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Dilated cardiomyopathy (DCM) or round heart disease is a muscle disease of the heart which is characterized by ventricular dilatation and abnormal systolic and diastolic left ventricular function. In animals, including turkeys and humans, DCM is the major cause of morbidity and mortality which results from heart failure. In the turkey, DCM can be idiopathic or induced. Since idiopathic or spontaneous DCM occurs in about 1-4% of normal turkeys, it is of significant concern to the poultry industry. In this study, it was proposed that the incidence and severity of DCM in the turkey may have a genetic basis. To test this hypothesis, I investigated differences in the incidence and severity of DCM in five domesticated turkey varieties including Blue Slate (BS), Bourbon Red (BR), Narragansett (N), Royal Palm (RP) and Spanish Black (SB). Preliminary investigations tested the reliability of echocardiography (ECHO) as a non-invasive and non-destructive technique for diagnosing DCM in a large number of birds from hatch to four weeks-of-age. One-day-old poults for both the preliminary and hypothesis testing investigations were obtained from Privett Hatcheries (Portales, New Mexico). The birds were raised under standard management conditions. In the preliminary investigation and to test my hypothesis, DCM was induced by feeding birds ad libitum standard diets containing 700 parts per million furazolidone. Results of the preliminary investigations showed that left ventricular end-diastolic dimension (LVEDD) and left ventricular end-systolic dimension (LVESD) were the most consistent ECHO indicators of DCM from hatch to 4 weeks-of-age. Variety differences in response to furazolidone were evaluated using these parameters as well as percent mortality. At 9 days-of-age, differences between control and treatment birds for percent mortality and LVESD were significant in the RP variety only but significant for LVEDD in RP and SB. At 29 and 33 days-of-age, all the pair-wise comparisons between control and treatment birds were significant for both LVEDD and LVESD. On average, the BR variety had the smallest dilatation of the heart and lowest mortality at 33 days-of-age when compared to other varieties. The results described in this thesis show, for the first time, variety differences in the turkey's response to diets containing furazolidone. They provide strong evidence that, like previous reports for idiopathic DCM, an animal's response to Fz-induced DCM has a strong genetic component. / Master of Science

Pasteurella multocida causes diseases in many animal species including fowl cholera, a septicemic disease of poultry and other birds. Pathogenesis of the disease has been studied by many investigators by the systemic administration of the organism in poultry. However, only a few studies have been done as to the respiratory pathogenesis of the organism. The objective of the study was to investigate the fate of P. multocida after the intratracheal administration in turkeys The fate of four strains of Pasteurella multocida was studied after their intratracheal inoculation in young adult turkeys. Viable bacterial counts were made in respiratory tissues as well as in the liver, spleen and blood at 6 and 9 hrs after the inoculation of approximately 10⁹ viable organisms of each strain. A virulent, encapsulated strain, P-1059, invaded systemically by 6 hrs postinoculation (PI) and multiplied vigorously in all tissues and organs examined. A blue colony mutant of P-1059, T-325, which does not possess a thick layer of capsule, as well as CU vaccine strain, invaded the parenchymal organs, but did not show significant increase in viable counts at 9 hrs PI compared with at 6 hrs PI. Another vaccine strain, M-9, also invaded blood and internal organs by 6 hrs PI, however, its viable counts showed no significant change between 6 and 9 hrs PI, or in some tissues significant decrease at 9 hrs PI. The results indicate that all the four strains possess high capacity to invade respiratory tissues with varying capacity to persist in host tissues. The lesions caused by two strains of Pasteurella multocida (P-1059 and M-9) were observed after their intratracheal inoculation in young adult turkeys. The lesions were observed in the respiratory organs at 0, 0.25, 0.5, 1, 2, 3, and 6 hrs after inoculation of approximately 10⁹ viable organisms of each strain. Both virulent strain, P-1059 and non-virulent vaccine strain, M-9, have capacity to invade and multiply in the tissues examined. Macroscopicly, the lesions in the lung and in the airsac were found as early as 1 hr PI, including the infected lung was foamy and the airsac became cloudy. They became more severe by 2 to 6 hrs PI. Microscopicly, hecerophiles were present, occasionally, in the lung, trachea and airsac by 0 to 1 hr after inoculation. Then they became more severe by 2 to 6 hrs PI. By 6 hrs PI, there were diffuse heterophiles infiltration in the trachea, lung, anc airsac. The lung vascular was edema. The trachea ciliate and mucous gland was cystic or hyperplasia, and the airsac shewed increased in thickness and cloudiness. These results of study indicate that the lesion caused by P-1059 and vaccine strain, M-9, were not significantly different. / Graduation date: 1992

Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves 169-184). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves 169-184). Also available on the Internet.

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