A trial population of black soldier fly larvae was raised on organic waste generated by the White Oak Pastures red meat abattoir during the summer months of 2012-2013. Two different rearing approaches were utilized and an experiment was conducted to determine the rate of biomass conversion of organic waste to mature soldier fly larvae over the course of one generation.
The production of free range organic poultry is economically and sustainably challenging for producers. The extended growing period required to raise mature, free range birds is generally twice that (12 weeks) of those raised in industrial chicken houses (6 weeks) (McMurray Hatchery, 2014) . Because birds are kept longer, all associated costs are higher per bird. Although free range poultry do receive a portion of their diet from their environment they also must be provided a supplemental feed in order to receive enough nourishment for proper development (Darre, n.d.). The cost and availability of commercial organic feed can fluctuate with market demand and is generally more expensive than industrially suited feeds. In order for organic farmers to be competitive in raising free range poultry they must find ways to lower their operating costs. By developing a lower cost, higher protein organic feed source, theoretically poultry could be raised to maturity faster, thus reducing operating expenditures. Black soldier fly larvae (Hermetia illucens, BSF) have been demonstrated to provide adequate fat and protein levels compared to traditional feed in the diets of fish, swine, and poultry, comprising 42% protein and 35% fat (Sheppard et al., 1995). Additionally, BSF make a natural, low-cost management and nutrient recycling system for manure and other sources of bio-waste (Newton et al., 2005). A recent study conducted at the Wageningen University and Research Center in Wageningen, Netherlands has indicated a strong feasibility of creating and maintaining large-scale feeding programs for swine and poultry using insect protein (Veldkamp et al., 2012).
References cited:Darre, M.J. (n.d.) Everything You Need To Know About Raising Broiler Chickens. Retrieved from http://www.uvm.edu/newfarmer/production/livestock/Growing%20Broilers-Darre.pdfMcMurray Hatchery (2014). Red Ranger Broiler. Retrieved from http://www.mcmurrayhatchery.com McMurray Hatchery (2014). Jumbo Cornish X Rocks. Retrieved from http://www.mcmurrayhatchery.comNewton, G.L., D.C. Sheppard, D.W. Watson, G.J. Burtle, C.R. Dove, J.K. Tomberlin, and E.E. Thelen. (2005). The black soldier fly, Hermetia illucens, as a manure management / resource recovery tool. Proceedings Symp. State of the Science: Animal Manure and Waste Manag. Jan. 5-7, 2005, San Antonio, TX.Sheppard, D.C., Newton, G.L., Thompson, S.A., & Savage, S. (1995). A value added manure management system using the black soldier fly. Bioresource Technology, 50: 275-279.Veldkamp, T., van Duinkerken, G., van Huis, A., Lakemond, C.M.M., Ottevanger, E., Bosch, G., & van Boekel, M.A.J.S. (2012). Insects as a sustainable feed ingredient in pigand poultry diets – a feasibility study. Wageningen UR Livestock Research, Report 638.
The objective of the research is to test the effectiveness of BSF as a value adding tool in the production of supplemental organic free range poultry feed. This project seeks to further strengthen the Serengeti Model now in use at White Oak Pastures by filling a gap in the model that currently exists. Because over 60 chicken flocks (containing approximately 500 birds per flock) freely range on 80 acres there is a great need for supplemental feed. This research seeks to document how many pounds of eviscerate (X), with the help of black soldier fly (BSF) larvae, will consistently produce one hundred pounds of poultry feed (Z) in the form of BSF larvae, and how long (Y) it will take to accomplish the transformation: (X + BSF) x Y = Z (100 pounds of feed).
During the summer of 2012, BSF were raised exclusively in four ProtaPods™ (http://www.thebiopod.com/pages/pages/protapod.html) on private farmland in a location with access to a 4-acre organic garden, open broiler pasture, and an on-site red meat abattoir. The ProtaPods were located underneath a solar voltaic array where they were shaded and protected from rain. Egg traps were constructed from corrugated cardboard strips and secured with Velcro inside bins containing wet chicken feed, located throughout two hoop houses which contained chicks up to three weeks of age. Egg clusters were collected daily and placed in a separate bin to hatch. Filled egg traps were placed over a screen of ¼” hardware cloth and suspended over moist chicken feed. A screen top prevented other flies from ovipositing in the bin. When the hatched larvae were big enough to see they were dumped into the ProtaPods, rotating between the four active ProtaPods in sequence. Mature larvae which migrated out of the ProtaPod and fell into a collection bucket were harvested on a daily basis. The ProtaPods were fed a mix of about 75% meat scraps and 25% vegetable waste. Broken raw eggs were fed as available. Each ProtaPod was fed 2-3 pounds of material every other day during the peak of summer, and once a week in the fall when BSF activity levels decreased. Over the winter months one ProtaPod was maintained and fed weekly inside an 82-square-foot heated plastic greenhouse, and the remaining three ProtaPods were left to enter dormancy.During the following summer of 2013 three of the four ProtaPods were relocated to a field containing compost windrows in active decomposition, situated between open cattle pasture and mixed hardwood forest. This location was chosen to allow newly matured BSF greater proximity to the forest, where the majority of lekking and mating behavior is believed to occur (Tomberlin & Sheppard, 2001). Young larvae and eggs were added to each ProtaPod to boost the active BSF colonies and attract gravid BSF females. Egg collection traps were placed in and around each ProtaPod and eggs were collected daily. Several additional egg traps and the fourth ProtaPod were placed in an open 10’x40’ hoophouse which was constructed within a 1-acre orchard, situated between broiler pasture and a mixed hardwood forest containing a shallow pond. All eggs that could be collected were reared as daily batches inside the hoophouse in shallow 15”x20”x5” bins. Newly hatched larvae were fed a diet of moist