Growth response of three Oreochromis niloticus strains to feed restriction

Growth of fry from three test strains of Nile tilapia (CLSU, ISRAEL and NIFI) fed restrictively and non-restrictively were compared. Four-week old fry were matched for size with similarly aged red tilapia fry which served as an internal reference. Fish were stocked in 60l aquaria at a ratio of 25 tests:25 reference fish. Test fish were fed commercial fish feed ad libitum during the initial and final two weeks and rations of the same feed at 10% of the fish biomass during weeks 3 and 4. Control fish were fed commercial fish feed ad libitum throughout the six week experiment. Although feed restriction retarded growth in all three test strains, growth differed significantly between strains. Under both restrictive and nonrestrictive feeding regimes, the ISRAEL strain grew better than the CLSU and NIFI strains