So once again, I must apologize- but really for two things.

1. I am so sorry it has been a couple of weeks since I last wrote a post for the blog. I feel like I have been missing out on great conversation with friends from around the world when I do not post frequently.  

2. I started a new record system so I can keep up with the papers/topics that I discuss in each post. What does this mean? Well, it keep me from being too redundant by discussing the same articles over and over again.  So, please accept my apologies (again) if I am about to review a paper that I had previously discussed.... but I will say- if I am discussing the same paper again, it is because I think so highly of it! So highly, I feel it is necessary to review it again.

Today's paper for discussion is (drumroll please):

Diener, S., C. Zurbrugg, and K. Tockner. 2009. Conversion of organic material by black soldier fly larvae: establishing optimal feeding rates. Waste Management Research 27: 603-610.

This is a great paper by my friend and colleague Dr. Stefan Diener!  (A little back story- Stefan and I met a number of years ago... probably a decade or more when he came to visit me in Texas. He spent a few days meeting with me and discussing BSF as well as enjoying good Texas BBQ (if you visit Texas, here is a list of the best BBQ places). We have been good friends ever since!  He is such a leader in the development of the BSF for waste management and protein production.  I have so much respect for him!)

Now - how about his paper?

The take-home message from his study is feed rate matters (I am pretty sure we have talked about this before).  In this study, they fed BSFL a standard diet at different rates. They determined that there is a threshold at which overfeeding the BSFL occurs. There are a couple of key points here.

1. Feed rate will be dictated by what you feed them (some diets can be provided at much higher rates than others- for example, vegetable waste vs meat by-products).
2. Overfeeding can result in larval mortality as the larvae cannot digest it fast enough to prevent pathogen proliferation.
3. Overfeeding will reduce BSFL conversion rates.
4. Underfeeding will prolong larval development.
5. All diets need to be tested to determine an optimal rate.

Well... hopefully I am still on track in terms of providing useful information. I will start digging through my citations to review every paper on BSF that I have filed away... from the earliest to the latest. That way- you can develop your library too!

All the best,
Jeff Tomberlin, PhD, BSF librarian
Twitter: @FliesFacility
Director, EVO Conversion Systems

A lot has been discussed about the production of fish (aquaculture) when using feed derived from BSF. In fact, a recent article indicated Protix will be producing salmon (a traditional model for BSF) fed BSF feed. In fact, they are branding it due to its uniqueness (in a very good way) as related to production.

However, for most, the actual appropriate means for producing fishmeal either with complete or partial replacement by BSF meal is not known.

A study that was just published in the Journal of Insects as Food and Feed addressed this topic for feed produced with BSF as well as crickets. 

Physico-chemical properties of extruded aquafeed pellets containing black soldier fly (Hermetia illucens) larvae and adult cricket (Acheta domesticus) meals

What I found interesting about this paper is the authors focused on the actual production of the pellet to be fed to fish. They addressed some features that I believe many researchers historically have not considered.  

They examine:

1. Floatability
2. Expansion rate
3. Bulk density
4. Durability index
5. Water absorption index
6. Water solubility index
7. Water stability of extruded pellets

Why is this important? While BSF can be mass produced- how do we present them to fish or other mass produced species in aquaculture in order to maximize production, conversion, and production.
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What did they find (information verbatim from the abstract)?

• Pellet floatability was not influenced by the type of insect meal but the interaction between level of inclusion and moisture content of the feed at extrusion.
• Pellets with high floatability >90% were produced from all feed blends at 30 g/100 g moisture content.
• Expansion ratio, was not influenced by type of insect meal or the level of inclusion but by the moisture content whereby feed blends extruded at 30 g/100 g moisture gave pellets with high expansion ratio ~60%.
• Bulk density was influenced by the interaction of the three factors.
• Pellet durability and water absorption indices were not influenced by the investigated factors or their interactions.
• Processed pellets were generally highly durable (99%) out of water, but the stability in water was significantly influenced by the interaction of type of insect meal level of inclusion and moisture content at extrusion.
• Water solubility increased with increasing extrusion moisture. Overall, it was possible to process good quality extruded pellets with 75% BSFM or 75% ACM at 30 g/100 g feed moisture. 

What does it mean? From my perspective, it means several things;
1) Mechanization: industry needs to develop appropriate equipment for production of BSF meal for aquaculture (maybe equipment already exists-  but BSF companies will need to decide if they want to produce the meal or sell to another company for mass production.

2) Economics: Either decision listed in the first point impacts price of the product. What is optimal for the aquaculture industry still needs to be determined. Is BSF a higher quality product for aquaculture (rhetorical question)?  We also know this will be dependent on the species being mass-produced. Some are higher value per ton than others. 

3) Genetics & Nutrition: Does quality of the BSF produced impact all of the factors previously investigated for this sample of BSF? I suspect it does as the protein and fat content will vary across production lines (depending on genetics of population- shout out to my colleagues Christoph Sandrock and Christine Picard for their population genetics research with BSF) as well as what they are fed.

4) Durability: This is not with regards to durability of the pellet produced but more about shelf-life. How to produce this product and then store it prior to use. Are there conditions under which the feed will need to be stored in order to prevent nutrient or product degradation.

5) Volume: One thing everyone should always be thinking about- how much BSF do you need to produce in order to supply an aquaculture production facility?  The math is mind-boggling! 

These are a few potential items to consider with production... and I am sure there are many more. So, if you think of something... please reply and share with everyone.

Great news!  The Tomberlin lab recently published a paper where they examined the production of noxious odors associated with animal waste and demonstrated BSF larvae actually suppress many of these odors- another major win for the BSF as sustainable agriculture.

The article is fresh off the press:

Beskin, K. V., C. D. Holcomb, J. A. Cammack, T. L. Crippen, A. H. Knap, S. T. Sweet, and J. K. Tomberlin. Larval digestion of different manure types by the black soldier fly (Diptera: Stratiomyidae) impacts associated volatile emissions. Waste Management.

As many of you know, livestock production plays a critical role in protein production in many parts of the world. As economies of countries grow, so does the livestock industry.  With that said, there are issues (USDA website contains a review) associated with this industry- or as I like to say- opportunities. 

We know the BSF can be used to recycle these wastes- especially manure produced by cattle, poultry, or swine.  We also know that by recycling such wastes and producing protein there is less likelihood of the waste impacting the environment. This makes sense; I mean, if it isn't sitting on the ground decomposing but rather being quickly recycled by the BSF, let issues, right?

Well, the study by Beskin et al (2018) is one of the first to quantify the reduction in noxious odors associated with swine, dairy, and poultry manure by the BSF.  What did they determine?

Black soldier fly larvae reduced emissions of all volatile organic compounds by 87% or greater.

This study is a bench top study- so more work is needed at the industrial scale- just to make sure there results from Beskin et al. (2018) are translatable.  But, regardless, these results are very promising.

Great job, Kelly Beskin and team at Tomberlin lab!! 
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