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What is Hypoxia Humans, Chicken and Fish?

  

What is hypoxia in Humans, Chicken and Fish?

Hypoxia refers to the decrease in the oxygen content of the body. The oxygen partial pressure of a normal person is 80-100mm/Hg. By taking arterial blood for blood gas analysis, the oxygen partial pressure can be measured. When some diseases occur, the partial pressure of oxygen will drop, and when it is less than 60mm/Hg, it is called respiratory failure, that is, hypoxia. Hypoxia can be manifested as dyspnea, cyanosis is the purplish extremities of the extremities and lips, which is the symptom of hypoxia. After the symptoms of hypoxia appear, it is necessary to determine whether the hypoxia is caused by severe pneumonia, the onset of bronchial asthma, chronic obstructive pulmonary disease, or the hypoxia caused by a large amount of pleural effusion and pulmonary embolism, and find and remove the cause. It is the most fundamental treatment.

 

Before removing the cause, give oxygen to correct the hypoxic state. Because of the lack of oxygen in the body, various organs, including the brain, kidney, liver, heart, etc., need oxygen supply, and long-term hypoxia will lead to the failure of the corresponding organs. For patients with hypoxia and respiratory failure, oxygen therapy is usually given. 

The commonly used oxygen therapy is nasal cannula oxygen inhalation and mask oxygen inhalation. Patients with chronic obstructive pulmonary disease are often also chronic type II respiratory failure patients, that is, patients with both decreased oxygen partial pressure and carbon dioxide retention, such patients require low-flow oxygen inhalation. After giving oxygen therapy, it is necessary to review the blood gas in time to determine whether the oxygen flow is appropriate.

 

Signs and symptoms of Hypoxia

 

A condition in which the oxygenation of tissues and cells is insufficient. Caused by insufficient supply or poor utilization of oxygen at the cellular level.

 

Classification of Hypoxia

Hypoxia can be caused by a variety of causes, including acute and chronic disease processes, accidental asphyxia, and hypotension. The consequences all seriously affect the oxygenation process in tissues and cells. It can be divided into the following 4 categories.

 

The result of decreased arterial blood oxygenation. According to its effect on respiration and oxygen transport, it can be divided into two types:

 

(1) Hypotonic hypoxic hypoxia

 It is characterized by a decrease in arterial partial pressure of oxygen and oxygen content in arterial blood, and activation of chemoreceptors due to reduced oxygen partial pressure. 

Cyanosis may occur if the hemoglobin concentration is normal. Commonly seen in cattle grazing above 2,500 meters above sea level. Difficulty and weakness in breathing (in livestock), called altitude sickness. The incidence is particularly high in cattle born at low altitudes. 

The early signs are edema on the ventral surface of the body, especially in the chest, so it is also called chest disease. 

It can also be caused by any pathological process sufficient to cause a decrease in arterial partial pressure of oxygen, including airway obstruction, reduced ventilation surface or permeability of the lung, and disruption of the pulmonary circulation.

 

(2) Isotonic hypoxic hypoxia

It is characterized by decreased arterial oxygen content, normal partial pressure of oxygen, and no excitation of chemoreceptors. No signs of cyanosis. Blood can be chocolate-colored due to methemoglobinemia. 

Common in nitrite poisoning and chlorate poisoning, both of which can convert hemoglobin to methemoglobin, thereby causing anemia hypoxia. It is also seen in livestock with severe anemia, so it is also known as anemia hypoxia.

 

Hypodynamic hypoxia

Caused by reduced blood flow, also known as hypoxia. With or without arterial hypoxia, the basic defect is that the molecular weight of hemoglobin flowing through tissue capillaries is much lower than normal. There are also two types:

 

(1) Ischemic hypodynamic hypoxia

Among them, the local feature is local arterial insufficiency, showing local pallor and pain. Common in arterial embolism, thrombosis and spasm. 

Systemic features are arterial insufficiency, hypotension, and metabolic acidosis. 

