The effect of storage of cereal grain and enzyme supplementation on measurements of AME and broiler chick performance

There is a concern that feeding newly harvested cereal grain results in poo r performance in poultry. A broiler chick apparent metabolizable energy (AM E) bioassay was used to measure changes in feeding value of wheat (n = 14), hulless (n = 10) and hulled (n = 14) barley with or without a commercial e nzyme appropriate for wheat- or barley-based diets. In the broiler chick bi oassay, four pens of six male broiler chicks were fed ad lib, from 4 to 17 d, diets containing 80% of a test cereal grain and a high-protein basal mix ture containing 1% "celite" as an acid-insoluble ash marker, Each of the ce real-grain-based diets, with or without enzyme, was tested within 3 mo of h arvest and again 6 mo later. With cereal grain storage there were consistent (P <0.05) increases in feed intake (FI) between 4 and 17 d and body weight (BW) at 17 d of age with wh eat-based diets fed with (12.5 and 16.9%, respectively, for FI and BW) or w ithout (16.1 and 22.7%) enzyme. In hulless barley diets without enzyme, the re was a significant improvement in BW (7.5%) with storage, while storage h ad a significant effect on FI and BW (2.9 and 6.3%, respectively) when fed with enzyme. For all other barley diets there was a positive effect of stor age on FI and BW, but it was not significant. Feed conversion ratios decrea sed marginally (P >0.05) with storage of cereal grain. AME of diets was imp roved within each period by enzyme supplementation. However, there were mea surable decreases (P <0.05) in AME with storage of cereal grains for the th ree cereal grains with enzyme supplementation (ranging from -3.2 to -8.2%). The r(2) of the above measurements for the different sources of cereal gra in between storage periods ranged from 0.65 to 0.94, indicating that the re lative ranking of the cereal grains, with respect to feeding value, remaine d similar during storage. Increases in FI with storage were not significant ly related to the attempts of the broiler chicks, to maintain metabolizable energy (ME) intake. Therefore, this increases our concerns that "factors" in newly harvested cereal grains may exist and that they may limit voluntar y feed intake and/or growth.