The buzz on insect-based diets: a new hypoallergenic protein source? – DVM 360

© 2022 MJH Life Sciences and dvm360 | Veterinary News, Veterinarian Insights, Medicine, Pet Care. All rights reserved.

© 2022 MJH Life Sciences^™ and dvm360 | Veterinary News, Veterinarian Insights, Medicine, Pet Care. All rights reserved.

A boarded dermatologist breaks down the current state of research on insect-based diets
Content submitted by Thrive Pet Healthcare, a dvm360® Strategic Alliance Partner
While the consumption of insects is widely practiced in certain parts of the world such as Africa, South America, and Asia, it is not as commonplace in Westernized countries such as the United States. The perception of insects as harmful, dirty, and distasteful are just several reasons why it may take longer for entomophagy, or the practice of eating insects, to become more mainstream in Westernized cultures. As a food source, insects offer numerous environmental advantages such as less land use, feed and water requirement, fewer greenhouse gas emission and feed conversion efficiency.¹ In addition to their reduced environmental impact, insects are high in protein as well as vitamins, minerals, and lipids. With these environmental and nutritional benefits, insects offer a promising solution as an alternative and sustainable protein source. While it may take time to change public perception of eating insects, their incorporation into animal feed has been more widely accepted. Considerable research has demonstrated the efficacy and safety of the black soldier fly (Hermetia illucens) larvae (BSFL) in poultry, swine, and aquaculture species.^2-6 The addition of a small amount of insect meal to chicken diets was also found to have the beneficial effect of stimulating the colonization by probiotic and commensal bacteria, which may help as barriers against pathogenic bacterial infections.⁷
European countries have embraced the use of insects as pet food ingredients and several dog foods using insects as a protein source have been on the market for several years. Recently, companies such as Mars PetCare and Nestle Purina have launched their own insect-based diets.
In January 2021, the Ingredient Definition Committee of the Association of American Feed Control Officials (AAFCO) approved BSFL for use in adult maintenance adult dog food and treats. With this approval veterinarians should expect more clients exploring such diets, especially as a novel protein for dogs with adverse food reactions. While AAFCO has only approved BSFL for use in adult maintenance at this time (approval of BSFL for cat food is expected in 2022), other promising, well-studied insects for feed include the yellow mealworm (Tenebrio molitor) larvae, house cricket (Acheta domesticus), and silkworms (Bombyx mori).
On average, the protein content of edible insects range from 35% to 60% dry weight or 10% to 25% fresh weight, which are higher than plant protein sources, including cereal, soybeans, and lentils.^8-10 At the upper range, insects provide more protein than even meat and chicken eggs.¹¹ Studies shown that dogs can consume diets containing black soldier fly (Hermetia illucens) larvae,^12-16 tropical house cricket (Gryllodes sigillatus),¹⁷ housefly (Musca domestica) larvae, lesser mealworm (Alphitobius diaperinus) and yellow mealworm (Tenebrio molitor)^12,13 without adverse effects on health or nutrient digestibility, even if used as almost total replacements for common protein sources.⁸ Higher fecal output was observed in dogs fed tropical house cricket (Gryllodes sigillatus) due to the higher indigestible chitin content in crickets compared to chicken meal. Although a higher fecal output was observed, there were no differences in fecal score or stool quality.¹⁸
The introduction of insect-based diets to the market has piqued interest in whether they could be used as a novel protein diet for patients with adverse food reactions. While allergic reactions could occur due to the insect protein itself (primary sensitization), in Westernized countries where the consumption of insects is not as commonplace, the more inherent risk is whether an allergic reaction could occur due to cross-reactivity. Cross-reactivity occurs when IgE recognizes and binds similar allergenic molecules present in different species. Tropomyosin and arginine kinase are two molecules that have been found responsible for cross-reactivity between insects and other arthropods. A recent study demonstrated IgE from canine sera sensitized to storage mites bound to yellow mealworm (Tenebrio molitor) proteins.¹⁹ It is important to note that IgE binding doesn’t necessarily mean that an allergic reaction will occur, but it does raise the possibility that the protein could trigger an allergic reaction. Many reports in human medicine also suggest the possibility of cross-reactions between insects and other arthropods. Subjects with food allergy to shellfish developed food allergy after eating cicadas²⁰ and vegetable worms.²¹ In a double-blind placebo-controlled food challenge, 87% shrimp-allergic and shrimp/house dust mite-allergic patients experienced symptoms after eating yellow mealworm.²²
As insects are expected to become more widely used as a protein source in pet food, more research is needed to investigate the significance of cross-reactivity between insects and arthropods. Since it is reported that atopic dermatitis may affect 3-15% of the dog population²³ and house dust mite allergens are the most common allergens recognized by the circulating IgE of atopic dogs, caution is needed in using insects as a protein source for these patients.
A factor that may affect the potential allergenicity of insect proteins is the post harvesting processing method employed. It is known that processing (thermal or pressure) and/or hydrolysis of food allergen proteins affects the allergenicity of feed.²⁴ Incorporation of such food processing methods may be able to reduce cross-reactivity and the allergenicity of edible insects.
References
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