Defining the effects of wheat type, water inclusion level, and wet-diet restriction on variability in performance of broilers fed wheat-based diets with added water

The objectives of the study were to determine if feed conversion ratio (FCR) in broilers fed wet Hard Red Spring (HRS) as compared to Durum-based wheat diets could be reduced by: (a) diluting HRS with Durum wheat, (b) pelleting of the wheat, (c) adding different levels of water to the diet, or (d) restricting intake of diets to which water was added. Three wheat types [Durum, HRS and a Composite (50:50) sample] were ground, with one portion of the ground grain being pelleted and reground before both forms of each wheat type were included at 80% of a basal broiler diet. All diets were supplemented with a commercial wheat enzyme and fed as a mash. Each of the six diets was fed in one of four feed regimens: DRY (as is); WET1.2 (DRY with 1.2 g water g^-1 feed); WET0.6 (DRY with 0.6 g water g^-1 feed); and RWET1.2 [WET1.2 diet treatment restricted-fed to 120% of the previous dayʹs DRY feed intake (on an air-dried basis) for each diet type]. This provided 24 dietary treatments each fed to six cages of five male broilers from I to 2 Id of age. The wet diets were prepared daily. Among the feed regimens WET1.2 resulted in the significantly highest 21-d body weight. The significant increase in feed intake and FCR of HRS-based diets with added water was reduced significantly by diluting this wheat with Durum wheat. Feeding the unpelleted Composite wheat sample significantly improved growth rate over either wheat alone, presumably due to an improved balance of nutrients. Pelleting significantly reduced intake of wet HRS-based diets and increased apparent metabolisable energy (AME), resulting in a marked reduction in FCR compared to unpelleted diets. There was some value in using less water in HRS-based, but not in Durum-based diets, with respect to FCR and metabolisable energy retention. Physical restrictions of feed intake reduced FCR of wet (WET1.2) unpelleted HRS diets, but did not affect the same diet when wheat was pelleted. Further work is required to establish the optimum consistency of feed in a wet form to maximize feed intake and growth while minimizing FCR.