Influence of genetic line on lipid metabolism traits of rabbit muscle

Abstract

[EN] The effects of genetic line on intramuscular fat content, perirenal fat content, and activity of some enzymes involved in lipid metabolism were studied. One hundred twenty animals from 3 synthetic lines, A and V selected for litter size at weaning and R selected for growth rate between weaning and slaughter, were used in this experiment. One-half of the rabbits were slaughtered at 9 or 13 wk of age, and perirenal fat content (PF) and 2 muscles, LM and semimembranosus proprius (SP), were studied. Semimembranosus proprius muscle showed greater lipogenic [glucose-6-phosphate dehydrogenase (G6PDH) and fatty acid synthase (FAS)] and oxidative enzyme activities [beta-hydroxyacyl-CoA dehydrogenase (HAD) and citrate synthase (CS)] compared with LM. Longissimus muscle had less lipogenic and more glycolytic activity (lactate dehydrogenase (LDH)] than SP. Enzymatic activity and lipid content were affected by age. Lipogenic and glycolytic enzyme activity increased from 9 to 13 wk of age in SP muscle. In LM, lipogenic activity remained stable, but glycolytic activity increased and lipolytic and oxidative activity decreased with age. Genetic line had an influence on lipogenic, lipolytic, and oxidative enzyme activities, which was related to differences in muscle lipid content (IMF). Line A showed greater lipogenic (G6PDH and malic enzyme) and lipolytic activity (neutral lipase), which was associated with a greater IMF in this line. In SP muscle, line R showed a greater HAD activity than lines A and V, and CS activity was greater in lines R and A than in line V. In LM, no differences between lines were found for oxidative enzymes. The relationship between IMF and PF was different between lines, with lines A and V showing positive correlation values (r - 0.56 and r - 0.70, respectively) and line R no relationship between both traits (r - 0.06). Results from this study showed that lipogenic and oxidative enzyme activity are related to muscle lipid deposition. Genetic line had an effect on metabolic enzyme activity and, consequently, on IMF deposition.