The carbon source used in aquaculture is. What? The carbon source in water is carbon dioxide, which is also needed in water to reduce the content of ammonia nitrogen in water. If the content of ammonia nitrogen in water is high, the phenomenon of fish floating head will appear, which will lead to a large number of fish deaths in severe cases.
First, the accumulation and harm of ammonia nitrogen in fish pond water
The harm of ammonia nitrogen to aquatic organisms mainly refers to the harm of nonionic ammonia, that is, ammonia gas. After non-ionic ammonia enters aquatic organisms, it has a significant impact on enzymatic hydrolysis and membrane stability, which is characterized by dyspnea, non-feeding, decreased resistance, convulsions, coma and so on, and even leads to a large number of aquatic organisms' deaths. In addition, the high concentration of ammonia nitrogen enriched in organisms can be converted into nitrite, which is a strong oxidant, not only poisoning organisms, but also causing cancer.
Second, prevent and degrade excessive ammonia nitrogen in fish ponds.
According to the fishery water quality standard, the concentration of ammonia in aquaculture production should be controlled below 0.02 mg/L. At present, we can reduce the content of ammonia nitrogen in fish pond water from the following three aspects, degrade ammonia nitrogen and prevent ammonia nitrogen poisoning.
(1) Scientific aquaculture production
1, do a good job of dredging, change water frequently, and keep the water fresh.
2. Overfeeding feed is one of the main causes of ammonia nitrogen pollution, so it is necessary to reduce feed coefficient, improve feed utilization rate and reduce fecal excretion of cultured organisms.
3. Use hydrochloric acid or acetic acid to adjust the PH value to below 7.0 to reduce the toxicity of ammonia nitrogen, and then use adsorbents such as zeolite powder and medical stone to remove ammonia nitrogen from water.
(b) Using microalgae to reduce ammonia nitrogen in water.
Microalgae is a unicellular algae, which uses water as electron donor, light energy as energy and nitrogen, phosphorus and other nutrients to synthesize organic matter. It can absorb ammonia nitrogen in water and convert it into nitrogen-containing substances such as amino acids, which is a natural bait for aquatic organisms. Microalgae can also produce a lot of oxygen. Sufficient oxygen in water can promote the conversion of nitrite to nitrate, reduce the foul smell caused by lack of oxygen in water, improve the ecological environment of water, inhibit and reduce the toxic effect of ammonia nitrogen on fish, improve fish appetite and feed utilization rate, and promote fish growth and development.
(3) using microbial agents to degrade ammonia nitrogen in fish ponds.
Microbial preparation is an active bacterial preparation containing a large number of beneficial bacteria after microbial cells screened from the natural environment are cultured and propagated. Generally, microbial preparations are divided into two categories: liquid and solid (powder). Fish pond water is a dynamic balance system composed of many microorganisms, and beneficial bacteria and harmful bacteria coexist. When beneficial microorganisms are added to the water, the growth of harmful bacteria can be inhibited by mass reproduction. At the same time, through the metabolism of beneficial microorganisms, the excess nutrients and other harmful substances in the water are reduced, which has obvious regulatory effect on degrading ammonia nitrogen, organic matter and increasing dissolved oxygen in the fish pond water. At the same time, it can also adjust the pH value of water, promote the release of nitrogen and phosphorus in sediment and promote the growth of plankton.
The special microbial inoculum for Jinshui products is developed by Kangyuan Oasis Biotechnology (Beijing) Co., Ltd., which is an efficient compound microbial flora preparation cultivated by a variety of beneficial microorganisms such as yeast, actinomycetes, lactic acid bacteria and photosynthetic bacteria through special methods. There are both decomposing bacteria and synthetic bacteria in the flora; There are anaerobic bacteria, facultative bacteria and aerobic bacteria, which are an organism with many kinds of bacteria coexisting. In the process of its growth, the flora can rapidly decompose the organic matter in sewage, and at the same time, rely on mutual proliferation and synergy to metabolize antioxidant substances, generate a stable and complex ecosystem, inhibit the growth and reproduction of harmful microorganisms, and activate protozoa, microorganisms and aquatic plants with water purification function. Through the comprehensive action of these organisms, the purpose of purifying water quality is achieved.
