Dietary l-Carnitine Supplementation in Obese Cats Alters Carnitine Metabolism and Decreases Ketosis during Fasting and Induced Hepatic Lipidosis

Abstract

This study was designed to determine whether dietary carnitine supplement could protect cats from ketosis and improve carnitine and lipid metabolism in experimental feline hepatic lipidosis (FHL). Lean spayed queens received a diet containing 40 (CL group, n = 7) or 1000 (CH group, n = 4) mg/kg of L-carnitine during obesity development. Plasma fatty acid, beta-hydroxybutyrate and carnitine, and liver and muscle carnitine concentrations were measured during experimental induction of FHL and after treatment. In control cats (CL group), fasting and FHL increased the plasma concentrations of fatty acids two- to threefold (P < 0.0001) and beta-hydroxybutyrate > 10-fold (from a basal 0.22 +/- 0.03 to 1.70 +/- 0.73 after 3 wk fasting and 3.13 +/- 0.49 mmol/L during FHL). In carnitine-supplemented cats, these variables increased significantly (P < 0.0001) only during FHL (beta-hydroxybutyrate, 1.42 +/- 0.17 mmol/L). L-Carnitine supplementation significantly increased plasma, muscle and liver carnitine concentrations. Liver carnitine concentration increased dramatically from the obese state to FHL in nonsupplemented cats, but not in supplemented cats, which suggests de novo synthesis of carnitine from endogenous amino acids in control cats and reversible storage in supplemented cats. These results demonstrate the protective effect of a dietary L-carnitine supplement against fasting ketosis during obesity induction. Increasing the L-carnitine level of diets in cats with low energy requirements, such as after neutering, and a high risk of obesity could therefore be recommended.

The effects of graded levels of calorie restriction: IX. Global metabolomic screen reveals modulation of carnitines, sphingolipids and bile acids in the liver of C57BL/6 mice

“…L‐carnitine shuttles fatty acids across the mitochondrial membrane, where they can be processed by β‐oxidation enzymes to ultimately generate ATP (Flanagan et al ., 2010; Pekala et al ., 2011). Studies have shown that L‐carnitine supplementation has positive effects in obese and diabetic humans, as well as benefits in cats and mice (Levin et al ., 1999; Blanchard et al ., 2002; Mingorance et al ., 2012). The L‐carnitine biosynthesis pathway was significantly upregulated at 30 and 40CR, and all metabolites detected in this pathway showed a graded response (Fig.…”

Hypercarnivory and the brain: protein requirements of cats reconsidered

“…In keeping with this greater need of cats for brain substrates, the cat develops hyperketonaemia more rapidly and to a greater degree than the dog during total starvation (Owen et al 1967;De Bruijne 1979;Blanchard et al 2002). A special case is the mink (M. vison) in that predicted RCMR of adult Fig.…”

“…Adult cats fed very low-carbohydrate diets (B10% of ME) do not develop hyperketonaemia (Chugani et al 1991;Dobenecker et al 1998;Pazak et al 1998;Blanchard et al 2002;Thiess et al 2004). Nevertheless, cats develop significant hyperketonaemia during starvation (Blanchard et al 2002) and in insulin-deficient diabetes (Stadie et al 1940), indicating that lack of ketone body accumulation in cats on very low-carbohydrate diets is not due to a defect in ketogenesis.…”

“…Nevertheless, cats develop significant hyperketonaemia during starvation (Blanchard et al 2002) and in insulin-deficient diabetes (Stadie et al 1940), indicating that lack of ketone body accumulation in cats on very low-carbohydrate diets is not due to a defect in ketogenesis. This metabolic pattern in cats is consistent with high rates of gluconeogenesis sufficient to suppress ketogenesis in the fed state, and reduction of gluconeogenesis and gradual substitution of glucose by ketone bodies to spare protein during prolonged starvation, as indicated by a reduction in daily nitrogen loss (FUNL \ EUNL; Table 1).…”

Serum Beta Hydroxybutyrate Concentrations in Cats with Chronic Kidney Disease, Hyperthyroidism, or Hepatic Lipidosis

“…Twenty‐six and a half percent of 215 ill cats had an increased serum BHB;5 and while diabetic cats had the highest BHB, cats with hepatic lipidosis (HL) were also found to have significantly higher BHB than cats with other conditions 5. Several older studies demonstrate increased BHB in both naturally occurring and starvation‐induced HL in cats 6, 7, 8. However, no prospective studies have been done evaluating BHB in clinically relevant numbers of cats with other conditions, and no recent prospective studies of BHB in HL cats have been performed.…”