Abstract: The purpose of this study was to investigate the variation of differential metabolites in mammary carcinomas bearing cats and healthy cats, and to explore the relationship between differential metabolites and the occurrence of feline mammary carcinomas. In this study, 6 feline mammary carcinomas serum samples were selected as test (T) group. Meanwhile, 6 healthy cats with similar age and same breed were selected as control (C) group. Serum samples were detected by ultra-high performance liquid tandem chromatography quadrupole time of flight mass spectrometry (LC-MS). Differential metabolites were screened by principal component analysis (PCA), orthogonal projections to latent structures-discriminant analysis (OPLS-DA) and Student's t-test. Then the hierarchical clustering analysis (HCA) was carried out for the screened differential metabolites. The KEGG annotation and the metabolic pathway of differential metabolites were analyzed. The results showed that a total of 159 differential metabolites were identified in the 2 groups. Compared with C group, 49 differential metabolites were down-regulated and 110 differential metabolites were up-regulated in T group. Finally, a total of 5 differential metabolites which closely related to feline mammary carcinomas were selected. Ergothioneine (EGT) and creatine in T group were down-regulated, while indolelactic acid (IAA), choline and uric acid were up-regulated compared to C group. These differential metabolites indicated that during the development of feline mammary carcinomas, the body changes involved multiple metabolic pathways, such as glycine, serine and threonine metabolism, arginine and proline metabolism, histidine metabolism, tryptophan metabolism, purine metabolism and glycerophospholipid metabolism. This study provides a new idea for further research of the pathogenesis of feline mammary carcinomas.

Key words: feline, mammary carcinomas, LC-MS, differential metabolites