Aquaculture

Fragola Spa and the
fish feed

Fragola spa is a partner of leading multinational companies in the production of fish feed.

With the design and construction of complete turnkey plants, we solve together all the challenges of a fish feed production plant, with technology that is perfected year after year:

Let’s take a look at the main challenges:

Fine grinding:

it is common knowledge that the first factor to ensure a good extrusion process is the grain size of the flour. The required fineness can be achieved by using high-performance mills, which can reach grain sizes of less than 200 microns with 50% of the quantity of the ground product. Fragola has produced a dedicated line: the MF120 high speed hammer mills.

In addition to this, Fragola offers a line of dedicated conveyors to safeguard the integrity of the kibble.

Fully automated dosing systems for the management of micro and medium nutrients.

Rapid mixing of raw materials and with variation coefficients of less than 3%.

Cooling efficiency with both static and rotary coolers.

Advanced systems for the recovery of extruded product waste at the beginning and end of the cycle and systems for partially drying kibble with high moisture content before being pneumatically conveyed to the dryer.

Coating:

the extruded product coating process is essential for the protein and lipid intake that fish need, a high nutritional value ensures best conversion rates and for this reason the vacuum coating technology is crucial. Thanks to our machines, the liquids sprayed in an environment with pressure values ranging from 400 to 200 mbar, are optimally absorbed inside the kibble (sponge effect) leaving the external surface dry, while adding up to 25% of liquid.

Aquaculture

In 2016, global fish production reached 171 million tonnes, of which aquaculture, or fish farming, accounts for 47%, i.e. 80 million tonnes. The turnover is estimated at 362 billion dollars, of which 232 billion for aquaculture.

From 1961 to 2016 the average annual increase in world fish consumption was 3.2%, greater than population growth: 1.6%, and than average meat consumption (all types of meat): 2.8 %.

Per capita consumption has grown from 9 Kg in 1961 to 20.2 Kg in 2015.

The fishing volume of wild fish has been relatively steady since the 1980s and fish farming is responsible for this significant growth. It still continues to grow more than any other food industry with an annual rate of over 5%.

Speaking of Italy: the data for 2020 indicate an average per capita consumption of 29 kg, against a European one of 22-23 Kg; with trout, sea bream and sea bass the most widely produced species.

The Extrusion Process

In fish and mollusk farming, feed plays a primary role, accounting for approximately 50% of production costs and representing the most important component. The main raw materials historically used in fish feed production are fish meal and fish oil. However, plant-based raw materials such as soybean and cereal glutens (corn and wheat), processed animal proteins, as well as insect and algae meals are increasingly being introduced. These new raw materials will make it possible to address the challenges of a future that will require increasing quantities of fish, driven by rising consumption trends and global population growth. Numerous factors determine the selection of feed ingredients to provide the best possible diet. These include digestive system structure, size and age of the animal, water temperature and characteristics, and farming methodology (intensive, semi-intensive, extensive). Regarding species, fish can be classified as carnivorous, herbivorous, or omnivorous. While herbivorous and omnivorous species predominate in Asia, carnivorous species prevail in Europe and the Americas. It is worth noting that carnivorous fish require a protein content ranging from 30% to 55%, significantly higher than that of terrestrial livestock species such as poultry (18–23%) and pigs (14–16%). In general, many fish species achieve excellent feed conversion ratios. Among cold-water species, trout reaches conversion ratios close to 1:1. Among marine species, sea bream and sea bass both produce 1 kg of flesh with approximately 1.4 kg of feed.

Advantages of Extrusion in Fish Feed Production

Let us examine the advantages that the extrusion process offers to aquaculture in the production of feed for fish and mollusks.

These advantages ultimately allow for reduced use of fish meal in feed formulations, resulting in significant savings in raw material procurement.

Improved digestibility is achieved for proteins through thermal denaturation during the cooking process, and for carbohydrates through complete starch gelatinization (starch being the main carbohydrate present in cereals). This process converts starch into easily digestible simple sugars, unlike raw starches which are poorly digestible by fish.

Elimination of Many Pathogens

Significant reduction of microbial contamination, such as Salmonella, due to the thermal shock occurring inside the extruder.

Due to the sudden pressure drop and consequent steam expansion, the pellet expands as it exits the extruder die. After drying, it becomes porous and friable.
These characteristics, combined with vacuum coating technology, allow for substantial additions of oils and fats (up to 25%), resulting in increased nutritional values.

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