Feed Additives in Aquaculture: Types, Benefits and Uses in Fish and Shrimp Farming

Introduction

Feed is one of the most important inputs in fish and shrimp farming. It provides the nutrients required for growth, energy, body development and normal biological functions. However, modern aquaculture feed is not limited to basic nutrients such as protein, lipids, carbohydrates, vitamins and minerals. Many feed formulations also include additional ingredients known as feed additives.

Feed additives are used for specific purposes, such as supporting digestion, improving feed quality, maintaining gut health, supplying essential nutrients and helping animals use feed efficiently.

Different types of additives are available in the aquaculture industry, including probiotics, prebiotics, enzymes, organic acids, antioxidants, vitamins, minerals and other functional ingredients.

However, not every additive is suitable for every farm. Its usefulness depends on the cultured species, feed formulation, growth stage, farming conditions, product quality and correct application.

In this guide, we explain what aquaculture feed additives are, their major types, why they are used, what farmers should check before purchasing them and how to select suitable products for their farms.

What Are Feed Additives in Aquaculture?

Feed additives are ingredients included in aquaculture feed in relatively small quantities to perform specific nutritional, technological or functional roles.

They are used in fish and shrimp diets to support different aspects of feed quality, digestion, nutrient utilisation and animal health.

Unlike major feed ingredients such as fish meal, soybean meal, wheat flour and oils, additives are generally included for a particular purpose.

Why Are Feed Additives Used?

Feed additives may be used to:

Support digestive functions.

Improve nutrient utilisation.

Maintain gut microbial balance.

Supply specific vitamins and minerals.

Protect feed from oxidation.

Improve pellet quality.

Support normal growth and development.

Help manage nutritional deficiencies.

Support animal health as part of good farm management.

Important: Feed additives are not medicines and should not be expected to cure diseases. They cannot replace good-quality feed, water-quality management, biosecurity or veterinary guidance.

Major Types of Feed Additives Used in Aquaculture

There are several categories of feed additives used in commercial fish and shrimp farming.

A. Probiotics

Probiotics are live microorganisms that, when administered in adequate amounts, provide a health benefit to the host.

Commonly used microbial groups in aquaculture products include certain species of:

Bacillus.

Lactobacillus.

Pediococcus.

Enterococcus.

Selected yeasts.

The organisms and their effects depend on the specific strain and product.

Why are probiotics used?

To support a favourable gut microbial environment.

To support digestion and nutrient utilisation.

To help maintain intestinal health.

To support normal immune functions.

To help maintain microbial balance.

What should farmers check?

Microbial species and strain.

Viable count, such as CFU per gram.

Expiry date.

Storage requirements.

Compatibility with feed processing.

Recommended dosage and application method.

Not all probiotic strains produce the same results. A product's performance should be evaluated based on its specific strain and supporting evidence.

B. Prebiotics

Prebiotics are substances selectively used by host microorganisms that provide a health benefit.

They may support beneficial microbial populations in the digestive tract.

Examples used in aquaculture products include:

Mannan oligosaccharides (MOS).

Fructooligosaccharides (FOS).

Inulin.

Certain other fermentable carbohydrates.

Why are prebiotics used?

To support gut microbial balance.

To support digestive health.

To improve the conditions for beneficial microorganisms.

To support normal animal health.

What should farmers check?

Type of prebiotic.

Ingredient concentration.

Recommended inclusion level.

Product quality.

Suitability for the cultured species.

C. Enzymes

Enzymes help break down feed components into smaller substances that can be digested and absorbed.

Examples include:

Protease – helps break down proteins.

Amylase – helps break down starch.

Lipase – helps break down fats.

Phytase – helps release phosphorus from phytate in suitable feed formulations.

Cellulase – helps break down certain plant fibre components.

Why are enzymes used?

To support digestion of specific feed components.

To improve nutrient availability.

To reduce certain nutrient losses.

To support feed utilisation.

What should farmers check?

Enzyme type.

Enzyme activity units.

Heat stability.

Compatibility with feed ingredients.

Recommended dosage.

Storage conditions.

Enzyme effectiveness depends on the feed formulation, processing conditions and the target nutrient.

