Insect Protein – All the Rage: Insect protein as an alternate and renewable protein source for dog foods is a hot topic these days. I have written previously about a Mars-funded study that examined the in vitro (laboratory) digestibility of various adult and larval insects. Indeed, in addition to Mars jumping into the bug market, Nestle-Purina recently launched a test market for cricket-containing dog food. Insect-based treats abound these days, with the aptly named Jiminy’s offering several options.
- We eat bugs: It is estimated that nearly one-third of humans on the planet regularly include insects in their diet. The larval forms of many species can provide a rich source of high quality protein and fat, at levels similar to those found in meat and fish.
- Insects are sustainable and environmentally friendly: Compared with meat sources of food protein, insect farming is highly efficient and requires less land, water, and feed resources.
- Insect proteins meet dogs’ needs: One of the few studies of multiple insect species compared the amino acid content of different insects with the NRC amino acid requirements of dogs and cats. I wrote about this work previously in “Want Flies with that Shake?” The researchers found that the majority of insect species that they examined contained sufficient concentrations of protein, essential amino acids, and taurine to meet or exceed the NRC requirements for growth for dogs and cats (1). Who knew?
Studies? We need studies! Regardless of the hype, there are still a relatively limited number of controlled studies that have examined the digestibility, nutrient content, and safety of feeding insect protein to dogs.
Here are summaries of what we currently know:
Is Bug Protein of High Quality? In addition to the amino acid study mentioned above, a second group of researchers compared the in vitro protein quality of a range of different insects (2). They examined several of the life stages of houseflies, black soldier flies, crickets, meal worms, roaches and cockroaches.
In case you need a primer on a bug’s life, here is the the black soldier fly:
They compared these different bug protein sources to the meat protein sources that are more commonly (much more commonly) included in dog foods – poultry meal, fish meal and soybean meal. Results: Bug crude protein levels varied between ~ 45 and 65 percent of dry matter, with adult crickets having the highest level at 71 percent. These levels were similar to those reported in fish and poultry meal and somewhat higher than levels in soybean meal. Two insect proteins that were rated as high quality were the pupae stages of houseflies and black soldier flies.
- Adequate protein quality? Probably. (Need feeding studies that measure protein quality when actually fed to dogs)
Can Dogs Digest Bug Protein? When tested in vitro (i.e. in the laboratory), the protein digestibility of black soldier fly larvae and yellow meal worms were 89 and 92 percent, respectively (3). These values are comparable to those of high quality animal protein meals. When actually fed to dogs, an extruded dry dog food containing black soldier fly larvae as its primary protein source had higher digestibility values than the control food that contain venison meal (4). The nutrient content of the two foods was similar, but the bug-containing dog food was found to be significantly more digestible than the animal-protein containing food. Protein digestibility values when fed were lower than the reported in vitro values, but still respectable. Additionally, when a second group of researchers fed dogs a food containing up to 24 percent cricket meal, all levels of cricket protein supported normal gut health, feces production and gut microbiome diversity (5). In homes, owners of dogs who were fed a food containing meal worm protein as its primary protein source did not notice any difference in feces frequency or quality in their dogs (6).
- Digestible? Yes.
Will Dogs Eat Bug Protein? This one is a bit of a no-brainer, actually. (Written by someone whose dogs happily snarf up anything they can find, catch or smell whilst rooting about on walks). Regardless, this is an important question, especially for pet food producers. All of the previously noted studies reported high diet acceptability. In addition, when researchers specifically targeted dogs’ olfactory (scenting) reactions to three bug species that are used in foods (crickets, black soldier flies, meal worms), the dogs were as attracted to the bug smells as they were to the control scent – a dry, extruded dog food (7). (Note: I am not sure if this says as much about the control food as about the bugs, but there you are).
- Tasty to dogs? Of course.
Will Owners Accept Bug Protein? The jury is still out on this one, especially in the United States. While the companies that are testing insect-based dog foods are definitely collecting this type of data, there are no published studies to date (nor would I expect any soon, unless an independent researcher conducts a study).
- Owner acceptance? Unknown.
Is Eating Bugs Safe? Personally, for me, this is the most concerning question of all. Although there are insect-containing foods (and many treats) already on the market, there are no long-term safety studies of any of these ingredients. The longest feeding study that has been reported lasted only 42 days – a bit longer than a month. Given the common but questionable industry practice of advising owners to feed a single brand of food to their dog throughout the dog’s natural life, 42 days does not seem to be adequate for ensuring dogs’ safety and long-term health. Similar to other novel pet food ingredients, it can be argued that we need additional safety studies to ensure that long-term health is supported with these new forms of dietary protein. (Clearly, this one bugs me a bit…..).
- Long-term safety? Unknown.
Take Away for Dog Folks: The information that we currently have tells us that certain insect protein sources, specifically black soldier fly larvae, crickets, and yellow meal worms, can provide an acceptable and digestible protein source for dogs. The exoskeleton material, chitin, that comes along with bug protein may also provide a source of non-fermentable fiber. Given that our current animal protein production methods on the planet are not sustainable and that bugs already make up a substantial part of human diets worldwide, it seems that including insect protein in dog foods may be an acceptable and sustainable solution. Personally, I am waiting for a few more studies that include longer periods of feeding and the inclusions of standard measures of health before I jump completely onto the insect bandwagon. Stay tuned (listen for crickets) – Hopefully, we will see these soon.
Hearing Crickets? You and your dog may both be, in the near future!
- McCuster S, Buff PR, Yu Z, Fascetti AJ. Amino acid content of selected plant, algae and insect species: A search for alternative protein sources for use in pet foods. Journal of Nutritional Science 2014;3:e39;1-5.
- Bosch G, Zhang S, Oonincx AB, Hendriks WH. Protein quality of insects as potential ingredients for dog and cat foods. Journal of Nutritional Science 2014; 3:e29:1-4.
- Bosch G,, Vervoort JJM, Hendriks WH. In vitro digestibility and fermentability of selected insects for dog foods. Animal Feed Science and Technology 2016; 221:174-184.
- Russo N, Pagani E, Schiavone A, et al. In vivo and in vitro digestibility of extruded dog foods with Hermetia illucens. Italian Journal of Animal Science 2019;18;s1-pg 107.
- Jarett Jk, CArlson A, Serao MR, et al. Diets with and without edible cricket support a similar level of diversity in the gut microbiome of dogs. Peer J 2019; 7:e7661 DOI 10.7717/peerj.7661.
- Leriche I, Fournel S, Chala V. Assessment of the digestive tolerance in dogs of a new diet based on insects as the protein source. Proceedings of the 21st European Society of Veterinary and Comparative Nutrition Congress, Cirencester 2017;p. 203.
- Kieronczyk B, Rawski M, Pawelczyk P, et al. Do insects smell attractive to dogs? A comparison of dog reactions to insects and commercial feed aromas – a preliminary study. Annals of Animal Science 2018; 18:795-800.