Technical communication

20 years aquaculture shrimp master cast feed secrets

Farmers have their own strategies on feeding time, most of which are taught by the old shrimp of the previous generation. There are three meals, four meals, and five meals. So here's the problem! No matter how many meals, should the feeding time and feeding amount be fixed? I believe that most of the farmers in the actual breeding process are fixed time fixed amount of feeding or fine tuning according to the weather. However, this approach is problematic, or not perfect! Temperature and dissolved oxygen, two important factors affecting prawn feeding, were ignored.

First, the feeding time and feeding amount should be adjusted flexibly according to the change of dissolved oxygen

Shrimp feeding was normal when dissolved oxygen in the pond was greater than 5mg/L. When it gets below 3, it basically stops eating. Because of this, feeding time and feeding amount should be adjusted according to dissolved oxygen, or even stop feeding.

(Relationship between feeding and dissolved oxygen in prawn)

Dissolved oxygen in pond >5mg\L Prawn state Prawn feeding is normal

The feed utilization rate of 3-4mg\L prawns with dissolved oxygen in pond decreased by 20%

The state of prawns with dissolved oxygen of 2-3mg\L in pond stopped feeding and their constitution deteriorated

(A) The first meal to be careful, staring at dissolved oxygen

Dissolved oxygen in the pond reached its lowest point of the day at 6 a.m. And at this time is often a lot of farmers choose to feed the first meal time. It is recommended to focus on dissolved oxygen at this time, and there are two options when it is below 4mg/L. The first option is to turn on the aerator an hour earlier and bring up the dissolved oxygen. The second option is to wait. As the light intensifies, the photosynthesis of the algae quickly lifts the dissolved oxygen in the pond, which is then fed.

Take Mr. Yang's pond, where a Water quality monitor was installed, for example. According to the Water quality monitoring curve, on August 27, the dissolved oxygen in the morning was 4mg, and if the feed was fed at this time, the utilization rate of feed would decrease by 20%. Residual bait can be bad for the bottom. Therefore, Boss Yang chose plan two, delaying feeding, until the dissolved oxygen in the pond rose to about 5 to start feeding!

Yang also has a pond. According to the simplified water quality curve of the pond (shown in the picture), on the same day, the dissolved oxygen in the pond at 6 am was 7.8mg\L, which can be fed normally.

2. Feeding time and feeding quantity should be adjusted flexibly according to temperature changes.

The temperature

Prawn state

< 9 degrees Celsius

Shrimp death

13 to 15 degrees Celsius

Prawns half unconscious, transport temperature

< 18 ° C

The prawns are no longer feeding

23 degrees Celsius

Minimum temperature for normal growth of prawn

25 to 32 degrees Celsius

The higher the temperature, the faster the growth temperature range

34 degrees Celsius

Feeding of prawns slows down

Above 43 degrees Celsius

Shrimp death

① The temperature is lower than 25° or higher than 32°.

The fastest growing temperature range of prawns is 25-32°. Prawns will eat slower when the temperature is lower than 25° or higher than 34°. We also need to look at the temperature parameters when feeding.

② If the temperature changes more than 3° for a short time, feeding can be reduced.

When the temperature exceeds 3°, prawns will have a stress response, and the feeding of prawns will drop a lot. As can be seen from the curve, the temperature difference in this pond reaches 5°, so feeding should be reduced or not, the water level should be deepened, the water volume is large, and the temperature change will not be too d RAStic and the stress response will be reduced.

Conclusion: Ponds feeding time should be based on the dissolved oxygen and temperature of the pond, rather than the mechanization to perform traditional experience, dissolved oxygen pond too low or the temperature is not suitable for feeding not only wastes the feed, will corrupt the pond bottom, through the data, choose high dissolved oxygen, the suitable temperature for feeding can improve feed utilization, reduce the waste of cost reduction, and can grow fast, Form a virtuous circle!