D. Organic Acids and Their Salts

Organic acids are used in some aquaculture feed formulations to support feed preservation, digestive conditions and microbial management.

Examples include:

Formic acid.

Propionic acid.

Citric acid.

Lactic acid.

Butyric acid.

Selected organic acid salts.

Why are organic acids used?

To help control certain undesirable microorganisms in feed or the digestive tract.

To support digestive conditions.

To help preserve feed quality in suitable formulations.

To support nutrient utilisation.

What should farmers check?

Type of acid or salt.

Concentration.

Product formulation.

Recommended inclusion level.

Safety and handling instructions.

Suitability for the target species.

The effects vary with acid type, dose, feed formulation and species.

E. Vitamins

Vitamins are essential nutrients required in relatively small quantities for normal body functions.

Examples include:

Vitamin A.

Vitamin D.

Vitamin E.

Vitamin K.

Vitamin C.

B-complex vitamins.

Why are vitamins used?

To support metabolism.

To support normal growth.

To maintain tissue functions.

To support normal immune functions.

To prevent or correct nutritional deficiencies.

Vitamin requirements vary according to species, life stage, feed ingredients and production conditions.

F. Minerals

Minerals are essential nutrients that support body structure and physiological processes.

Important minerals include:

Calcium.

Phosphorus.

Magnesium.

Zinc.

Iron.

Copper.

Manganese.

Selenium.

Why are minerals used?

To support normal growth.

To support enzyme activity.

To maintain physiological functions.

To support skeletal development in fish.

To support shell formation and moulting-related functions in shrimp.

Mineral requirements and availability vary with species, water salinity, feed composition and farming conditions.

G. Antioxidants

Antioxidants help protect feed ingredients, especially fats and oils, from oxidation.

Examples include approved antioxidant ingredients such as:

Tocopherols.

Certain permitted synthetic antioxidants.

Other approved antioxidant compounds.

Why are antioxidants used?

To help protect feed fats from oxidation.

To maintain feed freshness.

To reduce rancidity.

To support feed shelf life when properly formulated.

Farmers should check the product's approved use, concentration and label information.

H. Immunostimulants and Functional Ingredients

Some feed products contain functional ingredients intended to support normal immune responses or other physiological functions.

Examples may include:

Beta-glucans.

Certain yeast-derived products.

Nucleotide-based ingredients.

Selected plant-derived ingredients.

Their effects depend on the specific ingredient, purity, dose and species. They should not be treated as replacements for disease prevention or treatment.

I. Pigments and Carotenoids

Pigments are included in some aquaculture diets for specific nutritional or colour-related purposes.

Examples include:

Astaxanthin.

Other approved carotenoids.

They may be used in species-specific diets to support pigmentation and other biological functions.

Their inclusion should follow nutritional requirements and applicable regulations.

Benefits of Feed Additives in Fish and Shrimp Farming

When correctly selected and used, suitable feed additives may support several aspects of aquaculture production.

A. Support Digestive Health

Certain probiotics, prebiotics and enzymes may support digestive processes and gut microbial balance.

B. Improve Nutrient Utilisation

Suitable enzymes and other functional ingredients may help animals use specific nutrients more effectively.

C. Support Feed Quality

Antioxidants and approved preservation ingredients can help maintain feed quality during storage.

D. Support Normal Growth

A well-balanced feed containing required nutrients and suitable additives can support healthy growth.

E. Help Maintain Gut Microbial Balance

Selected probiotics and prebiotics may support a favourable microbial environment in the digestive tract.

F. Support Nutritional Requirements

Vitamin and mineral additives can help meet nutritional requirements when the basic feed formulation does not provide sufficient amounts.

Note: Benefits are product- and species-specific. Results are not guaranteed, and additives should be evaluated through reliable farm records or appropriate trials.

Difference Between Probiotics, Prebiotics and Enzymes

These three additive categories are often discussed together, but they perform different functions.

Probiotics: Live microorganisms intended to provide a health benefit when administered in adequate amounts.

Prebiotics: Substances selectively used by beneficial microorganisms that provide a health benefit.

