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" Effect of Tetratrichomonas gallinarum on Production Parameters in Commercial Turkeys and Development of a Cochlosoma anatis Infection Model "
Keen, Kelly Grace
Gimeno, Isabel
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Latin Dissertation
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| Language of Document
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English
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| Record Number
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1105121
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| Doc. No
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TLpq2298170140
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| Main Entry
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Gimeno, Isabel
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Keen, Kelly Grace
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| Title & Author
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Effect of Tetratrichomonas gallinarum on Production Parameters in Commercial Turkeys and Development of a Cochlosoma anatis Infection Model\ Keen, Kelly GraceGimeno, Isabel
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| College
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North Carolina State University
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| Date
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2019
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| student score
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2019
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| Degree
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M.Sc.
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| Page No
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110
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| Abstract
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Tetratrichomonas gallinarum and Cochlosoma anatis are flagellated parasites whose host range include commercial turkeys. Found in the intestinal tract of infected birds, these protozoa have been suggested to be enteric pathogens. However, the pathogenicity of T. gallinarum and C. anatis can vary, ranging from no outward signs of disease to severe enteritis and increased in flock mortality. Due to the inconsistent onset of disease during infection, the importance of T. gallinarum and C. anatis as pathogens to the poultry industry is questionable. The removal of antiparasitic drugs, such as nitroimidazoles, from poultry production has increased the prevalence of both T. gallinarum and C. anatis. A general lack of knowledge necessitates a need for research aimed at better understanding the etiology and epidemiology of both organisms. Current turkey industry practice includes T. gallinarum diagnostics at 4-6 weeks. However, there is no current literature detailing the changes in body weight (BW), body weight gain (BWG), and feed efficiency (FCR) during a T. gallinarum infection. Assessing whether a T. gallinarum infection causes decreases in growth performance would determine if this parasite alone negatively impacts the turkey industry. In Manuscript I, two separate bird trials were conducted to test the effects of different field isolates of T. gallinarum on growth performance in commercial toms. Weekly BW, BWG, and FCR data were collected for both trials and lesion scoring was conducted at trial termination. The first trial demonstrated no statistical differences (p<0.05) in growth performance parameters or lesion formation between infected and uninfected groups. However, infected turkeys consistently had lower BW and BWG for the entirety of the trial. The second trial increased sample size to improve statistical power, used two different T. gallinarum isolates, and included a decreased threonine diet to add nutritional stress on the birds. Birds fed the decreased threonine diet consistently had lower BW and BWG, but there was not an interaction effect of decreased threonine and infection, regardless of isolate type used. Differences in BWG, feed intake, and FCR due to infection were observed during weeks 3-5, but there were no significant changes in cumulative data. Similarly, there was not a consistent effect of isolate type on production parameters or lesion development. The results from these bird trials demonstrate that turkeys infected with a single field isolate of T. gallinarum have limited pathology. It is possible that under alternative conditions, such as a co-infection with a secondary microorganism, T. gallinarum may exacerbate enteritis in turkeys. Reports of C. anatis infections in the literature and in fields reports suggest that secondary factors, such as co-infection and sex, are responsible for the variability seen in disease outcomes. The second objective of this thesis was to analyze field data of commercial flocks naturally infected with C. anatis (in literature review) and develop an infection model that would allow for downstream experiments testing epidemiological factors related to a C. anatis infection (Manuscript II). In Manuscript II, two bird trials were conducted investigating the effects of bird sex and co-infection on disease severity during a C. anatis infection of commercial turkeys. The first trial demonstrated a significant decrease in BW of both female and male infected turkeys and earlier disease onset in infected females. The second trial also demonstrated a significant decrease in BW for both sexes and earlier disease onset for infected females, but there was not a significant effect of co-infection with T. gallinarum on BW. The results from these studies demonstrates the inability for T. gallinarum to cause disease, while C. anatis can act as a pathogen in turkeys.
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Animal diseases
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Animal sciences
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Parasitology
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