Common in acute heart failure, such as endemic muscular dystrophy (selenium and vitamin E deficiency) and peripheral circulatory failure in calves. It is also often caused by sepsis.

 

(2) Congestive hypodynamic hypoxia

Among them, local features such as obstruction of venous return, edema, capillary congestion and cyanosis are common in sites with thrombosis and external pressure. Systemic elevated systemic venous pressure, accompanied by capillary and venous congestion and cyanosis, is common in congestive heart failure caused by severe disease of the myocardium and pericardium, and polycythemia in cattle with chronic mountain sickness.

 

Showing oxygen safety levels

Tissue toxicity hypoxia

A metabolic disorder characterized by normal oxygen content and oxygen tension in the air, but the cells are unable to utilize the transported oxygen due to disruption of the enzymatic systems and electron transport chains in the air. For example, in the case of livestock hydrogen cyanide poisoning, the cyanide ion can interact with the ferric iron of cytochrome oxidase, and the iron is kept in the ferric state, so that the electron transport is stopped, the cellular respiratory chain is interrupted, and finally the cell is hypoxic. The blood of the affected animal is cherry red, and turns dark red in the long course of the disease, showing depression (cerebral hypoxia), muscle tremors, difficulty breathing, and pink mucous membranes.

 

Excessive hypoxia

The increase in local or systemic oxygen use relatively exceeds the oxygen supply. It is the result of strenuous muscle exercise. Also seen after electroshock-induced convulsions.

 

Effects of hypoxia and clinical manifestations

The clinically detectable signs of hypoxia are hypoxia of various organ systems and tissues, cell dysfunction or cell death. The manifestations of hypoxia may be localized or systemic, with varying degrees. 

Different tissues and organ systems respond to hypoxia in different ways. Some are sensitive to the effects of hypoxia. For example, nerve cells can die in a few minutes without oxygen due to reduced blood flow, but fibroblasts can survive for a long time without oxygen. 

Myocardial cells are rapidly damaged and die in the presence of hypoxia. 

Tachycardia is a response of cardiomyocytes to the effects of hypoxia. 

Renal tubular uptake is altered by hypoxia, and renal ischemia is an important cause of acute renal failure. 

Centrilobular cells are particularly sensitive to hypoxia and are prone to liver dysfunction, cell death, and centrilobular fibrosis. 

In addition, hypoxia can also alter blood flow into tissues, generally the lower the oxygen concentration in tissues, the more blood flow to them. 

There is also a compensatory mechanism in chronic hypoxia. For example, renal hypoxia can eventually stimulate the bone marrow to enhance the production of red blood cells, thereby enhancing the oxygen supply capacity of the blood, which is common in animals living at high altitudes.

 

 

What is Anti-hypoxia technology for fish ponds in winter?

Fish activity decreases in winter. Although the oxygen demand is not high, fish ponds are easy to freeze in winter, and the water surface cannot directly dissolve oxygen in the air. In addition, plants such as aquatic plants in the water body produce oxygen due to the decrease in temperature and the weakening of photosynthesis. If the amount drops, it is easy to cause hypoxia in the water, affecting the growth of fish, and in severe cases, it can lead to the death of fish. 

Farmers should take effective measures in a timely manner to prevent hypoxia in fish ponds. Specifically, the following points should be done:

 

1. Ice breaking and oxygenation

After the water surface is frozen, the ice surface should be smashed every morning and evening. Generally, 5-6 square meters of ice holes should be smashed every 667 square meters. freeze.

 

2. Remove snow

During the freezing period in winter, if there is snowy weather, the snow on the ice surface of the fish pond should be removed in time, so that the sun shines on the fish pond water, so as to ensure the normal photosynthesis of green plants in the water.

 

3. Add new water

In addition to maintaining the highest water level to increase oxygen and keep warm during the winter, new water should be injected regularly to improve the living environment of the fish and increase dissolved oxygen, generally once every 20 days. 

