It has been found that insects contain a high nutritional value with respect to their protein, fatty-acid, mineral and trace-element content. Over the past few years, insect protein has evolved into a pet food market, with insect protein diets eliciting ecological and ethical value.
With a growing human population that is expected to reach 9 to 11 billion people by 2050 (Kępińska-Pacelik and Biel, 2022), there will inevitably be an increased demand for food sources and resources. This, combined with an increased demand for pet foods with a higher proportion of animal protein, exerts a strong pressure on natural resources that is only predicted to increase in the coming years. In 2023, 57 percent of UK households housed 38 million pets (Martins, 2023). As such, insect protein use in pet food could provide an alternative that does not rely on finite and depleting global resources.
History and future projection of insect protein diets
There is a long history of humankind using insects for their nutritional value. As early as 23 AD, insects were a big part of human diets, with the ancient Greeks considering them a delicacy. However, the culture of insect consumption has not been lost; it is known that 2.5 million people currently eat insects worldwide, with some countries still considering insects a dietary staple.
The pet food industry as a whole is growing significantly, with global sales of pet food reaching an all-time high. In a report published in November 2024 by Fortune Business Insights, it was estimated that the global pet food market size was valued at USD 126.66 billion in 2024, a figure that is projected to increase to USD 193.65 billion by 2032 (FBI, 2024). The number of commercial insect protein diets available on the market for pet owners is also growing continuously. With many companies using branding such as “pet superfoods”, the popularity of these diets as a pet food choice is clearly rapidly evolving.
The Global Insect-Based Pet Food Market Report in 2024 found that the value of the insect-based pet food market was valued at USD 8.31 billion in 2023 and is forecast to approximately double in value (to USD 16.72 billion) by 2031 (Insight Ace, 2024). This predicted growth is largely attributed to an increased demand for sustainable food sources.
The value of the insect-based pet food market was valued at USD 8.31 billion in 2023 and is forecast to approximately double in value [to USD 16.72 billion] by 2031
What is the nutritional value of insect protein diets?
Protein and amino acids
The main ingredients of commercial insect-based protein diets are meal and fat from black soldier fly larvae, mealworm larvae and adult house crickets. These ingredients are then processed into meals of dry and wet foods or as treats. There are huge differences in the nutritional composition of insect species, and the developmental stage of the insects (larvae, pupae or adults) can influence the nutritional value. Other factors, such as sex, the diet they are fed during the rearing and fattening periods, and the environmental conditions, will also influence the nutritional value.
Nutritional quality, which can be described as a protein’s ability to meet basic amino acid requirements, is based on the composition and digestibility of amino acid proteins
Nutritional quality, which can be described as a protein’s ability to meet basic amino acid requirements, is based on the composition and digestibility of amino acid proteins. Being rich in both protein and amino acids, insects have high nutritional value.
Kępińska-Pacelik and Biel (2022) found that the most promising source of protein was black soldier fly larvae, which averaged 40 to 44 percent crude protein content. In terms of essential amino acid content, black soldier fly larvae had 45.2g/100g dry matter (DM) protein compared to 21.3g/100g DM protein in chicken, while pork was found to contain 19.09g/100g DM protein. The authors also found that the essential amino acid content of crickets was comparable to the main ingredients of canine diets (egg, chicken, pork and beef). Cricket meal has a higher protein concentration, therefore a smaller daily portion is necessary compared to chicken: close to 33 percent of the portion size of chicken meat is required to cover the protein requirements of a dog.
Lipids and energy
Insects provide a large amount of energy due to their high lipid content, especially in larvae. The main saturated fatty acid in mealworm larvae and crickets is palmitic acid, which is considered healthy. Lauric acid is the main fatty acid in black soldier fly larvae, a fatty acid that demonstrates antimicrobial activity against Gram-positive bacteria and viruses. Lauric acid, therefore, plays an important role in increasing immune response, and also functions to regulate cholesterol levels.
The lipid content of black solider flies was found to be 35 to 40 percent (Kępińska-Pacelik and Biel, 2022), meaning it is considered an energy-rich insect, abundant in both proteins and lipids. Again, fatty acid content can vary hugely depending on feeding regimes, environmental conditions and insect age.
Mineral content
The third component considered when analysing the nutritional value of insect meal is its mineral content, such as ash, which is high in black soldier fly larvae. Considering their anatomy, which includes a protein-rich exoskeleton that is high in chitin, insects tend to have a lower mineral but higher fibre content. Chitin is also indigestible due to animals lacking chitinase.
Insects are, however, rich in microminerals, including copper, iron, magnesium, manganese, phosphorus, selenium and zinc. Insects with calcified exoskeletons generally have a much higher mineral composition. It has also been found that protein derivatives from black soldier fly larvae have some antioxidant potential due to their free radical scavenging activity.
