B. Gangadhar¹ , H. Umalatha¹ , G. Hegde¹ , N. Sridhar¹ , Perar Keshavanath²

1 ICAR-Central Institute of Freshwater Aquaculture, Regional Research Centre, Hesaraghatta Lake P.O., Bangalore, India
2 Department of Aquaculture, College of Fisheries, Karnataka Veterinary, Animal and Fisheries Sciences University, Mangalore, India
Author    Correspondence author
International Journal of Aquaculture, 2016, Vol. 6, No. 7   
Received: 25 Mar., 2016    Accepted: 28 Mar., 2016    Published: 29 Mar., 2016

This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

This study compared the taxonomic and proximate composition of periphyton grown on sugarcane bagasse with that of free plankton. The activity of major digestive enzymes in periphyton and free plankton extracts was analysed in order to quantify their possible exogenous digestive enzyme contribution to fish. In periphyton, plankton belonging to Chlorophyceae were dominant (25.3%), followed by Cyanophyceae (19.7%), Bacillariophyceae (16.9%), Conjugatophyceae (8.4%), Desmidaceae (4.2%), Euglenophyceae (5.6%), Ulvophyceae (4.2%), Dinophyceae (1.4%), Xanthophyeae (1.4%), Florideophyceae (1.4%) and Trebouxiophyceae (1.4%). Free plankton consisted of Chlorophyceae (24.2%), Cyanophyceae (15.1%), Bacillariophyceae (9.1%), Conjugatophyceae (6.1%), Coscinodiscophyceae (3%), and Trebouxiophyceae (3%). Zooplankton formed 39% of free plankton as against 10% of periphyton. Proximate composition of plankton was superior with higher levels (P<0.05) of crude protein, fat and NFE, whereas crude fibre and ash content was higher in periphyton. The activity of majority of the digestive proteases, amylase and cellulase was higher in plankton, while that of chymotrypsin was higher in periphyton; lipase activity did not show any difference between plankton and periphyton. The results indicate that periphyton can serve as an additional natural food source, especially for herbivorous fish.

Periphyton; Plankton; Digestive enzymes; Proximate composition; Taxonomy

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