If the water quality of the pond deteriorates and the phenomenon of aging occurs, the old water and harmful substances in the pond should be discharged in time.

 

4. Appropriate fertilization

When the water quality of the fish pond is thin, a certain amount of inorganic fertilizer can be applied at noon on a sunny day, which can not only promote the growth and warmth of phytoplankton in the water, but also increase the dissolved oxygen in the water through photosynthesis. The fertilizer should contain both nitrogen and phosphorus. ingredients.

 

5. Stir the pond regularly

The purpose is to turn the bottom mud, mix the upper and lower water bodies, promote the rapid decomposition of harmful substances at the bottom of the pond, and at the same time ensure that the fish will not suffer from hypoxia during the wintering period. 

The method is to stir part of the bottom of the pond with a bamboo pole at noon on a sunny day, and then stir another part of the bottom of the pond after a period of time.

 

6. Sprinkle the medicine

Regularly put an appropriate amount of quicklime, bleaching powder and other chemicals into the pond to increase the dissolved oxygen in the fish pond and improve the water quality

Diagram showing hypoxia in fish

 

 

Winter and spring brooding to prevent hypoxia in chickens

In the south, although the climate in winter and spring is not as cold as that in the north, it is also necessary to do a good job of preventing cold and keeping warm, especially every time a cold wave comes. But because of this, chicken breeders often fail to scientifically handle the relationship between keeping the house warm and keeping the air fresh and oxygen sufficient, especially in the brooding stage, which is particularly serious. 

There are different degrees of hypoxia in chicken houses in spring, which affects and threatens the normal growth of chickens, thus directly affecting the efficiency of chicken raising.

 

1. The performance of hypoxia

Hypoxic chickens initially showed depression, screaming, mouth breathing, panting, neck and head shaking, reluctance to eat, stop drinking, cyanosis of the beak, cyanosis of the whole body, and blue feet in severe cases. Fall to the ground and die. 

At autopsy, the trachea and bronchi of the dead chicken were congested, the tracheal cavity was full of viscous secretions, the blood was black or dark red, or the blood coagulation was poor, the lung lobes were enlarged, edema, and occasionally the kidneys were enlarged, dark red, and the heart was enlarged.

 

2. Preventive measures

In order to prevent hypoxia in the brooding room so as not to affect the growth and development of chicks and threaten the safety of chicks, the following measures can be taken:

 

1. Timely expansion of the brooding area: In winter and spring, in order to stabilize the temperature and meet the thermal insulation requirements, a "house within a house" should be built in the chicken coop. In order to save energy and facilitate management, the scope of brooding should be narrowed at the beginning, but because chicks grow faster and consume more oxygen, the building of a "house within a house" brooding room should appropriately expand the area of ​​brooding according to the age of the chicks to expand the scope and oxygen capacity of chicks. Try to avoid the density is too high, the area is too small and prone to hypoxia.

 

2. Choose a suitable heat source: In order to avoid some heat sources competing with chicks for oxygen, and to avoid some heat sources from releasing harmful gases and smog when burning to produce heat, therefore, when heating brooding, you should try to avoid choosing such as firewood, coal and charcoal. 

Wood bran and other fuels that are directly burned by open fire, but should use power supply, or use the heat preservation form of kang road heat preservation. 

According to the author's experience, as the lighting of the brooding room, electric lamps can be used, but the best way to heat and keep warm is the kang road. 

One of the advantages is:

To avoid the influence of the rest and growth of the chicks due to the strong light during the heat preservation of the electric lamp.

The second is that the heat preservation of the kang road can Make the floor of the brooding room warm and dry, which is beneficial to protect the abdomen of the chicks from being attacked by cold, which is beneficial to growth and reduce the incidence of disease.

The third is that because of the heating of the road, the entrance of the road can be set outdoors, even if it is caused by burning firewood, coal, charcoal, wood, etc. 

There is no contradiction in competing for oxygen with chicks when bran.