Enzymes: Biological catalysts that help break down specific feed components.

Farmers should not assume that all three products perform the same function. Their selection should depend on the problem or nutritional objective being addressed.

How to Choose the Right Feed Additive for Your Farm

Selecting a feed additive requires more than comparing brand names or prices.

Farmers should first identify the actual farm requirement.

A. Identify the Objective

Ask what you want to achieve:

Support digestive health?

Improve digestion of specific nutrients?

Supply missing vitamins or minerals?

Protect feed from oxidation?

Support gut microbial balance?

Improve feed manufacturing or storage quality?

Choose a product designed for the identified purpose.

B. Check the Product Composition

Read the product label carefully.

Check:

Active ingredients.

Microbial strains, where relevant.

Enzyme activity, where relevant.

Ingredient concentration.

Carrier materials.

Recommended dosage.

C. Check Product Quality

Look for:

Manufacturing details.

Batch number.

Manufacturing date.

Expiry date.

Storage requirements.

Quality certifications or test reports, where available.

D. Check Species Suitability

A product suitable for one species or culture system may not produce the same results in another.

Confirm suitability for shrimp, tilapia, carp, pangasius or the species being cultured.

E. Compare Cost and Practical Use

Compare the cost per kilogram of feed treated, not just the price of the product pack.

Also consider:

Dosage.

Application method.

Product shelf life.

Storage requirements.

Availability.

Technical support.

How Feed Additives Are Applied in Aquaculture

The application method depends on the type of additive and the manufacturer's instructions.

Common methods include:

A. Factory-Level Feed Inclusion

Some additives are incorporated during feed manufacturing.

This method may provide more uniform distribution, depending on the ingredient and processing conditions.

B. Feed Top-Coating

Certain additives can be applied to finished feed using a suitable coating or binding method.

Farmers must follow the manufacturer's instructions to achieve even application.

C. Mixing With Feed

Some products are designed to be mixed with feed before feeding.

Correct mixing is important to reduce uneven distribution.

D. Supplementation Through a Specific Feeding Programme

Certain nutritional additives may be supplied according to a defined feeding schedule.

The schedule and dosage must be based on the product instructions and the nutritional objective.

Important: Some additives, particularly live microorganisms and enzymes, may be sensitive to heat, moisture, storage conditions or incompatible chemicals. Never assume that every product can be mixed with every feed or treatment.

Common Mistakes Farmers Should Avoid

Selecting additives only because of brand popularity.

Using products without understanding their ingredients.

Applying higher doses than recommended.

Mixing incompatible products.

Ignoring storage instructions.

Using expired products.

Expecting additives to cure diseases.

Using multiple products without a clear objective.

Ignoring the quality of the main feed.

Changing the feeding programme without monitoring results.

Assuming all probiotic strains provide the same benefits.

Evaluating a product only by short-term observations.

Complete Checklist Before Buying Feed Additives

Use this checklist before selecting any feed additive for your fish or shrimp farm.

A. Farm Requirement

Identify the actual farm requirement.

Understand the purpose of the additive.

Confirm the cultured species.

Consider the animal's growth stage.

Review current feed and water-quality conditions.

Avoid buying products without a clear objective.

B. Product Composition

Check active ingredients.

Review microbial strains for probiotics.

Check CFU count and viability information where relevant.

Check enzyme type and activity units where relevant.

Review vitamin and mineral composition.

Check concentration and carrier materials.

Review product specifications.

C. Product Quality

Verify the manufacturer.

Check batch or lot number.

Check manufacturing date.

Check expiry date.

Review storage instructions.

Request a technical data sheet if needed.

Check quality test reports where available.

D. Dosage and Application

Read the recommended dosage.

Confirm the application method.

Check whether a binder is required.

Confirm mixing compatibility.

Check heat and moisture sensitivity.

Follow the recommended feeding schedule.

E. Cost and Performance

Compare product price.

Calculate cost per kg of feed treated.

Review the expected benefit.

Check product availability.

Evaluate technical support.

Maintain records to assess actual performance.

F. Storage and Handling

Store the product according to instructions.

Protect it from direct sunlight if required.

