饲料磷水平对吉富罗非鱼肠道磷和脂肪酸转运及甘油三酯沉积的影响

Effects of dietary phosphorus levels on phosphorus and fatty acid transport and triglyceride deposition in the intestine of GIFT tilapia (Oreochromis niloticus)

  • 摘要: 为了探究饲料中不同磷水平对吉富罗非鱼肠道磷和脂肪酸转运及甘油三脂沉积的影响,实验配制了3组不同磷水平的饲料 1.21% (LPD)、1.75% (MPD)和2.66 % (HPD),投喂吉富罗非鱼10周。结果显示,与LPD组相比,HPD组显著增加吉富罗非鱼肠道钠磷协同转运体SLC34A2基因(95.7%)和蛋白(200.1%)的表达,增加肠道组织总磷含量(79.2%);HPD组上调脂肪酸吸收基因cd36、fabp1、fabp2和fatp1及甘油三酯合成基因dgat1的表达(11.2%~54.0%),下调脂肪酸转运基因apob-100的表达(37.7%),增加游离脂肪酸(NEFA)的含量(241.1%)。与LPD组相比,HPD组显著增加吉富罗非鱼肠道组织甘油三酯(TG)的含量(42.9%)。研究表明,饲料中高磷水平可增加肠道组织TG的含量,上调脂肪酸吸收途径和抑制脂肪酸排出途径。

     

    Abstract: Phosphorus is an important mineral element in animals, and it is an essential component of bone, phospholipids, nucleoproteins and nucleic acids. However, there are few studies on effects of dietary phosphorus on phosphorus content, fatty acid transport and lipid deposition in the intestines. The present study was conducted to explore the effect of dietary phosphorus levels on phosphorus and fatty acid transport, and lipid metabolism in the intestines of GIFT tilapia. Three diets were formulated with phosphorus at the levels of 1.21% (LPD), 1.75% (MPD), 2.66% (HPD). The diets were fed to juvenile GIFT tilapia for 10 weeks. Compared with the LPD group, HPD group significantly increased gene (95.7%) and protein expression (200.1%) of the SLC34A2 and total phosphorus content (79.2%) of the intestine. Compared with the LPD group, the HPD group up-regulated the expression of the fatty acid absorption-related genes cd36, fabp1, fabp2, and fatp1 and the TG synthesis-related genes dgat1(by 11.2% to 54.0%) , down-regulated the expression of the fatty acid transport-related genes apob-100 (37.7%), and increased the content of non-esterified fatty acid (NEFA) (241.1%) in the intestine. HPD also increased TG content (42.9%). In conclusion, our study showed that high dietary phosphorus increased intestinal TG content by inhibiting the fatty acid export and up-regulating the fatty acid absorption. Our study may provide a basis for the further elucidation into the mechanism of dietary phosphorus influencing phosphorus and lipid metabolism in fish.

     

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