Fourth, there is also no harmful gas and smoke released when burning wood, coal, charcoal, and wood bran, which endangers the growth and safety of chicks.

Fifth, tunnel insulation It can make the humidity in the brooding room smaller, and the litter and chicken excrement are not easily fermented, thereby reducing harmful gases and oxygen consumption.

 

3. Reasonably solve the contradiction between thermal insulation and ventilation: thermal insulation and ventilation are two contradictory aspects. How to better unify the two aspects of the shield to solve the problem, the author believes that the following methods can be used: 

In order to make the air in the brooding room relatively fresh, the temperature is relatively reasonable, and the humidity is relatively suitable, it is possible to judge whether the indoor humidity is relatively reasonable through mesh observation. 

If the plastic film has no water droplets, the humidity is correspondingly reasonable. The freshness of the air can be judged by the fact that people can’t smell the odor after entering, and people don’t feel depressed and depressed, the air is relatively fresh and the amount of oxygen is more, and vice versa, the air is dirty and the oxygen is insufficient. 

According to this judgment method, when it is found that the humidity is too high or the air is too dirty, the chicken farmer should open the gap at the top of the brooding room and near the ground to let the dirty air and water vapor go away from the top, and let the fresh air from the close the gaps on the ground flow in (this is mainly due to the natural phenomenon of cold air sinking and hot air rising, so that the air forms convection) to achieve the purpose of ventilation. 

As for how big the gap is and how long it takes, it should be determined according to the number of chickens, the size of the brooding room, the air pollution and humidity, and the temperature. 

There are more chickens, the air is dirty, the humidity is high, and the gap of high temperature can be larger and longer, otherwise it should be smaller and shorter. But there is a principle that must be paid attention to is that the chicks must not be cold and sick, and it is better to ventilate in this way several times a day, rather than completely ventilated at one time.

 

4. Timely replacement of litter and excrement: When talking about the reasons for the lack of oxygen, the author has already mentioned that the fermentation of litter and excrement under a certain humidity and temperature will consume some oxygen in the brooding room, and will discharge toxic substances. 

In order to prevent and reduce the occurrence of this phenomenon, timely replacement of litter and excrement is a way to reduce and prevent hypoxia in the brooding room. Be careful not to open all the barriers used for heat preservation, and you should choose a time when the weather is sunny and the temperature is high, and quickly put back new litter.

 

5. Spray oxygen-enhancing drugs: In order to prevent hypoxia in the brooding room, if pure oxygen is used, firstly, it will cost a lot, and the cost will be high, and secondly, it will be more troublesome to work. 

Peracetic acid is a broad-spectrum high-efficiency chemical disinfection drug that is unstable but can release oxygen and acetic acid. 

The disinfection of chicken coops can neutralize some harmful alkaline gases, which can be described as "three birds with one stone".

Diagram showing hypoxia in chicken


 

4 Methods of preventing hypoxia in raising broilers in winter

Strengthen the ventilation in the house The air in the house is fresh, and the chickens love to grow and develop well. Due to the high body temperature of chickens, the amount of gas they breathe is more than 2 times larger than that of mammals, so they need more oxygen. 

The solution is to strengthen the ventilation in the chicken house to ensure that there is enough fresh air, the chickens will be lively and healthy, and they will be less sick. Ventilation is equivalent to oxygenation, usually every 2 to 3 hours. 20 to 30 minutes each time. 

The house temperature should be raised before ventilation, and attention should be paid not to blow the wind directly to the chicken body during ventilation to prevent the chicken from getting cold.

 

Reduce stocking density Broilers are generally raised in large groups, with large flocks and large numbers. Under high-density rearing conditions, chickens will lack oxygen in the air and increase carbon dioxide. 

