UK pulses can play huge part in solving poultry’s emission issues
Increasing the rate at which pulses are included in poultry rations can play a huge role in reducing the sector’s greenhouse gas emissions, new UK research has shown.
Imported soya in both broiler and layer feed is the single greatest contributing factor to the industry’s CO₂ figures.
But work carried out over the past 18 months by partners of The Nitrogen Climate Smart (NCS) Project has shown that processed beans can be fed to birds at higher rates than previously thought.
Small-scale studies at SRUC in Scotland, and commercial trials run by feed company ABN have both concluded there is more room for beans.
The Andersons Centre calculates that if UK pulses made up 30% of poultry rations in the future, it would result in a saving of one million tonnes of carbon.
The work was presented at the cross-industry From Soya to Sustainability conference in Peterborough in January.
Meaningful progress
Monogastric expert Professor Jos Houdijk from SRUC and ABN’s Senior Poultry Nutritionist, Brian Kenyon, provided updates on trials conducted as part of workstream four in the NCS project, which looks at how beans can be incorporated more into monogastric or specifically, poultry diets.
Professor Houdijk outlined feeding trials showing that post-harvest processing of beans can overcome previous limitations associated with higher bean inclusion in poultry rations.
Part of the work focused on layers, as earlier research suggested that 5–10% inclusion of whole beans could be achieved without compromising performance.
“Our question was: if we process the beans, can we increase that? Because if, through processing, we increase the nutritional value of the faba bean, we should, in theory, be able to replace more soybean,” Prof Houdijk says.
“When we feed more beans to poultry, we get a dent in production efficiency because the animal can’t digest it,” Prof Houdijk reveals. “But when we de-hull or de-hull and toast beans, that dent is taken away.
“This work tells us that, both in broilers and in laying hens, processing beans helps us increase the soya replacement potential of faba beans.”
The trial diets included whole beans, de-hulled beans, and de-hulled and toasted beans, fed at inclusion rates of 10%, 20% and 30%.
“From a purely pragmatic point of view, the biggest win came from the de-hulling,” Prof Houdijk says. “Whether toasting provides significant extra benefits is something to be discussed further, although the data currently suggests the extra benefit is probably relatively small.”
One interesting observation was that feeding poultry faba beans resulted in darker yolks, particularly when they were toasted.
“Consumers like darker yolks, so it may well be that these eggs could demand higher prices,” he adds.
Broilers and layers
ABN’s Senior Poultry Nutritionist, Brian Kenyon, has extrapolated this work into commercial broiler and laying flocks.
“We’re getting more confident in using beans to feed poultry and livestock. It’s not unusual to use it in a diet, but what we’re doing is increasing the level. Even boosting inclusion from 5% to 10% of the poultry diet is going to have a significant impact on the carbon emissions from UK agriculture.”
The broiler trial achieved an average 27% reduction in soya content and a 14% reduction in carbon emissions with a 10% pulse inclusion. The layer trial, despite some challenges, reached a 7.5% pulse inclusion and delivered a 24–26% reduction in soya content.
Further work using de-hulled beans in a free-range egg flock, compared with a control flock fed a conventional soya-based ration, has also produced positive outcomes.
“There has been no real impact on egg size from introducing beans into the ration, and everything is looking good,” he says.
A large-scale trial involving 80,000 broilers fed de-hulled beans is ongoing, with early results indicating a 20% reduction in soya use and an 11% reduction in carbon emissions.
“We’ve also got on the ground a series of broiler trials looking at an extruded bean and OSR product. So, instead of 50/50, we’re pushing the pulse content to 90/10, so really pushing the pulse component part of the diet.”
Achievable targets
The conference heard how a combination of science, applied research, farmer-led trials and growing supply chain engagement is creating the right conditions for a major shift towards domestic pulse production.
Notable progress has been made in key areas of the supply chain where, previously, doubts had been cast on whether unsustainable proteins, such as uncertified South American soya, could ever be replaced.
This work forms part of the Nitrogen Efficient Plants for Climate Smart Arable Cropping Systems Project, a four-year, £5.9M research programme involving 200 UK farms and 17 partner organisations. The project aims to deliver a reduction of 3.4Mt CO₂e per year by increasing pulse and legume crops to 20% of arable rotations across the UK and replacing 50% of imported soya meal in livestock rations with home-grown legumes.