Meeting Abstract
As a major physiological system centrally involved in cellular renewal and repair, immune function is an essential component of body maintenance and survival. Immune defenses can be energetically expensive. Hence, the activities of metabolic active organs, such as liver, can be expected to be elevated as a result of immune defense activation. On the other hand, some pathogens can be immunosuppressive which would decrease immune response eventually leads to low levels of metabolic capacities in organs. Mycoplasma gallisepticum (Mg) is a bacterium that is a well-known pathogen of domestic chickens, turkeys and songbirds. In house finch (Haemorhous mexicanus), in addition to causing a respiratory infection, it would also infect the conjunctiva of the eye causing conspicuous swelling. In order to study the activities of immune defense system, we measured mitochondrial respiration, reactive oxygen species production, and oxidative damage in livers of house finches infected with or without Mg. To our surprise, MG did not changes both basal and maximal mitochondrial respiration capacities or mitochondrial reactive oxygen species production rate. However, Mg infected finches showed lower oxidative lipid and protein damage in liver when compared to uninfected counterparts. This result supported the immunosuppression hypothesis, where Mg decreased immune function of infected house finches. Low metabolic demand caused by immunosuppressive property of Mg could result in relatively low oxidative damage for infected house finches.