Especially in high temperature brooding and high humidity, the lack of fresh air for a long time will often cause the chicks to be weak and sickly, and the rate of dead chickens will increase. In chicken houses with high stocking density, the chance of airborne infectious diseases increases, especially when the ammonia content is high, respiratory diseases are often induced. Therefore, to reduce the stocking density, 9 chickens of about 1.5 kg can be raised per square meter. If they are raised online, the density can be doubled.

 

Pay attention to heat preservation methods Some farms only emphasize heat preservation, but ignore ventilation, close doors and windows, and ventilate from time to time, resulting in severe hypoxia in the chicken house, and carbon dioxide poisoning often occurs. Especially when using a coal stove to keep warm, the stove sometimes runs off or pours smoke, which is more prone to gas poisoning. Even if it is heated normally, it competes with chickens for oxygen, which is prone to carbon monoxide poisoning. (also known as gas poisoning), pay special attention. 

It is best to build the stove in the doorway outside the house, which can effectively avoid the poisoning of harmful gases.

 

Prevent stress chickens from being sensitive, timid and frightened, any new sounds, colors, unfamiliar movements and the sudden appearance of objects will cause chickens to be disturbed, screaming, and even a series of abnormal events such as frightening, frying or running away. 

Harmful stress will consume a lot of physical energy of the chicken, increase the oxygen consumption of the chicken, and be more harmful to the growth and weight gain of the chicken. Therefore, it is necessary to maintain the normal and orderly life of broilers, and keep the chickens quiet and stable, so as to reduce the losses caused by various stresses.

 


Prevention of hypoxia in winter broiler chickens

Strengthen the ventilation in the house The air in the house is fresh, and the chickens love to grow and develop well. 

Due to the high body temperature of chickens, the amount of gas they breathe is more than 2 times larger than that of mammals, so they need more oxygen. 

The solution is to strengthen the ventilation in the chicken house to ensure that there is enough fresh air, the chickens will be lively and healthy, and they will be less sick. Ventilation is equivalent to oxygenation, usually every 2 to 3 hours. 20 to 30 minutes each time. 

The house temperature should be raised before ventilation, and attention should be paid not to blow the wind directly to the chicken body during ventilation to prevent the chicken from getting cold.

 

Reduce stocking density Broilers are generally raised in large groups, with large flocks and large numbers. Under high-density rearing conditions, chickens will lack oxygen in the air and increase carbon dioxide. Especially in high temperature brooding and high humidity, the lack of fresh air for a long time will often cause the chicks to be weak and sickly, and the rate of dead chickens will increase. 

In chicken houses with high stocking density, the chance of airborne infectious diseases increases, especially when the ammonia content is high, respiratory diseases are often induced. Therefore, to reduce the stocking density, 9 chickens of about 1.5 kg can be raised per square meter. If they are raised online, the density can be doubled.

 

Pay attention to heat preservation methods Some farms only emphasize heat preservation, but ignore ventilation, close doors and windows, and ventilate from time to time, resulting in severe hypoxia in the chicken house, and carbon dioxide poisoning often occurs. Especially when using a coal stove to keep warm, the stove sometimes runs off or pours smoke, which is more prone to gas poisoning. Even if it is heated normally, it competes with chickens for oxygen, which is prone to carbon monoxide poisoning. (also known as gas poisoning), pay special attention. 

It is best to build the stove in the doorway outside the house, which can effectively avoid the poisoning of harmful gases.

 

Prevent stress chickens from being sensitive, timid and frightened, any new sounds, colors, unfamiliar movements and the sudden appearance of objects will cause chickens to be disturbed, screaming, and even a series of abnormal events such as frightening, frying or running away. 

Harmful stress will consume a lot of physical energy of the chicken, increase the oxygen consumption of the chicken, and be more harmful to the growth and weight gain of the chicken. Therefore, it is necessary to maintain the normal and orderly life of broilers, and keep the chickens quiet and stable, so as to reduce the losses caused by various stresses.

 

 

Spring broiler chickens should prevent hypoxia

The body temperature of chickens is high, the amount of gas they breathe is more than twice that of mammals, and they need more oxygen. Only by strengthening the ventilation in the chicken house and ensuring enough fresh air can the chickens be lively and healthy and less sick. 

