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

摘要:为了探究饲料中不同磷水平对罗非鱼肠道磷和脂肪酸转运及甘油三脂沉积的影响，我们配制了3组不同磷水平的饲料，饲料中磷含量分别为1.21 %（LPD）、1.75 %（MPD）和2.66 %（HPD）），用配制的饲料投喂罗非鱼10周。结果显示：与LPD组相比，HPD组显著增加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组显著增加罗非鱼肠道组织甘油三酯（TG）的含量（42.9%）。 综上，我们的研究表明，饲料中高磷水平增加肠道组织TG的含量，上调脂肪酸吸收途径和抑制脂肪酸排出途径。我们的研究为深入揭示磷影响鱼类磷代谢及脂类代谢的机理奠定基础。

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

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 and lipid metabolism for 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 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 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 upregulated 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%) , downregulated 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 phosphorus dietary increased intestinal TG content by inhibiting the fatty acid export and upregulating the fatty acid absorption. Our study built a good basis for the further elucidation into the mechanism of dietary phosphorus influencing phosphorus and lipid metabolism in fish.