Nutritional effects on mineral metabolism in cats with chronic kidney disease

The relevance of this study arises from the high prevalence of mineral metabolism disorders in cats with chronic kidney disease (CKD), which are accompanied by the development of hypercalcaemia and hyperphosphataemia and have a significant impact on prognosis and quality of life. Accordingly, the aim of the study was to assess the effect of different dietary calcium-to-phosphorus ratios on calcium-phosphorus homeostasis and the overall condition of cats with stage II CKD. The principal research method involved a comparative evaluation of clinical and biochemical parameters in animals depending on diet type, which enabled a comprehensive assessment of mineral metabolism changes. The study included fourteen cats divided into two groups. Group 1 animals received feed with a higher calcium-to-phosphorus ratio (1.71) and restricted phosphorus content, whereas group 2 cats were fed a diet with a moderate calcium-to-phosphorus ratio (1.33). Over a six-month period, blood biochemical parameters were monitored, including total and ionised calcium, phosphorus, creatinine, urea, and symmetric dimethylarginine concentrations. In addition, the cats’ clinical condition, body weight, muscle condition, body condition score, and arterial blood pressure were assessed, all of which remained stable in both experimental groups. It was found that cats in group 1 showed an increase in calcium levels, while cats in group 2 developed ionised hypercalcaemia. In group 2 cats, calcium levels remained stable without signs of hyperphosphataemia. Azotaemic markers did not differ significantly between the groups. Based on the obtained results, it was established that excessive phosphorus restriction leading to a high calcium-to-phosphorus ratio did not provide additional benefits in controlling phosphataemia but increased the risk of calcium metabolism disturbances. The material of this article holds practical value for veterinary clinicians, as it experimentally confirms the advisability of using diets with a moderate calcium-to-phosphorus ratio at early stages of chronic kidney disease in cats