Thesis (M.S.)--University of Wisconsin--Madison, 1965. / eContent provider-neutral record in process. Description based on print version record. Bibliography: l. 45-50.

Thesis (M.S.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains vii, 59 p. : ill. Includes abstract. Includes bibliographical references (p. 43-45).

Thesis (Ph.D.)--University of Missouri-Columbia, 2004. / Typescript. Vita. Includes bibliographical references (leaves 173-181). Also available on the Internet.

Thesis (Ph.D.)--University of Missouri-Columbia, 2004. / Typescript. Vita. Includes bibliographical references (leaves 173-181). Also available on the Internet.

Four experiments were conducted to evaluate the efficacy and safety of a microbial phytase (Novo SP938) in weanling and grower pigs, and starter turkeys fed corn-soybean meal based diets. Pig and turkey BW and pen feed consumption were recorded weekly. Fecal and excreta samples were collected for determination of Ca and P digestibility. At the end of all experiments animals were slaughtered, and 10th ribs or right foot for pigs, and both middle toes for turkeys were removed for bone analysis. In pigs performance, bone measurements, and digestibilities of P and Ca increased as levels of phytase increased. Concentration of P and Ca in the feces decreased as dietary phytase increased. In turkeys, BW gain and toe ash increased as nonphytate P or phytase increased, when added to a low-P diet. Concentrations of P and Ca decreased as phytase was added to the diet. Based on nonlinear or linear equations, the average P equivalency of 500 U phytase/kg feed was .64 and .67 g of inorganic P for pigs and turkeys, respectively. There were no adverse effects of feeding 10,000 U phytase/kg feed in pigs and turkeys. Supplementation with Novo SP938 phytase was effective in improving performance, bone mineralization, P and Ca utilization, and decreasing P and Ca concentrations in the feces of pigs and excreta of young turkeys fed low-P diets, with no health effects, even at very high supplementation rates. / Master of Science

No description available.

Hemorrhagic Enteritis (HE) vaccine is perhaps the most commonly used vaccine in the turkey industry. Although it provides protection against clinical disease, the vaccine is still thought to produce transient immunosuppression. In the field, HE still remains a significant concern for turkey producers. Research conducted over the years has shown that management stressors such as movement of turkeys from brooding to finishing environments and the timing of these stressors may influence the short-term response to vaccination. Strategic stress application may be of benefit in the optimization of protective responses and the development of vaccination protocols without detrimental effects on performance. Ascorbic acid may also have important implications on social stress and may play a role in immunity and response to HE vaccination in turkeys. Trials were conducted to examine the interrelationship among social stress, nutrition (vitamin C), immunity and their influence on response to hemorrhagic enteritis virus (HEV) vaccination. Stress is unavoidable, however if it is managed properly, it can be beneficial. In this dissertation, it was first demonstrated that stress in the form of social disruption can have negative physiological and immunological effects on turkey poults and that these effects can be alleviated with the addition of 300mg/kg vitamin C to the diet. Secondly, it was also demonstrated that when stress is applied on the day of vaccination, response to HEV vaccination can be improved. Thirdly, vitamin C supplementation at 300mg/kg can improve responses to HEV vaccination. However, it was concluded that vitamin C supplementation during periods of simultaneous stress application and vaccination does not provide benefit to response to vaccination. / Ph. D.

Ornithobacterium rhinotracheale (ORT) is a Gram-negative bacterium that causes respiratory disease in poultry characterized by rhinitis, tracheitis, and pneumonia with mortality averaging 2-3%. In the Shenandoah Valley of Virginia, the seroprevalence for ORT among turkey flocks as determined by enzyme-linked immunosorbent assay (ELISA) was found to be 70.9% (n=175). Additionally, the seroprevalence for hemorrhagic enteritis virus (vaccine induced), Bordetella avium, and paramyxovirus-1 was 100%, 74.8%, and 6.3% respectively. No significant interactions were detected. The type strain of ORT is characteristically non-hemolytic at least for 96 hours at 37°C on Columbia Blood Agar. In recent years, atypical isolates that rapidly produce hemolysis have been isolated with increasing frequency. A variety of in vitro tests were used to determine differences between representative isolates of the hemolytic (H) and non-hemolytic (NH) phenotypes. Findings suggest that the H isolate contains a 4 kb plasmid similar to that found in Reimerella anatipestifer. No plasmid was found in the NH isolate. Differences in growth characteristics and resistance to tetracyclines were also noted. No differences in proteins, biochemical characteristics or 16S rRNA sequences were found, the latter serving as confirmation that the isolates were both ORT. Embryo inoculation was used to assess virulence. No significant differences were observed and most embryos survived through to the day of hatch (pip) despite the fact that ORT could be re-isolated. In turkey poults however, the H phenotype did appear less virulent. A significant depression in weight gain was noted for birds inoculated intratracheally with the NH isolate at 7 days post-inoculation (dpi). NH inoculates also had significantly higher antibody levels on ELISA at 14 and 21 dpi and histopathological lesion scores for lung at 7, 14, and 21 dpi. The NH isolate could be re-isolated from NH-inoculated poults through 21 dpi; whereas the H isolate could only be re-isolated through 14 dpi. In conclusion, there are numerous differences between the NH and H isolates found in the field with the H isolate appearing less virulent and as such, making it a potential vaccine candidate. The phenotypic difference appears to correlate with this, but may not suffice to explain it. / Ph. D.

No description available.

No description available.