CATDOLL : CATDOLL: What is stress in fish? What causes stress in fish?

1. What is stress in fish?

Causes of fish stress: Stress is a phenomenon of non-specific, physiological tension in fish caused by certain stress factors. Stress response is an abnormal state of fish when their tolerance to adverse environmental factors reaches or approaches the limit, rather than an independent disease. A series of abnormal symptoms of fish caused by stress factors are collectively referred to as stress syndrome. Adverse stimuli that deviate from the normal living range of fish are stressors. For fish, the main stress factors include physical factors such as low temperature, high temperature, vibration, chemical factors such as low dissolved oxygen, water pollution, and biological factors such as pathogenic microorganisms and parasites, as well as social and mental factors such as high density, netting, pool division, and transportation.

Stress factors can cause excitement of the sympathetic nerves of fish, increase the concentration of catecholamines epinephrine and norepinephrine in the blood, and then increase the cortisol hormone in the blood.

Therefore, stressed fish will show abnormal behavior, decreased appetite, inhibited growth, reduced fertility, increased skin permeability, decreased resistance to disease, and even death.

2. What causes fish stress?

Causes of fish stress: Stress is a phenomenon of non-specific, physiological tension in fish caused by certain stress factors. Stress reaction is an abnormal state of fish when their tolerance to adverse environmental factors reaches or approaches the limit, rather than an independent disease. A series of abnormal symptoms of fish caused by stress factors are collectively referred to as stress syndrome. Adverse stimuli that deviate from the normal living range of fish are stressors.

For fish, the main stress factors include physical factors such as low temperature, high temperature, vibration, chemical factors such as low dissolved oxygen and water pollution, biological factors such as pathogenic microorganisms and parasites, as well as social and mental factors such as high density, netting, pond separation, and transportation.

Stress factors can cause excitement of the sympathetic nerves of fish, increase the concentration of catecholamines epinephrine and norepinephrine in the blood, and then increase the cortisol hormone in the blood.

Therefore, stressed fish will show abnormal behavior, decreased appetite, inhibited growth, reduced fertility, increased skin permeability, decreased resistance to disease, and even death.

3. How to help fish overcome stress response when fishing?

If you want to improve the quality of fish, you need to raise fish ecologically, save some costs, improve the quality of fish and increase profits. So how to raise fish ecologically? The so-called ecological fish farming is to raise a variety of fish in the same water body, which not only feeds a certain amount of artificial feed, but also makes full use of the food resources of the water body itself. At the same time, it can also connect the aquatic ecosystem with the terrestrial ecosystem, so as to achieve a complementary and mutually beneficial effect and achieve ecological fish farming.

The feed should be nutritionally comprehensive and balanced, and should be fed as much as possible, with the feeding frequency increased accordingly, to provide more feeding opportunities for weaker fish. In addition, timely pond division and round-robin catch of adult fish can keep the size of fish in the same pond basically consistent and avoid polarization. During the breeding period, it is forbidden to use moldy or spoiled feed, and it is not advisable to directly use unprocessed raw grain. It is best to prepare full-price compound granular feed according to the nutritional requirements of fish, and the particle size of the feed should be palatable. In this way, polarization will not occur, which will be detrimental to the overall growth of the fish.

Changing water and keeping the water clean is a key point. In late summer or early autumn, use the method of large water changes to replace 1/2 of the pond water, drain first and then fill, drain aquaculture wastewater as much as possible, and change the water once every week. By changing the water twice in a row, the growth environment of fish can be improved. Many farmers do not pay attention to large water changes, and keep the water in the same pond until the end, which makes the water quality age and affects the growth of fish. It is also necessary to pay attention to timely oxygenation and the application of quicklime, water quality improvers, microbial preparations, etc. to improve water quality, but the implementation of these measures must be flexibly mastered according to specific circumstances. Improper use can also cause unnecessary economic losses.

It is also necessary to control the water temperature. When changing the water in the pond, if the temperature of the external water is significantly lower than that of the pond water, do not change the water too much to avoid a sudden drop in the pond water temperature, which may cause a stress response in the fish. If you use external water such as well water, you must expose it to the sun, aerate it, and then change the water after the water body warms up to keep the pond water temperature stable and reduce the stress response of the fish. In addition, autumn is a season of frequent rainstorms and heavy rain. The temperature of rainwater is significantly lower than that of the pond water. If rainwater enters the pond in a short period of time, it often causes a sudden change in the pond water temperature, which can cause symptoms such as colds in fish. Therefore, you must always pay attention to the water temperature and the impact on the fish school.

