Black Soldier Fly Larvae as a Tool for Managing Animal Waste and Providing a Food Source for the Aquaculture Industry

Project Overview

Project Type: Research and Education
Funds awarded in 2006: $117,682.00
Projected End Date: 12/31/2009
Region: Western
State: Idaho
Principal Investigator:
Sophie St-Hilaire
Idaho State University

Annual Reports


  • Animals: fish
  • Animal Products: dairy


  • Animal Production: feed/forage, manure management
  • Education and Training: demonstration, extension, farmer to farmer
  • Farm Business Management: value added
  • Production Systems: holistic management
  • Sustainable Communities: sustainability measures


    Results of our 8 week rainbow trout feed trail suggests fish will grow on a black soldier fly- based diet and the taste of the fish is not affected. During the summer of 2008 we grew black soldier flies in an outside facility on a dairy farm near Twin Falls, Idaho. We were able to demonstrate approximately 40% dry matter reduction in the laboratory and in our pilot on-farm system. We were only partially successful at harvesting prepupae from our system. The poor harvests were attributed to 1) the cold night-time temperatures (~50 F or lower), when the larvae are most active, 2) lack of fish offal in the diet in some containers, and 3) the prepupae’s inability to efficiently migrate out of our large containers. Given our results from the farm study, raising black soldier flies in Idaho will most likely require a temperature controlled environment and modification to the rearing units. Once this is achieved there will be a number of potential uses for the prepupae by-product.

    Project objectives:

    1. 1) Determine, using a 20-week feed trial in rainbow trout: a) whether the feed conversion ratio (weight of feed fed / weight gain) of fish fed omega fatty acid enhanced prepupae and cow manure fed prepupae at 25% and 50% fishmeal replacement are equal to or better than the commercial control diet, and b) the optimal inclusion level for prepupae in rainbow trout diets (i.e. 25% or 50% fish meal replacement) to achieve a feed conversion ratio that is equal or better than the a commercial diet.

      2) Determine (and demonstrate on a small scale) at least one method of adapting proven techniques of raising larvae to cold-weather climates (e.g., Idaho) and to cow manure.

      3) Develop and provide a cost-benefit analysis to each of the industries participating in the project: One for using black soldier fly larvae for manure reduction on diaries in Idaho, and another for using black soldier fly prepupae as a partial replacement for fishmeal and fish oil in rainbow trout diets.

      4) After the successful completion of objectives 1, 2, and 3, identify rainbow trout producers, feed manufacture(s), a maggot producer, and dairy producers in Idaho to plan and design a commercial pilot-scale demonstration project. By the end of the project, the target is to have all industry partners in place for seeking and obtaining the necessary funds for such a pilot commercial project.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.