PSV-B-19 Dietary choline supplementation increases transmethylation through the one-carbon cycle in overweight cats

Abstract

The objective of this study was to determine the dose-response relationship between dietary choline intake and one-carbon cycle activity in overweight cats at maintenance energy requirements. This study was approved by the University of Guelph Animal Care Committee (AUP#4118). Overweight (body condition score:≥6/9) adult male neutered cats (n = 14) received each of five choline chloride doses individually for three weeks in a 5x5 latin square design. Doses were based on body weight (BW) and the daily recommended allowance (RA) for choline for adult cats (63 mg/kg BW0.67). Doses were: 2xRA (126 mg/kg BW0.67), 4xRA (252 mg/kg BW0.67), 6xRA (378 mg/kg BW0.67), 8xRA (504 mg/kg BW0.67), and control (no additional choline). Choline was administered onto the commercial extruded cat food (3620 mg choline/kg diet), given once a day at maintenance energy requirements (130 kcal/kg BW0.4). Fasted serum samples were analyzed for metabolomics through quantitative nuclear magnetic resonance (NMR) spectroscopy and direct infusion mass spectrometry (DI-MS) at the end of each period. Data was analyzed using proc GLIMMIX in SAS, with group and period as the random effects, and dose as the fixed effect. Statistical significance was considered at P < 0.05. Tukey’s post-hoc test was performed to assess multiple comparisons. Choline at 6x and 8x RA appears to increase transmethylation through the one-carbon cycle, as suggested by increased serum betaine, dimethylglycine (DMG) and methionine (P < 0.05). Carnitine, methylated by s-adenosylmethionine (SAM), increased (P < 0.05). Serine and threonine, precursors for the biosynthesis of homocysteine, appear to have been spared (P < 0.05). Supplemental dietary choline (6x and 8xRA) may be beneficial for overweight cats, as it may increase activity of the one-carbon cycle and methyl status; which are necessary for hepatic function. To better understand the impact of choline on methylation reactions, the quantification of specific proteins, gene expression and/or conversion rates is required.

Dietary choline, but not L-carnitine, increases circulating lipid and lipoprotein concentrations, without affecting body composition, energy expenditure or respiratory quotient in lean and obese male cats during weight maintenance

“…As previously detailed in Rankovic et al (22), nutrient analysis of the diet (Table 1) was performed using methods described by the Association of Official Analytical Chemists (AOAC) and the American Oil Chemist Society (AOCS) (Bureau Veritas, Mississauga, ON, Canada) (38,39). This included the measurement of moisture (AOAC 935.29), crude protein (AOAC 990.03), crude fat (AOAC 920.39), crude fiber (AOCS Ba6a-05), ash (AOAC 942.05), total dietary fiber (AOAC 991.…”

“…As per previous research (22), choline (PuraChol, 70% aqueous choline chloride, 52.2% choline ion; Balchem Corporation, New Hampton, NY, United States of America) was supplemented to provide a daily choline intake of six times the recommended allowance (RA) for dietary choline published by the National Research Council (NRC) [6 x 63 mg/kg BW 0.67 (378 mg/kg BW 0.67 )] (22,41). The choline was measured daily, before feeding, with an adjustable volume pipette (Research plus TM Variable Adjustable Volume Pipette: 100-1,000 µL Single-Channel, Eppendorf Canada Ltd., Mississauga, ON, Canada).…”

“…Cats were acclimated to the chambers, using the methods previously outlined by Gooding et al (42). Calibration of gases and protocol followed the methods previously described (22,25).…”

“…Previous research in mammals, including cats, found that choline deficiency leads to the development of fatty liver, which can be reversed and/or prevented when dietary choline is added back to the diet in sufficient quantities (18)(19)(20). In cats, increased dietary choline supplementation leads to increased concentrations of serum lipids and lipoproteins in both obese and overweight cats (21,22), suggesting increased lipid hepatic mobilization through the synthesis and secretion of VLDL from the liver. Additionally, choline and its derivative betaine may reduce fat mass gain, as suggested in livestock species and growing kittens fed ad libitum post-gonadectomy (23)(24)(25).…”

“…Nutrients and nutraceuticals that can reduce the risk of hepatic lipid accumulation in obese cats and assist in mitigating weight gain would benefit the pet food industry and the veterinary community. Currently, there is evidence that dietary choline may provide such benefits to overweight and obese cats (21,22). However, there have been no studies comparing the lipotropic benefits of dietary choline to L-carnitine, a dietary supplement commonly used by the pet food industry.…”