Effects of supplemental phytase on growth, nutrient digestibility and anti-oxidant enzyme activity in the gills of juvenile mrigal, Cirrhinus mrigala (Hamilton 1882) fed distillers dried grains with soluble based diets

Abstract

A 90-day feeding trial was conducted to investigate the effects of phytase supplemented Distiller’s Dried Grains with Soluble (DDGS) based diet on the production performance, tissue composition, nutrient digestibility and activity of anti-oxidant enzymes in the gills of mrigal (Cirrhinus mrigala) juveniles. Six experimental diets were formulated to contain increasing levels of supplemental phytase, 0 (D1), 250 (D2), 500 (D3), 750 (D4), 1000 (D5), and 1250 (D6) phytase (FTU/kg). Each experimental diet was randomly assigned and fed three times daily to triplicate groups of 180 fish. Significant increase in body weight gain and specific growth rate, feed conversion and protein efficiency ratios of groups fed up to 750 FTU/kg were observed. Broken line analysis of Specific Growth Rate showed that the optimal dietary phytase level of mrigal juveniles is 750 FTU /kg or higher than this dose. Results among protein, lipid, moisture, ash and P contents of whole body, muscle, liver and viscera were not significantly different as phytase level increased from 250 FTU/kg to 1250 FTU/kg (D2 to D6). It was concluded that phytase at the rate of 750 FTU /kg is the optimum dose for the enhanced growth in juvenile mrigal.

Keywords

• Phytase level
• Cirrhinus mrigala
• specific growth rate
• phosphorus retention
• growth