Scottish farm operations manager Alistair McBain NSch 2023 has published his Nuffield Farming report 'From Beans to Bugs – Alternative Proteins to Drive Net Zero Egg Production', sponsored by The MacRobert Trust.

The full report is now available on the Nuffield Farming report library. Alistair's report video can be found on the Nuffield Farming YouTube channel and a recording of him presenting at the Nuffield Farming Conference can be found here.

During his Scholarship, Alistair travelled to Canada, the USA, Brazil, Argentina, the United Kingdom, Sweden, the Netherlands, and Germany.

In his report, Alistair said: "Soya in laying hen diets accounts for around 60% of the total carbon footprint (CFP) of an egg, so reducing or removing soya from diets will have a significant effect on reducing carbon emissions."

During his Scholarship, Alistair reviewed alternative protein sources to drive egg production towards net zero emissions.

Alistair noted that grain legumes, particularly faba beans, are of interest in the UK as a home-grown source of protein, with recent breeding advancements in breeding creating low vicine varieties. "Anti-nutritional compounds have limited the use of faba bean in laying diets up until now due to effects on performance and mortality. Further investment is needed to breed varieties with increased yields of protein, disease resistance and early maturity."

He also explored the use of industry by-products, including DDGS from bioethanol production and processed animal proteins: "One of the main problems with the use of by-products is their variability in nutritional value. Constant monitoring is required to correctly formulate diets to meet the nutritional requirements of laying hens.

"Novel protein sources such as insect protein fed on low-grade food waste, and single-cell proteins grown on captured CO₂ from industrial processes have great potential in providing protein sources with a negative carbon footprint, vital for offsetting unavoidable emissions on the road to net zero."

Alistair concluded that currently none of the alternative protein sources studied are a complete replacement for soya: "A combination of alternative protein sources is required to significantly reduce or replace soya completely, resulting in an increase in the cost of the diet.

"Support is required to cover the cost of using alternative proteins either through investment in finding solutions to reduce the cost of production of the alternatives, i.e. plant breeding or scaling insect protein production, or increasing the price paid to egg producers, potentially through differentiated egg brands," concluded Alistair.

Study objectives

• Assess the nutritional profile of alternative protein sources to determine their suitability for feeding to laying hens.
• Assess the carbon footprint of each alternative protein, to assess its suitability to drive egg production towards net zero carbon emissions.

Key messages

1. Soya in layer diets currently contributes to around 60% of the carbon footprint of an egg. Using alternative proteins has the potential to significantly reduce the carbon footprint.
2. No single alternative protein source can be considered a direct replacement for soya. A combination of protein sources and in many cases the addition of synthetic amino acids are required to produce a diet with the correct nutritional profile.
3. Constant analysis is required to assess the variability in the nutritional quality of many alternatives, particularly industry by-products.
4. Development in novel protein sources such as insect protein and single-cell proteins have the most potential for reducing the carbon footprint.