Management of obesity in cats

Missense variants in MC4R gene are associated with obesity in cats

Obesity stands out as the most common multifactorial nutritional problem affecting domestic cats. According to studies, the prevalence of overweight or obese cats varies between 11.5% and 63%. Various factors such as breed, age, gender, reproductive status, owner-pet relationship, diet type, and environmental factors have been identified as potential risk factors for the development of obesity in cats. Among the genes involved in regulating energy balance, one of the prominent genes is melanocortin-4 receptor gene (MC4R). A specific missense variant in the feline MC4R gene (c.92 C > T) has been associated with overweight in diabetic domestic shorthaired cats. In this study, it was aimed to determine the polymorphisms in MC4R gene in random bred cats and cats belonging to a registered breed in Turkey and to investigate their relationship with obesity. Blood samples from 30 obese and 20 non-obese cats were collected into sterile vacuum EDTA tubes. Exon 1 of the MC4R was amplified and sequenced. As a result of DNA sequence analysis, we identified a total of six SNPs in the feline MC4R gene, four of which were found for the first time in this study. As a result of comparing allele frequencies in obese and non-obese cats, a significant relationship was found between SNP rs783632116 and obesity. The results of regression analyses evaluating the effects of SNP genotypes, sex and infertility status on feline Body Mass Index (fBMI) indicated that non-synonymous SNPs rs783632116, ss11356259660 and ss11356259661 were significantly associated with fBMI.

Restricted feeding of weight control diets induces weight loss and affects body composition, voluntary physical activity, blood metabolites, hormones, and oxidative stress markers, and fecal metabolites and microbiota of obese cats

Feline obesity puts many cats at risk for comorbidities such as hepatic lipidosis, diabetes mellitus, urinary tract diseases, and others. Restricted feeding of specially formulated diets may improve feline health and safely support weight loss while maintaining lean mass. The objective of this study was to determine the effects of restricted intake of weight control diets on weight loss, body composition, voluntary physical activity, serum metabolic and inflammatory markers, and fecal metabolites and microbiota of obese cats. Twenty-four obese adult domestic shorthair cats [body weight (BW) = 5.51 ± 0.92 kg; body condition score (BCS) = 8.44 ± 0.53] were used. A leading grocery brand diet was fed during a 4-wk baseline to identify intake needed to maintain BW. After baseline (week 0), cats were allotted to one of 2 weight control diets (DRY or CAN) and fed to lose 1.5% BW per week for 18 wk. At baseline and 6, 12, 18 wk after weight loss, dual-energy x-ray absorptiometry scans were performed, blood and fecal samples were collected, and voluntary physical activity was measured. Change from baseline data was analyzed statistically using the Mixed Models procedure of SAS, with P < 0.05 being significant and P < 0.10 being trends. BW was reduced by 1.54 ± 0.51% per week. Restricted feeding of both diets led to BW (P < 0.01) and fat mass loss (P < 0.01), reduced BCS (P < 0.01), reduced leptin (P < 0.01) and insulin (P < 0.01) concentrations, and increased superoxide dismutase (P < 0.01) and active ghrelin (P < 0.01) concentrations. Change from baseline fecal scores was reduced (P < 0.01) with restricted feeding and weight loss, while total short-chain fatty acid, acetate, and propionate concentration reductions were greater (P < 0.05) in cats fed CAN than those fed DRY. Fecal bacterial alpha diversity measures increased (P < 0.01) with restricted feeding and weight loss. Fecal bacterial beta diversity was altered by time in all cats, with week 0 being different (P < 0.05) than weeks 6, 12, and 18. Change from baseline relative abundances of 3 fecal bacterial phyla and over 30 fecal bacterial genera were impacted (P < 0.05) or tended to be impacted (P < 0.10) by dietary treatment. Our data demonstrate that restricted feeding of both weight control diets was an effective means for weight loss in obese adult domestic cats. Some changes were also impacted by diet, highlighting the importance of diet formulation and format, and nutrient composition in weight control diets.

