CATDOLL : CATDOLL: What role do fish scales play for fish?

1. What role do fish scales play for fish?

1. Fish scales have the function of protecting the fish body and making the fish grow healthily;

2. Fish scales can reduce the collision between fish and external objects, thereby reducing friction;

3. Fish scales can fully preserve the water of fish and will not cause water loss.

First of all, fish scales are the second life of fish. Without the protection of fish scales, the life span of fish may be greatly reduced, and they may even die at birth. Fish are also more prone to skin diseases. Relatively speaking, fish scales indirectly prevent the growth of skin diseases and can also reduce the impact when attacked by other species.

Secondly, fish scales can greatly reduce the friction on the fish body. Fish must live in water, and friction is inevitable when in contact with water all year round. If they encounter mud and sand, the friction coefficient will be very large. Fish scales can greatly reduce the harm caused by friction to fish.

Finally, for freshwater fish, there is an osmotic pressure balance. Long-term contact with water makes the fish scales act like a thin film that isolates the water, thus creating a dynamic balance effect, so that the fish's body will greatly reduce contact with water.

2. What are the effects of different fish feed types on fish growth?

If it is the same series of feed, for example, from the fingerling stage to the rearing stage, and then to the adult stage, there is no problem using the same series of feed.

However, if the nutritional proportions of fish from different series or different manufacturers are generally different, it is likely to lead to nutritional deficiencies, such as vitamins, methionine, lysine, etc. The lack of these essential nutrients will cause mild cases of slow growth and decreased immunity of the fish, and severe cases will cause deficiency syndromes and developmental deformities.

3. What effect does vitamin C fat have on fish?

Regulate the growth of fish, promote development and maintain their own stability. Fat is beneficial to health and is generally added to the feed at a rate of one kilogram per ton.

4. What is the role of purslane in fish farming?

In fish farming, purslane is not only a good feed for fish, but also a good Chinese medicine for preventing fish diseases, such as skin rot and eye rot of turtles and enteritis of fish. Usage: To prevent enteritis and skin rot of turtles, turtles and fish, take fresh orally, 50% purslane, 30% dandelion and 20% herba euphorbiae are blended into a slurry at a ratio of 10% of the daily dry feed, remove the residue and take the juice and add it to the feed to make granules, feed for 7 to 10 days every month.

If fine dry powder is used, mix it into the feed at a ratio of 1.5% of the daily dry feed and feed it for 8 consecutive days per month. However, the fine powder must be soaked in warm water for 2 hours before mixing.

5. What are the effects of using florfenicol on fish?

Origin of Florfenicol "Chloramphenicol" is an antibiotic that everyone is familiar with, but chloramphenicol has very serious side effects after use (it can inhibit bone marrow and cause aplastic anemia in animals). Therefore, starting in 2002, all animals that can be eaten by humans were banned from using chloramphenicol, including pigs, chickens, ducks, fish, etc. Since then, based on chloramphenicol, a chloramphenicol derivative "thiamphenicol" was produced after its improvement. Compared with chloramphenicol, thiamphenicol has enhanced bactericidal ability and reduced side effects, but there is still a small probability of symptoms such as "bone marrow suppression" and "anemia". Therefore, thiamphenicol is still a little lacking in perfection, so its use in animals is subject to certain restrictions. In the late 1980s, after further improvements to thiamphenicol, a new derivative was finally obtained, which further enhanced its bactericidal ability and completely eliminated the side effect of "anemia". This is Florfenicol. (Figure 1.1)

2. The development history of florfenicol Just as the new veterinary drug "Meiting" has an alternative effect on the banned drug malachite green, the emergence of florfenicol also caused a sensation in the entire scientific community. Since florfenicol was first used in Japan to treat marine fish in 1990, after nearly 30 years of verification in Europe, the United States, China, etc., florfenicol is still a safe and efficient bactericidal drug. In 2013, China's Haibei Biological successfully launched Haifukang, a special florfenicol for aquaculture, after scientific formulation.

3. The current status of florfenicol application in my country In many areas, florfenicol has a high price and low frequency of use, so there are many misunderstandings about it. Many people believe that florfenicol has strong bactericidal power and great side effects, and improper use will cause fish to die more severely, so they will not choose florfenicol unless it is absolutely necessary.

6. What role do fish play in the marine ecosystem?

Compared with other groups, fish have a unique position in aquatic ecosystems. Generally speaking, fish are the climax community in aquatic ecosystems and are the target of fishing in most cases. There are many different groups of fish, and the relationships between them are complex. Under the influence of environmental factors, fish will produce various adaptive changes. At the same time, as the climax community, fish play an important role in the existence and abundance of other groups.

