Effect of Single or Double Exposures to Hydrogen Peroxide or Iodine on Salmonid Egg Survival and Bacterial Growth

Abstract

Four disinfection tests were conducted on the eggs of cutthroat trout Oncorhynchus clarkii, rainbow trout O. mykiss, and brown trout Salmo trutta. In each egg test, the effects of treating twice were determined, which simulated treatment at both the brood source and the receiving hatchery. Cutthroat trout eggs were treated at 1 h and again at 3 or 6 h after fertilization. Survival to the eyed stage was greater for eggs treated with 100 mg/L iodine for 10 min (86.9%) than with 1.5% hydrogen peroxide (H 2 O 2 ) for 2 min (82.4%); the timing of the second disinfection had no effect on egg survival. Bacterial growth was significantly greater among H 2 O 2 -treated eggs. For eyed rainbow trout eggs, 2,000 mg/L iodine for 10 min was toxic (<11% hatch), but eggs treated either once or twice with hydrogen peroxide (1% H 2 O 2 for 2 min) survived to hatch, as did the controls. Bacterial growth was significantly greater on eggs treated with H 2 O 2 than control eggs treated with 100 mg/L iodine for 10 min. In a subsequent test with eyed rainbow trout eggs exposed to 1,000 mg/L iodine for 15 min either once or twice, hatching rates did not significantly differ from those of controls. Bacterial growth was significantly lower after 1,000-mg/L iodine treatment than in controls treated with 100 mg/L. In the fourth test, survival to hatch of eyed brown trout eggs treated with 1,000 mg/L iodine once or twice did not differ from that of controls. For bacterial control, double treatments are safe at iodine doses of no more than 1,000 mg/L or when 1% H 2 O 2 is used. The bacteriological results suggest that a single or double dose of 1,000 mg/L iodine provides the best control of bacterial growth.

Comparison of in vitro and in vivo antibacterial efficacy for the control of Flavobacterium psychrophilum in rainbow trout (Oncorhynchus mykiss)fry: the first genotypical evidence in West Aegean region of Turkey

“…Flavobacterium psychrophilum infection is still treated with antibiotics. Different pharmacological agents have been evaluated for the prevention and treatment of RTFS in trials (4,5).…”

Disinfection of teleost eggs: a review

“…; Wagner et al . ). Depending on the study, larvae were monitored for a period between 2 (Stuart et al .…”

“…; Wagner et al . ) or mixing the homogenate with preheated fluid agar, before pouring into Petri dishes (Ben‐Atia et al . ; Katharios et al .…”

“…; Wagner et al . ,c). Although this technique offers the most precise results, it is very time‐consuming and virtually impossible in large‐scale experiments.…”

Evaluation of Glutaraldehyde, Chloramine-T, Bronopol, Incimaxx Aquatic® and Hydrogen Peroxide as Biocides against Flavobacterium psychrophilum for Sanitization of Rainbow Trout Eyed Eggs

“…Hydrogen peroxide as a strong oxidizing agent is widely used by aquaculture industry to treat fungal infections of fish with recommended concentration for bath treatments (500 ppm for 20 min; [31]) as well as to sanitize fish eggs for concentrations ranging from 500 until to 30,000 ppm for few minutes to 60 min [32,33]. While hydrogen peroxide is a useful and environmental friendly biocide, it can promote or boost, in some cases, fish infections (e.g., Tenacibaculum maritimum in turbot [34]).…”