Nutritional Value of Black Soldier Fly Larvae: A Beginner's Guide

🪰 Black soldier flies (BSF) occupy a privileged place in the world of edible insects.

Also know by their scientific name Hermetia illucens, these animals are increasingly recognized for their potential in sustainable food systems.

BSF larvae can convert protein-poor organic wastes into high-value protein, fat and fertilizers.

This makes them an excellent alternative to traditional feed and a key component of circular farming practices.

In addition, there are other non-food applications of the substances obtained from this BSF, such as chitin and peptides, which are of interest to the medical, pharmaceutical and cosmetic industries.

This new edition of Insect Academy will delve into the specifics of the nutritional value of black soldier fly larvae, discussing their proteins, fats, amino acids, minerals, vitamins, and fibers.

Let's take a look at them!

🚩 HIGHLIGHTS:

• BSF larvae have a protein content ranging from 30% to 56% on a dry matter basis

• Regardless of diet, BSF larvae exhibit a consistent amino acid profile.

• These insect larvae have significant amounts of lauric acid, known for its antimicrobial and prebiotic properties.

• BSF larvae are particularly rich in minerals such as calcium, magnesium, iron, and zinc.

Proteins

BSF larvae are rich in proteins, with a content ranging from 30% to 56% on a dry matter basis.

This high protein level makes them a promising ingredient in animal feed, such as poultry, pets and aquaculture species.

💡 And potentially for human consumption.

The protein content of these larvae changes with age, typically decreasing as the larvae mature, whereas the fat content is seen to increase.

This dynamic is crucial for determining the optimal harvest time to maximize protein yield.

Once defatted, BSF larvae meal can have crude protein levels above 60% and lower lipid percentages.

Amino acids

It’s believed that BSF larvae have a consistent amino acid profile regardless of diet.

A study showed that prepuae raised on eight different diets had similar amino acid patterns.

This suggests that for holometabolous species amino acid patterns are fixed within a specific life stage.

Holometabolous species are those that, through metamorphosis, go from egg to larva, pupa and adult state.

This characteristic covers both the BSF and other edible insects, such as mealworms and houseflies.

▶️ The amino acid content of BSF larvae is not as affected by external factors as some of the other nutritional components; however, studies have shown that amino acid content does vary throughout the life of the larvae, with higher levels of essential amino acids in younger larvae, typically between 4 and 6 days of age.

Fats and fatty acids

The lipid content in BSF larvae is also noteworthy, ranging from 20% to 41% on a dry matter basis.

In the short larval stage, the nutritional composition of insects undergoes significant changes.

The fat content tends to increase as the larvae age, in contrast to the protein content, which decreases during this period.

A study documented the protein content in the larval stage decreasing from 61% (DM) at 5 days old to 44% at 15 days old and 42% at 20 days old, whereas the fat content increased from 13% (DM) at 5 days old to 19% and 23% at days 15 and 20, respectively.

The larvae fatty acid profile is dominated by lauric acid, known for its antimicrobial and prebiotic properties on livestock.

It is important to clarify that the high lauric acid content is independent of the diet.

In addition, these insects have far lower polyunsaturated fatty acid percentages than insects such as housefly larvae, mealworms, and adult crickets.

🐟 Therefore, this issue might be overcome by varying the fatty acids in their substrates, such as by using fish offal to enhance Omega-3 fatty-acid content.

Minerals

BSF larvae are particularly rich in minerals such as:

• Calcium: 890 mg/100 g

• Magnesium: 390 mg/100g

• Iron: 2.5 mg/100 g

• Zinc: 10 mg/100 g

Note that these are average values.

Calcium is the most abundant mineral in BSF larvae, with an average of almost 8% by dry weight compared to less than 1% for other insects.

On the other hand, the magnesium content of larvae can be up to 10 times higher than other edible insects.

This is likely the result of their mineralised exoskeleton in which minerals such as calcium and magnesium form a complex with chitin.

Other minenarls that can be found in the larvae, with controlled feed and processing technologies, are potassium, phosphorus, manganese and copper.

Vitamins

Compared to other edible insects, BSF larvae contain notable amounts of Vitamin E, ranging from 10 to 235 IU vitamin E/kg on a dry matter basis.

Vitamins B1, B2, and C are also present in the larvae when oven-dried.

Finally, BSF adults contain very low levels of vitamin A, but larvae do not contain this vitamin.

Fibre

Carbohydrates are virtually absent in the insect body but fibre is present in significant amounts.

This fibre consists primarily of chitin and sclerotised proteins, which are components of the insect exoskeleton.

Crude fibre contents tend to increase with the age increase of the BSF larvae, which can be up to 10% on a dry matter basis.

However, these values may fluctuate depending on processing methods and specific diets used during larval rearing.

BSF larvae offers a promising and sustainable alternative to traditional protein sources in both animal feed and potentially for human nutrition.

It is worth noting that the pet food industry is one of the industries with the highest adoption of BSF larvae, thanks to the numerous proven health benefits for dogs and cats fed with these insects.

The ability of the BSF larvae to be reared on organic waste, coupled with their rich nutritional profile, positions them as a key component in future sustainable food systems.

🪰 If you want to know more about the nutritional value of black soldier fly larvae, in the comments I leave the bibliographic sources consulted for this article.

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👋 See you in the next edition!