Rapeseed cake as a soybean meal substitute in Acheta domesticus diets: productive performance, body composition and economic efficiency under two amino acid supplementation strategies
This study demonstrates that rapeseed cake is a viable, cost-effective substitute for soybean meal in *Acheta domesticus* diets, as high inclusion levels (80%) actually improve growth and survival when synthetic amino acid supplementation is removed.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
The global food system is under pressure to feed a growing population while reducing the environmental toll of traditional farming. In this search for sustainable solutions, edible insects have emerged as a promising alternative. Among them, the house cricket is gaining attention in Western markets for its high protein content and ability to be raised on a large scale. However, raising these insects commercially faces a significant hurdle: the cost of feed. Most cricket farms currently rely on commercial poultry feed, which uses soybean meal as its primary protein source. This ingredient is expensive and competes directly with food for humans and other livestock. To make cricket farming more viable, researchers are looking for cheaper, locally available alternatives. One such candidate is rapeseed cake, a byproduct of making biodiesel that is rich in protein and abundant in Europe. Yet, a lingering question remains. Commercial poultry feeds are often fortified with synthetic amino acids, the building blocks of protein, to ensure chickens grow quickly. Cricket farmers have simply copied this practice, assuming crickets need the same boost. But no one has ever tested whether crickets actually require these extra supplements, or if they can thrive on a simpler diet made from basic ingredients.
A recent study set out to answer this question by testing how crickets perform on diets where soybean meal is partially replaced by rapeseed cake, with and without the addition of synthetic amino acids. The researchers raised thousands of crickets over a period of thirty-five days, feeding them six different types of food. These diets ranged from a standard control mix to ones where half or even eighty percent of the soybean meal was swapped out for rapeseed cake. Half of these groups received the extra synthetic amino acids, while the other half did not. The goal was to see if the crickets could grow just as well, or perhaps even better, without the expensive additives, especially when the diet relied heavily on the rapeseed byproduct.
The results were surprising and clear. The addition of synthetic amino acids made no difference to the crickets' growth or survival when the diet contained mostly soybean meal. However, when the diet was heavily loaded with rapeseed cake, the story changed completely. In the groups fed eighty percent rapeseed cake, the crickets that received the synthetic amino supplements actually performed worse. They ate less food, grew less, and had a lower survival rate compared to their neighbors who ate the same rapeseed-heavy diet but received no supplements at all. The crickets on the unsupplemented, eighty percent rapeseed diet were the most successful of all. They ate the most food, gained the most weight, and had the highest survival rate, with nearly ninety percent of them living to the end of the experiment. They also developed into adults faster than the crickets on any other diet.
This finding suggests that the common practice of adding synthetic amino acids to cricket feed is unnecessary and can even be harmful when using certain plant-based ingredients. The researchers found that the base ingredients—soybean meal, rapeseed cake, and grains—already provided enough of the necessary nutrients for the crickets to thrive. In fact, the crickets on the high-rapeseed diet seemed to compensate for the lower protein content by eating more, a natural behavior that allowed them to reach their full potential without artificial help. The study also revealed that the crickets on the rapeseed diets ended up with higher body fat levels, not because the rapeseed itself was fatty, but because the overall balance of protein and carbohydrates in the food changed. This shift in body composition is a natural result of the diet's structure rather than a flaw in the ingredient.
From an economic perspective, the study showed that removing the unnecessary amino acid supplements could lower production costs, particularly when using high levels of rapeseed cake. The cost to produce a kilogram of cricket biomass was lowest for the diets that balanced rapeseed inclusion with the removal of synthetic additives. While the price of the feed itself varied, the efficiency of the crickets in converting that feed into body mass was the deciding factor. The most productive group, the ones on the eighty percent rapeseed diet without supplements, turned out to be the most efficient, proving that a simpler, locally sourced feeding strategy can outperform the complex, fortified formulas currently in use.
Ultimately, this research challenges the assumption that insect farming must mimic poultry farming to be successful. It demonstrates that crickets have their own nutritional needs that are met by a diverse mix of plant proteins and grains, without the need for expensive chemical fortification. By switching to locally available byproducts like rapeseed cake and stripping away the redundant supplements, farmers can create a more sustainable and cost-effective system. The study confirms that the house cricket does not need the same dietary boost as a chicken; it simply needs a balanced diet that respects its unique biology. This insight offers a clear path forward for the industry, suggesting that the future of sustainable insect protein lies in simplifying the feed, not complicating it.
Drowning in papers in your field?
Get daily digests of the most novel papers matching your research keywords — with technical summaries, in your language.