In a study on cultivation of Nile tilapia in earthen ponds (each of 1 faddan
area) under poly-culture semi-intensive system, betsfin was added 10 diet offered to
1!1 pond (1 Kgflon), 2as! pond (2 Kgfton) and 3~ pond (1 Kg besides biopolym 600
ml/ton). Biopolym was added to diet of 4!l! pond (600 milton) but sprayed on 5!l!
pond's water (1500 ml then 600 ml each 2 weeks). The 6^1ll pond was a control.
without additives. The experimental duration was 6 months. The ~ pond gave the
best results, i.e. the highest average body weight. total and daily body gains, growth
rates (relative and specific), total productivity (10.675 tonlfaddan), muscular protein %,
radius of the muscular bundles, total surface area occupied by the muscular
bundles/mm² (Ihe least thickness of connective tissues between muscular bundles
and thickness of skin and subcutaneous layer), and highest net return (21.970
thousand LElfaddan).