Qualitative algal analysis from the fish-gut: tested in the rice fish cropping system

ABSTRACT

Algae constitute a major proportion of fish food in rice-fish culture system. Study of algal preferences and their availability in the natural environment might be important for developing natural fish feed. Preparation of formulated feeds using under-exploited materials such as algae not only reduces production costs, but also increases procurement accessibility of locally available alternative ingredients. Methodological difficulties were being encountered in the processing and identification of ingested algal material from fish guts during the study. A new approach was thus developed to make the analysis easier, simple and accurate. For the purpose, algal ingestion by Cyprinus carpio.L stocked in a rice-fish cropping system was undertaken. The intact guts or gut contents of 25 fishes were transferred directly to five different solid nutrient mediums to study the species of algae consumed by the fish. The method adopted was found to be simpler, accurate and more convenient compared to conventional technique for gut analysis. Moreover, the methodology also reduces the number of fishes 'sacrificed' for the study