枯草芽孢杆菌对草鱼肝脏脂质代谢的调节作用

为研究益生枯草芽孢杆菌(Bacillus subtilis)对草鱼(Ctenopharyngodon idella)肝脏脂质代谢及抗氧化功能的影响, 实验设置对照组(Con组)、Aeromonas hydrophila组(Ah组)、Aeromonas hydrophila+Bacillus subtilis组(Ah+Bs组)、Bacillus subtilis+Aeromonas hydrophila组(Bs+Ah组), 三个实验组均腹腔注射1×105 CFU/fish嗜水气单胞菌(Aeromonas hydrophila), 枯草芽孢杆菌饲料含菌量为1×107 CFU/g, 实验周期为56d, 并于第28和第56天取样。结果表明, 与Ah组相比, 投喂枯草芽孢杆菌饲料后, (1)体增重率、特定生长率显著增加(P<0.05); (2) 28d时肝脏油红O染色脂滴面积及脂肪含量显著下降(P<0.05); (3)调节血脂代谢及缓解肝脏损伤: 血清胆固醇、甘油三酯、高密度脂蛋白胆固醇、低密度脂蛋白胆固醇含量升高, 谷草转氨酶和谷丙转氨酶活性显著降低(P<0.05); (4)调节脂质代谢: 28d时乙酰辅酶A羧化酶的表达水平下调, 脂蛋白脂酶及脂肪甘油三酯脂肪酶的表达水平上调; (5)增强肝脏抗氧化能力、减少脂质过氧化的发生: 肝脏超氧化物歧化酶、过氧化氢酶、谷胱甘肽、总抗氧化能力提高; 丙二醛及过氧化氢含量降低。综上, 在饲料中添加益生枯草芽孢杆菌可以增强草鱼的抗氧化能力, 缓解机体因嗜水气单胞菌感染造成的肝脏损伤, 调节肝脏脂质代谢功能, 减少脂质在肝脏中的积累, 并促进草鱼的生长。

EFFECTS OF BACILLUS SUBTILIS ON THE HEPATIC LIPID METABOLISM OF CTENOPHARYNGODN IDELLUS

To investigate the effects of Bacillus subtilis on the hepatic lipid metabolism and antioxidant function, the grass carp were randomly divided into 4 groups: control group (Con), Aeromonas hydrophila group (Ah), Aeromonas hydrophila+Bacillus subtilis (Ah+Bs) group and Bacillus subtilis+Aeromonas hydrophila group (Bs+Ah), and the three experimental groups were intraperitoneally injected with 1×105 CFU/fish A. hydrophila, and B. subtilis diet contained 1×107 CFU/g for a trial of 56 days. The results showed that two groups fed with B. subtilis had higher weight gain rate and special growth rate compared with the Ah group (P<0.05). B. subtilis significantly decreased liver lipid droplet size and the hepatic lipid content at day 28 (P<0.05), increased the content of serum cholesterol, triglyceride, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol and reduced activities of aspartate aminotransferaseand alanine aminotransferase. B. subtilis downregulated the expression of acetyl-CoA carboxylase alpha and upregulated the expression of lipoprotein lipase and adipose triglyceride lipase on day 28. B. subtilis enhanced superoxide dismutase, catalase, glutathione and total antioxidant capacity, and diminished malondialdehyde and hydrogen peroxide. In conclusion, probiotic B. subtilis supplementation can promote growth, enhance the antioxidant function, reduce the liver damage caused by infection of A. hydrophila, regulate the hepatic lipid metabolism, and reduce the hepatic lipid accumulation in grass carp.