(White Shrimp Research) – In order to assess the application of AZUNO products of United Phat Technology Co., Ltd. to intensive shrimp farming in terms of water quality, disease prevention, shrimp growth, feed system, economic and technical efficiency. The company has edied with Ths. Do Van Hoang, aquaculture expert, conducts research to assess product application in ponds in the Mekong Delta.

Experimental layout

Table 1: Description of experimental formula tests

Farming system

Shrimp ponds with an area of 2,000 m2, 2m deep, lined with tarpaulins around the shore, with sewers and sewers, the pond is fitted with 2 water fans (12-18 wings) for the first 2 months and added 1 fan from the 3rd month. The pond is arranged 2 feeding sieves to monitor the amount of feed used by shrimp after each feeding. Around the pond there is a mesh fence to prevent crabs, mice from entering the pond; above there is a tension to prevent birds.

Pond Renovation and Water Preparation

Before the start of the experiment, the pond was slugs sludge bottom and dried for 5 days. Water is supplied from the pond through a fine filter bag to prevent fish and crustaceans from entering the pond. When the water level in the pond reaches 1m, apply cao lime to raise the pH above 8 and then continue to apply NPK with a dose of 3kg – 5kg / 1000^m3 to cause color. After about 7 days the water level reaches 20 cm, the water supply to 1.4 m. Check water quality at 30 cm, alkaline 120 mg/l and ph 8.2 can be stocked.

Stocking

Shrimp breeding was purchased from the African company, the size of Post larvae 15 shrimp. Before stocking, shrimp breeding is sampled negative for the virus causing systoccal disease, Vibrio parahaemolyticus (bacteria that cause early death of shrimp disease – EMS). Shrimp are stocked at a density of 80 shrimp per ^sqm.

Care and management

Feeding shrimp

Shrimp are fed with industrial feed (UP feed, 40% raw protein) daily at 7h, 10h, 16h, 19h with a ratio of 30%, 25%, 30%, and 15% each. Feeding dosage: From day 1 to day 10: feeding 3 kg/100,000/day and increasing by 10%/day; From the 11th to the 20th day is 6 kg/100,000 varieties/day and increased by 8%/day. From 20-30 days feed 11 kg / 100,000 varieties / day and increase 6% / day. From the 30th day onwards feeding is based on the amount of food in the sieve. To train shrimp to get used to sieve, from the 25th day onwards used sieve to determine the amount of food.

Shrimp Health Management

Regularly observe the body color, bearing, hemancreatic body of shrimp and swimming activity, the degree of reflection of shrimp. Normal shrimp liver is dark brown liver, clear liver mass. Check the feed in the digestive system of the shrimp is full or empty, the ability to find bait is positive or not. Observe whether the sub-department is intact or not, whether there are manifestations of infection or some other disease (crusting, softening of the shell). Periodically 10-15 days per shrimp sample collection to check the health of farmed shrimp.

Tracking targets

– Analysis targets: Vibrio bacteria total measured by TCBS jelly plate coating method; Vibrio parahaemolyticus by Vibrio parahaemolyticus measurement kit on the market.

– Daily water quality measurement: salinity measure meter, pH, alkalinity. Nh3/NH4₊, H₂^S, N_O2, DO measured by DR 2400 spectral machine.

– Feed conversion system (FCR).

FCR = feed used/harvested shrimp volume.

– Survival rate (TLS).

TLS (%)= 100 x (number of harvests/initial quantities).

Results

Fluctuations of water quality factors

The test system consists of 9 ponds, each 2000m². Experimental ponds were implemented at the same time, so the hydrolysing targets were nearly identical and less variable. Some basic hydrolymification indicators in NT countries such as:

– The average salinity in the NT is 21 – 22 ‰, angst in the range of 18 – 25‰;

– pH of the average NT 8.1 – 8.2, angst in the range of 7.7 – 8.6;

– The average alkaline of NT’s is 113 – 120 mg/l, angst in the range is 100 – 140 mg/l.

In general, the basic hydrolymification targets are within the scope of adapting and in line with the development of white shrimp (MARD, HCMC, 2009).

