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


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

Dr Helen Masey O’Neil and Prof Julian Wiseman

School of Biosciences, University of Nottingham, Sutton Bonington Campus LE12 5RD

June 2013


The objectives of the project were to characterise precisely defined genetic stocks of wheat for nutritional value so that it can be predicted accurately, leading to reduced variability in broiler performance and greater confidence in the use of this raw material. Such improvements in bird performance would also reduce diffuse pollution associated with poor-quality diets fed to poultry.

Wheats can be classified as either hard or soft, depending on their milling properties, although gradations of ‘hard’ and ‘soft’ exist and, as such, a discrete numeric classification should be used. A range of wheats were bred for nutritional and physico-chemical analysis based on the cultivar crosses ‘BS’; Beaver (soft) x Soissons (hard) and ‘RIL’; Avalon (hard) x Hobbit (soft). There is much genetic variation possible within the classifications ‘hard’ and ‘soft’ and there are also seasonal and environmental effects. Plant breeders can adjust texture using marker assisted selection or phenotypic selection.

Subsequent nutritional assessment showed that there is a significant correlation between total pentosan content of the wheat and Avicheck viscosity (an in vitro assessment used to predict the nutritional value of wheat for poultry and how wheats will respond positively to the addition of exogenous dietary enzymes). With 2007 wheats, there was a significant effect of wheat on Apparent Metabolisable Energy (AME). When wheats were grouped into hard or soft categories ‘hard’ wheats had increased AME and Dry Matter Digestibility (DMD). However with 2008 samples, feed conversion ratio (FCR) improved with diets containing ‘soft’ wheats. A non-linear effect of hardness on Coefficient of Apparent Digestibility (CAD) of starch in BS was obtained; hardness 34 and 73 having the lowest ileal digestibility compared to 41 and 63. No other significant effects on nutritional parameters were found.

There appears to be no relationship between hardness and pasting potential when measured using Rapid Visco-Analysis (RVA). Viscosities appeared to be higher and more consistent in 2007 than 2008. This could suggest that there was less amylase damage in 2007, supporting the conclusion of breeding work. The RVA could predict nutritional quality, and specifically nitrogen (N) retention, of wheat for poultry.

As N retention is inversely correlated with diffuse pollution potential, this development is of considerable importance to the overall project objectives. At this stage, it is not possible to quantify changes in diffuse pollution. Further studies, to involve both the poultry sector but also the feed industry (in formulating more accurate diets), would be necessary in generating further data to confirm the ability of RVA as a predictor of diffuse pollution.

HGCA Project Number: 3180 

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