Fishery biology is a part of aquatic biology. It mainly studies the biological characteristics of fish populations and their relationship with the environment, and then explains the economy and rationality of fisheries. Reasonable fishery development lies in ensuring good water environment conditions and obtaining the maximum output of continuously high-quality fishery products from the waters. On the basis of understanding fish feeding habits, reproduction, growth, intraspecific and interspecific relationships, further studying the laws of changes in fish populations and their relationship with human activities and the environment is the theoretical basis for ensuring reasonable fishery production.

7. What role does light play in the growth of mulberry trees?

What are the effects of external environmental conditions on the growth of mulberry trees?

illumination

Mulberry trees are light-loving plants. Under sufficient light conditions, they can synthesize a large amount of organic matter to provide for the normal growth and development of mulberry trees. Such mulberry trees generally have dark green leaves, thick leather, high dry matter accumulation, high leaf quality and high yield. Raising silkworms with such mulberry leaves will make the silkworms strong and produce a large amount of cocoons. Therefore, when planting mulberry trees, sufficient growth space should be left.

temperature

Temperature is one of the necessary conditions for the growth and development of mulberry trees. When the ground temperature reaches above 5℃ in spring, the absorption function of the mulberry root system begins to increase, and new roots begin to grow at 10℃. This is the best time to plant mulberry trees. The root system grows best when the ground temperature reaches 30℃. Different temperatures determine the germination, growth, and dormancy of mulberry trees. The best growth temperature for mulberry trees is 20-30℃. When it reaches below 10℃ and above 35℃, its growth is inhibited.

Moisture

The soil moisture content suitable for mulberry growth is 70% to 80% of the soil's maximum water holding capacity. If there is insufficient water, the growth of mulberry trees will be significantly weakened or stagnant, the water content of mulberry leaves will be low, the leaf quality will be poor, and severe leaves will turn yellow and fall off. If there is drought in early spring, germination will be delayed and the germination rate will be reduced. However, if there is too much water in the soil, the leaf quality will also be poor, which will cause root rot.

Air

The air in the mulberry garden should be smooth, with sufficient oxygen and carbon dioxide to supply the normal growth and development of mulberry trees, and also reduce the damage of pests and diseases. In addition, if there are too many toxic gases in the air, it will seriously affect the normal growth and development of mulberry trees and the quality of mulberry leaves.

soil

The best soil for mulberry trees is loam and sandy loam. Mulberry trees can grow normally at a pH value between 6.5 and 8.5. When planting mulberry trees, choose a plot with deep, moist and fertile soil.

8. What effects does potassium fertilizer have on sugarcane growth?

Generally, it is most suitable after the soil is cultivated. Balanced fertilizer is used in the seedling stage. In addition, sugarcane is difficult to grow well with compound fertilizer alone. It also needs to rely on foliar fertilizer to supplement nutrition. It is good to use Zhuangfengsu + 920 to lengthen and thicken.

9. What role does potassium play in flower growth?

(1) Potassium can promote photosynthesis. It increases the intensity of photosynthesis and promotes the accumulation of potassium in seeds, tubers and fruits. Potassium is an activator of more than 60 enzymes in flowers and plants, and can promote a variety of metabolic activities in the body. Adequate potassium supply can enhance enzyme activity, which is beneficial to the operation and transformation of nutrients and the synthesis of organic matter.

(2) When potassium is adequately supplied, carbohydrate synthesis is strong. The cellulose and lignin content is high, which enhances the flowers' resistance to drought, cold, disease, and lodging.

(3) Potassium acts as an activator in certain processes of protein formation. It can make flower seeds fuller and increase their weight; it can also improve the shape of tubers, promote early maturity, make them mature more uniformly, enhance their resistance to decay, and prolong the storage period; it can also promote the development of the root system.

10. What is the effect of the atmosphere on water?

The environmental conditions on Earth are extremely superior. Astronomers have not yet discovered another planet with a similar environment to Earth. The superiority of the Earth's environment is mainly reflected in the fact that it has a large amount of liquid water. It can be said that it is precisely because of liquid water that Earth can produce a prosperous ecosystem and a high level of human civilization. The great role of liquid water is that it is the best solvent. It can carry nutrients or waste materials to realize the metabolic process that is indispensable to life phenomena. Water is also an indispensable substance for the production of life phenomena. Therefore, water is called life substance or water of life. Liquid water is also a basic factor in the macroscopic evolution of the Earth's environment. It penetrates into rocks, breaks them up, and carries the fine particles in them to settle on the plains. It is the reason for the formation of soil parent material. Under the action of water, the entry of organic matter makes the soil fertile.

