Assessing the feasibility, safety, and nutritional quality of using wild-caught pest flies in animal feed

Authors: VAN NEST, KORTNEE - Kansas State University; SWISTEK, SABRINA - Mississippi State University; Olmstead, Morgan; De La Mota-Peynado, Alina; Ewing, Robert; Brabec, Daniel - Dan; Mitzel, Dana; Oppert, Brenda; Cohnstaedt, Lee; Shults, Phillip

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/23/2023
Publication Date: N/A
Citation: N/A

Interpretive Summary: Researchers have looked into using insects raised in laboratories as food for animals, but not much has been studied about using insects caught in the wild for this purpose. The concern is that catching enough wild insects might be hard, but it might also cause problems for the environment and spread diseases. Still, there is a need for a new source of sustainable protein for use in animal feed, and insects represent an potential untapped source. This study looked at whether we could catch enough pest flies from farms to use in feed, checked to see if they were safe to eat, and tested ways of cleaning them up. A new trapping device was used near livestock and it collected more than 11 lbs of pest insects, mainly house flies. Even though many pest were removed from the farm, it didn't reduce the overall number of house flies present. In looking at the flies themselves, we found different kinds of bacteria in flies from different farms and during different times of the year. We then tested two ways of getting rid of this bacteria. It worked to kill many of the bacteria carried by these flies, but not all of them. It is also still not clear if the flies could make animals sick. Luckily, the steps taken to clean the flies didn't make them less nutritious. More research is needed to be sure if using wild-caught insects for animal food is truly safe, but these results show that it might be possible.

Technical Abstract: Studies have investigated the potential of using farmed insects in animal feeds, however, little research has been done using wild-caught insects for this purpose. Concerns about inadequate quantities collected, environmental impacts, and the spread of pathogens contribute to the preferred utilization of farmed insects. Nevertheless, by harvesting certain pest species from intensified agricultural operations, producers could provide their animals with an affordable and sustainable protein source while also reducing pest populations. This study explores the possibility of collecting large quantities of pest flies from livestock operations and analyzes the flies’ nutritional content and potential pathogen load as well as various disinfection methods. Using a newly designed mass collection trapping device, we collected over 5 kg of biomass, primarily house flies, from a poultry facility. While a substantial number of pests were removed from the environment, there was no reduction in the fly population. Short-read sequencing was used to compare the bacterial communities carried by flies from differing source populations, and the bacteria species present in the fly samples varied based on farm type and collection time. Drying and milling the wild-caught flies as well as applying an additional heat treatment significantly reduced the number of culturable bacteria present in or on the flies, though their pathogenicity remains unknown. Importantly, these disinfection methods did not affect the nutritional value of the processed flies. Further research will be necessary to fully assess the safety and viability of integrating wild-caught insects into livestock feed, however, these data show promising results in favor of such a system.