Circular Economics, Food Waste and Aquaponics

After carefully packing the veg box orders for Matter Wholefoods in Easton, Jon agrees that I can take the bumped, bruised and past-it veg that didn’t make the veg-box cut over to the warehouse to give to Heather to cook up for the eager warehouse occupants currently hiring our classroom space for 10 days for some time-constrained charity fundraiser work. On the way I drive by the lovely Park Bakery on St John’s Lane and they donate some of their yesterday’s bread to the cause. I’m greeted with smiling faces when I arrive on site. If we go back Wednesday evening we may even get cake I whisper to Heather out of earshot of the volunteers.

We have access in our neighbourhood to a lot of waste streams. Fruit and veg waste, bread, spent brewery grain and trub (yeast) – we intend to find ways to reduce this waste, by turning it into feed for new processes (circular economics) – as part of wanting to build a truly regenerative farm. This in mind, we did – way back on our pilot site – some experiments with Black Soldier Fly – Hermetia illucens (a common fly of the family Stratiomyidae) and include them in our commercial aquaponics course. This year Beca Beeby from Humble by Nature (She is literally Lord of the Flies) is coming to share her unique experience of farming with black soldier flies in the system as part of our commercial aquaponics course in May.

With our flies we had some issues with low libido, and stench, but we made it in the end once we build our ‘mile high club’ for our flies. And they are amazing insects!

HermetiaillucensBlack Soldier Fly Larvae compost a diverse range of food waste streams and their prepupae (tough shell-covered bodies that look a bit like woodlice) are then a resource-efficient and high nutrient substitute for wild-catch fishmeal (highly unsustainable) that could have a significant beneficial economic and environmental impacts.

Black Soldier Fly Larvae (BSFL) as a feed have been trialled extensively on the small scale for over 30 years, and are found to be a compelling potential commercial feedstuff for other food-animals. When dried (for easy storage) the prepupae (BSFP) contain 42% protein and 35% fat. In combination with other ingredients, BSFP have been trialled successfully as a feed for rainbow trout and catfish achieving good growth and health results. Studies indicate that BSFP can replace >25% of a fish meal in a diet with no negative effect on growth in rainbow trout and in channel catfish – so we think it will be similar for our eels.

The big one for us down’t farm is that insects could be legally used in fish feeds in Europe as early as next July after the EU voted in December to accept proposed amendments to legislation governing farmed insects used in animal feeds. Not that we were worried – Food safety and bacterial considerations for using this feed are so far favorable. In China, the USSR, USA, Mexico and Eastern Europe BSFP have been fed to poultry, pigs, shrimp, various species of fish, turtles and frogs – no problems. Moreover anti-microbial factors were recorded reducing the chance of feed transmitting pathogens wherein BSFL have been shown to significantly reduced E. coli 0157:H7 and Salmonella enterica in hen manure (pretty good going).

You can buy Black Soldier Fly Larvae from our shop if you want to try to grow them for yourself.

Oh and here is my Black Soldier Fly reading list with references from the above:

Newton, G. L., C. V. Booram, R. W. Barker, and O. M. Hale. 1977. Dried Hermetia illucens larvae meal as a supplement for swine. J. Anim. Sci. 44:395-399.

St-Hilaire, S., K. Cranfill, M. A. McGuire, E. E. Mosley, J. K. Tomberlin, L. Newton, W. Sealey, C. Sheppard, and S. Irvin. 2007b. Fish ofal recycling by the black soldier fly produces a foodstuff high in Omega-3 fatty acids. J. World Aquaculture Soc. 38:309-313.

Newton, L., C. Sheppard, W. Watson, G. Burtle, and R. Dove. 2004. Using the black soldier fly, Hermetia illucens, as a value-added tool for the management of swine manure. Univ. Of Georgia, College of Agric. & Environ. Sci., Dept. Of Anim. & Dairy Sci. Annual Report.

St-Hilaire, S., C. Sheppard, J. K. Tomberlin, S. Irving, L. Newton, M. A. McGuire, E. E. Mosley, R. W. Hardy and W. Sealey. 2007a. Fly prepupae as a feedstuff for rainbow trout, Oncorhynchus mykiss. J. World Aquaculture Soc. 38:59-67.

Newton, L., C. Sheppard, W. Watson, G. Burtle, and R. Dove. 2004. Using the black soldier fly, Hermetia illucens, as a value-added tool for the management of swine manure. Univ. Of Georgia, College of Agric. & Environ. Sci., Dept. Of Anim. & Dairy Sci. Annual Report.

“Research Summary: Black Soldier Fly Prepupae – A Compelling Alternative to Fish Meal and Fish Oil”

Erickson, M. C., M. Islam, C. Sheppard, J. Liao, and M. P. Doyle. 2004. Reduction of Escherichia coli 0157:H7 and Salmonella enterica serovar Enteritidis in chicken manure by larvae of the black soldier fly. J. Food Protection. 67:685-690.





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