The role of feed processing and fiber addition on improving the nutrition and growth performance of broilers

Doctor of PhilosophyDepartment of Grain Science and IndustryCharles StarkThree experiments were conducted to study the growth performance, relative gizzard weights, intestinal morphology, and blood serum parameters response of broiler chickens fed crumbled pellets, mash diets, and diets containing increasing levels of wheat bran with or without exogenous enzyme supplementation. In Experiment 1, a common corn-soybean meal (corn-SBM) diet was formulated to meet or exceed the nutritional requirements of Cobb 500 broiler starter, grower, and finisher birds and fed to 900 chicks raised in floor pens. Dietary treatments were fed to only starter chicks to evaluate the impact of starter feed form on subsequent growth performance of broiler chickens and comprised of 1) mash diet, 2) 7 d crumbles followed by 14 d mash, 3) 14 d crumbles followed by 7 d mash, and 4) 21 d crumbles. Results indicated that feeding crumbles increased (P < 0.001) BW, ADG, ADFI, and improved (P < 0.001) FCR of broilers compared to feeding the mash diet. In Experiment 2, a study was conducted to determine the effects of crumble size and quality on broiler performance. A common corn-SBM diet was formulated and fed to 300 Cobb 500 broiler chicks raised in battery cages for 21 d. Broilers were fed a mash diet (M), micro-pellets (MP), and coarse- or fine-crumbles with or without the fines removed. Results showed that feeding MP or crumbles resulted in increased (P < 0.001) BW, ADG, ADFI, and improved (P < 0.001) FCR of broilers compared to feeding the M diet. Removing the fines from the crumbles further improved the BW and FCR of broilers fed the crumbled diets. Additionally, feeding M increased the relative gizzard weight of broilers compared to those fed MP or crumbles. In Experiment 3, the growth performance, intestinal morphometry, and blood serum parameters of broilers fed diets containing increasing levels of wheat bran (WB) and supplemented with exogenous multi-enzyme containing Xylanase, β-Glucanase, and Phytase (XGP) was evaluated in a 42-d trial. Four basal diets were formulated to meet or exceed the nutritional requirements of Cobb 500 broiler starter, grower, and finisher birds. A common starter diet was fed to all day-old chicks for 7 d with treatment diets fed to grower and finisher birds only. A total of 720 seven-day-old broilers were raised in 48 floor pens and fed diets with or without supplemental XGP. The addition of XGP had no effects on BW, ADFI, ADG, and FCR. Supplementation of the 12% WB with XGP resulted in similar performance as the 0% WB diets. The addition of both the WB and XGP increased the villi height, villi height: crypt depth but had no influence on crypt depth. Additionally, XGP increased (P < 0.01) high density lipoprotein-cholesterol, but decreased red blood cells, hemoglobin, and cholesterol concentration of the blood