Prawn farming is a lucrative aquaculture business, but profitability depends on efficient feeding practices. Overfeeding increases costs and pollutes the water, while underfeeding stunts growth and reduces yields. Determining the optimal feeding frequency is crucial for maximizing growth rates, survival, and profit margins.
This guide explores:
- The nutritional needs of prawns
- Factors influencing feeding frequency
- Recommended feeding schedules for different growth stages
- Best practices for cost-effective feeding
- Impact of feeding on water quality and health
- Strategies to maximize feed efficiency and profitability
Table of Contents
1. Understanding Prawn Nutritional Needs
Prawns require a balanced diet rich in:
- Protein (28-35% for juveniles, 25-28% for adults)
- Lipids (6-8%) for energy
- Carbohydrates (20-25%)
- Vitamins & Minerals (calcium, phosphorus, and essential trace elements)
Commercial prawn feeds are formulated to meet these needs, but feeding frequency determines how efficiently nutrients are absorbed.
2. Factors Affecting Feeding Frequency
Several factors influence how often prawns should be fed:
A. Prawn Size and Growth Stage
- Post-Larvae (PL) Stage (0.1-1g): Require frequent feeding (4-6 times/day) due to high metabolic rates.
- Juvenile Stage (1-10g): Can be fed 3-4 times/day.
- Sub-Adult to Adult Stage (10g+): Fed 2-3 times/day.
B. Water Temperature
- Optimal (28-32°C): Higher metabolism → feed 3-4 times/day.
- Below 25°C: Reduced appetite → feed 1-2 times/day.
C. Dissolved Oxygen (DO) Levels
- High DO (>5 mg/L): Prawns feed actively → more frequent feeding.
- Low DO (<3 mg/L): Reduced feeding → adjust frequency to avoid waste.
D. Stocking Density
- High density: More competition → increase feeding frequency.
- Low density: Less competition → reduce frequency to prevent overfeeding.
E. Feed Type
- Floating pellets: Allow better monitoring → can be fed 2-3 times/day.
- Sinking pellets: May require more frequent feeding if uneaten feed is lost.
3. Recommended Feeding Frequency by Growth Stage
A. Post-Larvae (PL) Stage (First 30 Days)
- Feeding Frequency: 4-6 times/day
- Feed Type: Crumbled or powdered starter feed (40-50% protein)
- Key Consideration: Small stomach capacity requires frequent, small meals.
B. Juvenile Stage (1-3 Months)
- Feeding Frequency: 3-4 times/day
- Feed Type: Small pellets (2-3mm, 35-40% protein)
- Key Consideration: Growth is rapid; adjust based on consumption rates.
C. Grow-Out Stage (3-6 Months)
- Feeding Frequency: 2-3 times/day
- Feed Type: 3-5mm pellets (28-32% protein)
- Key Consideration: Monitor feed conversion ratio (FCR) to avoid waste.
D. Adult/Maturation Stage (6+ Months)
- Feeding Frequency: 2 times/day
- Feed Type: 5-6mm pellets (25-28% protein)
- Key Consideration: Reduce frequency to maintain water quality.
4. Best Practices for Cost-Effective Feeding
A. Use Feeding Trays
- Place feed in trays to monitor consumption.
- Adjust feeding amounts based on leftover feed.
B. Follow the “80% Satiation Rule”
- Feed only 80% of estimated consumption to prevent overfeeding.
- Reduces waste and maintains water quality.
C. Feed During Peak Activity Times
- Prawns are most active at dawn and dusk.
- Schedule major feedings during these periods.
D. Adjust Based on Weather & Water Conditions
- Reduce feeding on cloudy, rainy, or low-oxygen days.
- Increase aeration if feeding heavily.
E. Record Feed Conversion Ratio (FCR)
- Ideal FCR: 1.2-1.8 (1.2kg feed = 1kg prawn growth).
- Higher FCR indicates inefficiency—adjust feeding strategy.
5. Impact of Feeding on Water Quality & Health
Overfeeding leads to:
- Ammonia & Nitrite Spikes → toxic to prawns.
- Algae Blooms → oxygen depletion.
- Higher Disease Risk → bacterial/fungal outbreaks.
Solution:
- Remove uneaten feed after 2 hours.
- Conduct regular water testing (ammonia, nitrite, pH).
- Use probiotics to improve digestion and water quality.
6. Strategies to Maximize Profitability
A. Automated Feeders
- Ensure consistent feeding times.
- Reduce labor costs.
B. Supplemental Natural Feeds
- Use plankton, worms, or insects to reduce feed costs.
- Improves nutrition and reduces dependence on pellets.
C. Phase Feeding
- Adjust protein levels based on growth stage.
- Reduces costs without compromising growth.
D. Batch Harvesting
- Harvest larger prawns first, allowing smaller ones to grow.
- Optimizes feed use and increases overall yield.
7. Common Feeding Mistakes to Avoid
- Overfeeding → Wastes feed, pollutes water.
- Underfeeding → Stunts growth, increases cannibalism.
- Irregular Feeding Times → Stress and uneven growth.
- Poor-Quality Feed → Low growth rates, higher mortality.
Here are ten frequently asked questions (FAQs) about prawns:
1. What is the difference between prawns and shrimp?
Prawns and shrimp are different crustaceans. Prawns have three pairs of claw-like legs, while shrimp have two. Prawns also have branching gills and a straighter body compared to shrimp.
2. Are prawns healthy to eat?
Yes, prawns are a good source of protein, low in fat, and rich in omega-3 fatty acids, vitamins (B12, E), and minerals (selenium, zinc). However, they contain cholesterol, so moderation is advised for some diets.
3. How can I tell if prawns are fresh?
Fresh prawns should have a firm texture, a mild ocean-like smell (not fishy), and a translucent appearance. Avoid prawns with black spots, a slimy texture, or a strong ammonia odor.
4. How should I store fresh prawns?
Keep fresh prawns in the coldest part of the fridge (0–4°C) and use them within 1–2 days. For longer storage, freeze them in an airtight container for up to 3 months.
5. Can you eat prawns raw?
Raw prawns can carry parasites or bacteria, so it’s safer to cook them thoroughly. If consuming raw (e.g., in sushi), ensure they are sashimi-grade and properly frozen to kill pathogens.
6. How do you peel and devein prawns?
- Remove the head (if attached).
- Peel off the shell, leaving the tail if desired.
- Make a shallow cut along the back and remove the dark digestive tract (vein) with a knife or toothpick.
7. What’s the best way to cook prawns?
Prawns cook quickly (2–3 minutes per side) and can be grilled, boiled, fried, or sautéed. Overcooking makes them rubbery—they’re done when they turn opaque and pink.
8. Why do prawns turn pink when cooked?
The color change is due to a protein called astaxanthin, which is naturally present in prawns but bound to other molecules. Heat releases astaxanthin, turning the prawns pink.
9. Are prawns safe for people with shellfish allergies?
No. Prawns are shellfish, and people with shellfish allergies should avoid them as they can trigger severe allergic reactions.
10. Are farmed or wild-caught prawns better?
- Wild prawns are often considered tastier but may have sustainability concerns.
- Farmed prawns can be more eco-friendly if responsibly sourced (look for certifications like ASC or MSC), but some farms use antibiotics or harm mangroves.