饲料氧化鱼油引起草鱼肠道结构损伤、通透性增加

为了探讨饲料氧化鱼油对草鱼(Ctenopharyngodon idellus)肠道组织结构及其通透性的影响, 本实验以豆油、鱼油及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(4S2OF)、4%氧化鱼油(2S4OF)及6%氧化鱼油(6OF) 5组等氮、等能的半纯化饲料。经72d池塘网箱养殖后, 实验结果显示: (1)氧化鱼油显著增加(P0.05)草鱼血清和肠道MDA含量、增加肠道GSH含量(P0.05), 但随氧化产物含量上升GSH含量出现下降。(2)氧化鱼油会显著降低肠道内胆汁酸的含量(P0.05)。(3)氧化鱼油会显著增加肠道绒毛中杯状细胞的数量(P0.05), 且随着氧化产物的增加, 肠道微绒毛高度呈现先上升后下降趋势。(4)氧化鱼油会导致肠道紧密连接间隙增大, 增加肠道通透性, 使血清中D-乳酸及内毒素含量显著增加(P0.05)。结果表明, 饲料中鱼油氧化产物损伤了草鱼肠道组织结构, 尤其是肠道上皮细胞紧密连接结构损伤严重, 从而破坏了肠道黏膜的机械屏障功能, 使肠道通透性显著增加, 肠道细菌内毒素等发生转移。鱼油氧化产物会引起草鱼肠道氧化与抗氧化应激反应, 干扰草鱼肝-肠正常胆汁酸循环, 致使草鱼肠道胆汁酸不足。

EFFECTS OF DIETARY OXIDIZED FISH OIL ON THE INTESTINAL STRUCTURE AND PERMEABILITY OF GRASS CARP (CTENOPHARYNGODON IDELLUS)

To investigate effects of oxidized fish oil on the structure and permeability of intestine of grass carp (Cteno-pharyngodon idellus), five iso-nitrogen and iso-energy diets were formulated with soybean oil, fish oil and oxidized fish oil at different concentrations:6%fish oil, 6%soybean oil, 2%oxidized fish oil and 4%soybean oil, 4%oxidized fish oil, and 2%soybean oil, 6%oxidized fish oil, respectively. Compared with the 6%soybean oil, the oxidative product of fish oil at low level increased serum and intestine MDA and GSH content but diminished the GSH content at high level. The oxidized fish oil significantly reduced intestine bile acid content (P<0.05). The oxidized fish oil en-hanced the number of goblet cell (P<0.05), The microvilli of intestine was enlarged by low oxidized fish oil level and atrophied by high level. Serum D-lactic acid and endotoxin content increased significantly by oxidized fish oil because of the enlarged gap between tight junction, the hyperplasia and edema of villi. Thus, the oxidized fish oil might damage the intestinal epithelial tight junction and destroy the intestinal mucosal epithelium, which would increase intestinal oxidative stress and interfere the bile acids-cholesterol circulation of grass carp.