Avoid excess heat and moisture.

Keep the packaging properly closed.

Follow expiry and stock rotation.

Keep products away from incompatible chemicals.

Step-by-Step Guide to Using Feed Additives in Aquaculture

Step 1: Identify the Farm Problem or Objective

First, identify why you need an additive.

For example, you may want to support digestive health, supply a specific nutrient or protect feed from oxidation.

Do not select a product simply because it is popular in the market.

Step 2: Review Existing Feed Quality

Check the nutritional composition of the existing feed.

Identify whether the feed already provides sufficient protein, lipids, vitamins and minerals.

An additive cannot correct every problem caused by an unsuitable base feed.

Step 3: Select the Appropriate Additive Category

Choose the category based on the objective:

Probiotics for selected microbial and gut-health applications.

Prebiotics for supporting beneficial microbial activity.

Enzymes for breaking down specific feed components.

Organic acids for selected feed and digestive applications.

Vitamins and minerals for nutritional requirements.

Antioxidants for protecting feed ingredients from oxidation.

Step 4: Verify the Product Details

Check the active ingredients, concentration, batch number, expiry date and manufacturer information.

For probiotics, review strain identity and viable count. For enzymes, check the activity units and recommended conditions of use.

Step 5: Confirm Species Suitability

Check whether the product is designed and supported for the species being cultured.

Do not assume that a product used in shrimp farming will produce the same results in fish farming.

Step 6: Read the Dosage Instructions

Follow the manufacturer's recommended dosage and application method.

Do not increase the dose without technical advice.

Step 7: Check Compatibility

Before mixing the product with feed or other additives, check whether they are compatible.

Pay special attention to live microorganisms, enzymes, heat-sensitive ingredients and chemical treatments.

Step 8: Apply the Product Correctly

Use the recommended mixing, coating or manufacturing method.

Ensure that the product is distributed evenly throughout the intended feed quantity.

Step 9: Store the Product Properly

Follow the label instructions for temperature, moisture protection and shelf life.

Improper storage can reduce product quality, particularly for live microbial products.

Step 10: Monitor Feeding Response

Observe:

Feed consumption.

Feeding behaviour.

Uneaten feed.

Shrimp or fish activity.

Growth.

General health condition.

Step 11: Maintain Farm Records

Record:

Product name.

Additive category.

Batch number.

Dosage.

Application date.

Feed quantity treated.

Application method.

Observations.

Product cost.

Step 12: Evaluate the Results

Compare performance with previous records or a suitable control group where practical.

Consider feed consumption, growth, survival, FCR and overall production costs.

Remember that water quality, stocking conditions and health status can influence results. Avoid attributing every improvement or decline to one additive.

1. How to Evaluate Whether a Feed Additive Is Working

Farmers should evaluate products using measurable observations rather than promotional claims.

Useful measurements include:

Feed consumption.

Average body weight.

Growth rate.

Survival rate.

Feed conversion ratio.

Feed cost per kg of biomass gain.

Health observations.

Water-quality trends, where relevant.

Whenever possible, compare similar groups under similar farming conditions.

A small, well-recorded farm trial may provide more useful information than changing several products at once.

Best Practices for Feed Additive Management

Select additives based on a clear requirement.

Buy products from reliable manufacturers.

Check the active ingredients and product specifications.

Follow the recommended dosage.

Avoid unnecessary combinations.

Store products correctly.

Maintain good-quality base feed.

Monitor feeding response.

Maintain suitable water quality.

Follow farm biosecurity practices.

Keep product and performance records.

Seek advice from a qualified aquaculture nutritionist or aquatic animal health professional when required.

Conclusion

Feed additives play an important role in modern aquaculture feed management. Probiotics, prebiotics, enzymes, organic acids, vitamins, minerals, antioxidants and other functional ingredients are used for different purposes.

However, no single additive is suitable for every farm. Farmers should understand the product's composition, purpose, quality, dosage and application method before using it.

The best approach is to identify the actual farm requirement, select a suitable product, apply it correctly and evaluate the results using farm records.

Feed additives should support a good feeding and farm-management programme, not replace it.