A comparison of the energy availability for chickens of ground and whole grain samples of two wheat varieties.

1. The objective of this study was to examine whether the energy availabilities of two wheat samples, which differed in endosperm hardness, were changed when they were fed ground or as whole grains to chickens. Wheat samples of a variety Haven (hard endosperm) and a variety Riband (soft endosperm), both harvested in 1993 from the same growing site, were used in the experiment. 2. True metabolisable energy (TMEn) was measured in a flock of 24 adult cockerels and the mean of all the samples was 14.68 MJ/kg dry matter (DM). The TMEn of ground wheat was 0.306 MJ/kg DM greater (P < 0.05) than whole grain. There was no significant difference (P > 0.05) in TMEn between the Riband and Haven wheat samples and there were no (P > 0.05) variety x wheat form interactions. 3. The apparent metabolisable energy (AMEn) of the wheat samples was determined with 96 broiler chickens from 19 to 27 d of age. Different amounts of either whole or ground wheat samples were added to a basal diet. Extrapolation of the regression lines indicated AMEn concentrations (MJ/kg DM) of ground Haven 14.33, whole Haven 14.28 ground Riband 14.33 and whole Riband 14.51. There was no evidence (P > 0.05) that whole grain wheat had a different AMEn than ground wheat. 4. A feeding trial used 192 broiler chickens in 48 cages from 24 to 42 d of age. They were fed on a broiler grower diet either mixed with ground wheat before pelleting or with the pelleted grower diet loosely mixed with the whole wheat. There were no differences (P > 0.05) between the 2 wheat varieties or the diet form in growth rates or food conversion ratios. The growth rates of the broilers given a conventional grower and finisher dietary regimen tended (P > 0.05) to be slightly greater than the broilers given the wheat-diluted diets.