Leaching of feed nutrients, economic losses to fish farming

Abstract

Seven isoproteic 40% crude protein diets were formulated and each diet was bound with different binding agents from wheat flour (WFS), Cassava tuber (CS), Maize offal (MOS), Paddy rice (RS), Yellow maize grains (YMS), Sorghum grains (SS) and Synthetic Carboxymethyl-Cellulose (CMC) as control binder. All binding agents were incorporated at 2%. Total proteins and total lipids retention at 10, 20, 30 and 60 minutes were observed in the laboratory. There were decreasing trends in the nutrients retention at increasing time of immersion in water with the lipids nutrients retention higher (P > 0.05) than the proteins. The diets were also fed to groups of Clarias gariepinus fingerlings (mean weight 2.12 ± 0.02 g) in outdoor concrete tanks. The growth and feed utilization were very related to the records produced from the nutrients retention with the WFS, CS, MOS and RS fishes recording significant differences (P < 0.05) in mean final weight; mean weight gain and feed conversion ratio over YMS and SS among the local binding agents. The economic evaluation was highest (P < 0.05) in CMC in net production value, value of fish, cost of feed, gross profit, incidence of cost and the least in profit index. However, CS binder was recommended because of its abundance in the tropics; higher nutrients retention; higher growth and feed utilization and higher economic evaluation indices among the local binders.


Key words: Retention, Leaching, Diets, Catfish, Binding agents, Economic values.


Journal of Aquatic Sciences Vol.18(2) 2003: 119-124