Naked oats: metabolisable energy yield from a range of varieties in broilers, cockerels and turkeys

Abstract

1. Naked oats belong to the same species as ‘common oats’, Avena sativa, but have a non-lignified husk which readily becomes detached during harvesting. The absence of the indigestible husk can be predicted to give an increased metabolisable energy (ME) content for poultry.

2. Measurements of true metabolisable energy (TME_N) were performed on 3-week-old broiler chicks (Cobb males), adult cockerels (ISA Brown, greater than one year old) and 7-week-old turkeys (BUT T8 males). The measurements were repeated in 2000, 2001 and 2002, with some measurements on a subset of varieties in 2004.

3. High-oil naked oat lines yielded 12% more energy (TME_N) than wheat. Naked oats, excluding the experimental high-oil lines, yielded 8·5% more energy than simultaneously assayed wheat samples.

4. In samples from the 2004 harvest, conventional oats gave TME_N values about 13% lower than those of wheat.

5. The addition of β-glucanase produced an increase of about 4% in the apparent metabolisable energy (AME) of oats for broiler chickens. This effect was associated with a 70% decrease in the jejunal viscosity of broilers receiving a 500 g/kg naked-oat diet.

6. The oil content of naked oats was about 5 times greater than that of wheat, with the high-oil lines rising to more than 6 times greater. Naked oats had a lower starch content than wheat but not sufficiently lower to negate the energy benefits of the higher oil content. The crude protein (CP) contents of naked oats were similar to those of wheat, with the high-oil varieties tending to be higher in CP also.

Acknowledgements

This work was supported by DEFRA as part of the AFENO Project. The authors gratefully acknowledge discussion with partners in the project: Cark Maunsell (Oat Services); Cliff Nixey (British United Turkeys Ltd); Chris Green (Senova [formerly SWSeed] Ltd); Richard Mason (GB Seeds Ltd); Anthony Waller (Bernard Matthews Ltd); John Reed (Sun Valley Ltd); Peter Woodward and Stewart Easdon (formerly of Sun Valley Ltd). Caroline McCorquodale, Roslin Institute, is acknowledged for advice on and assistance with statistical analysis.