Fertilizing algae can increase the nutrients in the water. Phosphorus fertilizer and nitrogen fertilizer are the most likely to be lacking in the water. When fertilizing water quality, attention should be paid to topdressing. Phosphorus fertilizer should be applied first, followed by nitrogen fertilizer. The order cannot be reversed. Inorganic quick-acting fertilizers are generally used for topdressing in aquaculture ponds, such as urea, superphosphate, potassium dihydrogen phosphate, etc., and they should be applied in small amounts and multiple times. Each time, 1.5 kg of urea and 2.5 kg of superphosphate or 1 kg of potassium dihydrogen phosphate should be applied per mu of water surface. Fertilizers should be dissolved in water separately and evenly sprinkled throughout the pond (fertilizers cannot be mixed and sprinkled). The application time and frequency should be flexibly controlled according to the water quality. However, it must be applied flexibly, and it should not be too much.

In summer and autumn, we should take both internal and external measures to prevent fish diseases. Internal and external measures mainly include adding drugs to the bait to enhance the fish's resistance and prevent diseases. For example, adding astragalus polysaccharides, vitamin C, vitamin E, allicin, etc. to the bait, feeding according to the course of treatment, and feeding for 4 to 6 days can achieve better disease prevention effects. When making medicated bait, the drug needs to be dissolved in an appropriate amount of water, sprayed with a small sprayer, and evenly attached to the surface of the granular bait. It should be fed after drying slightly; external treatment mainly involves insecticide and sterilization.

Carry out insecticide treatment 2 to 3 times at the beginning of summer, late summer and the beginning of autumn, or mid-autumn festival to effectively prevent the occurrence of parasitic diseases; carry out sterilization once at the Grain Full solar term and the White Dew solar term respectively, using chlorine dioxide, dibromohydantoin, povidone iodine and other bactericidal drugs at the required dosage until the disease prevention effect is good.

There are many harmful organisms that are very harmful to fish. For example, various water birds pose a threat to fish at all times, water snakes and water rats directly eat fish, frogs and wild fish compete with fish for bait, dissolved oxygen, and space. Therefore, it is necessary to take timely measures such as hanging wire mesh on the edge of the pool, isolating with mesh, manually expelling and capturing to eliminate harmful organisms that invade the pond. Therefore, in order to protect the fruits of our labor, it is necessary to take these prevention and control measures.

Another basic rule is that you need to always observe the water body's dryness and waterlogging to prevent the fish from lacking water due to insufficient water. Pay more attention to pond maintenance during the rainy season to prevent the fish from jumping away. So it is best to make an emergency reservoir yourself.

4. Long-distance fish transportation technology?

1. Nylon bags filled with oxygen and sealed for transportation

It is suitable for transportation by water, land and air. It is characterized by small size, convenient use and carrying, high shipping density, high survival rate, and can maintain oxygen for more than 30 hours at a time. It is currently an ideal and widely used means of transportation. Commonly used nylon bags are generally 80-100 cm long, 35-40 cm wide, and have a capacity of about 20 liters. After about one-third of the volume of water is injected, a certain number of fry or fish species are put in, the air in the bag is squeezed out, and oxygen is filled in from the bag mouth with a leather tube. Then the bag mouth is folded, tied with a thin rope or rubber band, and placed flat in a wooden box or carton, so that the water and oxygen in the nylon bag have a larger contact surface. The density of fish should be determined according to the water temperature, the quality of the fry and the transportation time. When the water temperature is about 25℃, each bag can hold 50,000 to 80,000 fry, or 5,000 to 8,000 summer flowers. The transportation time does not exceed 24 hours, and there is no need to change water and inflate. The survival rate can reach more than 90%.

2. Inflate and seal plastic barrels for transportation

Plastic barrel transportation is an improvement on nylon bag transportation. Its advantages are that the packaging is not easy to be damaged, no other additional packaging is required, loading and unloading is convenient, it can be placed in overlapping positions, and it is easy to use. It is especially suitable for areas with rugged roads and severe bumps during transportation. Plastic barrels are generally 60 cm long, 40 cm wide, 12 cm high, and have a capacity of about 30 liters. There is an inlet and outlet with a diameter of 5 cm and an injection and exhaust hole with a diameter of 2.5 cm. The hole is equipped with a check valve needle. The inlet and outlet and the injection and exhaust holes are all equipped with push-type inner plugs and bolt outer covers. When used, 15 kg of water is loaded and about 60,000 fry are placed. Inflate 10 to 12 liters. If the transportation time does not exceed 24 hours, the survival rate can reach more than 95%.

3. Canvas box (basket) transportation

Because the box mouth is wide, it is convenient for changing water and feeding, so it is often used for long-distance transportation on cars, trains, and ships. There are two types of canvas boxes, square and round, with wooden and iron frames supporting them. The volume is about 1 cubic meter. There are also larger ones, which are selected according to the transportation situation. When used, three-quarters of the total volume is filled with water. When the water temperature is 20-25℃, the small box can hold 300,000-350,000 fish and 20,000-25,000 summer flower fish; when the water temperature is around 15℃, it can hold 6,000-8,000 2-inch fish or 3,000-4,000 3-inch fish. During transportation, there must be a dedicated person to manage it and pay attention to checking and changing the water.

