Background: Etroplus suratensis is omnivorous feeder, but mainly feeds on filamentous algae especially Spirogyra. The preference of pearlspot towards Spirogyra as an important food item, made us utilize the Spirogyra as an ingredient in the feed of pearlspot at different levels to evaluate its impact on growth and other parameters. 
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Methods: The experiment was conducted to evaluate the effect of Spirogyra on bio growth performance, digestive enzyme activity and haematology of E. suratensis. The experiment was performed with different levels of Spirogyra incorporated diet - S0, 10, 12.5, 15, 17.5, 20, 22.5 and 25%. The pearlspot fingerlings of initial weight of 14.91&plusmn;0.11 was stocked in the 300 litre FRP tank for 60 days. 
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Result: The highest growth performance of pearlspot was found in 22.5% Spirogyra incorporated diet. The average weight gain was highest in 22.5% SP (26.55&plusmn;0.22 g), followed by 20% SP (26.11&plusmn;0.25 g), control (25.83&plusmn;0.47 g), 25% SP (24.78&plusmn;0.15 g), 17.5% SP (24.46&plusmn;0.16 g), 15% SP (23.03&plusmn; 0.16 g), 12.5% SP (22.21&plusmn;0.34 g), 10% SP (22.16&plusmn;0.80 g). The digestive enzyme activity of amylase (0.026&plusmn;0.001 U mg protein-1 min-1), protease (0.164&plusmn;0.02 U mg protein-1 min-1) and lipase (0.486&plusmn;0.01 U mg protein-1 min-1) were found to be highest in 22.5%SP treatment, followed by other treatments. The haematology parameters RBC and WBC count increased with increase in the incorporation of Spirogyra in diet. The study concluded that the incorporation of Spirogyra at 22.5% improved the growth performance and feed utilization of pearlspot. 
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Effect of Different Levels of Spirogyra Incorporated Diet on Bio Growth Performance, Digestive Enzyme Activity and Haematology of Etroplus suratensis&nbsp;