Effects of weight loss and feeding specially formulated diets on the body composition, blood metabolite profiles, voluntary physical activity, and fecal metabolites and microbiota of overweight cats

Feline obesity is a common and preventable disease, posing a myriad of health risks and detriments. Specially formulated diets and restricted feeding may serve as an intervention strategy to promote weight loss and improve feline health. In this study, our objective was to determine the effects of restricted feeding and weight loss on body composition, voluntary physical activity, blood hormones and metabolites, and fecal microbiota of overweight cats. Twenty-two overweight adult spayed female and neutered male cats [body weight (BW) = 5.70 ± 1.0 kg; body condition score (BCS) = 7.68 ± 0.6; age = 4 ± 0.4 yr] were used in a weight loss study. A control diet (OR) was fed during a 4-wk baseline to identify intake needed to maintain BW. After baseline (week 0), cats were allotted to OR or a test diet (FT) and fed to lose ~1.0% BW/wk for 24 wk. At baseline and 6, 12, 18, and 24 wk after weight loss, dual-energy x-ray absorptiometry scans were performed and blood samples were collected. Voluntary physical activity was measured at weeks 0, 8, 16, and 24. Fecal samples were collected at weeks 0, 4, 8, 12, 16, 20, and 24. Change from baseline data were analyzed statistically using the Mixed Models procedure of SAS, with P < 0.05 considered significant. Restricted feeding of both diets led to weight and fat mass loss, lower BCS, and lower blood triglyceride and leptin concentrations. Cats fed the FT diet had a greater reduction in blood triglycerides and cholesterol than cats fed the OR diet. Restricted feeding and weight loss reduced fecal short-chain fatty acid, branched-chain fatty acid, phenol, and indole concentrations. Fecal valerate concentrations were affected by diet, with cats fed the OR diet having a greater reduction than those fed the FT diet. Fecal bacterial alpha diversity was not affected, but fecal bacterial beta diversity analysis showed clustering by diet. Restricted feeding and weight loss affected relative abundances of 7 fecal bacterial genera, while dietary intervention affected change from baseline relative abundances of 2 fecal bacterial phyla and 20 fecal bacterial genera. Our data demonstrate that restricted feeding promoted controlled and safe weight and fat loss, reduced blood lipids and leptin concentrations, and shifted fecal metabolites and microbiota. Some changes were also impacted by diet, highlighting the importance of ingredient and nutrient composition in weight loss diets.

Properties of Foods That Impact Appetite Regulation in Cats

Overweight and obesity are common in global pet cat populations which makes it important to understand how properties of food affect appetite (food motivation). In four experiments, we studied this by using a model of operant conditioning for assessing appetite in which cats could press a lever for food rewards. There was no effect of protein status on motivation for protein, when evaluated in a cross-over design with cats receiving low protein (LP) or high protein (HP) foods for 14 days. Cats obtained similar numbers of HP and LP rewards, irrespective of whether their daily food was HP or LP (mixed-effects model, P = 0.550 for food × reward, P = 0.151 for reward). High dietary protein reduced food motivation when we regressed protein levels in 12 commercial foods (12.0 to 27.4 g crude protein/MJ metabolizable energy; P = 0.022) fed for 2 days and tested at 5 h postprandially on the third day whereas fiber levels were without effect (3.8 to 17.8 g non-starch polysaccharides/MJ; P = 0.992). Dietary fiber may reduce appetite depending on its physicochemical properties and we tested the effect of a gelling fiber (alginate), viscous fiber (psyllium) and a fermentable fiber (inulin). Cats received test foods as well as control foods for 3 days and were tested on the third day at 3 h (alginate), 5 h (psyllium) or 8 h (inulin) postprandially. Enriching the food with alginate (P = 0.379) or psyllium (P = 0.153) did not affect the number of rewards obtained, but the feeding of the inulin-enriched food did make the cats obtain fewer rewards than when they received the control food (P = 0.001). Finally, cooking or grinding of dietary meat increased the number of rewards obtained by cats, on day 3 at 3 h postprandial, without evidence for additive effects of these treatments (P = 0.014 for grinding × cooking). This study shows that dietary content of protein or fiber, and the grinding or cooking of meat, all affect appetite in cats as expected, though some predicted effects remained undetected and clearly details regarding food properties matter. These and future findings can guide the designing of foods that promote satiety and prevent over-eating in meal-fed cats.