The Effect of Hydrogen Peroxide on the Hatch Rate and Saprolegnia spp. Infestation of Channel Catfish Eggs

摘要

Fungal infestations of channel catfish Ictalurus punctatus eggs can lower hatch rate, which requires the producer to spawn more channel catfish or risk fingerling shortages. Hydrogen peroxide (H sub(2)O sub(2)) treatments (0.0, 15.6, 31.3, 62.5, 125, 250, 500, 1,000, 2,000, and 4,000 mg/L) were evaluated to determine their effect on channel catfish hatch rate (number of fryumber of eggs 100) and control of naturally occurring infestations of fungi Saprolegnia spp. in an experimental compartmentalized trough hatching system. Experiments were run at water temperatures of 23.2-24.0 degree C, dissolved oxygen concentrations of 4.5-6.8 mg/L (53-79% saturation), total alkalinity of 209-217 mg/L, and total hardness of 91-110 mg/L. Treatments were applied to hatching compartments while well water was flowing at a rate of one water exchange every 30 min and egg density was 2.5 g eggs/L of water. Observations for fungal development were made daily, and the maximum measure of fungal growth was recorded. An initial range-finding study demonstrated that H sub(2)O sub(2) concentrations greater than 500 mg/L lowered the hatch rate. In later experiments, concentrations of 125, 250, and 500 mg/L applied for 6 d significantly increased the hatch rate and reduced fungal growth when compared with the controls. The 250-mg/L H sub(2)O sub(2) treatment had the highest mean hatch rate (64.4% compared with 24.7% for the controls), lowest incidence of fungal infestation (27.3% compared with 100% for the control), and the lowest average fungal growth (an average measure of 0.95 cm compared with 7.23 cm for the controls).