Some key factors influencing the development of farmed shrimp

According to Boys, 1990 ammonia gas content ₍NH3/_N^H4+), _NO2 and DO are the main factors influencing the growth and development of farmed shrimp. These factors in experimental ponds fluctuate within the range of adaption for white shrimp development and differences are not statistically meaningful (p>0.05). According to QCVN 02 – 19: 2014/BNNPTNT stipulated that white shrimp farming establishments must maintain do-> 3.5mg/l; Ammonia (_NH3/_N^H4+) < 0,3mg/l.

Table 2: Key factors influencing the growth of farmed shrimp

Notes:

Figures for each column (average ± standard deviation)

In the same column, the same letter shows a statistically meaningless difference (P>0.05).

The content of Ammonia g_as ₍^NH3/NH4+) in NT’s tends to increase over time, near the harvest time of NT2 and UTI higher than 0.3 mg/l as prescribed by QCVN 02 – 19: 2014/BNNPTNT but the harvest preparation time should also have little effect on farmed shrimp.

Chart 1: NH3 (NH4+₎ fl_u^ctuations over time in NT

NO2 content in NT’_s tends to change continuously over time but always < 0,5 mg/l theo quy định của QCVN 02 – 19 : 2014/BNNPTNT. At the end of the harvest, no2 content tends to i_ncrease and is more likely to exceed 0.5 if microbial use is not used periodically.

Map 2: No2 fluctu_ations over time in NT’s

Volatility of Vibrio sp. and Vibrio parahaemolyticus

Table 3: Average Vibrio sp. and Vibrio parahaemolyticus in aquaculture tanks

Notes:

Figures for each column (average ± standard deviation)

In the same column, the same letter shows a statistically meaningless difference (P>0.05).

The vibrio sp. average of NT2 is lowest compared to other NTCs but this average difference is not statistically meaningful (P>0.05) and Vibrio parahaemolyticus of NTC is 2.58 CFU/ml lowest compared to other cognitive tests but the difference is not statistically meaningful (p>0.05).

Vibrio sp.and Vibrio parahaemolytiucus in white shrimp farming tanks fluctuates quite similarly to the cycles used during the culture process. At some point there were appearances of Vibrio sp. in breeding tanks > 1,000 CFU/ml. However, after processing the composition according to each NT, Vibrio sp. decreased significantly and quite quickly.

Technical criteria

Growth of farmed shrimp

After 90 days of farming, NT2 reached an average weight of 17.17 ± 1,04a g/off, the average shrimp size was 144 ± 1.3a mm/chi^ld, the highest compared to the rest of the samples. This suggests that preparations such as AZUNO-CLEAR, AZUNO-DETOX and AZUNO-PRO with actual dosages 1.5 times higher than the recommended dose have a good supporting effect on the growth of farmed shrimp compared to current preparations used in intensive white shrimp farming.

Chart 3: Shrimp size (mm/child) over culture time

Chart 4: Shrimp weight (g/child) over culture time

Figure 1: Size of shrimp when used and do not use the composition at 15 days of culture (from top to bottom: NT1 and NT2)

Figure 2: Size of shrimp when used and do not use the composition in 30 days of culture (from top to bottom: ND1 and NT2)

Figure 3: Size of shrimp when used and do not use the composition in 60 days of culture (from top to bottom: ND1 and NT2)

Figure 4: Size of shrimp when used and do not use the composition in 90 days of culture (from top to bottom: dna, NT1 and NT2)

Survival rate of farmed shrimp

The survival rate of farmed shrimp decreases over time. After 90 days of farming NT2 has the highest survival rate of 81.50% compared to other NTCs of 81.20% (NT1) and 81.03% (NT1) respectively. In general, the survival rate of the tanks is consistent with the current intensive white shrimp farming process and the difference is not statistically meaningful (p>0.05).

Chart 5: Survival rate of aquaculture tanks

Conclusion

AZUNO-CLEAR, AZUNO-DETOX and AZUNO-PRO have worked:

– Effective control of toxic gases NH3_, NO2 ₍fluctuation of different environmental targets is not statistically meaningful p>0.05).

– Effective control of the density of pathogenic Vibrio sp. and Vibrio parahaemolyticus bacteria.

– Contribute to the stable growth of white shrimp intensively farmed in test tanks compared to the test tanks (using microorganisms according to current procedures).

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