For example, Bacillus subtilis, by separating and screening a variety of Bacillus subtilis, produces special bacteria that can improve the intestinal microecology of cultured animals, improve their digestive function and promote the healthy growth of cultured animals. Because of the characteristics of spore propagation, spores have strong resistance to high temperature, dryness and chemicals, so Bacillus is less affected by temperature, humidity and chemicals during processing or application, which is especially suitable for making active microbial preparations and widely used in aquaculture.
Three. abstract
Excessive ammonia nitrogen is a problem that cannot be ignored in aquaculture production. Aquaculture operators should manage scientifically, dredge in time and change water reasonably. Once ammonia nitrogen is marked in aquatic organisms, it should be treated in time to reduce losses.
What is the role of multi-dimension in aquaculture stress? There are many names on the market, but Vc and Ve add some sucrose. The functions are as follows: 1, supplementing the nutrition of aquatic species and improving the disease resistance; 2, increase the transportation links, improve the compressive capacity. Such dimensions should be added for a long time, and the dosage should be controlled.
What if the breeding density is too high?
Which aquaculture waters are suitable for aquaculture water purification bacteria? Did it work? Please, cultured water purification strains are suitable for aquaculture waters: reservoirs, lakes, ponds, reservoirs, rivers, cages, seawater beaches and other brackish water bodies. They have broad-spectrum and efficient functions of fertilization, water transfer and water quality stabilization, and are suitable for grass, crucian carp, carp, silver carp, bighead carp, herring and catfish. . Main functions: First, reduce pathogenic microorganisms and harmful algae, obviously enhance the immunity and disease resistance of cultured objects, reduce the incidence and improve the survival rate. Users reported that the original solution of EM bacteria could nearly double the survival rate of crab seedlings, and the survival rate of China grouper increased from 30% to over 70%. Second, increase the number of beneficial microorganisms. There are many zooplankton and beneficial algae on the water surface, especially red worms, which cover the water surface continuously. 3. Stabilize and improve water quality. The water body is bright in color, tasteless, non-corrosive, and has no odor such as hydrogen sulfide and ammonia. The visibility is long and stable at 25-50 cm, and the water change time can be extended by more than 2 times. Four, fish and shrimp manure, impurities, scraps at the bottom of the pool will not become silt but loose sand. Five, promote growth, weight gain rate increased significantly. Practice has proved that in the same environment, after using EM bacteria liquid, it can be put on the market 10- 15 days in advance, the average yield per mu is increased by 20%-35%, the spawning amount is increased by 25%, and the spawning time is prolonged. Experiments show that the spawning time of purified aquaculture water is prolonged by nearly 70 days at room temperature, the hatching rate is good, the bait is odorless, and the aquaculture environment is improved. Agbio.
Remember to adopt
Which aquaculture waters are suitable for aquaculture water purification bacteria? Did it work? Please, cultured water purification strains are suitable for aquaculture waters: reservoirs, lakes, ponds, reservoirs, rivers, cages, seawater beaches and other brackish water bodies. They have broad-spectrum and efficient functions of fertilizing, regulating water and stabilizing water quality, and are suitable for grass, crucian carp, carp, silver carp, bighead carp, herring, catfish and catfish. . Main functions: First, reduce pathogenic microorganisms and harmful algae, obviously enhance the immunity and disease resistance of cultured objects, reduce the incidence and improve the survival rate. Users reported that the original solution of EM bacteria could nearly double the survival rate of crab seedlings, and the survival rate of China grouper increased from 30% to over 70%. Second, increase the number of beneficial microorganisms. There are many zooplankton and beneficial algae on the water surface, especially red worms, which cover the water surface continuously. 3. Stabilize and improve water quality. The water body is bright in color, tasteless, non-corrosive, and has no odor such as hydrogen sulfide and ammonia. The visibility is long and stable at 25-50 cm, and the water change time can be extended by more than 2 times. Four, fish and shrimp manure, impurities, scraps at the bottom of the pool will not become silt but loose sand. Five, promote growth, weight gain rate increased significantly. Practice has proved that in the same environment, after using EM bacteria liquid, it can be put on the market 10- 15 days in advance, the average yield per mu is increased by 20%-35%, the spawning amount is increased by 25%, and the spawning time is prolonged. Experiments show that the spawning time of purified aquaculture water is prolonged by nearly 70 days at room temperature, the hatching rate is good, the bait is odorless, and the aquaculture environment is improved. Agbio.