4. Shoulder transport

Its characteristics are simple tools and low cost, but high labor intensity. Generally, bamboo baskets (lined with oilcloth) or wooden barrels are used. The barrels are filled with water two-thirds of the way, but not too full to avoid overflow. The water in the barrels should be slightly shaken when carrying to increase oxygen. For a journey of less than one day, each load of water is 20 to 25 liters, which can hold 40,000 to 60,000 fry, 5,000 to 6,000 summer croakers, or 1,000 to 2,000 2-inch fingerlings.

5. How to reduce stress response of piglets during long-distance transportation?

Anti-stress defense measures for transporting piglets: 1. Strengthen nutrition. Feed rich in protein, vitamins and minerals one week before transportation to improve the immunity and resistance of piglets.

At the same time, the piglets should be fed with feed from the production area during transportation. During long-distance transportation, they must be fed twice a day and provided with sufficient drinking water.

When arriving at the breeding ground, gradually transition the feed.

2. Try to create suitable transportation conditions. The most suitable temperature for pigs is 15-23℃. Overheating or overcooling will have an impact on pigs. Therefore, when transporting piglets in summer, choose cloudy days and nights to avoid high temperatures. Cover the vehicle with shade during transportation to prevent pigs from heatstroke. When transporting pigs in winter, choose windy and warm weather to avoid the invasion of cold air. There should be windproof and warm facilities in the vehicle to prevent pigs from getting cold and causing colds and illnesses. When transporting pigs, the vehicle speed should not be too fast, the brakes should not be too strong, and you should drive slowly in ditches and potholes, and slow down slowly to minimize sudden crowding and frightening of the pigs.

3. Anti-stress additives in feeding are vitamins. Adding vitamin C is beneficial to promote the normal secretion of adrenal cortex hormones, reduce physiological stress, help piglets maintain normal body temperature under heat stress conditions, and improve feed conversion rate; Vitamin B1 is involved in cell metabolism, especially in sugar metabolism. Vitamin B2 is an important component of the cell nucleus. Vitamin E protects cell membranes and prevents oxidation, and can reduce the permeability of cell membranes and reduce the release of inositol kinase in muscle cells during stress, thereby preventing stress interference. Vitamin E can also improve the disease resistance of livestock; Vitamin K is an anti-stress agent that resists drug-induced stress.

The second is electrolytes, such as sodium bicarbonate, potassium bicarbonate, potassium chloride, sodium chloride, etc. Electrolytes can maintain the acid-base balance in the livestock body and relieve heat stress; the third is the addition of amino acids. Adding a variety of amino acid additives to the feed within 1 week before and after the transportation of piglets can supplement the protein decomposition of the body's immune organs and immune cells caused by stress; the fourth is the addition of drugs. Since piglets are subjected to multiple stimulations before and after transportation, in order to reduce stress, a certain amount of tranquilizers can be added to the feed when transporting piglets, but the dosage must be calculated according to the length of transportation time to prevent excessive addition from causing morbidity.

4. Get the immunization done well. It is recommended to use Oldman products.

Generally, most piglets transported are weaned piglets. Therefore, it is necessary to do a good job of immunizing piglets from birth to weaning, such as preventing swine fever, swine paratyphoid, edema, etc., to ensure the health of piglets.

6. How to deal with stress reactions in mandarin fish during transportation?

Mandarin fish is a cold-blooded animal. It can sense the ambient water temperature through its lateral line and adjust its own temperature to be close to the ambient temperature at any time. Therefore, the temperature difference is large, which can easily cause a stress response in mandarin fish. In particular, mandarin fish is prone to strong stress response during transportation, and its body will become detached. After being placed in the temporary holding pond, the detached area is easily infected. In certain seasons and conditions, red spots and ulcers on the skin often occur, and in the most serious cases, death may occur.

It is recommended to use amino acids and biochemical fulvic acid for soaking and protection during transportation to avoid surface infection and reduce stress.

You can also use vitamin C to resist stress 2g/cubic water, and then 10 minutes later, sprinkle compound Chinese medicine preparations - such as Beijing Shengtaier's Xianglian solution 2ml/cubic water + Bencao Lilijing 1g/cubic water, sprinkle in the morning, and you can see the effect on the ulcer in the afternoon (the wound is gradually healing); another method is to sprinkle anti-stress vitamin C 10 minutes later and then use 1ml/cubic water for Rotten Gills and Fupi Kang, which is slower and takes two days to take effect. The drugs used in these two methods are edible.

