04/06/2015: Aquaculture view: Insects as Food and Feed Sources: Going against the Grain

by Dominique P Bureau, member of the IAF Editorial Panel

First published in International Aquafeed, May-June 2015

Entomophagy, or “insects as a food source” appears to be a very popular topic these days. Many global stakeholders are now identifying this practice as a future cornerstone of food security. For example, the Food and Agriculture Organisation (FAO) of the United Nations has identified edible insects as a subject of priority for investigation. In 2013, former US President Bill Clinton awarded the Hult prize to a social enterprise, Aspire, created by McGill University students, that aims to “develop and distribute affordable and sustainable insect farming technologies and increasing access to highly nutritious edible insects amongst the poorest, and therefore neediest, members of society”.

Image: Johan Hansson

Frankly, I am always a bit uneasy when people present a food production activity (farming) with such lofty narrative. However, who am I to argue against motherhood and apple pie?

One of the key selling aspects for entomophagy is the high efficiency of insects converting a variety of feed resources and the high nutritive value of insects, hence the emphasis on positioning insect farming or ranching as part of long term global food security. In that optic, the questions I have are the following:

1. Are insects as nutritious as they are assumed to be?
2. Is insect farming truly highly efficient?
3. Aren’t there any other ways to provide nutrients in a cost-effective and sustainable fashion?

Let me attempt to contribute to answering some of these questions but through what I know best, fish nutrition and feed formulation.

The nutritive value of insect biomass to fish
The use of insects in aquaculture is also a hot topic.  An increasing large number of ventures have been established around the world to produce insect biomass on a commercial scale and the aquaculture feed industry is clearly one of the markets that these ventures are targeting. This seems to be a natural fit since insects are a major component of the natural diet for many fish species.  Insects are usually rich in protein (40-70 percent on a dry matter basis) and lipids (up to 50 percent on a dry matter basis) and generally have relatively good essential amino acid and fatty acid profiles. They may therefore be valuable feed ingredients in formulated feeds for aquaculture species and this issue deserves to be seriously investigated.

Image: William Cho

I am aware of a significant number of research trials on this topic that were recently completed or in the pipeline. My research team, for one, recently completed a feeding trial with Super Worm Meal (SWM), a low chitin, high protein (~ 40 percent) and lipids (~40 percent) ingredients produced by grinding of the larvae of the tropical darkling beetle (Zophobas morio).
 
The results of our 12-week feeding trial with rainbow trout indicated that, overall, the nutritive value of SWM was rather comparable to that of other ingredients commonly used in salmonid fish feeds (corn gluten meal, poultry by-products meal, soybean meal, etc.). While we were able to obtain good performance with levels up to about 15 percent of SWM, the high content in saturated fatty acids and the limiting levels of lysine, histidine and valine appear to limit the potential of this ingredients to be incorporated at high levels in salmonid fish feeds.  Moreover, the cost of this type of ingredient is still very high and generally not truly competitive with that of other common fish feed ingredients, including fishmeal.

Insects as a feed ingredient for food and feed sources may sound really good but so far, from my perspective, from nutritional and economical perspectives we are coming a bit short. So, to try to answer my initial questions:

1. Yes, insects are nutritious but may be not the 'super food' many assume them to be. 
2. If we simply base ourselves on the 'economics', insect farming still appears to have a way to go before becoming a highly efficient 'food and feed production' activity.

In my opinion, insect production makes sense if they are used to convert very low value resources (crop residues, refuses from agro-industrial process, manure, etc) that cannot be efficiently or safely used as feed resources. In a recent paper, Lundy and Parella (2015) indicated the same thing: “identifying regionally scalable waste substrates of sufficient quality to produce crickets that have no direct competition from existing protein production systems might be the most promising path for producing crickets economically, with minimal ecological impact, and at a scale of relevance to the global protein supply.”

Image: John Flannery

Insects cannot make proteins and amino acids out of elemental N sources like primary producers (plant and algae) can. There is always a certain inefficiency of conversion when an animal feeds and metabolises nutrients.

Commercial aquaculture feeds are now composed mixtures of common plant commodities or co-products (grains, oilseed meals, grain milling by-products, etc) representing now 80-90 percent of the weight of the finished feed. I would not bet against soybean, corn, rapeseed, sunflower, rice and potato production as a means of ensuring global food security, and feeding of the aquaculture feed industry for years to come.

Agree or disagree? Let me know. dbureau@uoguelph.ca
 
Cited Reference:
Mark E. Lundy and Michael P. Parrella. 2015. Crickets Are Not a Free Lunch: Protein Capture from Scalable Organic Side-Streams via High-Density Populations of Acheta domesticus. PLOS ONE | DOI:10.1371/journal.pone.0118785.


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