Interaction of Dietary Coarse Corn with Litter Conditions on Broiler Live Performance and Gastrointestinal Tract Function

The successful application of whole wheat in the EU indicated that dietary structural material, such as coarsely ground corn (CC), could be included in US broiler diets to improve live performance. The main objective of this study was to evaluate the effects of broiler feed structure and litter conditions on broiler live performance, nutrient digestibility, and gastrointestinal tract (GIT) development and function in different scenarios. It was hypothesized that dietary CC inclusion and new litter condition may significantly improve broiler live performance and nutrient digestibility, as well as influence the functional development and motility of the broiler GIT. We also hypothesized that dietary CC would decrease feed cost and litter nitrogen, moisture, and ammonia emission. Our objective was to understand and quantify the effects of dietary structural material inclusion and litter management on broiler live performance and development of different GIT sections by measuring the relevant physical, morphological, and histological parameters of the GIT during broiler feeding trials.;Therefore, the focus of this dissertation was: 1) to study the impact of corn particle size distribution with litter conditions on broiler live performance and nutrient digestibility; 2) to investigate the influence of corn particle size distribution and litter condition on broiler GIT development and function by measuring the relevant physical, morphological, and histological parameters; 3) to investigate the effects of corn particle size distribution on broiler litter nitrogen, moisture, and ammonia emission; and 4) to quantify and develop a feeding regime of dietary corn particle size distribution that decreased feed cost while optimizing broiler live performance and GIT development and function.;The dissertation research carried out 2 cages studies, 4 floor studies, and 1 grinding cost analysis study. Experiment 1 evaluated the effects of six dietary CC inclusion levels in two feed form on broiler live performance, BW uniformity, relative gizzard weight, fecal nitrogen, and particle size preference behaviors of broiler raised in cages from 0 to 14 d of age. Experiment 2 and 3 investigated the effects of gender, litter conditions, and dietary CC inclusion on live performance, gizzard and proventriculus development, litter characteristics, and colon bacterial profiles of broiler raised on a litter-covered floor from 0 to 49 d of age. Experiment 4 was a 45 d cage study that investigated the effects of three dietary CC inclusions on broiler live performance, GIT development, apparent ileal digestibility (AID) of energy and nitrogen, jejunum digesta particle size distribution, and feed retention time. Experiment 5 evaluated the effects of two dietary CC inclusions and two litter conditions on broiler live performance, litter characteristics, GIT development, apparent ileal digestibility of energy and nitrogen, and intestinal morphology. Experiment 6 investigated the effects of two dietary CC inclusion and three different floor types on broiler live performance, litter characteristics, GIT development, apparent ileal digestibility of energy and nitrogen, intestinal morphology, and ammonia emission. Corn grinding cost by hammermill and roller mill was also compared.;In conclusion, dietary CC inclusion decreased feed cost, improved nitrogen and energy digestibility, altered GIT bacterial population, improved feed efficiency, and reduced litter ammonia emission through the modulation of GIT function as evidenced by increased gizzard weight, greater digesta retention time, decreased digesta pH, modified intestinal morphology structure, and decreased litter moisture and nitrogen. We also found that the effects of dietary CC inclusion could confound pellet quality, while new litter had only a marginal benefit on broiler live performance. Particle size distribution was found to be more important than the geometric mean diameter by mass (dgw) with regard to the paradoxical role of particle size on poultry feed manufacturing and nutrition.