What are the requirements of aquaculture for water source and water quality? 1, temperature; 18-35℃ is the normal temperature and 25-32℃ is the optimum growth temperature.
2.PH value; 6.5-8.5, when the fertilizer efficiency is lower than 6.5, the advantages cannot be exerted normally, the toxicity of ammonia nitrogen and hydrogen sulfide increases, and it is easy to float head due to lack of oxygen. 3. Salinity; 0- 1%, too high salt will affect the normal growth and reproduction of organisms in fresh water.
4. Ammonia nitrogen; 0-0.02 mg/L, too high will damage the gills of fish and mussels, and above 0.5 will lead to the inability to eat and breathe until death. 5. Hydrogen sulfide; 0-0. 1 mg/L, too high will damage the central nervous system of fish and mussels, and higher than 0.5 will cause disease or death.
6. Nitrite; 0-0.02 mg/L, too high will lead to hemorrhagic diseases, which is an important factor to induce fulminant diseases, and higher than 0.5 will lead to hemorrhagic diseases.
Sick or dead.
7. Available phosphorus; 0.2- 1 mg/L, lower than 0.2, affects the growth of high-quality algae in the water, and even blooms, which is not conducive to bighead carp.
Growth of silver carp and mussel.
8. Transparency; 20-30 cm, too high is not enough fertilizer, too low affects photosynthesis.
9. Dissolved oxygen; ≥3mg/L, less than 3mg/L will affect the fish's feeding, less than 2mg/L will appear floating head, less than 1mg/L will come out.
Now the pond is flooded until a large number of people die.
Among the many chemical properties of aquaculture water, dissolved gases, inorganic salts and organic matter dissolved in water are most closely related to fish. I. dissolved gases
There are many kinds of gases dissolved in water, and their main sources are two aspects. One is dissolved directly from the air into the water body, and the other is produced in the water body through the life activities of aquatic organisms and the chemical changes of sediments or substances in the water body. The dissolution of gas in water varies with the water environment, and the differences are as follows.
Is inversely proportional to the water temperature. With the increase of water temperature, gas dissolution decreases. It is proportional to atmospheric pressure, and the solubility of gas increases with the increase of atmospheric pressure. It is inversely proportional to the concentration of impurities in water, and water with more impurities will reduce the solubility of gas.
1, dissolved oxygen; The dissolved oxygen content in water is small and changeable. The saturation of dissolved oxygen in fresh water is only 8- 10 mg/L, which is less than 1/20 of the oxygen content in air, and the dissolved oxygen content in seawater is even less. This shows that the breathing conditions of fish in water are poor, and they are threatened by hypoxia and suffocation from time to time. It can be seen that it is important for aquaculture to master the dynamic law of dissolved oxygen in water.
There are two sources of dissolved oxygen in water: one is that the oxygen in the atmosphere contacts the water surface and dissolves into the water, and the other is the oxygen released by aquatic plants during photosynthesis. Oxygen dissolved in water in the atmosphere is less than110 of oxygen produced by plant photosynthesis.
2. Hydrogen sulfide; Hydrogen sulfide is formed by the decomposition of sulfur-containing organic matter under anoxic conditions, or by the reduction of sulfate to sulfide in sulfate-rich water, and then hydrogen sulfide is generated.
Sulfide and hydrogen sulfide are toxic to fish, and hydrogen sulfide is the most toxic. Generally speaking, most sulfides exist in the form of hydrogen sulfide under acidic conditions. When dissolved oxygen in water increases, hydrogen sulfide is oxidized and disappears. The toxic effect of hydrogen sulfide on fish is to combine with iron in hemoglobin, which makes hemoglobin lose its oxygen-carrying ability and leads to hypoxia in fish tissues. Therefore, special attention should be paid to the existence of hydrogen sulfide in aquaculture.
3. Ammonia nitrogen; Ammonia nitrogen is produced by the decomposition of organic matter when oxygen is insufficient, or by the reduction of oxygen-containing compounds by digestive bacteria. The final products of aquatic animal metabolism are excreted as ammonia. Ammonia nitrogen is toxic to aquatic organisms such as fish, even if its concentration is very low, it will inhibit the growth of fish, so we must pay close attention to it.