chicken feed until they were one week old, then switched to increasing daily rations of ground cattle eviscerate originating from the abattoir. Larvae were monitored for feed consumption and moisture on a daily basis and their feed rations were adjusted daily in order to provide no more feed than could be consumed over a 24 hour period. Whole batches of mature larvae were harvested when the majority of larvae in the batch had turned black and stopped feeding.An experiment was conducted at the end the 2013 season to quantify bioconversion rates using the batch-rearing method. In this experiment two batches of different sizes were created using 6,000 and 10,000 larvae held in 15”x20”x5” storage bins. Initial population size was determined by weighing a small subsample of 20 larvae and projecting the weight of the total batch to attain the desired population. The larvae were initially fed ground eviscerate at the rate of 1:1 in biomass (e.g., 30g eviscerate per 30g larvae). After this point the feed amount was gradually adjusted at a rate that maintained the 24-hour consumption rule for each batch. Larvae were fed exclusively ground eviscerate during the course of the experiment and the weight of each day’s ration was recorded. As it was impractical to weigh an entire batch of larvae, samples of 20 larvae from each batch were weighed at regular intervals to determine average larval weight. The experiment was ended after 45 days, when the majority of the larvae were mature and were no longer feeding. Each batch was screened to separate mature larvae from uneaten material and each component was weighed. The net weight of consumed eviscerate material was determined by subtracting the weight of uneaten material from the total weight of feed rations over the 45-day period. The conversion rate of eviscerate to larval weight was determined by dividing the net weight of consumed material by the final weight of mature larvae. Reference cited: Tomberlin, J.K. & Sheppard, D.C. (2001). Lekking behavior of the black soldier fly (Diptera: Stratiomyidae). Florida Entomologist, 84: 729-730.
As a result of this two-year project three full-time employees of the farm were trained in black soldier fly colony maintenance using ProtaPods and batch-rearing methods. Over the two active BSF growing seasons, an increase in yield was observed from the 2012 to the 2013 season, averaging 1-2lbs per day of mature larvae in 2012 and 3-4 pounds per day of mature larvae in 2013. This increase may be attributed to increased egg collection and a more efficient rearing system utilized in 2013. The results of the bioconversion rates experiment carried out in 2013 indicated that over a 45-day period of larval maturation, 9.3lb of net ground eviscerate was required to produce 0.77lb of mature larvae in the 6,000-larva batch and 13.8lb of eviscerate produced 1.28lb of mature larvae in the 10,000-larva batch. Using these conversion factors we can project that to produce one 100-pound batch of mature BSF containing approximately 780,000 larvae, a net total of 1080-1210 pounds of eviscerate would be required, or an average of 24-27 pounds of eviscerate per day. White Oak Pastures currently acquires over 3,500 pounds of eviscerate per day as a product of cattle processing, making the projected numbers very practical for the farm and leaving much room for expansion.
Educational & Outreach Activities
Moshman, Lori. “Black Soldier Fly Production for Feed and Bio-Waste Processing”. Written for the March 2014 APPPA Grit! newsletter.White Oak Pastures Coloring & Activity Book. (2013). Really Big Coloring Books, Inc. 16 pages. White Oak Pastures gives daily tours to farm visitors in which black soldier fly production is included as a part of each tour. A coloring and activity book highlighting BSF biology in addition to vegetable, egg, and meat production facts is available for no cost to visitors to the farm, as well as all 11 visitor and welcome centers in the state of Georgia. Recently an article highlighting White Oak Pastures’ SARE Grant results has been prepared for the APPPA Grit! newsletter, which is distributed to pastured poultry producers (http://www.apppa.org). Additionally, a half-day workshop will be taught at the farm in May covering black soldier fly rearing as a part of small-scale composting methods.
With this project we have demonstrated two feasible ways of rearing black soldier fly larvae during summer months to attain daily harvests of mature larvae which can be used immediately as a natural supplement to standard livestock diets. The bioconversion rates experiment conducted in 2013 has given us a realistic number to use as a basis for further experimentation and rearing efforts.
We hope to continue our efforts in black soldier fly breeding and construct a temperature controlled rearing facility to achieve year-round egg collection and feeding on the scale that would be required to supplement the diets of all of our free-range poultry species. Now that we have a basic conversion ratio of raw bio-waste to mature BSF larvae that is specific to our farm, our abattoir, and the surrounding natural areas, we have achieved a greater and more realistic understanding of what is required to attain our production goals. Using the knowledge and experience we have gained we will continue to educate the public about the role of BSF in nature and in agriculture, and we hope to inspire others to take advantage of natural BSF populations for home composting and livestock feeding endeavors.
The results of our captive BSF rearing efforts have indicated that new approaches are needed to produce black soldier fly larvae at a rate which would be optimal for supplementing the diets of the pastured poultry flocks on the farm. Although our harvest rate doubled from 2012 to 2013 with the streamlining of our production methods, so far our efforts have resulted in much smaller harvests than we had envisioned. Having an abundance of nutrient-rich organic bio-waste from our red meat abattoir, it is clear to us that the limiting factor in black soldier fly production is egg collection. In order to increase the abundance of eggs available to collect, we plan on increasing our egg traps and collecting in more locations around the farm; we will also begin planning the design of a temperature controlled facility in which BSF can be bred and harvested year-round.