Ciliate disease is caused by parasitism of ciliates such as polycontoles, twigs, and bellworms. Occurs throughout the year in the south, with the peak incidence from July to November. All aquaculture species are parasitized by ciliates, and when ciliate disease is severe, it can even lead to large-scale death of aquatic animals, with a mortality rate of up to 70% to 95%, especially crabs, crayfish, and penaeus vannamei. Coupled with the lack of understanding of ciliate disease by farmers, the discovery is not timely or improperly handled, often leading to more serious diseases, which catch people off guard.
The main symptoms and hazards of ciliate disease
Taking shrimp and crab as an example, at the beginning of the disease, shrimp and crab body surface have no obvious symptoms, but the action is relatively slow, the response to external stimuli is relatively slow, the water flowing out through the gills is slow, the mucus on the surface of the body has a slippery feeling, and a small number of ciliate protozoa and filamentous algae such as bell worms, tired branches, and oblique tube worms can be seen on microscopic examination. In the middle of the disease, the naked eye can already identify a small number of yellow-green or brown villi on the surface of the diseased shrimp and crabs, and 3 to 5 insect bodies can be found on a microscopic examination of a field of view. When microscopic examination of a visual field finds more than 5 insect bodies, the body is attached to thick attachments, the gills are hung with sludge and mucus increase, it can be judged as a serious infection, the jejunum can be seen anatomy, the liver is light yellow or dark brown or patterned, the muscles are inelastic, the gills are black, often secondary to bacterial infection, and it is more difficult to treat.
Due to the frequent shelling of shrimp and crabs in the early days, ciliates have a great impact on their normal growth and survival rate, so special attention should be paid to the breeding of crustaceans such as shrimps and crabs. When ciliate low-density parasitism, shrimp, crabs began to reduce material, eating abnormal, if not found in time, resulting in excess of bait, causing deterioration of water quality, which may eventually lead to poisoning and death in the whole pond; when high-density parasitism, shrimp, crab shelling difficulties, or even stop growing, even if successfully dehulled, due to ciliate parasitic site shell calcification, the emergence of new and old shell adhesions and injury, often secondary bacterial infection death.
The main cause of ciliate breeding
Ciliates live by ingesting organic detritus, bacteria, phytoplankton, etc. in the water body, and the appearance of ciliates in the pond just shows that there are too many organic spoilage and bacteria in the cultured water body, and the more ciliates, the more serious the organic pollution of the water body. Although ciliates are said to be the main force of self-purification of water bodies, in the breeding of water bodies, it is harmful and unhelpful to aquatic animals, and it is still necessary to eliminate the emergence of ciliates as much as possible. The following are the main causes of ciliate breeding during culture:
1. Improper use of products without regular modification
In the process of breeding, with the increase of feed feeding, organic matter such as residual bait and feces continue to accumulate at the bottom of the pond, resulting in deterioration of the substrate and the proliferation of harmful bacteria. If farmers ignore the importance of daily bottom change and fail to insist on regular bottom change, the organic spoilage and bacteria at the bottom of these ponds provide a good environment and nutrients for the growth of ciliates.
The use of inappropriate bottoming products, such as zeolite powder and other bottom modification products with adsorption effect, such products after the use of the water body becomes obviously clean and refreshing, but the suspended material is settled to the bottom of the pond, aggravating the deterioration of the substrate, will also increase the incidence of ciliates.
2. Improper fertilizer and water
Often use fertilizer water paste products fertilizer water, fertilizer water is fast, water color is often green and cool, good-looking, but it is easy to cultivate small algae that can be eaten by ciliates, providing a large number of natural bait for ciliates and promoting the growth and reproduction of ciliates.
There is also a common phenomenon, after the release of seedlings due to the large number of zooplankton such as rotifers caused by the sudden clear water quality, farmers in the case of no clear reason, they are in a hurry to topdress, once not on the continuous use, and finally the water is not fertilized, but the organic matter is greatly increased, the ammonia nitrogen index soared, and the bottom pollution intensified.
3. Poor physique of aquatic animals
Insufficient feeding or poor quality of bait (egg and duck feed, rice bran, wheat bran, etc.), aquatic animals are forced to eat bottom mud, dead algae, resulting in malnutrition at the seedling stage, poor physique, and decreased resistance to ciliates. In addition, low-pressure sweltering days, typhoons, rainstorms and other bad weather, pond water quality indicators sudden changes, prone to a large number of algae death, water mud and other phenomena, so that aquatic animals stress, will also cause physical decline, while dead algae is conducive to the growth and reproduction of ciliates.
4. Frequent disinfection
Although regular disinfection can kill some pathogenic bacteria, it will also kill beneficial bacteria and some algae, resulting in imbalance of the cultured aquatic bacteria phase algae phase, water quality mutations, resulting in different degrees of stress response in aquatic animals, and then a decline in physique.
Ciliate control programme
Aquaculture diseases, we have always advocated prevention over treatment. In the breeding environment, aquatic animals and ciliates can be regarded as two ecological populations that exist at the same time, and when environmental factors develop in the direction of favoring ciliate reproduction and not conducive to the growth of aquatic animals, diseases occur. Therefore, in the daily management, if you want to effectively prevent the occurrence of ciliate disease, you must pay attention to enhancing the physique of aquatic animals to improve disease resistance, and maintain the breeding environment towards the benign direction of suitable for the growth and reproduction of aquatic animals. Based on the practical experience of many farmers in Tangkou, Shanghai Taiyuan proposes the following two daily prevention plans for your reference.
Prevention programme one
Adhere to the routine use of 1 to 2 times a month to change the bottom of the product to purify, activate, transform the pool bottom of the excessive organic matter, maintain a good suitable for the survival of aquatic animals at the bottom environment, can effectively prevent a large number of ciliate outbreaks. According to the specific conditions of water quality, effervescent products can be applied in small quantities and multiple times to inhibit bacteriostatic and detoxify; the next day, fruit acid detoxification products and beneficial bacteria are cleared by a variety of beneficial bacteria to cultivate beneficial bacteria to promote microecological balance.
Prevention programme II
Throughout the breeding process, the em bacteria after being soaked and oxygenated with brown sugar are hung, and the microbial preparations rich in a variety of beneficial bacteria are regularly supplemented with brown sugar and amino acid granules after activation, so as to cultivate the beneficial bacterial phases of the bottom and water bodies, effectively improve the substrate environment, establish the micro-ecological balance of the water body, and thus reduce the incidence of cyanobacteria and other breeding diseases. In addition, according to the water quality, the use of low-content compound potassium persulfate products can also be used, and the effect of water purification and bottoming is more significant.
When the substrate has deteriorated, the bacteriological phase is out of balance (harmful flora multiplies in large numbers), and parasitic attachment of ciliates is found, the following measures are recommended:
First add 10 cm of water, then use potassium monopersulfate powder (250 g/mu ·m) and hard-shell anti-stress products rich in minerals and trace elements needed by crustaceans, and then use the bottom-modifying series products (150 g/mu·m) the next day for detoxification and bottoming.
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