Free Access
Reprod. Nutr. Dev.
Volume 44, Number 1, January-February 2004
Page(s) 1 - 16
Reprod. Nutr. Dev. 44 (2004) 1-16
DOI: 10.1051/rnd:2004011

Age-related relationships between muscle fat content and metabolic traits in growing rabbits

Florence Gondreta, Jean-François Hocquetteb and Patrick Herpina

a  INRA, Unité Mixte de Recherches sur le Veau et le Porc, 35590 Saint-Gilles, France
b  INRA, Unité de Recherches sur les Herbivores, 63122 Saint-Genès-Champanelle, France

(Received 8 April 2003; accepted 24 October 2003)

Abstract - This study was aimed at ascribing muscle fat accretion in growing rabbits to changes in several extra-muscular and intra-muscular metabolic pathways. At 10 wk or 20 wk of age (n = 8 per group), tissue lipid content and metabolic indicators of nutrient anabolic or catabolic pathways were simultaneously assessed in the liver, perirenal fat, the heart and the Longissimus lumborum (LL) muscle, together with plasma concentrations in energy-yielding metabolites. Lipid content significantly increased with age (P $\leq$ 0.01) in the glycolytic LL muscle (+67%) and the oxidative heart (+30%). In the former muscle, it was statistically correlated (r2 = 0.68; P < 0.01) to the changes in the orientation of muscle metabolism towards an enhanced lipogenic capacity and a depressed capacity for fatty acid transport and nutrient oxidation, and to indications of lower availability in plasma glucose and triglycerides. In the heart, age-related fat accretion was positively associated (r2 = 0.48, P < 0.01) to intrinsic metabolic changes towards an enhanced lipogenic capacity, together with a lower availability in plasma glucose. Variables representative of cardiac catabolic capacity tended to be negatively correlated to fat content in the heart (r2 = 0.15, P = 0.07). In growing rabbits, muscle fat content variation was proven to result from a reciprocal balance between catabolic and anabolic fatty acid fluxes, rather than to be assigned to one specific energy metabolic pathway.

Key words: rabbits / muscle / lipogenesis / fatty acid binding proteins / oxidation / lipoprotein lipase

Corresponding author: Florence Gondret

© INRA, EDP Sciences 2004