What role does humic acid play in aquaculture? Application of (1) in fertilizer and water: The earliest application of sodium humate in aquatic products originated from its fertilizer properties, not its nutritional components. In recent years, it has been proposed that carbon sources can supplement water bodies. It makes sense from this point of view, because sodium humate is the sodium salt of humic acid, a polymer organic weak acid, and the product of decomposition of plant residues, which is mainly composed of carbon, hydrogen, oxygen, nitrogen and other elements.
The data show that humic acid consists of 50%-60% carbon, 4%-6% hydrogen, 0/.5%-6.0% nitrogen, and most of the rest elements are oxygen. In addition, it also contains sulfur and phosphorus below 1%. Therefore, it is meaningful to use it as a supplement to water carbon source, but there is no relevant research on the effect of the supplementary carbon source on fertilizer and water.
(2) Purifying water quality: Because sodium humate is a relatively stable natural macromolecular organic substance with aromatic structure, it is a discontinuous network composed of sparse aromatic rings, and there are many cavities and pores in the structure. Because of its complex structure and various functional groups, it has high reactivity and strong adsorption performance.
Therefore, it can achieve the effect of purifying water quality in practical application, but the actual feedback effect shows that powder products come faster than flake products, and the main reason may be that powder products settle faster in water than flake products. At the same time, there may be another aspect to the effect of purifying water quality. Firstly, the porous structure provides a good breeding ground for beneficial organisms; Second, sodium humate itself can release nascent state oxygen, thus inhibiting the growth of some bacteria.
What is the prospect of aquaculture postgraduate entrance examination? It is still very promising in aquaculture enterprises. It has a bright future in Jiangnan area.
Aquaculture is a production activity of breeding, cultivating and fishing aquatic animals and plants under artificial control. Generally, it includes the whole process from fry to aquaculture under the management of artificial feeding. Broadly speaking, it can also include the proliferation of aquatic resources. Aquaculture includes coarse culture, intensive culture and high-density intensive culture. Coarse culture is to put fry in small and medium-sized natural waters and develop aquatic products entirely by natural bait, such as fish culture in lakes and reservoirs and shellfish culture in shallow seas. Intensive culture is to cultivate aquatic products in small water bodies by feeding and fertilizing, such as pond culture, cage culture and enclosure culture. High-density intensive culture adopts running water, temperature control, oxygenation and feeding high-quality bait, and carries out high-density culture in small water bodies to obtain high yield, such as running water for high-density fish culture and shrimp culture.
What effect does salt have on aquaculture? 1. Fish disinfection
Disinfect the fish with 5% salt before stocking. The method is: soak the fish in water with the water temperature of 15-20℃ 15-20 minutes to remove bacteria, rotifers, oblique worms and so on. Improve the survival rate of fish after entering the pool.
Second, increase dissolved oxygen.
Salt can increase the ion concentration in water, make suspended organic particles and colloids flocculate and settle to the bottom of the pond, reduce the consumption of dissolved oxygen and purify water. Therefore, if there is no aeration equipment or it is too late to aerate, you can use yellow mud water and salt water (yellow mud 10 kg per mu, add water to make a paste, add salt water 10 kg, and splash it after stirring) or salt water 10 kg/mu, which also has certain effects.
Third, mix in feed.
Salt helps digestion, but also has a certain bactericidal effect. Therefore, appropriate amount of salt can be added to the feed for mixed feeding. Especially before feeding chilled fish, some salt (65,438+0-2 kg salt per 50 kg chilled fish) can be added, which can remove sewage from chilled fish on the one hand, and play a bactericidal role on the other hand, and can also be eaten by fish to increase inorganic salts in the body.
Fourth, long-distance transportation.
In the transportation of adult fish, when the water temperature is lower than 20℃, the salt concentration of water is 3 ‰; When the water temperature is about 20℃, the salt content of water is 5 ‰; When the water temperature is 26℃ and the salt concentration is 7‰, the survival rate of adult fish can be improved.
Verb (abbreviation for verb) traps fish in the pond.
Adding about 0.5% salt to the bait, throwing the bait directly into the water surface full of water can quickly lure fish, and then fishing according to the conventional fishing method.
In addition, salt can also prevent diseases in aquaculture.