Experience in the treatment of enteritis in fish

In the process of aquaculture (especially in the large-scale cultivation of allogynogenetic silver crucian carp in the coastal tidal flat of northern Jiangsu), mariculturists often encounter the problem of slow growth or non-growth of their farmed fish. Through the detection of various water quality indexes (pH value, dissolved oxygen, ammonia nitrogen, nitrite nitrogen, hydrogen sulfide, etc.) in the water environment of the culture site, all of them are in line with the standard of culture water, and for the body detection and microscopic examination of cultured fish, no parasites were found on the Gill and body surface. There are no abnormal symptoms in the anus, but light pressure on the abdomen or "gelatinous feces", and sometimes it is found that there are long, transparent "colloids" between the formed feces; anatomical observation, liver variation (but not very obvious), redness at the back of the intestine (crucian carp is not very obvious); incision of the intestine found that the intestinal wall became white, thin (even transparent), and the internal mucosa of the intestine fell off seriously.

Through the introduction of the aquaculture management of farmers, according to the on-site detection combined with anatomy, the preliminary diagnosis of enteritis. Sampling and testing ten days after taking the following treatment measures, compared with the growth status before treatment, the growth rate was significantly improved, and there was no slow growth or non-growth of fish.

First of all, external use of primary disinfectants (dibromohydantoin, povidone iodine, etc.) to disinfect aquaculture water.

Secondly, take germicidal and anti-inflammatory drugs (norfloxacin or enrofloxacin or allicin, etc.) for 5 days while using disinfectants externally.

Third, EM bacteria, photosynthetic bacteria or Bacillus subtilis and other microbial preparations were sprinkled 48 hours after topical disinfectant to improve the external environment; after oral administration, enzyme preparations (plus enzyme probiotics) and microbial preparations such as photosynthetic bacteria or lactic acid bacteria were added to the feed to increase the total amount of beneficial microorganisms in intestinal digestion, repair intestinal mucosa and regulate the internal intestinal environment for 5 days.

Fourth, in the future culture management process, continue to maintain a good bottom material and water environment of the culture pond; every 10 days or so, enzyme preparations (adding enzyme probiotics) and microbial preparations such as photosynthetic bacteria or lactic acid bacteria are added to the feed to maintain the content of beneficial microorganisms in the intestinal tract for 3 days.

Experience: with the improvement of intensive culture level, the culture mode of feeding full price mixed pellet feed has replaced the traditional feeding mode such as grass, wheat bran, cake and so on. Due to the many advantages of full price combined with pellet feed culture (comprehensive nutrition, good palatability, low feed coefficient, convenient feeding, etc.), farmers ignore the prevention and treatment of enteritis in the process of fish culture. Mariculturists should pay close attention to the occurrence of fish enteritis in the process of breeding, so as to detect and control it in time.

The pathogen of fish enteritis (commonly known as "rotten intestinal plague") is intestinal type Aeromonas punctata, which is a conditional pathogen. This kind of bacteria exists in the intestines of fish during the whole culture process. But in healthy fish, the strain is not dominant and does not cause disease. When the deterioration of water quality, the decrease of dissolved oxygen, the feeding of deteriorated feed and irregular feeding, the resistance of fish decreases, which will lead to the occurrence of fish enteritis, therefore, enteritis may occur and develop in the whole culture cycle. In the process of aquaculture management, in order to create a good pond environment and maintain high dissolved oxygen in water, aquaculture operators should apply bait according to the principle of "quality, quantity, timing and fixed point", so as to improve the utilization rate of feed for farmed fish. reduce the pollution of residual bait to the water body.

Due to the particularity of the occurrence and development of fish enteritis, many farmers do not prevent and control the disease as a major disease in the process of culture, always wait until the disease is more serious and the disease is obvious (usually gray, black head, leaving the group and swimming alone). Slow movement, loss of appetite, slow swimming by the water or floating on the water, can be caught by hand. The abdomen is dilated and has erythema, the anus is red and swollen, yellow mucus flows out of the anus after gently squeezing the abdomen, dissection shows that the intestinal wall is congested and inflamed, there is no food in the intestine, only yellowish mucus, inner wall erosion), when it affects the feeding and growth of fish, only broad-spectrum germicidal and anti-inflammatory drugs such as allicin or norfloxacin are used directly, and no restorative measures are taken after the use of the drugs. The therapeutic effect is not very obvious. Therefore, after the occurrence of enteritis, the combination of external use and internal administration is used for treatment, and then microbial preparations must be used to improve the water environment and intestinal environment, so that it can be completely cured. In the process of culture management, farmers should often add beneficial microbial preparations or enzyme preparations to feed to improve the intestinal environment, promote digestion and absorption of feed, enhance physique and reduce the occurrence of enteritis.