total haemocytes count and knock-down of astakine (AST) further decreased it. Additionally, ammonia stress induced oxidative stress, leading to DNA damage and up-regulated expression of death receptor, mitochondrial, and endoplasmic reticulum stress pathways. Overall, this study enhances our understanding of risk management in shrimp aquaculture.