Digestibility
The digestibility of insect protein has been found to be good. Black soldier fly larvae inclusion in dog food can be a good source of protein without affecting nutrient digestibility and stool quality. The faecal consistency for dogs fed black soldier fly larvae meal does not alter.
| What about cats? Currently, there is very scarce information regarding the nutritional value of insect protein diets in cats. |
What are the benefits of insect protein diets?
Managing food-responsive diseases
Insect protein may be considered a useful alternative for dogs with food intolerances. Premrov Bajuk et al. (2021) found that food allergies make up around 25 percent of all allergic skin conditions in dogs with cutaneous signs, including pruritus and erythematous lesions of the face. A total of 20 dogs with atopic dermatitis and food-responsive allergies were fed insect protein food for two weeks. Their skin was examined and lesions scored at the end of this timeframe: improvement was seen in 12 of the 20 dogs. Coat quality was also assessed in 14 dogs, with an improvement seen in six of them. There was no change in pruritus assessment in this study.
Concerns with conventional meat-based diets: ethical considerations, environmental impact of farming and our carbon footprint
Recently there has been a global demand for more animal-derived protein sources due to the increasing human population and increasing standards of living in the Global South. As a result, there is increased competition for protein for human food, pet food and livestock feed. Meanwhile, the depletion of raw resources is becoming a serious global threat.
Insect production requires less water and land use, with 1g of edible chicken protein requiring two to three times more land and 50 percent more water than mealworms
Insect production requires less water and land use, with 1g of edible chicken protein requiring two to three times more land and 50 percent more water than mealworms (Liceaga, 2022). Deforestation for cattle ranches is also widespread, especially in financially vulnerable regions of the world; significantly less land is required to farm insects. Insect production has a lower water and carbon footprint than animal farming systems. Greenhouse gas emissions are also lower, with broiler chickens emitting 32 to 167 percent more CO2 emissions compared to mealworms (Liceaga, 2022). Greenhouse gas, ammonia and methane emissions also remain lower, and the feed conversion rate of insects is more efficient. Insects can be fed waste from many industries, from agro-industrial and household to forestry, slaughter plants and more.
Alternatively, from a sustainability point of view, conventional meat-based diets use materials that would otherwise be discarded and disposed of, including tripe, udders, chicken feet and pig trotters. These materials are by-products of meat used for human consumption and would otherwise be wasted.
Owner perception on feeding insect protein diets
A recent study found that owner perception of feeding insects was generally positive (Baptista da Silva et al., 2024). Both cat and dog owner attitudes were more positive towards insect protein diets if they understood both nutritional and sustainability benefits. Of the 435 people surveyed, 52 percent of dog owners and 62 percent of cat owners were positive about feeding their pets insect protein. Greater acceptance was also seen in cat owners who had consumed insect protein diets themselves. This is only set to increase as the pet food insect protein market grows and consumer awareness follows suit.
What are the disadvantages of insect protein diets for pets?
Contaminants
Due to the artificial manner in which they are produced, through breeding, pet food packaging, cooking and feeding, insect contamination is a risk. Contaminants that occur as a result of inadequate hygiene treatment include bacteria, fungi and mycotoxins. This is certainly something that must be monitored, as insects can be vectors for antimicrobial resistance genes. For example, Kępińska-Pacelik and Biel (2022) found Aspergillus and Staphylococcus aureus capable of producing toxins in contaminated crickets.
Further contamination with heavy metals, including copper, zinc and magnesium to name a few, has been found in insect protein diets. These heavy metals affect insect growth and have a currently unknown effect on the gut microbiota of insects. As such, there is an unknown risk for pets ingesting larvae that have absorbed these heavy metals, so the safety of these products for pets is not yet well understood.
Adverse food reactions
There is also a level of risk associated with insect-based diets triggering adverse food reactions, which could be related to cross-reactions with other allergens or primary sensitisation. In one study concerning mealworm larvae proteins and their binding to IgE, binding was confirmed but the difference between healthy and allergic dogs was negligible (Bajuk et al., 2021). Some cross-reactions were found in mite-allergic dogs that consumed mealworm protein, so a level of care should be taken when mealworm larvae is an ingredient in insect protein diets in these patients.
The nutritional needs of obligate carnivores
As cats are obligate carnivores, meeting their nutritional needs can be much more challenging due to the requirement for the essential amino acid taurine
As cats are obligate carnivores, meeting their nutritional needs can be much more challenging due to the requirement for the essential amino acid taurine. Most research seems to concern canine diets, with very little mention of feline insect protein diets.
