Effects Of α-linolenic Acid In Diets On Fatty Acids Composition Of Tissues And Lipid Metabolism Of Growing Meat Rabbits

The experiment was conducted to study the effects ofα-linolenic acid (ALA) on growth performance, blood lipids, immunity, liver and muscle fatty acid composition, meat qualityand liver acetyl-CoA carboxylase (ACC) and carnitine acyl transferase 1 (CPT1) mRNA expression of weaner to growing meat rabbits. The experiment was divided into two phases of Weaning -2 months and 2-3 months.Two hundred 1-month-old meat rabbits were randomly assigned to 5 groups with 40 replicates in each group and each replicate contained 1 rabbit. Rabbits in 5 groups were fed basal diet with 0, 0.1%, 0.2%, 0.3% and 0.4% ALA, respectively. The trial lasted for 7 days for adaptation, and 23 days for sampling. The results showed that: ALA had significant influence on ADI, ADG, F/G and the slaughter rate (P<0.05). ALA significantly decreased serum triglyceride (TG) (P=0.0012), cholesterol (P=0.0056) and low density lipoprotein (LDL) levels (P=0.0004). ALA had no significant influence on IgG, IgA and Spleen index, but 0.4% significantly reduced the level of IgM and liver index. ALA had no significant influence on liver and musculus longissimus dorsi fatty acid (SPA) (P>0.05), but significantly reduced the relative content of the hepatic monounsaturated fatty acids (MUFA) (P<0.05) and significantly increased the relative content of liver and musculus longissimus dorsi polyunsaturated fatty acids (PUFA) (P<0.05) and n-3 PUFA (P<0.0001), ALA significantly decreased n-6/n-3 ratio(P<0.01), and had no influence on the relative content of n-6 PUFA in all groups. ALA significantly increased (P=0.0168) LPL activity of blood and significantly increased (P<0.01) LPL, LH and LA activity of liver. ALA had significant influence on liver ACC and CPT1 mRNA expression (P=0.0002, P=0.0001, respectively).One hundred abd fifty 2-month-old meat rabbits were randomly assigned to 5 groups with 30 replicates in each group and each replicate contained 1 rabbit. Rabbits in 5 groups were fed basal diet with 0, 0.1%, 0.2%, 0.3% and 0.4% ALA, respectively. The trial lasted for 7 days for adaptation, and 23 days for sampling. The results showed that: ALA had no significant influence on ADG, F/G and the slaughter rate (P>0.05). ALA significantly decreased (P<0.01) serum triglyceride, cholesterol and very low density lipoprotein (VLDL) levels. ALA significant increased on serum IgA, IgM. ALA significantly increased (P<0.05) LPL and HLactivity of serum and significantly increased (P<0.05) LPL activity of liver. ALA had no significant influence on liver and musculus longissimus dorsi fatty acid (SPA) (P>0.05), but significantly reduced the relative content of the hepatic monounsaturated fatty acids (MUFA) (P<0.05) and significantly increased the relative content of liver and musculus longissimus dorsi polyunsaturated fatty acids (PUFA) (P<0.01) and n-3 PUFA (P<0.0001), ALA significantly decreased n-6/n-3 ratio(P<0.01), and had no influence on the relative content of n-6 PUFA in all groups. ALA significantly increased (P=0.0019) L value of musculus, and significantly decreased a value of musculus, but 0.1% and 0.2% had no significant influence with 0. ALA had no significant influence (P>0.05) on b value, PH, Shear force and Drip loss. ALA significantly decreased(P=0.0360)serum Insulin, and significantly increased (P=0.0268)serum leptin. ALA had significant influence on liver ACC and CPT1 mRNA expression (P<0.0001).