A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science, School of Environment, Resources, and Development

Thesis (M.Sc.) - Asian Institute of Technology, 1995

Two experiments were carried out to evaluate the possibility of using Triple super phosphate (TSP), 16:20, Rice bran and Duck manure as phosphorus sources in formulated fish feeds for Nile tilapia and to evaluate t he toxic effect of TSP on Nile tilapia. All male sex reversed Nile tilapia ( Oreochromis niloticus, 9.39- 10.37g) were used in both the experiments. Experiment 1 was conducted in netcages suspended in fertilized earthen ponds. Seven treatments including one non-feed treatment were used in this experiment: Treatment l(No-feed), treatment 2(-P) where fish fed with phosp horus non-supplemented diet acted as control 1 and treatments 3, 4, 5, 6 and 7 where fish fed with 3 % Dicalcium phosphate (DCP), 3 % TSP, 7 % 16:20 fertilizer, 30 % Rice bran and 30 % Duck manure supplemented diet respectively. Results s howed that the TSP and fertilizer 16:20 supplementation in diets as phosphorus sources were equivelent to DCP in terms of growth performence, feed utilization efficiency and final body composition of Nile tilapia. Rice bran and Duck manure were found not good phosphorus sources. Experiment 2 was conducted in recirculation water system to evaluate toxic effect of TSP on Nile tilapia by including 1-5 % of diet. Results indicates that the addition of TSP to feeds resulted in no mortality and toxic symptom on Nile tilapia upto 5 % inclusion level and hig hest growth performance and feed utilization efficiency obtained at 4 % Supplementation level in diet.