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What Is The Best Insect to Use for Fish Feed?

Updated: May 9, 2023


best insects for fish feed cover

Currently, in terms of amino acid composition and digestibility of proteins, the black soldier fly larvae meal is the insect meal fulfilling most farmed fish dietary needs. Many studies and feeding trials have concluded that black soldier fly larvae meal has the potential to replace fish meal, being high in protein and containing a good balance of amino acids essential for healthy fish growth. Other insect species, including the mealworm, the silkworm, and the housefly maggot are also used for aquafeed.


Context


We’ve all heard it when we were kids: fish is rich in protein and omega 3, both important to a healthy diet. However, there are only so many fish in our ocean and we’ve already started scraping the bottom of it.


Thankfully, there is an alternative to wild (over)fishing: aquaculture, i.e. fish farming. While aquaculture has been a fast-growing sector in agriculture (the fastest, in fact!), the way the farmed fish are fed constitutes a paradox, to say the least.


Indeed, these farmed fish are fed with fishmeal, a product essentially made from wild fishing, bycatch, and fish by-products. In other words, aquaculture still indirectly supports a fish industry with questionable practices.


To fight and hopefully soon put an end to this paradox, insect companies, including renowned Protix, Ynsect, and Innovafeed have been developing products destined to partially or completely replace fish meal: insect meal.


In this article, we explain what insect meal is, which insects are being considered as inputs for this novel insect meal, and which insect is currently most promising for aquafeed.


The source for this article is a paper published in 2022 by researchers Alfiko, Y., Xie, D., Astuti, R. T., Wong, J., & Wang, L.: "Insects as a feed ingredient for fish culture: Status and trends".


Let's dive in!


fish farm in lake

What is insect meal?


Insect meal is animal feed made of insects. From a nutritional standpoint, insect meal has proven to provide all nutrients, fats and proteins required to farm animals, including poultry, cattle, and fish. As importantly, producing insect meal requires less land and water than traditional animal feed, making it a more sustainable alternative.


For the last two decades, the use of insects to replace fish meals has been increasingly studied, with promising findings. Insect industry actors and researchers are convinced large-scale insect farming can provide a sustainable and profitable alternative to fish meal for aquaculture.


These findings have been confirmed by large-scale insect farms producing and commercializing insects to feed aquaculture species.


4 insect species currently used for aquafeeds.


1. Black soldier fly larvae

black soldier fly larvae

Black soldier fly larvae have been attracting a lot of attention in the past few years, not only for their nutritional properties but also for their ability to contribute to waste valorization. Indeed, black soldier fly larvae are known for their ability to consume all sorts of organic waste, including fruit and vegetable peels, animal manure, and even processed food such as bread, pasta, or rice. In turn, this waste consumption helps them grow into high-protein alternatives to traditional protein sources such as meat.


Given this high potential for sustainable and circular protein supply, researchers have conducted feeding tests to further assess what insect meal made of black soldier fly larvae could contribute to aquaculture.


Feeding tests were conducted with various fish species, including juvenile yellow catfish, Jian carp, rainbow trout, Atlantic salmon, European sea bass and juvenile turbot, amongst other species.


Results from these studies shed light on the potential of black soldier fly larvae meal to replace fish meal partially or completely in aquaculture. However, researchers still call for further trials and economic analyses to further assess the extent to which black soldier fly larvae meal can be beneficial to farmed fish health and growth, and how economically viable the option can be.


Notably, Alfiko et al. (2021) underline those rearing substrates (what is extracted from black soldier fly larvae) may need to be optimized and standardized to maximize both fish growth and the economic benefits of this type of insect meal.


2. Mealworm

mealworms

Along with the black soldier fly larvae, the mealworm is one of the insect species which has attracted the most attention as an alternative protein source, not only for animal consumption but also for human consumption.


In the aquaculture realm, mealworms have been included in feeding trials for fish species including the African catfish, yellow catfish, gilthead sea bream, rainbow trout, Baltic prawns, and European sea bass, with promising results.


Following these promising results, mealworms have been introduced as substitutes for fish meals in some aquaculture farms. While the benefits of mealworm meal for fish growth and health have been proven by several studies, the price per kg still represents a barrier to use in some countries.

Several companies, including mealworm pioneer Ynsect, are working to reduce production costs through scaling, notably.


3. Silkworm pupae


Silkworm pupae

In China and other Asian countries, silkworm pupae meal has been used as aquafeed for the last 4 decades. Several feeding trials have been conducted in the past years on different fish species, including common carp, tilapia, catfish, cyprinids, carnivorous chum salmon, Japanese seabass and other aquaculture species.


Overall, silkworm pupae meal has proved to be a good source of protein to replace at least a part of fish meal in aquaculture. While the benefits of using silkworm pupae meal have been demonstrated, a key challenge is to make them affordable and competitive compared to fish meals.


According to Alfiko et al. (2021), the price of dried silkworm pupa is much higher than fish meal: USD 3500/ton for dry silkworm pupa versus USD 1505/ton for fish meal in June 2021 (global market prices). In addition, other industrial uses – to produce functional foods and nutraceuticals - for the silkworm pupa are currently more profitable than its use in aquafeed.


4. Housefly maggot and housefly pupae

Housefly maggot

The housefly maggot has been used in feeding trials for tilapia, catfish, and swamp eel farming, notably. Currently, results present housefly maggot meal as an interesting alternative to fish meal in aquaculture.


Including housefly maggot meal into fish diets appears to reduce feed costs, boost fish growth and food-conversion ratio (amount of feed required to “x” kilos of fish). However, for some fish species, feeding trials showed housefly maggot meal could not completely replace fish meal, not having the right nutrients to sustain a full fish growth.


This requires further research at this stage!


Wrap up


The insects presented above have a promising future as components for aquafeed. Being protein, fat and calorie-rich, they have an interesting potential to provide farmed fish with the feed required for healthy and sustainable growth.


However, despite these benefits, none of these insects can completely replace fish meal to this day and can only be introduced into feed up to a certain percentage.


Finally, the economics behind the use of insect meal for aquafeed is still being refined, many insect feed companies are working hard to develop farming systems which will enable them to produce insect meal in industrial quantities, at a lower cost for fish farmers worldwide.


To all fish farmers out there


To all fish farmers out there: keep an eye on insect meal as an alternative to fish meal. Depending on the type of fish you're farming, different insect species may constitute healthy and sustainable alternatives to what you're currently feeding your fish.


While, in most cases, using other types of meals is still cheaper, many insect feed companies are working to scale their insect meal productions to commercialize products which are cheaper and make your fish healthier and grow faster.


In sum: stay tuned with the insect industry, it may well help transform your business and profitability for the best!


Source: Alfiko, Y., Xie, D., Astuti, R. T., Wong, J., & Wang, L. (2022). Insects as a feed ingredient for fish culture: Status and trends. Aquaculture and Fisheries, 7(2), 166-178.

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