The existence of liquid water requires an ideal atmospheric environment. The role of the atmosphere can be roughly summarized as follows:

First of all, the liquid state of water requires very strict temperature conditions. When the surface pressure is 1000 hPa, 0℃-100℃ is the condition for the existence of liquid water. The formation of this pressure and temperature is closely related to the mass of the atmosphere and the radiation properties of each layer of the earth. The temperature range of 100℃ is naturally very wide for humans, but in the universe, this range is extremely narrow. According to astronomical observations, the temperature on other planets and satellites is either a few hundred degrees high or a hundred degrees below zero. The fact that the temperature of the earth falls precisely in the narrow range for the existence of liquid water is the result of the combined effect of many factors.

Astronomical conditions are a basic reason. The sun is a big furnace, and the amount of solar radiation a planet receives is closely related to its distance from the sun. The distance between the earth and the sun is just right. In addition, this is also closely related to the speed of the earth's rotation. The change of day and night causes different parts of the earth to receive solar radiation in turn. Now, people already feel a big temperature difference in a 24-hour day and night. If the length of the day and night is 48 hours, or even if the earth does not rotate, then the sun-facing side will be very hot, while the temperature of several hundred degrees below zero will be low on the back side. In this case, it is difficult for water to exist on the ground in the form of liquid.

In addition, the temperature does not depend entirely on the amount of solar radiation, it also depends on the earth itself. The earth can reflect a certain amount of solar radiation and emit a certain amount of earth radiation. Any substance can emit heat in the form of radiation. The lower the temperature of the substance, the less heat it emits. The wavelength of the radiation tends to be long-wave, which is why the target can be seen with an infrared receiver at night. Solar radiation warms the surface of the earth. When the temperature of the surface is high, the photosynthesis of the radiating organic matter will increase accordingly. When the amount of radiation lost by the ground radiation is balanced with the amount of solar radiation it receives, the temperature will no longer rise. The temperature at this time is called the equilibrium temperature. It is significant that the temperature of most of the surface of the earth falls within the narrow range where liquid water exists, which is very rare in the universe.

The atmosphere is the middle layer between the surface and the universe. The atmosphere has a variety of effects on the radiation balance, among which the effect of greenhouse gases is very important. The content of greenhouse gases on the earth is just right. If there were no greenhouse gases in the atmosphere, the average surface temperature would be much lower, and most of the water would be frozen. On the contrary, if the greenhouse gases on the earth reached the level of Venus, the content of carbon dioxide would reach 95% of the atmospheric composition, and the temperature there would be as high as 470℃, and liquid water would be difficult to exist.

Another major contribution of the Earth's atmosphere is that it seals up the Earth's water and prevents it from escaping into space. As we all know, the lowest layer of the Earth's atmosphere is the troposphere, and above the troposphere is the stratosphere. In the stratosphere, air flows horizontally, and in this layer, water is blocked and cannot escape into space. The movement of water is limited to the troposphere and will never escape from the Earth. Without the protection of the atmosphere, no matter how abundant the amount of water is, it cannot be preserved forever for trillions of years.

The water content of air is closely related to its temperature. According to a rough estimate, for every 10°C increase in temperature, its water content is about doubled. The air that has absorbed enough water over the tropical ocean flows to the continent and rises when it encounters mountains or cold air. It is estimated that the temperature drops by 6°C for every 1,000-meter increase in altitude, so about half of its water content will condense into rain and fall to the ground after about 1,500 meters of rise, which is why the continent can be moisturized.

More importantly, the water cycle of the earth can be said to be mainly completed by the atmosphere. One of the greatest advantages of the earth's surface is the existence of two underlying surfaces with completely different properties: the continent and the ocean. The water is concentrated in the ocean. If there is no water cycle, the continent will become a waterless desert. However, the atmosphere plays the role of an executor of the mission of transporting water from the ocean to the continent, so that the continent can obtain water and become the base for the prosperity of the ecosystem and the emergence of a high level of human civilization.

Plant photosynthesis is the only production mechanism of organic matter on Earth. The raw materials and energy of photosynthesis are almost all taken from the atmosphere. After burning a tree, the remaining ash is generally less than one percent of the weight of the original tree, which means that the main raw materials for the growth of trees are carbon dioxide and precipitation provided by the atmosphere, while the minerals obtained from the soil are negligible. The atmosphere is also extremely important for the formation of life energy. People even regard the cessation of breathing as a sign of death, that is, when life is disconnected from the atmosphere, people leave the world.

From this we can see that the atmosphere creates an extremely well-designed home for us, and understanding and protecting the atmosphere should also be people’s bounden duty.