7. How many days is the stress period for long-distance transportation of sheep?

The stress period of long-distance transportation of sheep varies depending on individual differences of sheep, transportation conditions and environment. Generally speaking, sheep may experience a period of adaptation and stress when facing long-distance transportation, which is called the transportation stress period.

The specific duration of the stress period may vary depending on the breed, age, health status and transportation conditions of the sheep. Generally, the transportation stress period may last from a few days to about a week. During this period, the sheep may experience some discomfort and stress reactions, such as loss of appetite, anxiety, tension, weight loss, etc.

In order to reduce the impact of transportation stress on sheep, the following measures should be taken:

1. Advance adaptation: Before transportation, allow the sheep appropriate time to adapt to the transport vehicle, container and environment, and ensure good diet.

2. Proper space and ventilation: The transport container should provide enough space for the sheep to move around and ensure good ventilation conditions.

3. Water and feed: Ensure adequate supply of clean water and suitable feed to avoid further stress caused by dietary changes.

4. Control temperature and humidity: During transportation, it is best to control the appropriate temperature and humidity to avoid overheating or overcooling.

5. Relieve anxiety and stress: Consider using appropriate sedatives or medications to reduce the sheep's anxiety and stress.

The above suggestions are for reference only. Specific transportation plans and measures should comply with relevant laws and regulations and the guidance of veterinarians. In the process of transporting sheep, the most important thing is to ensure the welfare and health of the sheep. Therefore, it is recommended to consult with a veterinarian or relevant experts before transportation to develop a suitable transportation plan.

8. How many kilometers does it take for cattle to be stressed?

6 km

Cows need to be injected with stress hormones after 6 kilometers of transportation! 1. Stress is a syndrome of long-distance transportation of cattle, colds, fever, coughing, wheezing, pneumonia, foot-and-mouth disease, pulmonary disease, etc. 2. Long-distance transportation causes the resistance of cattle to decrease, or the resistance of cattle caught in the market is low or they have some hidden diseases, which requires us to adjust and supplement nutrients and minerals after we get home.

9. How to deal with cattle transport stress syndrome?

(1) Before boarding

The animals should have complete immunization records and quarantine procedures, and should be observed for several days before transportation to ensure that they are in good spirits and good feeding conditions. A comprehensive transportation plan should be planned, including the selection of transportation time and season, route planning, and the selection of transportation vehicle models and specifications, which can be adapted to the time and place. Good preparations should be made for items, medicines, personnel, etc.

Before loading, cattle and sheep should be on an empty stomach or half full. It is not advisable to load them after feeding to prevent excessive stomach contents and adverse reactions caused by the bumps in the vehicle.

When loading, the vehicle should be parked on a high platform so that the cattle and sheep can get on the vehicle automatically. The speed of getting on the vehicle should not be too fast to prevent crowding and injuries. After loading, the number of cattle and sheep should be counted.

(2) During transportation

The car should start or stop slowly and steadily, and should be driven at a constant speed during the journey to avoid sudden braking. The frequency of rest during transportation is generally to stop and check and rest once every 100 kilometers or 2-6 hours.

During transportation, special attention should be paid to prevent cattle from falling down. If a cattle is found to have fallen down, it should be promptly picked up to prevent it from being stepped on.

In summer, a canopy should be built during the day to transport cattle, and in winter, there should be windbreaks. Generally, cattle can be transported over short distances without fodder, but they need drinking water.

When traveling long distances, choose to park the vehicle at the designated time and place, place the vehicle in a cool place and check the condition of the cattle and sheep. You can add water in moderation but not excessively, and add a small amount of green fodder.

(3) Unloading

After arriving at the destination, the car can be parked on a high platform and the animals can be allowed to get off the car by themselves. Do not crowd. Make sure the animals get off the car safely and count the number of animals.

After getting off the vehicle, you cannot feed or water the cattle immediately. Let them rest for 5 to 6 hours before starting to drink water. The amount of water they drink should be limited. It is not advisable to feed them grass at this time, and do not feed them too much for the first feeding.

10. Why do fish die during transportation?

The main cause of death during transportation is lack of oxygen. The high density of fish (fish) and the limited dissolved oxygen content of the water in the transport container (water) are a pair of major contradictions in transportation.

Any factors that affect the changes in dissolved oxygen content in water and the fish's tolerance to low oxygen will affect the survival rate of live fish during transportation.

Therefore, the methods to improve the survival rate of fish transportation mainly include two aspects in principle:

First, it reduces the metabolic intensity of fish (reduces fish oxygen consumption);

The second is to improve the water quality of the transport water (maintain the oxygen content of the environment). Specifically, the following factors affect the survival rate of transport: fish species, specifications, physical characteristics, water temperature and quality during transportation, transportation time, distance and method, and bumpy road conditions, etc.