The effect of dietary Earth worm (Eisenia fetida) difference levels on water quality of Rainbow trout (Oncorhynchus mykiss) rearing tanks

This experiment was designed with the aim of effecting the use of live Eisenia fetida as a food supplement on the water quality of rainbow trout rearing tanks. Fish with a weight average of 58 g were placed in a completely randomized design in 4 treatments and each in 3 replicates. The fishes fed with different levels of 0, 25, 50 and 75% (control, T1, T2 and T3) of diets from live worms (including 50% moisture content) for 8 weeks at 18 °C. Comparing means obtained from water quality factors showed a significant difference in pH of control and other treatments and also do and tss among all treatment (P<0.05). The amovnt of TAN in the first sampling was significantly different from the above treatments, but this amount in the last sampling in dedicated a dearease in TAN and No significant difference was between treatment 2 and 3. The compersion of NO2 - and NO3 - inconsecuative sampling was found a significant decrease amony all treatment with increasing the amount of worm in the food (P<0.05). The use of worm at the level of 50% had the best growth and water quality of tanck reserver.