Effects Of Dietary Energy Levels And Sources On Muscle Lipid Metabolism Genes Expression In Pigs

The experiment was conducted with SYBR green RT-PCR method to evaluate effects of dietary energy levels and sources on muscle lipid metabolism genes expression in finishing Pigs.30 DLY barrows with a mean body weight of 64 kg were allotted randomly to three dietary treatments with ten replicates each group.Pigs were fed individually.Dietl was corn-soybean meal basal diet designed to supply 80%of the estimated DE need.Diet2 was the high carbohydrate diet with cornstarch supplying 20%energy need.Diet 3 was high fat diet with soybean oil supplying 20% energy need.Pigs were killed at 100 kg to determine backfat thickness,longissimus muscle area,MF content,genes expression and enzymes activities in relation to lipid metabolism.The results suggested that:①Backfat thickness and the IMF content significantly decreased in response to decreasing energy levers(P＜0.01),but longissimus muscle area increased(P＜0.01). Different energy sources have no effects on backfat thickness and longissimus muscle area(P＞0.05),but pigs fed Diet3 had higher IMF content,than pigs fed Diet2 (P＜0.05).②the activity of LPL was significantly decreased in response to decreasing energy levers(P＜0.01) and pigs fed Diet3 had higher the activity of LPL than pigs fed Diet2(P＜0.05),There were significantly positive correlations between IMF and the activity of LPL(P＜0.01).The activity of FAS didn't effect by Energy level,but pigs fed Diet2 had higher the activity of FAS than pigs fed Diet3(P＜0.01).③Decreasing diet energy levers decreased the mRNA expression of FAS, SREBP(P＜0.01),and increased CPT-1(P＜0.01),PPARγ(P＜0.01),PPARα(P＜0.01),when the same energy lever with different energy sources,pigs fed Diet3 had higher the expression of FAS(P＜0.05),SREBP(P＜0.05) mRNA,but lower the expression of CPT-1(P＜0.01),PPARγ(P＜0.01),PPARαmRNA(P＞0.05) mRNA than pigs fed Diet2.④the protein content and mRNA expression of the UCP3 significantly increased in response to decreasing energy levers(P＜0.01).When the same energy lever with different energy sources,pigs fed Diet3 had higher the protein content and mRNA expression of the UCP3 than pigs fed Diet2.(P＜0.05).The results indicated that dietary energy soures and levels can regulate muscle fat deposition by mediateing expression of genes related to muscular lipid metabolism.