Tests and trials continue to highlight the promise of insect feeds and the by-products of their production — but also show where a dose of realism is needed, according to speakers at an event hosted by Fera Science.
540,000 tonnes of insect protein is expected to be required by the UK’s pig and poultry sectors by 2050, said Ionie-Lee Smallwood, a senior consultant ADAS, while studies have suggested that 240,000 tonnes of that total could be sourced from insect farms in the UK.
“That’s essentially equivalent to the fifth of the UK’s projected 2050 soy import volumes or in context, the entirety of Tesco’s 2018 soy footprint. It is quite considerable, the potential scale for environmental improvement impacts that insect bioconversion for animal feed can produce,” Smallwood explained.
Better protein for layers?
For poultry farmers that could be interested in producing insects for feed on-site, a recent commercial-scale trial by the company Better Origin, which offers AI-controlled black soldier fly production units in a shipping container, provides considerable food for thought.
The work on a laying hen farm saw an uplift of 13 eggs per bird for those with insects included in their diet, with a 4% increase in body weight and body condition score improvement of 40%, said Ifan Huws from the company.
“Hens naturally roam and eat insects, they don’t eat a vegetarian diet…the uplift in performance is more natural,” Huws noted.
The trial’s results were independently verified by ADAS, and while the hens enjoyed better welfare using the system, the benefits could potentially run right down the supply chain.
Processors can market the sustainability and welfare credentials, and retailers are potentially able to provide food waste back into the system, fuelling the circular economy, he said. Another potential advantage for farmers is that using the system only demands about 10-15 minutes of the day.
From waste to co-product
While alternative protein production is one element to insect bioconversion, the waste produced is another, potentially no-less important aspect, said Professor Rob Lillywhite from the University of Warwick.
With 3.5 tonnes of frass (excrement mixed with uneaten feed and insect exoskeletons) generated for every tonne of insect protein, Europe could be producing 3-5million tonnes by 2030.
“We have to think of frass as a co-product rather than just a waste. Because it is an opportunity and that’s how I want people to see it. Developing a market for frass is arguably as important as developing a market for the protein,” he stressed.
Frass contains valuable plants nutrients, as well as chitin, which has properties which could help crops fight pests. With the price of synthetic nitrogen high and farmers increasingly on the look-out for cost-effective alternatives, Lillywhite’s team have been analysing just how good frass is as a fertiliser.
“Frass generally has between about one and a half and 5% nitrogen. This is way less than a synthetic fertiliser, but probably better than most composites and digestate, and possibly not up to the same value as biosolids. So, it’s a decent material, which we think will have a fertilising value, if we can show that it works,” he said.
Insect feeding substrate is key to the nutrient levels found in frass. Food waste, which is commonly used, tends to be low in nutrients, but with the introduction of more protein in insect diets, this could be improved. How soon that dietary change happens remains an open question.
Crop application choices crucial
In a number of trials both in greenhouses and fields using different crops, the effects of frass as a fertiliser have been promising.
“If you include fresh frass at 10% inclusion rates, you’re actually getting really good plant performance,” Lillywhite said.
There are limitations to its use. As a living substance, frass does have a microbial load and high ammonium content, which means it is not suitable for use in every arable setting.
“Would I add it to a field of newly emerged maize or sugar beet? No, I wouldn’t. Can I put it as a top dressing on to the crop of wheat? Absolutely, I can. So, I think we need to learn to understand how to use it. And I think that’s the phase that we’re in at the moment,” he added.