Does feed restriction and re-alimentation differently alIect lipid content and metabolism according to muscle type in pigs (Sus scrofa)?

This study aimed to investigate whether feed restriction and re-alimentation differently affect lipid content and activities of lipogenic or catabolic enzymes according to muscle types in pigs. At around 28 kg body mass (BW), sixty pigs (n = 30 per group) were allocated to either ad libitum (AL) or restricted/re-feeding (RA) regimens. After feed restriction (80 kg BW), lipid content was reduced (P < 0.01) in the oxidative rhomboideus (F-H) as in the glycolytic biceps femoris (BF) muscles of RA pigs compared with At, pigs. Lower activities (P < 0.05) of the lipogenic enzymes fatty acid synthase (FAS) and malic enzyme (ME) were observed in the RH but not in the BF of RA vs. AL pigs. After refeeding (110 kg BW), lipid content was restored in the RH, but was still 12% lower (P < 0.05) in the BF of RA compared with AL pigs. In the RH, the trend for an enhanced FAS activity and for a smaller weight-related decrease of ME activity in RA pigs than AL pigs during re-feeding, may have contributed to the muscle fat recovery observed in the RA pigs. In the BF, higher oxidative enzyme activities (P < 0.10) in RA pigs compared to AL pigs might explain the incomplete lipid recovery observed after re-feeding in the former animals. In conclusion, metabolic activities in response to restriction and re-feeding differed according to muscle metabolic type. (c) 2007 Elsevier Inc. All rights reserved.