RESEARCH COMMUNICATIONS OF THE 28th ECVIM-CA CONGRESS

A previous prospective randomised placebo‐controlled trial examined the effect of dietary phosphate restriction in healthy, non‐azotaemic cats >9 years (Geddes et al., 2016). Cats were assigned to test or control diet (protein 76 g/Mcal, 86 g/Mcal; phosphate 1.6 g/Mcal, 2.6g/Mcal). Blood samples were taken at baseline, 6 weeks, 6, 12 and 18 months on diet. No effect of phosphate restriction was observed on plasma fibroblast growth factor 23 (FGF23), a phosphaturic hormone shown to be predictive of development of azotaemia in cats > 10 years. Our understanding of normal plasma FGF23 concentration has developed. In a group of 46 healthy adult cats fed a maintenance diet, median concentration was 105 (81.4, 133) pg/mL. As a result, we reviewed data from the trial to determine whether feeding a senior diet reduced plasma FGF23 concentration in cats with FGF23 above the top 20 percentile of healthy adult cats.