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Reduction in diffuse pollution of poultry operations through selection of wheat cultivars of high and consistent nutritional quality. - LK0980

Reduction in diffuse pollution of poultry operations through selection of wheat cultivars of high and consistent nutritional quality.

The UK poultry industry produces 100,000 tonnes of Nitrogen and 90,000 tonnes of phosphate per year. A 3 percentage unit improvement in diet digestibility would reduce this amount by 7000 tonnes of Nitrogen and 6000 tonnes of phosphate. This equates to a reduced land requirement of 28000 hectares for Nitrogen disposal (assumes maximum Nitrogen application of 250 Kg total N per ha.). Associated with this is the production of ammonia-N by the poultry sector amounting to some 43.7 kT per annum. Therefore, improved nutritional value of wheat will, by definition, lead to reduced excreta output and lowered environmental impact.
Wheat quality, or more specifically its metabolisable energy (ME) value and starch digestibility, is far from constant, and has been reported to vary by as much as 5MJ/kg (from 10 to 15MJ ME/kg) for poultry. This variation is unacceptable and is transferred into variation in bird performance, increasing the proportion of birds that fall outside the weight range that attracts a premium price, the net result of which is a reduction in profitability. Such variability mitigates against the continued use of high levels of wheat in UK broiler diets and the feed industry is actively seeking alternative, more reliable raw materials.
Reasons for this variation are unclear but are thought to include differences in the concentration of soluble and insoluble non-starch polysaccharides -NSPs (viscosity and nutrient dilution respectively), resistant starches, enzyme inhibitors, variation in endogenous enzyme concentrations and, of course, variation in the chemical composition of wheat. The development of near-isogenic lines (or, at least, the use of samples of known genetic background) has allowed for significant advances to be made in this subject. A second characteristic is endosperm texture, and it has been established that soft wheats tend to be of better nutritional value than hard counterparts. However it is crucial to appreciate that endosperm texture exists as a continuum between very hard and very soft, not simply hard or soft as has been assumed. This ‘proof of principle’ of relating endosperm texture to nutritional value will inform future developments in providing definitive answers to the quantitative effects of endosperm texture by using wheat lines of precisely defined genetic constitution varying from ‘soft-softs’ to ‘hard-hards’. Advanced breeding lines will be assessed in parallel with the defined genetic stocks in order to ascertain the current level of variation available in UK sourced wheat varieties.
The programme plans to integrate plant breeding initiatives in the generation of cultivars that will be evaluated through a umber of in vitro and in vivo approaches; the latter will be based on digestibility leading to assessments of bird performance / health (and, indirectly, the safety of the product for the human consumer), and nutrient output (hence environmental impact). The former will include a range of physico-chemical measurements (tests adapted from the human food industry, viscosity, concentration of xylanase inhibitors), and will have the objective of screening cultivars for subsequent in vivo assessment and will lead to rapid measurements of wheat quality of value to all relevant sectors of the agricultural industry (feed conmpounders, end users, breeders).
Sustainable Arable LINK lists, as one of its priorities ‘Biotechnology, breeding and agronomy for specific end-users’ and the programme intends to develop plant breeding solutions to the problem of variability in nutritional quality of wheat. The result will be to assure a market for UK feed wheat, to improve sustainability of the arable sector and reduce diffuse pollution associated with wastes arising from the UK poultry sector.
Project Documents
• ABS - Abstract : LINK 0980 Final Report Abstract   (20k)
Time-Scale and Cost
From: 2006

To: 2009

Cost: £503,119
Contractor / Funded Organisations
Grampian Country Foods, Bernard Matthews Foods Ltd, John Innes Centre (BBSRC), University - Nottingham, University - Scottish Agricultural College, BOCM Pauls Ltd, Danisco Animal Nutrition, Nickerson UK Ltd, Home Grown Cereals Authority
Arable Farming              
Sustainable Production              
Wheat Production