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Development of Cellular and Molecular Methods to Characterize the Mechanisms of Common Infectious- and Non-infectious-based Diseases of Poultry
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Poultry production plays an important role in the global economy. Nevertheless, common infectious- and non-infectious-diseases of poultry negatively affect public health and cause economic losses. Salmonellosis is one of the infectious diseases caused by Salmonella infection. Salmonella Typhimurium (ST) is one of the most common serotypes that cause human gastrointestinal disease globally. Chickens do not show any clinical symptoms after ST infection. What makes the coexistence of ST in chicken gut is not completely understood. The intestinal organoid (IO) model has been widely used for studying molecular mechanisms of host-pathogen interactions in mammals. However, there are limited avian IO studies. The development of long-term avian IO for poultry research is needed. Recently, exosomes are reported to play important roles in host immunity to pathogen infection by regulating exosomal microRNA (miRNA) levels. However, the mechanism of exosomes in host-pathogen in chickens remains to be elucidated. One of the common non-infectious diseases in poultry is wooden breast (WB), a degenerative myopathy. While the etiology of WB is unknown, localized hypoxia and decreased lactate levels in WB indicate the presence of altered lactate metabolism. Therefore, the aims of these studies were to 1) develop avian IO and optimize their culture conditions, 2) elucidate the effects of ST on exosomal miRNA levels in broiler serum, and 3) investigate if altered lactate homeostasis was present in WB muscles. We have successfully developed and characterized the avian IO that recapitulates intestinal epithelial structure in vivo. The finding of up-regulated miRNAs in serum-derived exosomes due to the exposure of ST, while preliminary, suggests that exosomes may act as potential immunomodulators that are easily delivered to cells of different organs. Wooden breast muscles of broilers exhibited altered major proteins involved in lactate metabolism, suggesting that the development of agents targeting this pathway may provide a potential therapeutic treatment for reducing the incidence of WB myopathy. Ultimately, my work has a considerable impact on the future avian ex vivo intestinal study and helps us better understand the mechanism the Salmonella infection in poultry and WB, eventually leading to the discovery of pathogen and WB intervention strategies in poultry.
Zhao, Dan (2021). Development of Cellular and Molecular Methods to Characterize the Mechanisms of Common Infectious- and Non-infectious-based Diseases of Poultry. Doctoral dissertation, Texas A&M University. Available electronically from