| Fish ponds for growing silver carp and big-headed fries and common carp, silver carp and big-headed fingerlings, P. fulvidraco fingerling were sprayed with PSB under different water temperatures and different concentrations conditions. Results were analyzed based on following 5 indexes: hydrochemistry index,plankton biomass,fish disease control,promoting growth and economic benefits.The results showed that PSB sprayed could significantly affect the concentrations of Do, NHU桸 of water body. In common carp, silver carp and big-headed fingerlings ponds, when water temperature was 15~17癈, supersaturated Do were decreased by 56.84%, NRj桸 by 51.28%, plant plankton biomass were lessened by 27.64% from 890.92mg/L to 644.66mg/L in three days. Compared with control groups, Do was increased by 26.17%, 49.54% and 34.86%, NRp-N was decreased by 32.73%, 60.00% and 52.00%, plant plankton biomass by 4.04%, 23.32% and 10.89% in ^.fulvidraco ponds sprayed with 5g, lOg and 15g per cubic meter of PSB. In silver carp and big-headed fries ponds, Do was significantly increased by 24.05%, 80.78% and 75.48%, NR*桸 was decreased by 27.85%, 60.14%and 59.07%, while plant plankton biomass raised by 36.23%, 54.42% and 63.12%, respectively, compared with control ponds. The results of Do, NFLt?N and plant plankton biomass indicated that PSB with 30 billon cells per ml was the best treatment on improving water quality when applied at lOg per cubic meter of water.Results of fish disease control showed that PSB effectively reduced the number and breeding of pathogen of water body and it was beneficial to control saprolegniasis, tail-rot disease at 15~17癈 of water temperature. In hot summer, flaccid disease, gill-rot disease, congestion disease, sinergasilliasis and arguliosis could be controlled by PSB, furthermore, PSB applying at lOg per cubic meter could cure gill-rot disease, congestion disease of ^.fulvidraco; the survival rate of fish treated with PSB was higher 20% than medicine treatment groups. When experimental ponds were treated with PSB at lOg and 15g per cubic meter of water, arguliosis could be effectively controlled. For controlling fish disease, drastic stimulation didn t exist on fish body. The aim of the experiment was to indirectly control fish disease through improving existent environment of fish.Results of growth showed that PSB treatment at 15g per cubic meter of water could effectively promote the growth of different species of fish. In P.fulvidraco ponds,individual weights of P.fulvidraco were increased 4g, 9g and 15g, the yields were increased 6kg, 14kg and 24kg/mu, the feed coefficients were decreased 0.06, 0.56 and 0.73, the survival rates were increased by 0.91%, 2.15%and 3.34%. In silver carp and big-headed fries ponds, individual weights of P.fulvidraco were increased 7g, 15g and 17g, the yields were increased 4.3kg, 9.1kg and lOkg/mu, the feed coefficients were lessened 0.12, 0.52 and 0.67, the survival rates were increased by 0.57%, 4.99% and 5.21%, respectively. Growth of silver carp and big-headed fries ponds was positively related to plant plankton biomass of treat groups. The weight gain in ponds with low stock rate was higher than that in ponds with high stock rate.Results suggested that it was practical for culture of fingerling to apply PSB. |
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