肌醇对幼建鲤肠道抗氧化能力的作用和作用机制

Lipid peroxidation, protein oxidant, antioxidant status and gene expression of the intestine in juvenile Jian carp (Cyprinus carpio var. Jian) fed graded levels of myo-inositol (MI) (163.5, 232.7, 384.2, 535.8, 687.3, 838.8 and 990.3 mg/kg diet) for 60 days were investigated. MDA and PC contents significantly decreased with increasing dietary MI levels up to 535.8 and 838.8 mg/kg diet (P < 0.05), respectively, and leveled off thereafter (P > 0.05). Both ASA and AHR capacity were higher for fish fed MI-supplemented diets than MI-unsupplemented diet (P < 0.05). SOD activity in the intestine was higher for fish fed MI-supplemented diets than MI-unsupplemented diet (P < 0.05). Intestinal CAT activity significantly increased with increasing dietary MI levels up to 535.8 mg/kg diet (P < 0.05), and plateaued thereafter (P > 0.05). GST activity in the intestine was lower for fish fed diets containing MI ≤ 535.8 mg/kg diet than fish fed diets containing MI ≥ 687.3 mg/kg diet (P < 0.05). GPx activity was the lowest for fish fed MI-unsupplemented diet, followed by 232.7 mg MI/kg diet, and the highest for fish fed diets containing MI ≥ 687.3 mg/kg diet (P < 0.05). GR was the highest for fish fed diets containing ≥ 687.3 mg/kg diet, and the lowest for fish fed the 232.7 and 163.5 mg MI/kg diet (P < 0.05). GSH content significantly increased with increasing dietary MI levels up to 384.2 mg/kg diet (P < 0.05), and plateaued thereafter (P > 0.05). MI significantly increased the gene expression of CuZnSOD, MnSOD, CAT and GPx1b in the proximal intestine, CuZnSOD, CAT, GPx1a and GPx1b in the mid intestine of Jian carp (P < 0.05). MI decreased the mid intestinal MnSOD and proximal, mid and distal intestinal GR gene expression of Jian carp (P < 0.05). MI did not change the proximal intestinal MnSOD, diatal CuZnSOD, MnSOD, CAT, GPx1a and GPx1b gene expression. These results indicated that MI could enhance the non-enzymic and enzymic antioxidant ability to inhibit the lipid peroxidation and protein oxidation, which might be partly related to the up-regulated mRNA levels of CuZnSOD, CAT and GPx1b in the proximal intestine and mid intestine, as well as the GPx1a mRNA levels in the mid intestine of fish.