This study was aimed to evaluate the effects of dietary supplementation of probiotics Bacillus cereus (BC), B. subtilis (BS), Paracoccus marcusii (PM), and Lactobacillus plantarum (LP) on growth, immune response, antioxidant property, and intestine health of juvenile grass carp. Our results showed that dietary probiotics could promote the growth performance, which was significantly increased in BS, PM, and LP groups compared to the fish in Control group. Also, probiotics supplementation significantly enhanced the immunity of fish measured by the content of C3 and C4, and/or AKP activity in serum, and elevated antioxidant property of intestine accompanying by a significantly lower content of malondialdehyde. Compared to Control group, dietary B. cereus and B. subtilis significantly affected intestinal antioxidant system through Nrf2 signaling pathway by up-regulating the expression of catalase, CuZn superoxide dismutase and/or Mn superoxide dismutase, and further improved the intestinal barrier function by up-regulating mRNA levels of ZO-1, ZO-2, ZO-3, and Clauding-12. Besides, B. cereus, P. marcusii, and L. plantarum supplementation could decrease intestinal inflammation by suppressing TLR4 signaling pathway, meanwhile P. marcusii supplementation up-regulated the expression of ZO-2 and ZO-3. Overall, our results indicated that dietary B. cereus, B. subtilis, P. marcusii, and L. plantarum had a positive impact on the growth performance, immunity and antioxidant property of grass carp, and B. cereus, B. subtilis, and P. marcusii exerted benefits on the intestinal health through elevating antioxidant property and decreasing permeability of intestine.

这项研究的目的是评估膳食补充益生菌蜡状芽孢杆菌（BC），枯草芽孢杆菌（BS），马氏副球菌（PM）和植物乳杆菌的效果（LP）对少年草鱼的生长，免疫反应，抗氧化性能和肠道健康的影响。我们的结果表明，膳食益生菌可以促进生长性能，与对照组相比，BS，PM和LP组中的益生菌含量显着提高。同样，补充益生菌可以显着增强通过C3和C4含量和/或血清中AKP活性测得的鱼的免疫力，并通过显着降低丙二醛含量提高肠道抗氧化性能。与对照组相比，饮食中的蜡状芽孢杆菌和枯草芽孢杆菌通过上调过氧化氢酶，铜锌超氧化物歧化酶和/或锰超氧化物歧化酶的表达，通过Nrf2信号通路显着影响肠道抗氧化系统，并通过上调ZO-1，ZO-2， ZO-3和Clauding-12。此外，蜡状芽孢杆菌，马库氏假单胞菌和植物乳杆菌的添加可通过抑制TLR4信号传导途径来减轻肠道炎症，而马库氏假单胞菌的添加则上调ZO-2和ZO-3的表达。总体而言，我们的结果表明，饮食中的蜡状芽孢杆菌，枯草芽孢杆菌，马库斯霉和植物乳杆菌对草鱼的生长性能，免疫力和抗氧化性能具有积极影响，而蜡状芽孢杆菌，枯草芽孢杆菌和马库氏假单胞菌通过提高抗氧化性和降低肠的通透性而对肠道健康产生益处。