Importance of Feed management in Shrimp Farming and It’s control methods

Hello everyone,

          Myself SRIHARI N C, B.F.Sc., Here we are about to discuss Importance of Feed management in Shrimp Farming and It’s control methods.

(I)Feed Management and It’s Importance:

·       Proper feeding protocol and strict feeding management is essential for successful shrimp farming. As feed contributes about 50-60% of operational cost, some strategies should be aimed at controlling the Feed Conversion Ratio (FCR) and optimizing feed inputs.

·       Quiet often the failure of culture is blamed on quality of Post-larvae, although in the most cases, the origin of problem might be poor aquaculture management practices, which includes,

1.      FEED MANAGEMENT

2.      FEED SELECTION

(II)Feed Quality and Feed Selection:

·       Shrimp requires approximately 40 essential nutrients and this need is met by consuming both natural food and supplemental feed.

·       A formulated aqua feed (shrimp feed) must meet several criteria which includes both Physical and Nutritional Qualities.

A.Physical Qualities:

Physical Qualities	Why?
Pellet size	Suitable for animal mouth size
Uniformity of Appearance	very low size variation in pellet
Water Stability	High water stability (>3 hrs)
Attract ability and smell	Improves feed precision and reduce response time
Powder percentage	<0.1%
Color	Indicates quality

 

B.Nutritional Qualities:

Nutritional Quality	Quantity
Protein	35% - 40%
Lipid	6% - 8% & <10%
Minerals	13% - 15%
Moisture	<10%
Fiber	3% - 5%

(III) Feed Management:

·       Feed management starts immediately after stocking.

·       During first 30 Days Of Culture (DOC), feeding is followed by BLIND FEED CHART, which is purely based on assumptions.

·       After DOC 30, feed ration is calculated based on Periodical Cast net sampling, which provides us Average Body Weight (ABW) & Survival and Check tray Observation.

·       The daily feed rations can be offered at 3 to 4 hours interval, minimum of 4 times schedule of feeding must be followed and there must be a proper monitoring of feed consumption through check tray monitoring.

(IV)Feed Conversion Ratio (FCR):

·       FCR is defined as a “Quantity of feed used to increase the biomass by 1 kg”.

·       FCR plays a major role in profit margin. And controlling FCR has great impact on the profit margin. Here are some strategies to control FCR effectively .

(V)FCR Control strategies through Feed Management:

·       Feed should be evenly distributed around the pond in the feeding area.

·       Switching off Aerators ½ an hour prior to feeding time, to prevent the drifting of feed by water current

 

·       Strictly following the check tray observation time based on DOCs

DOCs	Check tray observation time
1 - 30	3 hours
30 - 45	2.5 hours
45 - 65	2 hours
65 - harvest	1.5 hours

 

·       Switching on Aerators only after checking check trays

·       Strictly following the check tray feed gram per kilogram of feed based on DOCs and ABW.

DOCs	Check tray feed (g/kg)
1-30	2 g
30-40	3g
40-50	4g
50-60	5g
60-70	6g
70-80	7g
80-90	8g
90-100	9g
100- harvest	10g

·       Strictly following the check tray chart and environmental parameters to adjust the feed ration, followed by check tray observation.

Check tray observation	Feed adjustment
No feed left and more animal	+10%
No feed left over	+5%
<5% left over	Follow the same
10% left over	-5%
20% - 30% left over	-15%
>50% left over	Skip the feed and continue next by +3%

 

·       Proper placement of Check tray in a flat bottom and slowly and in middle of feeding area which is having a surface area of 0.6 m² to 0.8m² with height of 2 – 3 inches

·       Can use any software or MS Excel to track the record of feeding behavior of animal during various environmental conditions and physiological conditions (molting).

(VI)Conclusion:

·       As I have said before, feed management is aimed at controlling FCR, many strategies are followed in various areas. Here I have briefly explained some of those strategies. So by following BMP in shrimp farming and feed management we can have a control over FCR in culture system and have high profit margin.

For further contact,

Mr. SRIHARI N C, B.F.Sc.,

+918270776354 (WhatsApp / Call)

Nitrite toxicity in Fresh water or Low Saline water Shrimp Farming and it's control strategies and preventive methods.

Hello everyone,

          Myself SRIHARI N C, B.F.Sc., Here we are about to discuss How Nitrite affects Shrimp farming and It's control strategies and Preventive methods.

(I) How Nitrite enters the aquaculture system?

• Nitrite (NO₂^- ) enters the system by Nitrification process, in which Total Ammonia (NH_{3 &} NH₄⁺) is oxidised to Nitrite by, Nitrosomonas and Nitrite is oxidised to Nitrate (NO₃^-) by Nitrobacter.

• Ammonia (NH_{3 &} NH₄⁺) enters the culture system through animal excreta, uneaten feed (excess feed), dead and decaying organisms, etc. and here the Nitrogen Cycle starts (Img.1)

(II) How does Nitrite (NO₂^-) affects animal metabolism:

• Tissue Hypoxia (Brown blood disease in Finfish) occurs when water contains high nitrite concentration. 

• Nitrite enters the blood stream through gills.

• Hemocyanin (Hemoglobin in Finfish) which transport oxygen in blood, combines with nitrite and forms Methemocyanin (Methemoglobin in Finfish) and losses it's ability to carry oxygen and there by resulting in inhibition of aerobic metabolism and initiation of anaerobic metabolism.

• This anaerobic metabolism results in mass mortality of Shrimp in culture system.

(III) Symptoms of nitrite toxicity in shrimps:

• Pale to dark brown colour gills

• Gasps for breath at water surface

• Reddish pigmentation on appendages

(IV) Treatment:

• Application of Common Salt could prevent a bad situation

• Increased dosage of probiotics (Nitrifying bacterial strains)

• Increased aeration

• Controlled feeding

• Application of oxygen enhancer to enhance dissolved oxygen

(V) How does Common Salt treatment prevents bad situation:

• In absence of Chloride, the animal's gill electron receptor has more affinity towards nitrite than oxygen.

• In presence of Chloride, the animal's gill electron receptor has more affinity towards chloride than nitrite and chloride gets eliminated from receptor when oxygen approaches the receptor.

(VI) Amount of Common Salt needed for the pond:

(VII) Preventive methods:

• Maintaining Dissolved oxygen level more than 5ppm (5mg/l)

• Controlled feeding

• Regular water sampling and applications

• Removal of waste (sludge) using Central drainage (shrimp toilet) method

• Maintain pH from 7.5 to 8.2

Conclusion

By following BMP in shrimp farming, we can control the nitrite toxicity in culture system and secure the animal. Applications of AHCP on scientific approach can reduce the cost of production effectively and can have better profit margin.

For further contact,

Mr. SRIHARI N C, B.F.Sc.,

+918270776354 (WhatsApp / Call)