How to treat fish enteritis? Sharing treatment experience

In the process of aquaculture (especially large-scale farming of allogynogenetic gibel carp on the coastal tidal flats of northern Jiangsu), farmers often encounter the problem that the fish they are raising grow slowly or do not grow at all. Through testing of various water quality indicators in the aquaculture water environment (pH, dissolved oxygen, ammonia nitrogen, nitrite nitrogen, hydrogen sulfide, etc.), all met aquaculture water standards; testing and microscopic examination of the farmed fish bodies found no parasites on the gills or body surface. There were no abnormal symptoms at the anus, but when the abdomen was gently pressed there was "gelatinous feces," and sometimes long, transparent "gel" connected the formed feces; dissection revealed liver variation (though not very obvious) and redness of the rear part of the intestine (less obvious in crucian carp); after cutting open the intestine, the intestinal wall was found to be white and relatively thin (even transparent), with severe sloughing of the intestinal inner mucosa.

Based on the farmer's description of the farming management situation, together with on-site testing and dissection findings, the preliminary diagnosis was enteritis. After the following treatment measures were taken, samples were collected and tested ten days later; compared with the growth condition before treatment, the growth rate had clearly improved, and there was no longer any phenomenon of slow growth or no growth in the fish.

First, apply a disinfectant externally once (dibromohydantoin, povidone-iodine, etc.) to disinfect the aquaculture water body.

Second, while applying the external disinfectant, orally administer bactericidal and anti-inflammatory drugs (norfloxacin or enrofloxacin or allicin, etc.) for 5 consecutive days.

Third, 48 hours after the external disinfectant application, splash microbial preparations such as EM bacteria, photosynthetic bacteria or Bacillus subtilis once to improve the external environment; after the oral medication is finished, add enzyme preparations (enzyme-added probiotics) and microbial preparations such as photosynthetic bacteria or lactobacillus spore bacteria to the feed and feed them, to increase the total amount of beneficial digestive microorganisms in the intestine, repair the intestinal mucosa, and regulate the internal intestinal environment of the body, for 5 consecutive days.

Fourth, in the subsequent farming management process, continue to maintain a good pond bottom and water body environment; about every 10 days, add enzyme preparations (enzyme-added probiotics) and microbial preparations such as photosynthetic bacteria or lactobacillus spore bacteria to the feed to maintain the content of beneficial microorganisms in the intestine, for 3 consecutive days.

Experience: With the improvement of intensive farming levels, the farming method of feeding full-price compound pellet feed has replaced traditional farming models such as feeding green grass, wheat bran and oilseed cakes. The many advantages of the full-price compound pellet feed farming method (comprehensive nutrition, good palatability, low feed coefficient, convenient feeding, etc.) have led farmers to neglect the prevention and treatment of enteritis during fish farming. No matter which method they use, farmers should pay close attention to the occurrence of fish enteritis and achieve timely detection and timely control.

The pathogen of fish enteritis (commonly known as "rotten intestine plague") is Aeromonas punctata f. intestinalis, an opportunistic pathogen. This bacterium is present in the intestine throughout the entire farming process of fish. However, in healthy fish, this bacterial species is not dominant and will not cause disease. When the water quality environment deteriorates, dissolved oxygen decreases, spoiled feed is fed, or feeding is not done at fixed times and fixed amounts, the fish body's resistance declines, which can cause the occurrence of fish enteritis; therefore, enteritis may occur and develop at any time throughout the entire farming cycle. During farming management, farmers should create a good pond environment, maintain relatively high dissolved oxygen in the water body, feed according to the "four fixed" principles (fixed quality, fixed quantity, fixed time, fixed location), improve the feed utilization rate of farmed fish, and reduce water body pollution from residual bait.

Because of the particularity of the occurrence and development of fish enteritis, many farmers do not treat this disease as a major disease for prevention and control during farming, and always wait until the condition is relatively serious and the symptoms are obvious (generally dark body color, black head, swimming alone away from the group, slow movement, reduced appetite, slowly swimming near the shore or floating on the water surface, can be caught by hand. The abdomen is swollen and has red spots, the anus is red and swollen, and when the abdomen is gently squeezed, yellow mucus flows out from the anus; dissection shows congestion and inflammation of the intestinal wall, no food in the intestine, only pale yellow mucus, and eroded inner wall), and only when feeding and growth are affected do they directly use broad-spectrum bactericidal and anti-inflammatory drugs such as allicin or norfloxacin for treatment, and after using the drugs they do not take restorative measures either, so the treatment results are all rather inconspicuous. Therefore, after enteritis occurs, use a method combining external application and oral administration for treatment, and afterward microbial preparations must be used to improve the water body environment and the intestinal environment; only in this way can it be completely cured. During farming management, farmers should often add beneficial microbial preparations or enzyme preparations to the feed to improve the intestinal environment, promote feed digestion and absorption, enhance physique, and reduce the occurrence of enteritis.