| The overall objective is to study the effects of LCn-3PUFA-enriched feed on fasting plasms glucose, fasting plasma insulin, fatty acids composition of tissues, lipid rafts, and phospholipids in growing pigs.12 castrated Largewhite pigs aged 90d±4d, weighted 28.7kg±1.3kg were assigned randomly into 2 groups. The control feed was provided with 3.6% soybean oil, and the DHA feed was provided with 7.5% DHA-gold. DE, CP, Ca, P content of diet in two groups were at the same level. The trial lasted for 35d. Before and after the trial, blood was collected and stored. At the end of the breeding,6 of either group were killed. Blood, adipose tissue and skeletal muscle were collected and stored. Measurements of this study contained fasting plasms glucose concentration, fasting plasma insulin concentration, fatty acids composition, insulin receptor content in lipid raft, GM3 centent in tissue and in lipid raft, fatty acids composition of phospholipids in adipose tissue. The major results of this study are shown as following.1. The effects of LCn-3PUFA on plasma measurement. Both FPG and FPI had no significant difference between two groups (P>0.05).2. The effects of LCn-3PUFA on FA composition in tissues. GC was used to measure FA percent in feed, adipose tissue and skeletal muscle. The major results were:(1) The FA of control feed were mainly C16:0, C18:1n-9c and C18:2n-6c. The FA of experimental feed were mainly C16:0, C18:2n-6c and C22:6n-3. n-3PUFA content in experimental feed is 3-fold of that in control feed. (2) Feeding with control feed or experimental feed had significant effects on FA composition in tissues. In adipose tissue of experimental group, C16:0, C18:0, C22:6n-3, LCn-3PUFA and SFA were significantly higher (P<0.01), and C18:2n-6c,18:3n-3, n-6PUFA and PUFA were significantly lower (P<0.01) than control group. In longissimus dorsi muscle and biceps femoris muscle of experimental group, LCn-3PUFA was significantly higher (P<0.01), C18:2n-6c, n-6PUFA and PUFA were significantly lower (P<0.01) than control group. The difference in FA composition in tissues was consistent with feed. DHA-gold extremely improved LCn-3PUFA content in adipose tissue and skeletal muscle. (3) FA had different content in different tissues. Content of C22:6n-3 was similar in tissues. C20:4n-6 content was the lowest in adipose tissue.3. The effects of LCn-3 PUFA on lipid rafts and phospholipids. The results were:(1) Lipid rafts were distributed in the third to fifth fraction and the most in the fourth. Both in homogenate and in lipid raft, IR content had no significant difference (P>0.05). Lipid raft had significant higher concentration of GM3 (P<0.01) than homogenate.GM3 content in DHA group had a tendency to be lower than control group, but the difference was not significant. (2) TLC was used to isolate phospholipids. Rf of PE, PS, PI and PC were 0.79,0.62,0.56 and 0.33, respectively. Phospholipids of adipose tissue were mainly PE and PC. PE and PC were not significantly influenced by LCn-3PUFA in this study.The conclusions of this study include:(1) LCn-3PUFA had no significant effects on fasting plasma glucose concentration and fasting plasma insulin concentration in this study. (2) LCn-3PUFA could significantly influence fatty acid profile in tissues, including adipose tissue and muscle, and had different effects on different tissues. (3) GM3 content in lipid raft was significantly higher than in total adipose tissue. LCn-3PUFA had a tendency to lower GM3 content in lipid raft, which meant LCn-3PUFA might have effects to regulate GM3 synthesis and accumulation in lipid raft. |
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