SOME FACTORS AFFECTING PROTEIN REQUIREMENTS FOR TILAPIA FISH

Abstract

The present study was carried out at the laboratory of Aquaculture Research, Faculty of Agriculture at Moshtohor, . . Zagazig University (Banha branch). The aim of this study is to

determine the optimum levels of protein and energy required for maximum growth of Nile tilapia, Oreochromis nilotica fry using different protein to energy ratio diets. Protein levels used in the present study were, 20, 25 and 30%, under three energy level for each protein level, 300, 330 and 360 kcal/100 g therefore nine diets were formulated and tested in eighteen aquaria (two replicates for each diet). Experiment sti11 for 8 weeks from 15. 7.200 I -15.9.2001.

Results obtained can be summarized as folJows:

- At experimental start, average body weight (BW) as affected by protein level were 15.35, 15.40 and 15.33 g and body lengths (BL) were 9.70, 9.73 and 9.63 cm for fish fed diets with 20, 25 and 30% protein respectively with insignificant differences in body weight or body length. After two weeks, there were significant differences in BW and BL where the increase in protein level followed by significantly increase in BW and BL and the effect still until experimental end, while differences in condition factor (K) due to protein level were not significant. - With respect to the effect of energy level in fish diets, at experimental start averages BW were 15.35, 15.37 and 15.33 g and BL were 9.65, 9.71 and 9.70 cm for fish fed diets with 300, 330 and 360 kcal/100 g diet, respectively with insignificant