Alteration of the haemocyte parameters, expression of immune-related and neurohormone bursicon genes of giant river prawn Macrobrachium rosenbergii (de Man) in the response to salinity stress and ammonia stress

We examined the effects of salinity stress and ammonia stress on alteration of the haemocyte count, phenoloxidase activity, expressions of immune-related genes including prophenoloxidase (proPO), crustin, heat shock protein 70 (HSP70), and expressions of stress-responsive neurohormone (Bur-alpha and Bur-beta) in the thoracic and abdominal ganglia of giant river prawn Macrobrachium. These parameters of prawn that subjected to salinity stress (transferred from 0 parts per thousand to 5 parts per thousand and 10 parts per thousand), and subjected to ammonia-nitrogen (ammonia-N) stress (transferred from 0 to 0.262 mg/L and 0.786 mg/L) were examined after 0, 3, 6, 24, 72 and 168 hr respectively. During the initial period of 3, 6 and 24 hr, granulocyte haemocyte (granular and semi-granular hemocyte) count and PO activity significantly decreased, while expressions of Bur-alpha and Bur-beta significantly increased. After 24 hr, granulocyte haemocyte count and PO activity significantly increased, whereas expressions of Bur-alpha and Bur-beta significantly decreased. The expressions of proPO, crustin and HSP70 were significantly downregulated in the prawn that subjected to salinity stress and ammonia-N stress at all time periods of 3-168 hr. In conclusion, changes in the granulocyte haemocyte count of M. rosenbergii following salinity stress and ammonia-N stress are closely associated with the changes of Bur-alpha and Bur-beta expressions.