And
ammonia nitrogen is also the main
stress factor that mainly restricts the aquaculture environment. The
high concentration of
ammonia nitrogen in the water can easily induce diseases of
shrimp seedlings, affect the growth of
shrimp seedlings, cause metabolic disorders of the body of shrimp seedlings and reduce their environmental adaptability, making shrimp seedlings vulnerable to stress. Infection of various hospital microorganisms reduces the
survival rate of seedlings and reduces the quality of shrimp seedlings
In addition, a large amount of residual bait and
feces are accumulated in the pond, and the
water quality is extremely deteriorated. A large number of
vibrio and fungi are bred in the pond, which seriously endangers the health of the shrimp seedlings, and can even cause a large number of shrimp seedlings in the whole pond to die in a short period of time.
The main problem of using compound feed is that the feed particles settle quickly in the
water body, the slow release speed is not good, and some particles dissolve in the water, so that the
nutrition of the feed is easily lost to the water, and it is not easy to be ingested by the shrimp seedlings, and at the same time cause
bacteria and fungi to multiply and pollute
Water body Artemia can provide a large amount of unsaturated fatty acids to shrimp seedlings, which is rich in
nutrition, but good Artemia eggs have a high hatch rate and are expensive, and poor Artemia eggs have a low hatch rate, and a large number of dead eggs and empty egg shells are brought into the pond. While polluting
water quality and breeding
bacteria, after being eaten by shrimp by mistake, it cannot be digested and absorbed by shrimp, and it is easy to block the intestinal tract of shrimp, resulting in the death of shrimp
Moreover, the
nutrition of the compound feed and Artemia worms is relatively simple, lacking some amino acids and vitamins required by the shrimp seedlings, the growth rate of the shrimp seedlings is not high, the quality of the shrimp seedlings on the market is average, and the
survival rate is low
[0007] 3. Poor adaptability
[0008] In industrial
seedling production, the temperature and
salinity control is relatively stable. Under normal circumstances, the temperature of Penaeus vannamei seedlings is 30°C-31°C, and some
seedling manufacturers use 33-34°C for cultivation in order to consider the cost of
seedling cultivation.
Shrimp seedlings, so as to achieve the rapid growth of shrimp seedlings, shorten the breeding time for the purpose, reduce the production cost, and increase the output of the factory. However, this constant temperature and high temperature seedling breeding mode makes the shrimp seedlings weaker in physique and poor in adaptability. It is difficult to show good adaptability to the pond environment after being put into the outer pond for cultivation
Poor
osmotic pressure adjustment ability of shrimp seedlings, poor tolerance to environmental salinity after entering the pond, and narrow adaptability to salinity range. Once the water salinity changes greatly, the shrimp seedlings will be weak and prone to
disease, resulting in survival in later breeding rate is not high
[0012] Due to the high
stocking density, single bait, and poor
water quality environment, the industrialized seedlings have average physique and
slow growth rate.
Especially in some nursery units, faced with a large number of
Vibrio and fungi in the pond, and a large number of shrimp morbidity, a large number of
antibiotics are used for
disease prevention and treatment, which further reduces the quality of shrimp
In addition, the
water temperature of the industrial seedlings in the early stage is stable, and after the shrimp seedlings enter the breeding pond in the later stage, the temperature, salinity, and water quality change greatly, and it is difficult for the shrimp seedlings to adapt, resulting in low growth rate and
slow growth rate.
[0013] 5. High cost
Among them, the cost of supporting feed and artemia used in large quantities is high, the maintenance cost of the boiler
temperature control system of supporting facilities is high, and the
water treatment facilities are complicated, including treatment systems such as sand tanks, foam separators, precision filters, dark
sedimentation tanks, and
water source treatment. High cost and many processes
And high-yield industrial seedlings cannot do without high investment, so that the price of high-quality shrimp seedlings remains high