The Effects of Feed Additives and the Use of a Novel Wood Boiler Heat Exchanger on Litter Quality, Broiler Performance, and Immune Status

Abstract

Experiments were conducted to investigate the effects of varying feed ingredients and heating systems on boiler performance metrics. Chapter Two investigated the effects of two corn-expressed phytases, differing in enzyme concentration within the grain (3,000 or 9,677 FTU/g), on broiler performance and tibia mineralization, when used as a component in pelleted feed. Dietary treatments included a positive control (PC), with industry-recommended levels of calcium and phosphorous, and a negative control (NC), lower in calcium and non-phytate phosphorous. Six diets containing corn-expressed phytase at high or low grain concentrations, formulated to 3,000, 6,000, or 9,000 FTU/kg, were created using the NC. Diets were conditioned at 70°C for 15s. Descriptive enzyme recovery post-pelleting (58-360%) and mixer coefficient of variation based on enzyme activity (8-24%) demonstrated variability with the phytase assay and did not show trends across treatment main effects. Diets were fed to Hubbard x Ross 708 (n=1,632) male broilers for 39d. On d21, five birds/pen were euthanized and tibiae were excised to determine tibia mineralization. Broilers fed the NC had increased d0-39 feed conversion ratio (FCR) compared to all other treatments (PPP Chapter Three examined the use of a muramidase in broiler diets. Muramidase breaks down peptidoglycans from bacterial cell debris in the gastrointestinal tract, improving nutrient utilization. The first objective of Chapter Three was to evaluate the effect of muramidase, conditioning temperature, and conditioning time on feed manufacture. The second objective was to evaluate muramidase activity and broiler performance when diets were conditioned at various temperatures and times. Experiment 1 consisted of a nutrient adequate, corn and soybean meal based diet (Basal), and the Basal+muramidase at 100K LSU(F)/kg diet. Both diet formulations were conditioned at 77, 82, or 88°C for 30 or 60 s. Feed manufacture was replicated across three days of manufacture. Experiment 2 utilized the Basal conditioned at 88°C for 30 and 60 s and the Basal+muramidase conditioned at 77, 82, or 88°C for 30 or 60 s. Crumbled diets were fed to 12 replications of ten male Hubbard x Ross 708 broiler chicks for 21 d. Increasing conditioning temperature decreased pellet mill motor load and increased hot pellet temperature (HPT) and pellet durability in Experiment 1 (PPExperiment 2 found that the inclusion of muramidase decreased FCR and increased live weight gain (LWG) for 30 s (PP>0.05). Muramidase improved performance post 30 s conditioning, regardless of conditioning temperature, compared to a nutrient adequate Basal. The objective of Chapter