Prevention and treatment of hemorrhagic disease in herring culture

I. Prevention

1. Block the pathogen

① provenance: cultivate healthy old fish species and improve their disease resistance. Establish the quarantine mechanism of parent fish and fish species.

② water source: require freshness, no pollution, set up influent pre-treatment facilities. In addition, separate influent and drainage systems reduce the chance of cross-infection.

③ bait source: in addition to not throwing spoiled bait, bait disinfection measures should be taken to prevent the disease from entering through the mouth.

2. Improve the environment

① thorough desilting disinfection: in order to put an end to the source of infection, in addition to thorough desilting, the pond should also be strictly disinfected. Methods such as exposure, ploughing and sprinkling quicklime and bleach can be taken.

Proper mixed culture and rotation culture of ②: it can give full play to the basis of pond bait, improve the water quality environment and reduce the relative density of herring. Rotational culture of different varieties can also reduce the environmental oppression caused by continuous culture of a single variety.

③ control culture density: high density makes the culture object appear stress reaction, lead to the decrease of immunity and increase the chance of mutual infection. It is suggested that the mixed culture density should be 50 ~ 150 tails / mu.

④ strengthen operation management: during the culture period, we should not only strengthen the disinfection measures of each operation procedure, but also explicitly prohibit the abuse of antibiotics in order to maintain the ecological balance of the microbial population in the water and improve the disease resistance of herring.

⑤ strengthens water quality monitoring: regularly tests whether the contents of harmful physical and chemical factors such as hydrogen sulfide, nitrite ions, toxic ammonia and heavy metal ions in water exceed the standard. In addition, strictly prevent the discharge of sewage from industrial and mining enterprises into the pool.

3. Drug prevention

With chemical medicine or Chinese herbal medicine, take the method of external elimination and internal administration for prevention. Generally, the water body is disinfected once or twice a month, and the bait is taken internally for 3 days for 5 days. But pay attention to the dose and course of treatment, otherwise it will lead to the emergence of drug-resistant pathogens, and make treatment more difficult. In addition, ecological prevention can also be used, such as the application of biological agents such as photosynthetic bacteria (PSB) and EM preparations.

4. Immunoprevention

It is a development direction to use vaccine to prevent herring bleeding disease. The parent fish or fish species are vaccinated or soaked before entering the pond, so that the fish species have a better immune ability. It is especially important in high-density monoculture or herring-based mode.

II. Treatment

TCCA granules or powders and other germicidal and disinfectant drugs were used with heavy manipulation (i.e. appropriate overdose) for 3 to 4 times, and combined with virulent and other drugs for 6 to 8 days. It can generally be effectively controlled.