Effects Of Dietary Energy Composition On Fatty Metabolism And Gene Expression In Piglets

Fifteen piglet (Duroc×Landrace×Yordshire) barrows with average body weight of16.65kgwere allotted randomly to three dietary treatments with five replicates each group. Digestibleenergy of diets were all14.6MJ/kg, and the protein level of diets were all17%.The ratio ofcarbohydrate energy value and vegetable fat energy value (CEV:FEV) were respectively5.28:1(group A),2.92:1(group B) and1.15:1(group C).The paper was designed to study theeffects of dietary energy composition on growth performance and nutrients metabolism inpiglets by the determination of growth performance and blood biochemical indicators and usingreal-time fluorescence quantitative PCR method to detect gene mRNA expression of fatmetabolism related enzymes.The results showed as follows：1. Under the conditions of equal digestible energy value and nitrogen，the CEV:FEV of thethree diets were respectively5.28:1，2.29:1and1.15:1.The results showed that average dailygain(ADG) were respectively736.48g/d,731.75g/d,709.52g/d, and average daily feed intake(ADFI) were respectively1.42kg/d,1.39kg/d,1.44kg/d. These two results both showed thatthere were no significantly difference(P>0.05). Feed/gain（F/G）of the three groups were1.92,1.89,2.03, while F/G of group B piglets was significantly decreased(P<0.05).Dietary energy composition changed serum concentration of glucose(GLU), triglyceride,cholesterol, high-density lipoprotein and low-density lipoprotein.The results showed that bloodglucose were decreased with decreasing dietary carbohydrate concentration, while the level oftriglyceride, cholesterol, high-density lipoprotein, low-density lipoprotein were increased.Concentration of GLU were9.33,9.07,7.89, respectively. Compared with group C, GLU ofgroup A and group B were significantly increased(P<0.01) by18.25%,14.96%. Serumconcentration of triglyceride were significantly lower in group A and group B than in group C(P<0.01), but there was no significantly difference between group A and group B (P>0.05).Theconcentration of cholesterol in serum was increased with the decrease of CEV:FEV, cholesterolof group B and group C were significantly higher than that of CEV:FEV in group A (P<0.01).Compared with high fatty energy group (CEV:FEV was1.15:1), high-density lipoproteinof group A and group B were significantly increased by54.1%(P<0.01) and32.5%(P<0.05).High carbohydrate group had significantly effect on low-density lipoprotein concentration(P<0.05).2. Under the conditions of equal digestible energy value and nitrogen, dietary energy composition influenced on mRNA expression of SREBP-1c, FASN, ACC and PPAR-α in liverand muscle of piglets.The mRNA expression of SREBP-1c and FASN were significantly increased in groupB(P<0.01). While the mRNA expression of ACC and FASN decreased, mRNA expression ofACC had no significantly (P>0.05) with dietary fatty concentration increasing. The mRNAexpression of PPAR-α was significantly increased in group B (P <0.01). The mRNA expressionof PPAR-α in liver of piglet was not significant between the high carbohydrate energy group andhigh fatty energy group (P>0.05). The mRNA expression of SREBP-1c,ACC and FASN inmuscle of group B were significantly increased compared with group A(P<0.01).Compared withhigh carbohydrate group, the mRNA expression of SREBP-1c, ACC and FASN of4.5%soybeanoil group was significantly increased by244.6%,115.5%,59.6%, respectively, and mRNAexpression of PPAR-α was decreased by17.4%(P>0.05).The mRNA expression of SREBP-1c, ACC, FASN in high fat group was increased, but was not significant (P>0.05), mRNAexpression of PPAR-α was significantly increased by72%(P <0.01).In conclusion, dietary energy composition had effects on feed conversion ratio, serumbiochemical indicators and lipid metabolism related enzyme gene expression in liver and muscleof piglet.Under the conditions of equal digestible energy value and nitrogen, dietary energyconstruction had little effect on the performance. When feed group B diet, feed conversion ratiowas higher than others of piglets. Decreasing the dietary energy construction value ratio couldhave effect on serum concentration of Glu, triglyceride, cholesterol, high-density lipoprotein andlow-density lipoprotein, and mRNA expression of fatty metabolism relates enzyme genes.