Imports of soya for animal feed in the UK and Europe could be replaced by home grown lupins, which would reduce costs, cut carbon emissions and even save rainforest. Sweet (edible) lupins are high in protein and, like other legumes such as peas and beans, they are capable of fixing nitrogen, meaning less fertiliser inputs.
A three-year project involving the UK universities of Aberystwyth and Leeds, together with 10 industry partners, concluded that yellow and blue lupins can provide animal feed comparable to that from soya for lambs, poultry and fish, says Liz Humphreys, project coordinator at Aberystwyth.
In South America, almost 4m ha of forests are destroyed every year, blamed largely on soya-dependent livestock farming, according to the charity WWF. Rocketing demand for meat from animals fed with soya means global production has increased 10-fold over the past 50 years, more than any other crop
‘Demand for soya is leading to land use conversion. The most efficient way to get carbon into the atmosphere is to chop down rainforests to cultivate soya,’ warns food security expert Tim Benton at Leeds. ‘Lupin looks like it could be a plan B. It gives good yields, grows locally and has high protein.’
The project showed that modern varieties of lupin are earlier maturing and give more reliable yields. And lupin could be grown on most livestock farms in the UK. Depending on the variety, the researchers say a digestible feed of between 28% and 42% protein can be made.
‘It will cost in the region of £100 per acre to grow lupins and a conservative estimate is 1t/acre, though 2t can be achieved. Soya’s price can fluctuate between £300 and £400/t,’ says Andy Strzelecki at UK ag services company Kelvin Cave.
‘The biggest thing is to persuade farmers to grow them. We only grow perhaps 4000ha in the UK and we’d need to increase that substantially for a feed mill to take it on,’ says Humphreys. ‘If, say, a big supermarket decided it wanted home grown feed to reduce imported soya in its food chain, that would create demand.’
Lupin can be harvested in August, at 25–30% moisture content, with a conventional combine; crimping machines crush the grains and apply a preservative. ‘A big advantage for livestock farmers is that they can then silage the crop, which avoids the need for specialist grain storage,’ says Strzelecki.
Birchgrove Eggs in Wales estimates that lupins would potentially save the organisation about £4000/year on feed in its 3000-bird unit, with some improvements such as more ‘redness’ to egg yolk. The trials were also positive for lambs, and there is international evidence to support lupin use in cattle; dairy production in Australia is already based on lupin protein.
On the aquaculture side, lupin performed well in trials for on rainbow trout, tilapia and common carp. Fish oil and fish meal was once the gold standard as aquaculture feed, but it now makes up 10%. ‘We are importing soya bean as a chief alternative to fish meal in Europe,’ says Simon Davies, formerly of Plymouth University, a partner in the project. ‘A good third of the diet can be based on this, which tends to be processed and expensive.’
‘Lupins are the only crop which will match the protein quality of soya. Peas, beans, clovers, lucerne, do not contain enough overall protein,’ adds project partner David McNaughton at Soya UK, and ‘also are lacking in digestibility characteristics and protein quality.’
The project – LUKAA, or Lupins in UK Agriculture and Aquaculture – was funded by Innovate UK and BBSRC.