The chicken house is generally ventilated once every 2 to 3 hours, 20 to 30 minutes each time. Raise the house temperature before ventilating, and pay attention to the fact that when ventilating, the wind cannot blow directly to the chicken body to prevent the chicken from getting cold.

 

Reduce stocking density

Broilers are generally raised in large groups, with a large number and high density, and there is insufficient oxygen in the air. Especially in high temperature brooding and high humidity, the lack of fresh air for a long time will often cause the chickens to be weak and sickly, the rate of dead chickens will increase, and the chance of transmitting diseases through the air will increase, especially when the ammonia content is high, it will often induce respiratory diseases. Therefore, to reduce the stocking density, 9 chickens of about 1.5 kg can be raised per square meter. If they are raised online, the density can be doubled.

 

Pay attention to the insulation method

Some farms only emphasize heat preservation and do not pay attention to ventilation, resulting in severe hypoxia in the chicken house, and carbon dioxide poisoning often occurs. Especially when using a coal stove to keep warm, the stove sometimes runs off or pours smoke, which is prone to gas poisoning. Even if it is heated normally, it will compete with chickens for oxygen. It is best to build the stove in the doorway outside the house, which can effectively avoid the poisoning of harmful gases.

 

Prevent stress

Chickens are sensitive and timid. The sudden appearance of any new sounds, colors, movements and items will cause adverse stress reactions in chickens, consume a lot of physical energy, increase oxygen consumption, and increase their growth and development. Heavy is more harmful. Therefore, it is necessary to maintain the normal and orderly life law of broilers, and keep the chickens quiet and stable.

 


Winter fish farming to prevent hypoxia

1. Adding and changing new water During the wintering period of the fish, in addition to maintaining the highest water level to increase oxygen and heat preservation, new water should be injected regularly to improve the living environment of the fish and increase dissolved oxygen. 

Generally, water injection once every 20 days. If the water quality of the pond deteriorates and the phenomenon of aging occurs, the old water and harmful substances in the pond should be discharged in time.

 

2. Appropriate fertilization When the water quality of the fish pond is thin, a certain inorganic fertilizer can be applied at noon on a sunny day, which can not only promote the growth and warmth of phytoplankton in the water, but also increase the dissolved oxygen in the water through photosynthesis. The fertilizer should contain nitrogen and phosphorus. Two ingredients.

 

3. The purpose of regularly stirring the pond is to loosen the bottom mud, mix the upper and lower water bodies, and promote the rapid decomposition of harmful substances at the bottom of the pond. 

The method is to stir part of the bottom of the pond with a bamboo pole at noon on a sunny day, and then stir another part of the bottom of the pond after a period of time.

 

4. Sprinkling chemicals Regularly put appropriate amount of quicklime, bleaching powder and other chemicals into the pond to increase the dissolved oxygen in the fish pond and improve the water quality.

 

 

 

Prevention of Hypoxia in Fish in late winter

Causes of Hypoxia in Fish

During wintering, although fish activities are less and oxygen consumption is also poor, if there is a lot of silt at the bottom of the pond, the decomposition of organic matter consumes oxygen, making the oxygen low, and the adjustment of water quality is neglected; or after freezing, there is insufficient light and photosynthesis is poor resulting in insufficient dissolved oxygen, which is also prone to fish hypoxia and floating head, and even the occurrence of dead fish accidents. Especially in the later period of wintering, due to the inability to keep up with winter management, the water quality is aging, and the decomposition of organic matter is intensified with the increase of water temperature.

 

Precaution against Hypoxia in Fish

For fishing ponds with sparse density and overwintering ponds, the stocking density of fingerlings should not be too high. 

Generally, 20,000 to 40,000 fingerlings with a size of 10 cm can be placed per mu to prevent hypoxia due to too high stocking density. 

