Fish Feed Machine Knowleagde

With the development of the aquaculture industry and technological progress, the density of aquaculture is getting higher and higher. As the most important method of aquaculture in my country’s aquaculture industry, the aquaculture density is also increasing year by year. The pond aquaculture system contains a lot of protein-containing feed Feeding, on the one hand, is used as bait for fish and shrimp, and has become the main source of animal bait in the intensive breeding process, but the incomplete use of nitrogenous substances also brings a severe test to the self-purification ability of the breeding ecosystem. The aquaculture water environment is the basis for the survival and growth of aquatic animals. Therefore, water quality management is related to the success or failure of aquaculture, and the control and management of ammonia nitrogen and nitrite are extremely important contents in water quality management. This article starts from the nitrogen in aquaculture ponds. Start with the source and the way out, try to explore the management of ammonia nitrogen and nitrite in aquaculture ponds.

The main hazards of excessive ammonia nitrogen are as follows:
First, it hinders the excretion of ammonia in aquatic animals. Most fish directly remove ammonia through their gills. If the concentration of ammonia nitrogen in the water is too high, it is difficult for fish to excrete ammonia, which ultimately affects the feeding and growth rate of fish.
Second, it is easy to corrode the gill tissue, destroy the mucosal layer of the gill tissue, and increase the chance of the gills being infected by various pathogens.
The third is to affect the respiration of the gills. Due to the destruction of the gill tissue, the gas exchange between the gill tissue and the water body is affected, and the gill's ability to absorb and transport dissolved oxygen in the water body is reduced.
The fourth is the impact of ammonia on osmotic pressure. The high concentration of ammonia in water increases the permeability of fish to water, thereby reducing the concentration of ions in the body. For the main cultured species of carps in my country, 0.05 mg/l is generally used as the allowable limit value of molecular ammonia in the cultured water.
The toxicity of nitrite is mainly reflected in the influence of blood to oxygen transport, resulting in hypoxia in the fish body and damage to organs and tissues. Nitrite can bind to hemoglobin in the blood and oxidize the divalent iron in hemoglobin to trivalent iron, so that hemoglobin loses its ability to transport oxygen. Nitrite can also relax the smooth muscle of small blood vessels and cause blood stasis. Aquatic animals that have long lived in a water environment with high nitrite are prone to slow growth, weak resistance to pathogens, and easy disease.

Regulation of excessive ammonia nitrogen and nitrite in aquaculture ponds.

The ammonia nitrogen and nitrite in aquaculture ponds are relatively high, and the treatment methods are generally as follows:
1.Water change: The fastest and most effective way to improve water quality is to change water, but the premise is that the quality of the source water is significantly better than that of the aquaculture pond water body. Otherwise, the water change will be meaningless. Therefore, the treatment of ammonia nitrogen and nitrite is too high, and the water change is only suitable for ponds with abundant water sources and good water source conditions. In actual production, with the discharge of industrial and agricultural sewage, many ponds use source water in the breeding process. Doesn't have such conditions.
2.Scientifically and reasonably feed the feed: According to the nutritional needs of different fish at different growth stages, the feed rate is optimized, and the feed rate is set reasonably, which is not only conducive to the full absorption and utilization of feed, but also reduces the burden of liver and gallbladder and the risk of infectious diseases. At the same time, it can also reduce the excretion of unused nitrogen, which can alleviate the high levels of ammonia nitrogen and nitrite to a certain extent.
3.Open more aerators: especially at noon on sunny days, use more aerators, on the one hand, to promote more ammonia in the water body to escape from the water body, on the other hand, to repay the oxygen debt at the bottom of the pond in time to maintain aerobic conditions at the bottom of the pond The environment promotes the decomposition of organic matter and the utilization of ammonia nitrogen by algae.
4.Applying phosphorus fertilizer to promote nitrogen with phosphorus: The principle of this treatment and nitrite method is that in most cases, phosphorus is a key factor that limits the primary productivity of aquaculture ponds. Through the application of phosphorus fertilizers, the phytoplankton in aquaculture ponds can be improved. Abundance, through phytoplankton's absorption and utilization of ammonium nitrogen and nitrate nitrogen, to reduce the level of ammonia nitrogen and nitrite in the water body, and to reduce ammonia nitrogen and nitrite in ponds through the application of phosphate fertilizer. It is only suitable for ponds with thinner water quality. For ponds with fatter water, the abundance of phytoplankton cannot be greatly increased due to the limitation of the entire pond culture ecosystem. Phosphate fertilizer also loses its meaning.
5.Adding nitrifying bacteria treatment: In the natural environment, the reproduction speed of nitrifying bacteria is slow, and it takes more than 20 hours to reproduce one generation in the natural environment, which is far lower than that of heteroaerobic bacteria. By artificially adding nitrifying bacteria, the deficiency of nitrifying bacteria in the pond ecosystem can be supplemented, and the level of ammonia nitrogen and nitrite in ponds can be reduced by enhancing nitrification. In the process of actual use, since most of the nitrifying bacteria are autotrophic aerobes, they have relatively high environmental requirements during the proliferation process, requiring a certain amount of dissolved oxygen, alkalinity and carbon sources in the water environment, and their growth rate is slow. Generally need to be used a few days in advance. Since nitrifying bacteria have much more stringent requirements on the pond water environment than other beneficial bacteria, they have poorer environmental adaptability to different aquaculture water bodies, which affects the expression of effects during use.
6.Chelating agents: Chelating agents such as sodium humate, sodium lignosulfonate, etc., through their own functional groups to combine ammonia nitrogen and nitrite in the water to achieve the purpose of reducing ammonia nitrogen and nitrite. There is a certain effect in the process of use, but the disadvantage is that the effect lasts for a short time.
7.Strong oxidizer bottom modification and chemical oxidizer used together: The principle of this method to reduce ammonia nitrogen and nitrite is to increase the oxidation-reduction potential at the bottom of the pond through strong oxidizer modification, and at the same time oxidize part of the organic matter at the bottom of the pond to reduce the source of ammonia nitrogen in the pond. On the other hand, by supplementing oxygen, more sufficient oxygen is provided for the nitrification of the pond to promote the progress of nitrification. The effect of this method lasts longer than the method using a chelating agent.
In the process of breeding, bacterial preparations that decompose organic matter in ponds are widely used. In the process of use, sometimes it will increase the level of ammonia nitrogen in breeding ponds. This is because in the middle and late stages of breeding, bacteria are decomposing residual bait and For organic matter such as feces, the C/N of the organic matter is relatively narrow, and the nitrogen generated by the decomposition of the organic matter is not fully utilized by the bacteria, and the decomposition process is accompanied by the mineralization of nitrogen.
8.Poisoning treatment: if the ammonia nitrogen or nitrite is too high, if the poisoning occurs, you can first use the organic acid antidote in the whole pond to reduce the stress of the fish, and then use the chelating agent such as sodium humate to treat the ammonia nitrogen and nitrous acid in the water. Salt is used as an emergency treatment to relieve the symptoms of poisoning, and chemical oxygenators should be used to increase oxygen that night. Then follow the normal steps to deal with the problem of high ammonia nitrogen and nitrite.