Immune injection to solve the four diseases of grass carp how to vaccinate grass carp in spring

Grass carp (Ctenopharyngodon idellus) is favored by consumers for its large size, delicate meat and few intermuscular spines. However, grass carp "four diseases" (red skin disease, Gill rot disease, enteritis, hemorrhagic disease) restrict the development of grass carp culture. Long-term practice has proved that grass carp immune injection is an effective way to solve the "four diseases" at present.

Grass carp immune injection

1. Principle:

Under the condition of low temperature (8 ℃-20 ℃), the metabolism of grass carp is weak. The new immune antigen dose of two-year-old grass carp can be obtained by injection. Induced by low temperature of 5-30 days (10 ℃-15 ℃), the injected grass carp can complete the first immunity. When the water temperature is above 20 ℃, the level of immune resistance of grass carp increases rapidly, thus reducing the incidence of two-year-old grass carp.

2. Methods:

1. Time choice. It is carried out in spring when the water temperature is 8 ℃ ~ 22 ℃. In the northern region, March, where the water temperature is low, is selected as far as possible, which is helpful to prevent water mildew. Infected grass carp should not be immunized by injection.

2. Fish fingerling preparation. All kinds of robust and disease-free grass carp species above 8.33cm can be immunized. Before injection, disinfect the fish with 0.5% saline solution for 5-10 minutes. In order to facilitate the production and operation, the fish can be anesthetized with trichlorfon aqueous solution.

3. Tool selection. Syringes, needles and dilution containers should be sterilized with 75% alcohol or boiling water. Fish with specifications below 9.99cm generally use injection needles of 4.00 or 11.66cm, those with specifications above 11.66cm generally use injection needles of 5.00 or 11.66cm, and fingerlings with specifications above 16.65cm generally use injection needles. In order to prevent the deep injury of the needle and the viscera of the fish during injection, a small plastic tube can be put on the needle, and the exposed tip is slightly longer than the thickness of the abdominal muscle of the fish.

4. Dilution of vaccine. The concentrated solution is diluted 10 times with 0.65% normal saline before use, and a bottle of diluted vaccine had better be used at one time. If it cannot be used up, the required amount can be extracted by syringe. After extraction, the needle eye is sealed with medical tape.

5. Injection site and dose. Injected at the base of the ventral fin of grass carp, the needle is 45 degrees with the fish body and pierced into the fish body. Fish with specifications below 9.99cm shall be injected with 0.5ml diluted vaccine per tail, fish with specifications in 9.99~16.65cm with 0.5ml diluted vaccine per tail, and fish with specifications above 16.65cm with 1ml diluted vaccine per tail.