Obesity is a health concern for domestic cats. Obesity and severe energy restriction predispose cats to feline hepatic lipidosis. As choline is linked to lipid metabolism, we hypothesized that dietary choline supplementation would assist in reducing hepatic fat through increased lipoprotein transport and fatty acid oxidation. Twelve obese cats (body condition score [BCS] ≥ 8/9) were split into two groups. Cats were fed a control (n = 6; 4587 mg choline/kg dry matter [DM]) or a high choline diet (n = 6; 18,957 mg choline/kg DM) for 5 weeks, for adult maintenance. On days 0 and 35, fasted blood was collected, and the body composition was assessed. Serum lipoprotein and biochemistry profiles, plasma amino acids and plasma acylcarnitines were analyzed. The body weight, BCS and body composition were unaffected (p > 0.05). Choline increased the serum cholesterol, triacylglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, very low-density lipoprotein cholesterol and plasma methionine (p < 0.05) and decreased the serum blood urea nitrogen and alkaline phosphatase (p < 0.05). Choline also reduced the plasma acylcarnitine to free carnitine ratio (p = 0.006). Choline may assist in eliminating hepatic fat through increased fat mobilization and enhanced methionine recycling.

Choline is beneficial for energy metabolism and growth in various species. Choline may work similarly in kittens at risk of obesity. Direct infusion mass spectrometry (Di-MS) and nuclear magnetic resonance (NMR) spectroscopy were used to investigate the metabolomic signatures of kittens supplemented with or without additional dietary choline for 12-weeks. Fifteen intact male kittens consumed a base-diet (3310 mg choline/kg DM) to their daily metabolizable energy requirement (DER) over an 11-week acclimation. Kittens were gonadectomized and assigned, based on body weight, to the base-diet (CONTROL, n=7) or the base-diet with 300mg/kgBW0.75 additional choline as choline chloride (CHOLINE, n=8) and offered three times their individual energy requirement divided into three meals. At weeks -1 and 12 fasted blood was sampled and serum analyzed for 130 metabolites via Di-MS and 51 metabolites via NMR spectroscopy. Changes in fasted metabolites were assessed using a repeated measures GLIMMIX procedure with time and group as fixed effects, and time as a repeated measure. Metabolites of one-carbon metabolism and lipids increased, and medium chain acyl carnitines decreased from week -1 to 12 for CHOLINE (P0.05). Increases in amino acid, biogenic amine and organic compound concentrations were observed in both groups (P<0.05). The results suggest impacts of dietary choline at greater intakes than currently recommended on one-carbon metabolism and fatty acid oxidation and these may promote healthy growth in post-gonadectomy kittens.

Gastric emptying rate (GER) may impact diabetes and obesity in humans and could provide a method to reduce canine weight gain. Starch, the most common source of carbohydrates (CHOs) in pet food, is classified as rapidly or slowly digestible, or resistant to digestion. This study investigated starch source effects in commercial extruded dog foods on the GER of 11 healthy adult Siberian Huskies. Test diets were classified as traditional, grain-free, whole-grain, and vegan. Dogs received each diet once, a glucose control twice, and acetaminophen (Ac) as a marker for GER in a randomized, partially replicated, 6 × 6 Latin square design. Pre- and post-prandial blood samples were collected at 16 timepoints from −15 to 480 min. Serum Ac concentrations were assessed via standard spectrophotometric assays and fitted with a mathematical model to estimate parameters of GER. Parameter values were subjected to ANOVA, with period and treatment as fixed effects and dog as a random effect. More total emptying (p = 0.074) occurred at a faster rate (p = 0.028) in dogs fed the grain-free diet, which contained the lowest total starch (34.03 ± 0.23%) and highest resistant starch (0.52 ± 0.007%). This research may benefit future diet formulations to reduce the prevalence of canine weight gain.