2022 Volume 57 Issue 3 Pages 95-102
The efficacy of Oxilink-SP, a food-additive-based disinfectant used in the environmental control of livestock pathogens, to prevent Saprolegnia infection of salmonid eggs was evaluated. In the laboratory, Oxilink-SP showed fungicidal activity against 5 species of Saprolegnia after immersion of rainbow trout Oncorhynchus mykiss eggs with Saprolegnia mycelia in a 10,000-fold dilution of Oxilink-SP for 30 min. In salmonid fish hatcheries, following immersion in a 5,000-fold dilution of Oxilink-SP for 30 min per day, hyphal growth on eggs of rainbow trout and white-spotted char Salvelinus leucomaenis was inhibited. This was not the case in masu salmon Oncorhynchus masou which may have been affected by water-borne molds of taxa other than Saprolegnia. Although rainbow trout eggs were slightly affected by treatment with Oxilink-SP in eyed-egg developmental stages and hatching, white-spotted char and masu salmon eggs were not affected. Furthermore, this treatment did not affect the incidence of fry deformity in all tested salmonid fish eggs. These results indicated that the disinfectant can prevent the spread of Saprolegnia species on salmonid eggs in hatcheries. We intend to use Oxilink-SP to safely manage fish eggs.
