A retrospective study of the frequency and factors associated with elevated serum aspartate aminotransferase activity in domestic rabbits

This study aimed to identify factors associated with elevated aspartate aminotransferase (AST) activity and to evaluate the frequency of elevated AST and its association with mortality in domestic rabbits. A retrospective cohort study was conducted between 2021 and 2022, including 1,435 rabbits that underwent blood testing for AST. A significant association was observed between health status and elevated AST activity (P < 0.001). Elevated AST activity was observed in 14.64% (95/649) of healthy rabbits and 33.97% (267/786) of diseased rabbits. Among the 138 rabbits that died during hospitalization, 79 (57.24%) had elevated AST activity. Several hematological and biochemical parameters were associated with elevated AST activity. Leukocytosis, leukopenia, neutropenia, lymphopenia, decreased RBC count, decreased hemoglobin, decreased hematocrit, and thrombocytopenia, elevated ALT, elevated BUN, and elevated creatinine showed positive associations, whereas erythrocytosis, elevated total protein, and elevated albumin showed negative associations. Among diseased rabbits, elevated AST activity was positively associated with several clinical signs, including abnormal mucous membranes, depressed mentation, anorexia, emaciation, hyperthermia, unconsciousness, weakness, decreased fecal output, abdominal pain, and dyspnea; hypersalivation showed an inverse association. Disease conditions positively associated with elevated AST activity included gastrointestinal hypomotility, allergic rhinitis, pneumonia, heat stroke, anaphylactic shock, renal disease, cardiovascular disease, hepatic disease, toxin ingestion, malnutrition, and hypoglycemia, whereas malocclusion showed an inverse association. Multivariable logistic regression showed that the presence of clinical illness (defined as clinical abnormalities or a documented diagnosis of any disease), underweight body condition score, and anemia (hematocrit