At the beginning of winter, some of the fish that have reached the market size can be caught and part of the market to reduce the pressure on the pond.

 

Improving water quality This is the key to management. The main thing to improve the water quality is to pay attention to adding and changing the water. 

Generally, the water should be changed once every 15 to 20 days, 10 cm to 20 cm each time. Usually, pay attention to observation. 

If the water quality is found to be poor, take adjustment measures in time; more attention should be paid to the late winter. Changes in water quality require a major water change in the beginning of spring, replacing 1/3-1/2 of the water to completely improve the water quality. 

It is best to measure the dissolved oxygen in the pool water frequently and keep the dissolved oxygen above 5 mg/L. 

If the dissolved oxygen is found to be too low, change the water in time and take other oxygen-enhancing measures to avoid accidents.

 

During the wintering period of timely fertilizer and water, pay close attention to the fertility of the pool water. For new pools and thin pools, topdressing manure is often performed. The specific amount of fertilizer application depends on the pond conditions. 30 cm to 35 cm is better, manure should be fully fermented before use, and excessive fertilization should be strictly prevented.

 

Pay attention to observation, and you should also insist on patrolling the pond during the wintering period, observe the activity of fish and water quality, find problems, and take emergency measures in time to avoid accidents.

 

 

 

A large number of fish died, is it lack of oxygen?

The incidence of tilapia hemorrhagic disease is characterized by a long epidemic season, and the outbreak season of the disease is from June to September. The water temperature at the time of onset is more than 25 . The morbidity and mortality rates are high. During the epidemic, the morbidity rate can reach 50%-70%. 

According to reports, the mortality rate can reach 30%-90%, and even the entire army will be wiped out. The types of disease are acute and chronic. Acute onset and death mostly occur within a week, while chronic onset lasts as long as two or three weeks or even two months. The disease area is wide, and both pond culture and reservoir cage culture can be affected. 

Symptoms: 

There are generally two types in practice. The first type is mainly manifested as hyperemia and redness on the body surface, which mostly occurs in the mandible, operculum, fins and other parts. 

The spleen, kidney, and gallbladder are enlarged, and the liver changes from normal reddish brown to khaki or grayish white. Such symptoms can cause acute death, and treatment will be more difficult if the right medicine is not prescribed in the early stage. 

The other type is mainly manifested as local congestion of the operculum and body surface, and sometimes there is also congestion around the orbit, the abdomen is enlarged, and there is pale yellow ascites in the abdominal cavity.

It is different from the typical symptoms of streptococcus, such as exophthalmos, hyperemia around the eyes, hyperemia and redness of the inner side of the operculum or severe bleeding. 

Causes of disease

In recent years, the stocking density and aquaculture production of tilapia have been greatly increased; the water quality of the pond has deteriorated seriously, the substrate is aging, the water quality in the growing season is not adjusted in time (in some places, the water cannot be changed all year round), ammonia nitrogen and nitrous acid in the pond water. 

The salt content is seriously exceeding the standard, which leads to the aging of the pool water and the proliferation of pathogenic bacteria in the water; the lack of necessary nutrients in the feed, and the feeding of spoiled and unhealthy feeds in the breeding will lead to qualitative lesions of the liver, kidneys and other organs, and the body's resistance will decline, causing bacteria to follow. 

In addition, some farmers did not prescribe the right medicines, and used pesticides and pesticides indiscriminately.

In addition, the long-term inbreeding of tilapia resulted in the serious degradation of its excellent genetic traits, or the degree of purification and rejuvenation of the hybrid tilapia parents was insufficient resulting in insufficient male rate of tilapia of its progeny hybrid lines, germplasm degradation, and germplasm degradation will inevitably lead to weakened disease resistance.

In addition, the singleness of pond-raised species is also one of the reasons for the outbreak of the same disease every year. 

Prevention

It is recommended that the stocking density is appropriate, and the silver carp and crucian carp should be raised in an appropriate amount to remove residual bait and regulate water quality. 

