Effect Of Ammonia And Nitrogen In Aquaculture On

- Jan 02, 2018-

At present, turtle breeding basically is the intensive culture of high output and high density, pond fish carrying a large amount of water environment is relatively poor, the ammonia nitrogen content in pond water related diseases caused by the high also appeared frequently, so it is necessary to carefully analyze the ammonia is produced, and how to reduce the content of ammonia nitrogen in the water, and to the timing of the content of ammonia in water were detected.

1. The main source of ammonia nitrogen

1. The decomposition of nitrogen containing organic matter produces ammonia nitrogen. In the turtle pond, feeding turtle feed, ice fish, snail meat and other feed residues as well as the death of the turtle and other wild fish bodies can be produced from the decomposition of ammonia.

2. When the water is anoxic, the nitrogen containing organic matter is reduced to the denitrifying bacteria to produce ammonia nitrogen. The important condition of denitrification is the anaerobic environment, when a fish pond eutrophication, the oxygen in the water is very low, and the temperature is relatively high, denitrifying bacteria such as Clostridium will restore water Nitrate Nitrite and ammonia.

3, a pet turtle, other fish and wild fish general metabolites discharged in ammonia form, causing the increase of ammonia nitrogen in water.

Two, the harm of ammonia nitrogen

In the intensive culture of soft shelled turtle ponds, if we can't change the water in a timely manner, the daily management is a little careless. It is easy to cause too low dissolved oxygen and high ammonia nitrogen in the water, which will affect the growth of the soft shelled turtle, or even get sick and die. This is mainly because the turtle except for the lungs, exchange of oxygen and carbon dioxide in the water is still using the inner wall of the capillary rich oropharyngeal mucosa, plastron cortex and cloaca with water. When water turtles and other aquatic animal excreta, bait and organic detritus continuously oxidized and decomposed, resulting in ammonia content increased, and the value of pH is relatively high, the transformation to the direction of ammonia ammonium ion high rate of ammonia increased exponentially, so ammonia is nitrification bacteria oxidation into nitrite, the nitrifying bacteria due to the sharp increase of ammonia was inhibited, the nitrite cannot be further oxidized to nitrate, resulting in a large accumulation of nitrite. Nitrite is a strong oxidant. It is absorbed by the soft shelled turtle and enters the blood to oxidize the two valent iron in the hemoglobin to trivalent iron, resulting in hypoxemia, causing hypoxia in all tissues, and gradually causing lesions and necrosis in all organs, resulting in mass death of the turtle.

After several years of turtle breeding, the author found that the requirement of tolerance to ammonia turtle is less than 0.4mg/L when the ammonia nitrogen in water is more than 0.6mg/L, if not to take timely measures, it will gradually appear turtle skin ulcer, perforation, and the development of the white plate, edema, emphysema and other diseases caused by large-scale outbreak of death.

In July 2000, Guangzhou city Panyu a turtle breeding appeared in such a situation, every day dozens of deaths, and later to the day hundreds, the diagnosis and treatment of disease brought to the author of turtle and water, the pond has killed a total of 4000 - 5000 by turtle, measuring water, ammonia nitrogen reached 1.5mg/L, nitrite 0.3mg/L. Of course, the death of the turtle has its complicated causes, but it can not be said that the high ammonia nitrogen in the water quality of the pond is an important pathogenic factor of the turtle.

Three, effective measures to reduce ammonia nitrogen

1, every time the dry pond, to the bottom of the pool splashing composite photosynthetic bacteria and enzymes and other biological agents, and raking loose sediment, then adding water to 10 cm, the organic waste in the sediment was fully absorbed and transformed.

2, feed on water, feed a little water, and use 3-5 nails to prevent it from being pushed into the water, and feed should be strictly controlled within 2-3 hours. Observe and record the feeding situation of the turtle every day, increase and reduce the amount of feed in time, and control the leftover and lost feed as far as possible to the minimum.

3, when the summer temperature is high, the floating plants with bamboo fixed water hyacinth or other aquatic water at the inlet of the pond or the food table, but the number can not be too much, too close when the growth or death plants to promptly remove, to maintain a certain number, achieve the purpose of purifying water quality, at the same time provide shade place to reach the purpose of cooling the local turtle.

4, because the water quality is generally bad at present, the author advocates using enough area of sedimentation tank to disinfect the water and then enter the pond. In addition, the pond should be washed and changed regularly to ensure that there is sufficient dissolved oxygen in the water to facilitate the normal respiration of the turtle and to accelerate the oxidation decomposition of organic compounds, such as nitrogen and so on.

5, in the pond take to keep bighead, silver carp, catfish and other local fish, make full use of turtle feed water loss and other organic substances, so as to regulate water quality, and increase economic benefits.

6. To clean up the dead carcass in the pond and the corpses of other fish, and the organic debris, such as the dead algae floating in the tuyere under the pond, should be removed in time.

7. The use of the feed board can not only make the turtle feed normally, but also make it easy to push the feed into the water.

8, regular bottom insurance net physical adsorbent (20ppm) with surrounding the pool and feeding areas, the degradation of ammonia, hydrogen sulfide and other toxic substances increase the dissolved oxygen content, stable water quality.