PERFORMANCE OF TILAPIA, CARP AND MULLET UNDER POLYCULTURE CONDITION

In order to study the effect of growth response of different fish species to different protein levels, an experiment has been carried out using diets with different protein content(11%, 17% and 25%) for feed‌ing cultured tilapia 5.aureus ; common carp Cyprinus Carpi°, silver carp Hypophthalmichthys molitrix and mullet Mugil cephalus and M. capito in Abbassa farm Sharkia governorate belonging to Central Laboratory for Aquaculture. Twelve rectangle earthem ponds, of 0.25 feddan each were used representing four treatment -three replicates each. The results showed that, differences in daily yield and total yield due to protein level were found to be significant (p < 0.01). The resuts showed significant differences (p < 0.001)among species in daily gain, daily yield and total yield . Correlation coefficients be‌tween productive traits ranged between (0.5 and 0.9). Keywords: Polyculture, tilapia, common carp, silver carp, mullet, gain, yield and protein levels.