亚麻籽和鱼油对蛋鸡蛋黄n-3多不饱和脂肪酸含量与肝脏脂肪酸代谢的影响

本试验旨在研究饲粮中添加亚麻籽和鱼油对蛋鸡蛋黄n-3多不饱和脂肪酸含量、肝脏脂肪酸组成及其合成代谢基因表达的影响。选择28周龄海兰褐壳蛋鸡96只,随机分为4组,每组24只。对照组饲喂基础饲粮,试验组分别在基础饲粮中添加10%亚麻籽、10%亚麻籽+5%鱼油和5%鱼油。饲养21 d后连续收集7 d鸡蛋,然后每组随机选取4只鸡屠宰取样。结果表明,与对照组相比:1)添加亚麻籽和鱼油均显著增加蛋黄中n-3多不饱和脂肪酸含量(P0.05),其中单独添加鱼油的蛋黄中二十二碳六烯酸(DHA)和二十碳五烯酸含量最高;2)试验组肝脏单不饱和脂肪酸比例均显著降低(P0.05),肝脏n-3多不饱和脂肪酸比例均显著增加(P0.05);3)单独添加鱼油显著降低肝脏脂肪酸延长酶1、脂肪酸延长酶2和去饱和酶(脂肪酸去饱和酶1、脂肪酸去饱和酶2和硬脂酰辅酶A去饱和酶1)基因表达水平(P0.05)。由此可见,蛋鸡饲粮中单独添加亚麻籽或鱼油可以富集蛋黄n-3多不饱和脂肪酸沉积;添加亚麻籽促进肝脏α-亚麻酸转化生成DHA过程,表现为上调脂肪酸延长酶和去饱和酶基因表达,添加鱼油显示相反结果。

Effects of Dietary Flaxseed and Fish Oil on n-3 Polyunsaturated Fatty Acid Content in Egg Yolk and Fatty Acid Metabolism in Liver of Hens

This experiment was conducted to investigate the effects of dietary flaxseed and fish oil on n-3 poly-unsaturated fatty acid content in egg yolk, fatty acid composition and fatty acid biosynthesis gene expression in liver of hens. Ninety-six Hyline Brown hens were divided into 4 groups with 24 hens per group. Hens in the control group were fed a basal diet, and those in trial groups were fed the basal diet+10% flaxseed, the basal diet+10% flaxseed+5% fish oil, and the basal diet+5% fish oil, respectively. Eggs were collected for 7 days after 21 days feeding, and then 4 hens in each group were slaughtered for samples. The results showed as fol-lows, compared with control group, 1) dietary flaxseed and fish oil significantly increased the n-3 polyunsatu-rated fatty acid contents in yolk ( P<0.05) , and contents of docosahexaenoic acid ( DHA) and timnodonic acid were the highest in yolk affected by dietary fish oil. 2) The liver monounsaturated fatty acid ratios were signifi-cantly decreased ( P<0.05) , and the liver n-3 polyunsaturated fatty acid ratios were significantly increased ( P<0.05) in all trial groups. 3) Dietary fish oil significantly decreased gene expressive levels of ELOVL fatty acid elongase 1, ELOVL fatty acid elongase 2 and fatty acid desaturase such as fatty acid desaturase 1, fatty acid desaturase 2 and stearoyl CoA desaturase 1 ( P<0.05) . In conclusion, dietary flaxseed or fish oil can concen-trate n-3 polyunsaturated fatty acid content in yolk of hens. Dietary flaxseed can promote generation process from α-linolenic acid to DHA, exhibiting up-regulating expressive levels of fatty acid elongase and desaturase genes. Dietary fish oil presented contrary results to flaxseed.