Ietalurus Punetaus, commonly known as pincerfish (referring to the fish whose tail fin is as large as a pincer), ditch catfish (not the Sichuan region called "ditch catfish"), belong to the catfish order, catfish family. Native to North America, it is a large freshwater fish with the advantages of heterogeneous food, fast growth, wide adaptability, strong disease resistance, and superior meat quality. American forktail catfish since 1985 from the United States to introduce the original species for domestication, in 1989 breeding success, after more than thirty years of development, now there is a serious breeding of inbreeds, resulting in frequent outbreaks of intractable diseases, is currently the most difficult thing, hindering the popularization of spotted forktail catfish, the current number of spotted forktail catfish intestinal sepsis is the most stubborn outbreak and epidemic, is listed as three types of animal diseases, need to be deliberately cautious.
<b>Pathogen of spotted fork-tailed catfish intestinal sepsis</b>
Edwardsiella ictaluri, with a body size of 0.5 m×1.75 m, is a gram-negative short bacillus with flagella around the body. It can move at 25 °C, but not at 37 °C. The bacteria grew slowly on the medium, and after 48 hours of incubation at 30 °C on the blood agar plate, colonies with a diameter of 2 mm were formed. The optimal growth temperature is 25~ 30 °C.
<b>(Diseased spotted forktail catfish with obvious bleeding from the jaw and abdomen) (Wang Kaiyu).</b>
<b>Epidemiological prevalence of spotted fork-tailed catfish intestinal sepsis</b>
The epidemic season is From May to June and from September to October, and the water temperature is 24 to 28 °C. Catfish intestinal sepsis is a disease caused by Eduardo salmon infected with catfish, mainly harming spotted catfish, white catfish, short spiny catfish, cloud catfish and other fish species. The disease can spread from fry to adult fish, and the bacteria can infect fish bodies in two ways: one is infected through the digestive tract, and the other is caused by infection of the nervous system in vitro.
<b>(The abdominal cavity of the diseased fish contains bloody ascites) (Wang Kaiyu).</b>
<b>Clinical symptoms of spotted fork-tailed catfish intestinal sepsis</b>
In the early stages of the disease, there are injuries of 3 mm to 5 mm in diameter on the side of the pectoral fin of the sick fish, and the external wound is needle-like, and it penetrates deep into the muscles. The sick fish hangs in the water with its head up and tail down, sometimes swimming in a spasmodic spiral, and then dies. Due to differences in catfish size and individual immunity, the clinical symptoms of catfish intestinal sepsis are not the same, showing both acute and chronic forms. There are two classic types: "head cap perforation type" and "intestinal sepsis type".
<b>(Diseased spotted forktail catfish top skin ulceration) (Wang Kaiyu).</b>
<b>(Diseased spotted forktail catfish top skin, skull ulceration) (Wang Kaiyu).</b>
(1) The perforated type of the head cover, also known as the chronic type.
The main manifestation is "head perforation", the initial site of infection of Edward's disease is the olfactory sac at the root of the nose, and then migrated to the brain through the olfactory organs, forming granulomatous inflammation in the brain. The diseased fish is mentally weak, sometimes in a spasmodic spiral-like swimming, and later festers between the two eyes of the head to form a deep hole, exposing the entire brain tissue, forming a lesion like a "saddle"; with the development of the disease, an ulcer is formed in the center of the lesion, which is manifested as a "head cap perforated type" disease.
<b>(Diseased fish develop hemorrhagic enteritis, intestinal congestion, bleeding, intestinal lumen is filled with bloody inflammatory exudate) (Wang Kaiyu)</b>
<b>(The gallbladder of the diseased fish is dilated, the wall of the capsule is thinned, and the sac is filled with bloody bile) (Wang Kaiyu).</b>
(2) Intestinal sepsis type, also known as acute type.
This type is the most common, with high mortality, and is characterized by sepsis and enteritis. Germs can cross the intestinal mucosa, causing systemic edema in sick fish, and anemia and prosthesis are common symptoms. The sick fish stop feeding, swim slowly, swim alone, or hang their heads up in the water; there are faded spots on the body surface, the abdomen of the sick or dead fish is swollen and expanded, the body surface and muscles are obviously congested or bleeding, some sick fish have protruding eyeballs, the gills are pale, the muscles are punctate and spotted, there is congestion, the gills, the abdomen, the jaws and the base of the fins are hyperemic, and the anus is red and swollen.
