The Function of Binders
Binders hold the food together so that it doesn’t come apart when it gets wet. Common binders are wheat, soybeans, or other products made from grains.
The Process of Extruding Fish Feed
In the process of making fish feed, the components are boiled under pressure and then pressed through a die to form pellets. This process affects the way the meal is put together, making it less likely to get wet.
Covering and Drying
After extrusion, oils or other nutrients are often put to the pellets. This adds another layer that keeps water out. After processing, the pellets are dried, which lowers their moisture content and makes them even more water-resistant.
Ingredient Selection
Value of Nutrition
- Proteins:
- Fish Meal: A major source of protein that comes from fish.
- Soybean meal: A source of protein that comes from plants.
- Krill: A protein source that enhances color due to its astaxanthin content.
- Fats:
- Fish Oil: Rich in omega-3 fatty acids, supports brain and vision functions.
- Flaxseed Oil: A plant-based source of omega-3.
- Carbohydrates:
- Wheat Germ: Provides energy and acts as a binder.
- Corn Gluten: Energy source that serves as a binding agent in pellets.
- Vitamins & Minerals:
- Seaweed: A natural source of essential minerals and vitamins.
- Spirulina: Rich in protein, vitamins, and minerals.
Behavior in Water
- Binders:
- Gelatin: Derived from animal collagen, it gives the food a firm structure.
- Agar-Agar: A plant-based gelatin substitute derived from seaweed.
- Water-Resistant Ingredients:
- Wax Esters: Help in making the food more water-resistant.
- Chitosan: Derived from the shells of crustaceans, it provides water resistance and has antimicrobial properties.
- Density Modifiers:
- Calcium Carbonate: Increases the weight of the pellet, making it sink faster.
- Puffed Grains: Used in floating pellets to reduce their density.
Palatability
- Taste Enhancers:
- Squid Meal: Enhances the taste and is a protein source.
- Brewer’s Yeast: Adds flavor and provides B-vitamins.
- Texture Modifiers:
- Guar Gum: Provides a smoother texture.
- Cellulose: Used to give a rougher texture.
Environmental Considerations
- Sustainability:
- Insect Meal: Black soldier fly larvae.
- Pea Protein: Plant-based protein.
- Not genetically modified and organic:
- Organic spirulina: Doesn’t have any synthetic fertilisers or pesticides in it.
- Corn gluten that isn’t genetically modified.
Formulations Made for a Certain Purpose
Slow-Sinking Pellets
- Purpose: For fish species that eat in the center of the water column. They move like real prey.
- How to Make Formulations:
- Adding gelatin: Makes the pellet more buoyant, which slows down its fall.
- Vegetable fibres: Trap small pockets of air, which makes the pellet less dense overall.
- Oil Balance: Reaches a balance to ensure that the particles still sink, although the speed is reduced.
Bottom-Feeding Pellets
- Purpose: Tailored for bottom dwellers, such as catfish and loaches. Rapid sinking ensures the food reaches them quickly.
- Formulation Techniques:
- More Oil: If there is more oil in the pellet, it can become denser.
- Starches and certain proteins: Help hold the pellet together better.
- Mineral Additives: Calcium carbonate and other things make the precipitation happen faster so it sinks faster.
Testing and Making Sure of Quality
Manufacturers test food by putting it in water and watching how it behaves to make sure it fits the standards they want.
