| dc.description.abstract | The objective of this dissertation was to determine if limestone (source and particle size), dietary calcium inclusion rate, or different protein sources have an impact on naturally occurring necrotic enteritis (NE) pathogenesis and resulting broiler performance. Two experiments were conducted. The first experiment was to determine the impact of limestone source and particle size, as well as, dietary calcium levels on the pathogenesis of NE. The second experiment was to evaluate the effects of animal protein, dietary calcium level, and limestone particle size supplementation on the pathogenesis of NE.
Experiment one determined that there was an interaction between particle size and dietary “calcium” levels on grower mortality. Birds fed high levels of fine particle size had increased mortality. Through day 35, there is a 3-way interaction with overall performance of the birds. Birds fed standard levels of coarse particle size of calcium source 1 decreased in body weight and increased feed conversion ratio. According to ileal digestible intake after the outbreak of NE, there was a compromise in absorption of phosphorus and amino acids. It was determined that the largest impact was seen with the standard particle size, therefore, experiment two used standard particle size of limestone source 1 and 2, as well as, both dietary calcium levels.
Experiment two investigated the role dietary protein sources, dietary calcium level, and limestone particle size have on the pathogenesis of NE. Up to d 15, birds fed low dietary levels of limestone source 1 in the veggie diets had a reduced body weight. Additionally, during the same time period, standard dietary levels of calcium in the all-veggie diets reduced the feed conversion ratio. Conclusively, birds fed animal protein in the diet had increased levels of mortality.
During both experiments, limestone had an impact on the overall performance of the birds. Mortality was increased during grower phase due to interactions with the limestone. In conclusion, limestone reduces the overall impact NE has on flocks and presents great potential in additional research moving forward. Findings show that limestone is more than just a dietary filler. | en |
