Effects of a high-protein, high-fiber diet rich in antioxidants and l-carnitine on body weight, body composition, metabolic status, and physical activity levels of cats after spay surgery.

Spay and neuter surgeries are useful in controlling pet populations, but increase obesity risk due to increased appetite, decreased metabolic rate, and decreased energy expenditure. Dietary management may help limit post-spay weight gain, but few research studies have been conducted in cats. Therefore, the objective of this study was to evaluate the effects of a high-protein, high-fiber diet (HPHF) compared to a moderate-protein, moderate-fiber diet (MPMF) in female cats following spay surgery. Twenty healthy female cats (9.5 ± 0.1 mo) were used. After a 4-wk baseline phase with cats fed MPMF to maintain body weight (BW), 16 cats were spayed and allotted to MPMF (n = 8) or HPHF (n = 8), with the remaining cats being sham-operated and fed MPMF (n = 4). Cats were fed to maintain BW for 12 wk and then allowed to eat up to twice that amount for another 12 wk. Daily food intake, twice weekly BW, and twice weekly body condition scores (BCS) were assessed. Back fat thickness (BF) using ultrasound, body composition using dual-energy X-ray absorptiometry (DEXA), feline body mass index (fBMI), body fat percentage estimates using zoometry measurements, serum metabolites, and voluntary physical activity levels were measured prior to spay (week 0) and every 6 wk post-spay. A treatment*time effect was observed for food intake (g/d), but not caloric intake (kcal ME/d). Caloric intake was affected by time and treatment, being reduced over the first 12 wk and reduced at higher amounts in HPHF and MPMF cats vs. sham cats. BW, BCS, and body fat percentage were affected over time. Treatment*time effects were observed for blood urea nitrogen, alkaline phosphatase, and fructosamine, whereas blood triglycerides, total cholesterol, creatinine, total protein, phosphorus, and bicarbonate were affected by time. Physical activity was reduced over time. Our results demonstrate that spay surgery affects food intake, BW, metabolism, and physical activity of cats. Dietary intervention in this study, however, led to minor changes.