Time and time again researchers are realizing that black soldier fly larvae (no – not your common pesky housefly) and other insects are an excellent alternative or partial replacement food source protein that also provides antimicrobial properties for companion and non-companion animals instead of soybean meal and other grains. Within the feed animal world, the diets of broiler chickens, from aquaculture (farm-raised fish), quails, quail eggs, egg laying hens and pigs all have proven the viability of insect or insect larvae meal replacement.
Now, please remember the logic we always try to impart: “one size does not fit all”. Indeed, all animals are different and, therefore, require different balances between food sources. Additionally, animal nutritionists have to consider such things as production yield, size, quality of life, digestibility for the animal and for the consumer. Case in point, crude protein contents of insect meal are considerably higher at 42–63%. But, that does not mean it is completely digestible. Hence, the reason we need to find a balance.
One of the hot topics is chitin, which is a fibrous substance consisting of polysaccharides that helps form the exoskeleton of insects. Some studies emphasize its positive prebiotic effect in certain birds, whereas other studies point out that chitin reduces protein digestibility in some birds.
For example, Secci et al. provided a base diet of soybean meal and one of Tenebrio Molitor (mealworm beetle) larvae meal to egg-laying quails. The mealworm larvae had exponentially higher amounts of protein, calcium, phosphorus, methionine and lysine. However, the chitin level in the larvae meal was 4.5% compared to zero in the soybean formula and may have been the limiting factor. That’s not to say the authors did not want to find a balance. They concluded that the inclusion of a defatted mealworm beetle larvae meal at 2.8 and 5.6% in laying quail diets negatively affected the laying performance and some physical characteristics of the eggs. This was due to the impairment of nutrient digestibility, in particular of crude protein, but they decided that the best inclusion level of defatted meal for laying quails seemed to be 1.4% of diet.
To illustrate, Giulia Secci’s work is not biased against insects, as she and several of her colleagues had discovered that defatted black soldier fly larvae meal (Hermetia illucens; BSFLM) is a suitable and total substitute for soybean meal in the diet of Lohmann Brown Classic laying hens.
In an earlier study, De Marco et al. showed that black soldier fly larvae and the mealworm beetle larvae were excellent sources of apparent metabolizable energy for broiler chickens and a valuable source of digestible amino acids. Specifically, the mealworm beetle larvae meal was the best.
Different insects. Different types of birds. Different purposes for the birds. Different amounts of meal.
The bulk of the research to date has circled around aquaculture and birds, along with the different types of insects. While this is still a primary focus, scientists are now working with agricultural pigs and companion cats.
With pigs, the study stated that absorbed amino acids (AA) from the full-fatted and defatted BSFLM utilization was not different despite some small differences in digestibility of the AA. This indicates that the absorbed AA from the two BSFLM sources were used equally to support protein retention in growing pigs, when they were included as the sole sources of dietary AA in the diets at 50% and 36.5%, respectively. Further, the synergy of the mono- and poly-unsaturated fatty acids, medium chain fatty acids, and chitin promoted increased nutrient absorption and reduced colonization of pathogenic bacteria in the gut of the newly weaned pig.
The study involving companion cats was preliminary and small in scope. The researchers stated that cats fed a semi-synthetic diet containing 4% BSFLM remained healthy with no clinically relevant changes in complete blood count and serum biochemistry parameters for 21 days.
The abundance and acceleration of excellent work from researchers around the world is amazing. Why are they doing it? For sustainability.
These researchers have the long view. Decreasing farmlands. Increasing populations. The volatile price of grain markets. The competition between farmland for ethanol, human and animal food. Climate change. None of them mentioned it, but also war.
Look at the war that besieges Ukraine from Russia. Ukraine is known as the “breadbasket of Europe” mostly by supplying sunflower oil, wheat and corn to the European Union and other countries. Europeans will find this a strain on their pocketbooks and some may face poverty due to the increased food prices. But these and other threats to less developed nations that depend upon the Ukraine could face famine.
References
Bovera, F., et al. “Use of Tenebrio molitor larvae meal as protein source in broiler diet: effect on growth performance, nutrient digestibility, and carcass and meat traits.” Journal of Animal Science, vol. 94, no. 2, Feb. 2016, pp. 639–647, https://doi.org/10.2527/jas.2015-9201.
Crosbie, Michelina, et al. “Standardized ileal digestible amino acids and net energy contents in full fat and defatted black soldier fly larvae meals (Hermetia illucens) fed to growing pigs.” Translational Animal Science, vol. 4, no. 3, July 2020, https://doi.org/10.1093/tas/txaa104.
Cullere, M., et al. “Black soldier fly as dietary protein source for broiler quails: apparent digestibility, excreta microbial load, feed choice, performance, carcass and meat traits.” Animal, vol. 10, no. 12, 2016, pp. 1923–1930, https://doi.org/10.1017/s1751731116001270.
De Marco, M., et al. “Nutritional value of two insect larval meals (Tenebrio molitor and Hermetia illucens) for broiler chickens: apparent nutrient digestibility, apparent ileal amino acid digestibility and apparent metabolizable energy.” Animal Feed Science and Technology, vol. 209, 2015, pp. 211–218, https://doi.org/10.1016/j.anifeedsci.2015.08.006.
Makkar, Harinder P.S., et al. “State-of-the-art on use of insects as animal feed.” Animal Feed Science and Technology, vol. 197, Nov. 2014, pp. 1–33, https://doi.org/10.1016/j.anifeedsci.2014.07.008.
Mwaniki, Z.N., and E. Kiarie. “Standardized ileal digestible amino acids and apparent metabolizable energy content in defatted black soldier fly larvae meal fed to broiler chickens.” Canadian Journal of Animal Science, vol. 99, no. 2, June 2019, pp. 211–217, https://doi.org/10.1139/cjas-2018-0111.
Mwaniki, Z., et al. “Complete replacement of soybean meal with defatted black soldier fly larvae meal in Shaver White hens feeding program (28–43 wks of age): impact on egg production, egg quality, organ weight, and apparent retention of components.” Poultry Science, vol. 99, no. 2, Feb. 2020, pp. 959–965, https://doi.org/10.1016/j.psj.2019.10.032.
Pezzali, Julia Guazzelli, and Anna Kate Shoveller. “Short Communication: the Effects of a Semi-Synthetic Diet with Inclusion of Black Soldier Fly Larvae Meal on Health Parameters of Healthy Adult Cats.” Journal of Animal Science, vol. 99, no. 10, 15 Oct. 2021, https://doi.org/10.1093/jas/skab290.
Schiavone, Achille, et al. “Nutritional value of a partially defatted and a highly defatted black soldier fly larvae (Hermetia illucens L.) meal for broiler chickens: apparent nutrient digestibility, apparent metabolizable energy and apparent ileal amino acid digestibility.” Journal of Animal Science and Biotechnology, vol. 8, no. 1, 1 June 2017, https://doi.org/10.1186/s40104-017-0181-5.
Secci, Giulia, et al. “In vivo performances, ileal digestibility, and physicochemical characterization of raw and boiled eggs as affected by Tenebrio molitor larvae meal at low inclusion rate in laying quail (Coturnix japonica) Diet.” Poultry Science, vol. 100, no. 12, 16 Sept. 2021, https://doi.org/10.1016/j.psj.2021.101487.
Secci, G., et al. “Quality of eggs from Lohmann Brown Classic laying hens fed black soldier fly meal as substitute for soya bean.” Animal, vol. 12, no. 10, 2018, pp. 2191–2197, https://doi.org/10.1017/s1751731117003603.