<b>(Protrusion of the eyeballs of the sick fish).</b>
Anatomy can be seen: the abdominal cavity has bloody ascites or blood or clear liquid, the outflow of ascites is not easy to coagulate, liver, spleen, gallbladder have different degrees of swelling, bleeding, stomach, intestinal dilation, liver has congestion spots, spleen, kidneys are purple-black, the intestinal wall is seriously congested, there is no food, the intestine is inflated or filled with yellow mucus, and sometimes accompanied by the appearance of the sleeve intestine.
<b>(A large number of small ulcer foci appear on the surface of the body of the diseased spotted forktail catfish) (Chen Hui).</b>
<b>Diagnostic methods of intestinal sepsis of spotted fork-tailed</b> catfish
The diagnosis of the diagnosis requires the identification of Gram-negative bacteria isolated from the target tissue, and a comprehensive diagnosis is made in combination with the clinical symptoms and pathological changes and pathological changes. At the seed stage, spotted catfish disease may be confused with this disease and can be distinguished by clinical symptoms and pathological changes and serological diagnosis.
<b>(The abdomen of the sick fish is swollen and swollen).</b>
<b>Precautions</b>
1. Improve the breeding environment, keep the water temperature stable, avoid strenuous operation, and feed high-quality feed to prevent the occurrence of catfish intestinal sepsis. Adding detoxifying Chinese herbs and vitamin C to the feed can enhance the resistance of catfish to catfish intestinal sepsis. Appropriate reduction of feed feeding during the onset of the disease can also significantly reduce the incidence of catfish intestinal sepsis.
During the temperature period (22 °C to 28 °C) of the onset temperature of catfish intestinal sepsis, try to avoid using irritating drugs to inhibit algae and kill parasites. For ponds that have become diseased, the ponds should be cleared in time to remove silt. Surviving spotted forktail catfish are cultured in isolation, and diseased fish, dead fish, etc. should be buried deeply.
2. In the epidemic season, adding natural plant drugs such as rhubarb, plate blue root, astragalus, houttuynia cordata, etc. to the feed can play a good preventive effect. The plant medicine is crushed to 60 mesh to 80 mesh, the drug is weighed according to the dose of 0.5 g to 0.8 g per kilogram of fish body, soaked in boiling water for 20 minutes to 30 minutes, and then mixed with feed.
3.10% povidone iodine solution 0.5 to 1 g/ m3, sprinkle the whole tank, once every 15 days.
4. The immunoprophylaxis effect is remarkable. Before fry or fingerlings are stocked, the use of inactivated vaccine soaking or oral immunization to prevent catfish enterocorticemia is effective.
<b>Treatment: Mainly taking drugs internally. </b>
1. Internal administration: when antibiotic drugs enrofloxacin and neomycin sulfate (choose any one), 0.1 grams per kilogram of fish weight, mix feed feeding, continuous service for 3 to 4 days.
2. Internal administration: when florfenicol, 0.05 grams per kilogram of fish weight, mix feed feeding, continuous feeding for 3 to 4 days can be used; when using antibiotics, pay attention to cross medication or drug resistance testing guidance.
3. Internal administration: three yellow powder. Add 2 g of rhubarb, 0.8 g of skullcap, 1.2 g of cork, plus 100 mg of vitamin C per kg of fish to the feed, once a day for 5 to 7 days.
4. Whole pool spilling: sodium dichloroisocyanurate or trichloroisocyanuric acid 0.3 ~ 0.5 g / cubic meter, or chlorine dioxide, bromochlorohydantoin 0.1 ~ 0.2 g / cubic meter. There is a certain therapeutic effect.
5. Commercially available catfish intestinal sepsis treatment drugs. (<b>This article is transferred from [</b><b>Splash Fish</b><b>].) If you have copyright questions, please contact</b> [email protected]<b>. </b>）