Protein biosynthesis in circulated fishponds
1988
Avnimelech, Y. | Mokady, S. (Technion-Israel Inst. of Technology, Haifa (Israel))
One of the problems involved with single cell protein (SCP) production is the need to harvest and to process the microorganisms grown in the system. This problem is avoided if microorganisms are grown and utilized in a fishpond. Continually mixed and aerated / circulated fishponds are effectively a very efficient mixed bed bioaerator, suitable for the production of SCP. Tilapia (Oreochromis aureus) were grown in tanks in which the water was circulated continually using air lift systems. Feed treatments consisted of (a) control, commercial pellets containing 25% protein, mainly from fish and soybean meals, (b) protein-poor feed, pellets made of wheat and sorghum meals (c) bacterial SCP diet, protein-poor pellets supplemented by daily addition of ammonium sulfate and cellulose. The added level for (c) was adjusted to replace the protein added with the commercial high protein pellets. It is anticipated that bacteria, getting their energy from the cellulose, will take up ammonium from the water and produce bacterial protein that will be utilized by the fish. Growth of fish receiving most of their protein as SCP (0.43 g/day) was somewhat lower than those receiving commercial pellets (0.75 g/day) but higher than that of fish grown on the protein-poor pellets alone (0.17 g/day). Protein and fat contents of fish grown on the SCP diet were similar to those fish grown with the commercial pellets. Tilapia can utilize bacterial SCP. It seems therefore possible to replace, at least partially, expensive protein sources by cheaper carbon and nitrogen sources.
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