The present experiment was carried during one growing season (100 days) in earthen ponds. The objective of the study is to develop guidelines for the integration of ducks and buffaloes with fish by developing practical systems for fish in polyculture system using duck and buffalo manures. The treatments applied are buffalo manure only (BM), buffalo manure with supplementary feed (BM+F), duck manure only (DM) and duck manure with supplementary feed (DM+F). Each treatment was performed in triplicate, each in an earthen pond of an area of 2000 m². Each pond was stocked with 3000 Nile tilapia (Oreochromis niloticus ), 940 blue tilapia (O. aureus ), and 60 common carp (Cyprinus carpio). The obtained results can be summarized as follow:
- At the experiment start, body weight and body length of Nile tilapia was relatively similar and after 30 days of the experiment, body weights among treatments groups were significantly different and these differences continued till harvesting where the DM+F treatment produced the heaviest and longest fish bodies compared to the other treatments.
- Body weight and body length of blue tilapia and common carp showed the same trend of Nile tilapia .
- Specific growth rate (SGR) of Nile tilapia, blue tilapia and common carp were higher in treatments received BM+F and DM compared to those received BM or DM only and the differences were significant.
- The higher total fish production was obtained by DM+F group followed in a significant decreasing order by the other groups, BM+F, DM and BM, respectively .
- The net return (total returns - total costs) were 5036, 4739, 6657 and 5741 LE for the different treatments, BM; BM+F; DM and DM+F, respectively. Therefore, DM group recorded the best returns compared to the other treatment.
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