Abstract
The aim of the study was to determine total antioxidative capacity (TAC) and zinc concentration in serum of dogs suffering from perianal tumours just before the start of the antihormonal treatment (AHT) and one and six months later. The study was performed on 45 dogs divided into two groups: control group suffering from non-malignant tumours (N = 24) and a group with malignant neoplastic changes (N = 21). Serum TAC and zinc concentrations were measured using photometric and atomic absorption spectrophotometric methods. Six months after the start of the AHT, TAC was significantly lower by 10.6% in dogs with malignant tumours when compared to controls (P = 0.03). In the non-malignant group, serum zinc concentration was higher before the treatment than in the malignant group, while the opposite results were observed six months later (P < 0.001). In the non-malignant group, gradually decreasing values of serum zinc concentration at each stage of the investigation were observed, while the opposite results were obtained in the malignant group (P < 0.05). The obtained results indicate that malignant neoplastic process is associated with significantly reduced TAC. Determination of serum zinc concentration in dogs with non-malignant and malignant perianal tumours may have practical diagnostic and prognostic values and may serve towards increasing the effectiveness of AHT monitoring.