Select high-quality and robust fish species, operate carefully, and prevent fish from being injured. Thoroughly clean and disinfect the pond, remove excess silt, and transport it away from the breeding site. 

Timely changing the water, adding new water, adjusting the water quality and keeping the water fresh can reduce the occurrence of fish diseases. Pay attention to nutrition, feed should be hygienic and high-quality, and do not feed spoiled or unclean feed. 

During the fish disease-prone period, use drugs (such as Yujianqing series) for regular prevention, and mix antibacterial drugs such as Yubikang and allicin into the feed to make bait for feeding. 

Treatment

Sprinkle 200-250ml/mu?m of Xinbo in the whole pond, once a day, twice in a row. If the water quality is poor or pesticides have been used indiscriminately at the onset of the disease, and the food intake has decreased, it can be splashed with Pond Jiedubao series, and then disinfected again after stabilization.

 Pay attention to feeding oxytetracycline 0.3-0.5%, Kaiweijiedusan 0.4%, Baogantai 0.5%, and sodium cholate can also be fed for ascites. In addition, there are also feeding sulfadiazine in production, and the effect is remarkable.

 

Management measures to prevent hypoxia in fish ponds in winter

Fish activity decreases in winter, but the fish pond freezes in winter, and the water surface cannot directly dissolve oxygen in the air. 

The phytoplankton in the water body decreases oxygen production due to lower temperature and weakened photosynthesis, which is easy to cause hypoxia in the water and affect fish. 

Severe species growth leads to fish kills. To prevent hypoxia in winter, you should do the following:

 

1. Ice breaking and oxygenation After the water surface is frozen, the ice surface must be smashed every morning and evening, with 5-6 square meters of ice eyes per mu.

 

Be sure to take out the smashed ice cubes so they don't freeze again.

 

2. Remove snow During the winter freezing period, the snow on the ice surface of the fish should be removed in time. The sun shines on the fish water to ensure the normal photosynthesis of the phytoplankton in the water.

 

3. Add new water In addition to maintaining the highest water level to increase oxygen and keep warm during the winter, pay attention to regularly adding new water to improve the living environment of the fish and increase the dissolved oxygen in the water. The old water and harmful substances in the pool are discharged in time, and 1/3 of each time is replaced and then new water is injected.

 

4. Appropriate fertilization When the water quality of the fish pond is thin, a certain amount of inorganic fertilizer can be applied at noon on a sunny day, which can promote the growth of phytoplankton in the water and increase the dissolved oxygen in the water.

 

5. Stir the pond water regularly The upper and lower water bodies are mixed to promote the decomposition of harmful substances at the bottom of the pond, so as to ensure that there will be no hypoxia during winter. 

At noon on a sunny day, use a bamboo pole to stir part of the bottom of the pond, and then stir another part of the bottom of the pond after a period of time.

 

6. Spill the medicine Regularly put an appropriate amount of quicklime and bleaching powder into the pond to increase the dissolved oxygen in the water and improve the water quality.

 

 

 

 

 

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  Difference Between Turnip Rutabaga Kohlrabi However, kohlrabi has no taste. If it is not peeled enough, it is easy to eat a mouthful of scum, so not many people eat it. If you eat it, it means stir fry or make soup. The close relative of kohlrabi, rutabaga, cabbage, is also called kohlrabi in the northeast. In the past month or so, who is the most worrying ingredient? There is no doubt that it is the kohlrabi.   The popularity of kohlrabi is due to a game of Nintendo-"Assemble!" Animal Crossing Friends Association.   In the game, rutabaga has a stock-like setting, which may make people get rich overnight or bankrupt. Some people may accidentally experience the cruelty of the "stock market casino".   What exactly is this fat kohlrabi? The most important thing is, is it delicious? 1. Although it looks a lot like a radish, rutabaga is actually a turnip Many people see the rutabaga in the game, their first reaction is: this is not a large white