by Martin Zorrilla, Head of R&D, Nutrition Technologies, UK


Insects can be a feed ingredient. Over the past decade this statement has gone from fringe proposal to a widely accepted fact. While research on six-legged feed has been around since the early 1980s, recent academic papers and signs of rapid private sector progress has popularised the concept.

However, the focal point of this progress has been narrow, with insects seen mostly as a pure fishmeal replacement, rather than a novel ingredient in their own right, with a range of functional benefits. There is of course a good reason for this. Fishmeal prices have been on an upward trend for the past couple of decades, and currently the market is experiencing extreme volatility and uncertainty. This alone has been enough for many to dedicate time and resources to alternative proteins.

However, a huge area of application that is often overlooked is the potential impact on animal health and performance for swine and poultry, as well as fish and crustaceans.

Insects, such as the Black Soldier Fly Larvae (BSFL), have a well-balanced amino acid profile which is capable of replacing fishmeal in carnivorous fish diets with far greater success than plant proteins. For example, in 2011, Sealey et al. found that BSFL meal can successfully replace up to 50 percent of the fishmeal in Rainbow trout diets.

However, focusing on the amino acid profile of insects understates the novelty of the innovation on our threshold. While traditional insect cultivation dates back 3,200 years, it is only in the past decade that high volume production has coincided with serious research on the effects of diets containing insectmeal.

This is despite the fact that insects make up the natural diet of so many of our livestock and aquaculture species in the wild. In effect, when we add insects to animal feed we are re-introducing our domesticated animals to their historical food sources. If we swap out fishmeal for insectmeal in poultry feed we are not "replacing fishmeal", we are doing away with an insect-replacement and using the real thing.















Unsurprisingly, natural diets make for healthy animals. Recent research on the functional benefits of insect-based feed have confirmed that significant impacts can be had for pig and poultry gut health, growth performance, and disease resistance. In 2015, Park et al. discovered a novel Antimicrobial Peptide (AMP) in the BSFL gut that inhibits a range of bacteria. Follow-up studies have confirmed that these AMPs can inhibit E. coli, S. aureus, and even fungi such as the plant pathogen Rhizoctonia solani. In a 2016 review Jozefiak and coauthors were very positive about the implications: "Insect antimicrobial peptides provide great hope due to the increasing global problem of bacterial resistance to antibiotics."

In addition to AMPs, Black Soldier Fly Larvae are rich in another antimicrobial compound: Medium-Chain Fatty Acids (MCFAs). MCFAs have garnered attention in the swine and poultry sectors for their ability to disrupt bacterial membranes, but high MCFA fractions are rare in vegetable oils.

The BSFL oil we produce at Nutrition Technologies is over 40 percent lauric acid (C-12), a well-studied MCFA. This makes it ideal for gut health in pre-starter and starter piglet diets. Even our full-fat BSFL meal contains a MCFA level high enough to reduce pathogens such as D-streptococci in weaned piglets, as reported by Spranghers et al. 2017.

The health impacts of insect meal on aquaculture species are understudied, yet early results are exciting. An industry study on Whiteleg Shrimp (L. vannamei) described a challenge test with the pathogen (Vibrio parahemolyticus) and found a 33 percent higher survival rate among shrimp fed mealworm protein. As Vibrio causes the devastating Early Mortality Syndrome (EMS) the implications for this result, particularly in South East Asia, are significant. At Nutrition Technologies we are conducting Australian government-funded trials in collaboration with Curtin University to study the immune modulatory effect of BSFL meal on Whiteleg Shrimp and Marron (Cherax cainii), results are to be released by July of this year.

In poultry, insect meal will do more than improve gut health. Several recent studies on laying hens have found gains in productivity, even when diets are formulated to replace fishmeal. In 2012 a paper by Park et al. found that including BSFL meal in layer diets increased egg performance, shell thickness and egg weight. The same year Secci et al. found that BSFL meal decreased cholesterol in eggs by 11 percent. One report by Dr Aidan Leek, 2015, even found that feeding live BSFL to chickens can be used to control outbreaks of pecking, due to the behavioral response of poultry to live insects.

Despite these promising results, it is important to remember that as an industry, our understanding of insectmeal is in its infancy. We are still learning, for example, what effect the insect shell biopolymer, chitin, has on digestibility. Another area of active research is how the insect diet can be modified to optimise the fatty acid composition of BSFL meal.

The pace of research has certainly increased.More academic reports on BSFL in aquaculture were published in 2017 than in the previous 11 years combined. Yet even if our understanding of insect based feed significantly advances in coming years, it will only be for the handful of species that are currently used in commercial production (there are over 1 million described insects species on earth).

As insect producers, the vastness of what we still do not know can be overwhelming, just as the scope of what is possible is exhilarating. As insectmeal becomes widely available, understanding its use and context will be key to achieving meaningful change in the animal feed industry.

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