Nutritional quality
Macronutrient content
The nutritional quality of insects depends on various different factors, including:
- species,
- development stage,
- their diet, as well as:
- environmental or abiotic factors (i.e., non-living chemical or physical elements of the environment, such as acidity, salinity, humidity, radiation, etc.)[1]
Macronutrients and notably proteins have been more researched compared to micronutrients.
On average, the crude protein (dry weight) content of mealworms is 43%-53%, while for the black soldier fly it is 32%-48%, which is almost similar to that of beef and chicken.[2]
Amino acid composition and digestibility are generally considered key indicators to assess protein quality.[3] Overall, data available singles out farmed insects as a high-quality protein source for the human diet.[4]
The protein content of the insect species under analysis as a feed source is also generally considered of good quality. In particular, their essential amino acid profiles are comparable to that of soybean meal.[5]
Because of their palatability, they are suitable replacements for soybean meal for feeding certain animal species (e.g., broilers, pigs).[6] However, with the exception of fish, recent studies conducted on black soldier fly larva meal fed to food-producing animals indicate that only partial replacement might be advisable as otherwise growth performance of the animals might be affected.[7]
Insects can be also source of other macronutrients. In the case of the yellow mealworm, fiber, fats and carbohydrates are present in higher quantities than in almost all conventional protein sources .[8] Compared to soy, the black soldier fly has a higher fat content, while its fiber content is similar and carbohydates content lower.[9]
Micronutrient content
Insects can also be a source of important micronutrients for both human and animal diet, although, significant differences can be observed across species.
From a food perspective, mealworms perform better than their conventional counterparts in terms of overall vitamin content, with this being more evident for beef and dairy but less for chicken.
The same can be said for the overall mineral content, with the notable exception of beef that has comparatively higher levels of iron, zinc and potassium, among others.[10], [11]
From a feed perspective, not all insect species are rich in micronutrients that are essential for animal requirements. For instance, most species present relatively low levels of calcium, with the black soldier fly being an exception.[12]
In addition, when reared indoors, mealworms may present lower levels of Vitamin D.[13]
When compared to soybean meal, insects perform better in terms of overall vitamin content, while the former presents, on average, higher levels of minerals.[14] Studies have shown the bioavailability of micronutrients in insects to be equivalent or higher than that found in beef meat.[15]
[1] van Huis A, Potential of Insects as Food and Feed in Assuring Food Security, Annual Review of Entomology Volume 58, 2013, p. 563-583.
[2] Selaledi L, Mbajiorgu CA and Mabelebele M, The use of yellow mealworm (T. molitor) as alternative source of protein in poultry diets: a review, Tropical Animal Health and Production 2019 Vol. 52, p. 7-16, https://doi.org/10.1007/s11250-019-0203 and Wang YS and Shelomi M, Review of Black Soldier Fly (Hermetia illucens) as Animal Feed and Human Food, Foods 2017, Vol. 6, Issue 10, p. 91, doi:10.3390/foods6100091.
[3] Malla N, Nørgaard JV and Roos N, Protein quality of edible insects in the view of current assessment methods, Animal Frontiers, 2023 as well as FAO, Dietary protein quality evaluation in human nutrition, Report of an FAQ Expert Consultation, Food and Nutrition Paper 92, 2011, available at https://www.fao.org/ag/humannutrition/35978-02317b979a686a57aa4593304ffc17f06.pdf.
[4] Malla N and Roos N, Are insects a good source of protein for humans?, J Insects Food Feed, 2023, 9(7), p. 841-844.
[5] Pinotti L, Giromini C, Ottoboni M, Tretola M,and Marchis D., Review: Insects and former foodstuffs for upgrading food waste biomasses/streams to feed ingredients for farm animals, Animal, 13(7), 2019, p. 1365-1375.
[6] Makkar HPS, Tran G, Heuzé V, Ankers A, State-of-the-art on use of insects as animal feed, Animal Feed Science and Technology, Volume 197, November 2014, p. 1-33.
[7] Facey H, Kithama M, Mohammadigheisar M, Huber H, Shoveller AK, Kiarie EG, Complete replacement of soybean meal with black soldier fly larvae meal in feeding program for broiler chickens from placement through to 49 days of age reduced growth performance and altered organs morphology, Poultry Science, Volume 102, Issue 1, January 2023, 10229; Gasco L., Renna M, Bellezza Oddon S, Rezaei Far A, Naser El Deen S and Veldkamp T, Insect meals in a circular economy and applications in monogastric diets, Animal Frontiers, 2023, Vol. 13, Issue 4, p. 81-90, https://doi.org/10.1093/af/vfad016 and Alfiko Y, Xie D, Astuti RT, Wong J and Wang L, Insects as a feed ingredient for fish culture: Status and trends, Aquaculture and Fisheries 2022, Vol. 7, Issue 2, p. 166-178, https://doi.org/10.1016/j.aaf.2021.10.004
[8] Toviho O.A., Bársony P. Nutrient Composition and Growth of Yellow Mealworm (Tenebrio molitor) at Different Ages and Stages of the Life Cycle, Agriculture 2022, 12(11), 1924; https://doi.org/10.3390/agriculture12111924-
[9] Lu S et al., Nutritional Composition of Black Soldier Fly Larvae (Hermetia illucens L.) and Its Potential Uses as Alternative Protein Sources in Animal Diets: A Review, Insects. 2022 Sep; 13(9): 831, 2022 Sep 13. Doi: 10.3390/insects13090831.
[10] Orkusz A, Edible Insects versus Meat—Nutritional Comparison: Knowledge of Their Composition Is the Key to Good Health’, Nutrients. 2021 Apr; 13(4): 1207.
2021.
[11] Dairy UK, The nutritional composition of dairy products: https://milk.co.uk/nutritional-composition-of-dairy/milk/ (accessed on 13 October 2023).
[12] Spranghers T, Ottoboni M, Klootwijk C, Ovyn A, Deboosere S, De Meulenaer B, Michiels J, Eeckhout M, De Clercq, P and De Smet S, Nutritional composition of black soldier fly (Hermetia illucens) prepupae reared on different organic waste substrates, J Science Food and Agriculture 97, 2017, p. 2594-2600.
[13] Oonincx DGAB and Finke MD, Insects as a complete nutritional source, J Insects Food Feed, 2023, 9(5), p. 541-543.
[14] Orkusz A, 2021, and Soybean meal nutrition: calories, carbs, GI, protein, fiber, fats https://foodstruct.com/food/soybean-meal (accessed on 13 October 2023).
[15] Parodi et al., 2018.