Lahnsteiner Franz, Dünser Anna
Federal Agency for Water Management, Institute for Water Ecology, Fisheries and Lake Research, Scharfling 18, A-5310 Mondsee, Austria; Fishfarm Kreuzstein, Oberburgau 28, 4866 Unterach, Austria.
J Genet Eng Biotechnol. 2025 Sep;23(3):100541. doi: 10.1016/j.jgeb.2025.100541. Epub 2025 Jul 28.
Disinfection of the interior of non-hardened eggs with iodophors (Buffodine®) is an established hygienic practice in salmonid aquaculture to prevent pathogen transmission from the broodstock fish to their offspring. As iodophors inhibit sperm motility, fertilization is first performed in a 0.75 % NaCl solution, followed by egg disinfection in a second step after fertilization is complete. Although this two-step egg disinfection procedure is simple to perform under laboratory conditions, it presents challenges for fish farms using mass stripping. The process involves two highly time-sensitive steps, requiring precise execution, as any errors can lead to fertilization failure or ineffective disinfection. A more practical approach would be to simplify disinfection into a single-step procedure. The present study demonstrates that non-hardened rainbow trout eggs can be fertilized and disinfected simultaneously using a one-step method with tosylchloramide (100 mg/l Chloramine T®) or peroxide (100 µl Wofasteril®) compounds in 0.75 % NaCl for 40 min. This procedure is feasible as the applied concentrations of Chloramine T and Wofasteril have only low impact on sperm motility. The one-step methods do also not negatively impact embryo and early larval development. Non-hardened rainbow trout egg disinfection methods with Chloramine T and Wofasteril were as effective as the conventional Buffodine method in reducing total bacterial load of eggs at 3 h post-fertilization (hpf), the point at which water hardening is complete. Reanalysis of total bacterial load after 22 days of development (embryo stage at the onset of eye pigmentation) proved Chloramine T more effective than Wofasteril and Buffodine. Microbiome composition differed significantly across developmental stages and disinfection treatments. Notable variations were observed between non-disinfected controls and eggs treated with Buffodine, Chloramine T, or Wofasteril, in persistent bacterial communities, stage-specific bacteria, and bacteria colonizing the chorion during embryogenesis. Buffodine treatment increased bacterial diversity, while Chloramine T and Wofasteril led to reduced diversity compared to the control. These findings are discussed in the context of microbiome stability and resilience, key factors for long-term fish health. In summary, the simplified one-step disinfection protocol offers practical advantages in reducing time-sensitive handling steps and improving efficiency in large-scale aquaculture operations. Moreover, it is environmentally preferable as both Wofasteril and Chloramine T are used at lower concentrations than Buffodine and degrade rapidly in water, leaving no harmful residues.
使用碘伏（百多帮®）对未硬化鱼卵内部进行消毒是鲑鱼养殖中一种既定的卫生做法，以防止病原体从亲鱼传播给它们的后代。由于碘伏会抑制精子活力，因此先在0.75%的氯化钠溶液中进行受精，然后在受精完成后的第二步进行鱼卵消毒。尽管这种两步鱼卵消毒程序在实验室条件下易于操作，但对于采用大量采卵的养鱼场来说存在挑战。该过程涉及两个对时间高度敏感的步骤，需要精确执行，因为任何错误都可能导致受精失败或消毒无效。一种更实用的方法是将消毒简化为单步程序。本研究表明，未硬化的虹鳟鱼卵可以在0.75%的氯化钠溶液中使用对甲苯磺酰氯胺（100mg/l氯胺T®）或过氧化物（100µl沃法斯特利®）化合物的单步方法同时进行受精和消毒40分钟。该程序是可行的，因为所应用的氯胺T和沃法斯特利浓度对精子活力的影响很小。单步方法也不会对胚胎和早期幼体发育产生负面影响。在受精后3小时（hpf，此时水硬化完成），用氯胺T和沃法斯特利对未硬化的虹鳟鱼卵进行消毒的方法在降低鱼卵总细菌负荷方面与传统的百多帮方法一样有效。在发育22天后（眼睛色素沉着开始时的胚胎阶段）对总细菌负荷进行重新分析，结果证明氯胺T比沃法斯特利和百多帮更有效。微生物群落组成在不同发育阶段和消毒处理之间存在显著差异。在未消毒的对照与用百多帮、氯胺T或沃法斯特利处理的鱼卵之间，在持久性细菌群落、阶段特异性细菌以及胚胎发育过程中定殖在卵膜上的细菌方面观察到了显著差异。百多帮处理增加了细菌多样性，而与对照相比，氯胺T和沃法斯特利导致多样性降低。这些发现是在微生物群落稳定性和恢复力的背景下进行讨论的，这是鱼类长期健康的关键因素。总之，简化的单步消毒方案在减少对时间敏感的处理步骤和提高大规模水产养殖作业效率方面具有实际优势。此外，它在环境方面更可取，因为沃法斯特利和氯胺T的使用浓度都低于百多帮，并且在水中迅速降解，不会留下有害残留物。
