Adenosine modulates heart rate and tissue glycogen of the giant freshwater prawn Macrobrachium rosenbergii (De Man, 1879)

Abstract

Transport of live crustaceans to market induces a variety of stressors, increases rates of mortality and results in a metabolic imbalance between adenosine triphosphate (ATP) supply and demand. Re-aligning ATP demands with impaired supply during transport should prolong survival. Adenosine acts as a “retaliatory” metabolite and has the potential to induce metabolic depression amid periods of energetic stress. Consequently, in this study, the effect on the metabolic markers, heart rate (HR), tail muscle glucose/ glycogen and haemolymph lactate from administering a range of adenosine concentrations (0.25, 2.5 and 25 mM; n = 6, 5 & 5 respectively) to the giant freshwater prawn (Macrobrachium rosenbergii) by injection was assessed over 3 h. Equivalent water volumes (vehicle) were injected into control animals (n = 5). Adenosine at 2.5 and 25 mM decreased heart rate 20–25 % from baseline for several hours. Free glucose and tail muscle glycogen decreased following treatment with adenosine at 2.5 mM, while haemolymph lactate remained unchanged across treatments. There were zero mortalities across all four treatments. This study shows that adenosine safely depresses the heart rate of M. rosenbergii and may mitigate the stresses associated with live transport.

Keywords

• Adenosine
• Crustaceans
• Transport stress
• Metabolic suppression