饲料氧化鱼油引起草鱼肠道黏膜结构屏障损伤

为了研究饲料氧化鱼油对草鱼肠道屏障结构和肠道通透性的影响。(实验目的)以豆油、鱼油、氧化鱼油作为饲料脂肪源,分别设计鱼油组(6F)、豆油组(6S)、2%氧化鱼油(2OF)、4%氧化鱼油(4OF)及6%氧化鱼油(6OF)5组等氮、等能半纯化饲料,在池塘网箱养殖草鱼(平均体重74.8士1.2)72d。采用实时荧光定量PCR(qRT-PCR)的方法,测定了草鱼肠道紧密连接蛋白中闭锁蛋白Occludin,闭合蛋白Claudin3、Claudin15a和胞浆蛋白ZO-1、ZO-2、ZO-3的基因表达活性,并结合肠黏膜细胞间紧密连接结构透射电镜观察结果、肠道通透性标志性指标测定结果综合分析。(实验方法)结果显示：在添加氧化鱼油后,(1)血清二胺氧化酶活性、内毒素和D-乳酸含量都出现显著增加(P<0.05)；(2)组成肠黏膜细胞间紧密连接结构的闭合蛋白Claudin-3、Claudin-15a和胞浆蛋白ZO-1、ZO-2、ZO-3基因表达活性显著下调(P<0.05),而闭锁蛋白Occludin基因表达活性出现不同程度的下调,但差异不显著(P>0.05)；(3)透射电镜观察结果显示肠黏膜细胞间紧密连接结构出现缝隙；⑷饲料中的AV值、POV值、MDA含量与闭合蛋白Claudin-3、Claudin-15a,胞浆蛋白ZO-1、ZO-2、ZO-3和闭锁蛋白Occludin基因表达活性均显示负相关关系的变化趋势,其中饲料POV值、MDA含量与胞浆蛋白ZO-1基因表达活性呈极显著负相关关系(P<0.05)。(实验结果)结果表明,在饲料中添加氧化鱼油后,氧化鱼油中的过氧化物、丙二醛等油脂氧化产物导致组成肠道黏膜细胞间紧密连接结构的蛋白基因表达活性显著下调、紧密连接物理性结构显著损伤,致使肠黏膜屏障结构的完整性被破坏、肠黏膜通透性显著增加。(实验结论)

The study on damage of intestinal mucosa barrier structure with oxidized fish oil diets in Ctenopharyngodon idella

A 72-day experiment was carried out to investigate the effect of oxidized fish oil on intestinal mucosa barrier structure and intestinal permeability of grass carp (Ctenopharyngodon idellus)(average weight 74.8 ± 1.2). Five diets containing different levels of soybean oil, fish oil and oxidized fish oil (6% fish oil, 6% soybean oil, 2% oxidized fish oil; 4% oxidized fish oil, 6% oxidized fish oil) were evaluate at Nitrogen and so on energy. Using qRT-QPCR method for quantitative detection of gene expression levels about atresia protein Occludin, closed protein Claudin3, Claudin15a and cytoplasmic protein ZO-1, ZO-2, ZO-3 in intestine , in addition TEM observations of intestinal mucosal cells tight junction and intestinal permeability index. The results showed that under oxidized fish oil, (1) Serum diamine oxidase activity, endotoxin and D-lactic acid content appeared significantly increased (P<0.05). (2) The gene expression of closed protein Claudin3, Claudin15a and cytoplasmic protein ZO-1, ZO-2, ZO-3 were significantly decreased. (3) The tight junction structure of intestinal mucosal cells appeared gap. (4) The value of AV, POV and the content of MDA in diet downregulated with closed protein Claudin3, Claudin15a and cytoplasmic protein ZO-1, ZO-2, ZO-3 gene expression, besides the value of POV and the content of MDA in diet significantly downregulated with cytoplasmic protein ZO-1 gene expression (P<0.05). Collectively, the present study demonstratesd that the damaged product of fish oil led to tight junction protein gene expression activity significantly decreased and tight junction physical structure significant damaged which resulting in intestinal barrier structure destroyed and intestinal permeability significantly increased.