饲料中胆汁酸对红鳍东方鲀脂肪酸组成及抗氧化能力的影响

Effect of dietary bile acid supplementation on fatty acid composition and anti-oxidative capacity of tiger puffer Takifugu rubripes

为研究饲料中添加胆汁酸对红鳍东方鲀脂肪酸组成及抗氧化能力的影响,以鱼油为主要脂肪源,配制5种等氮饲料,对初始体质量为14 g的红鳍东方鲀进行为期56 d的投喂养殖实验。设置适宜脂肪含量(8%)的对照组,并在对照组添加0.02%及0.10%的胆汁酸,分别获得低胆汁酸添加组(BA组)和高胆汁酸组(HBA组)。另设一高脂组(脂肪含量12.5%,HL组)及高脂+0.02%胆汁酸组(HLBA组)。结果表明,添加胆汁酸的处理组肌肉和肝脏MUFA均低于对照组,其中HBA组显著低于对照组(P<0.05)。肌肉中n-6PUFA含量在HLBA组和HL组显著低于其他组(P<0.05)。在适宜脂肪含量的3个处理组间,肝脏中的C20∶0、C16∶1n-7、C18∶1n-9、C18∶2n-6、C20∶4n-6、C18∶3n-3、C18∶4n-3、C20∶5n-3和C22∶6n-3都呈现随着胆汁酸添加量增加而降低的趋势。血清超氧化物歧化酶活性和谷胱甘肽过氧化物酶活性都有随着胆汁酸添加而升高的趋势,且在高脂组显著高于对照组(P<0.05);血清谷胱甘肽还原酶则呈现相反的趋势。肝脏中谷胱甘肽过氧化物酶1的mRNA相对表达量在对照组显著高于其他组,而BA组氧化还原酶1的基因表达量显著高于对照组;在高脂组添加胆汁酸显著升高了过氧化氢酶的基因表达量。综上所述,饲料中胆汁酸的添加降低了饲料及鱼体组织中一系列长链脂肪酸的含量,胆汁酸对血清抗氧化蛋白活性的影响与其对肝脏抗氧化相关基因表达的影响结果不一致。

A 56-days feeding trial was conducted with tiger puffer Takifugu rubripes(average initial body of 14 g),in order to investigate the effects of dietary bile acid supplementation on the fatty acid composition and anti-oxidative capacity.The feeding trial was conducted in indoor flow-through seawater system.Two diets with suitable(8.5%,diet C)or high lipid level(12.5%,diet HL)were prepared.BA as porcine bile extract mainly composed of hyodeoxycholic acid was supplemented into the two diets at the level of 0.02%to formulate diet BA and diet HLBA,respectively.A fifth diet was prepared by supplementing an excess level of porcine bile extract(0.10%)into diet C(diet HBA).Each diet was randomly fed to triplicate tanks.The results showed that the MUFA contents in liver and muscle were reduced by dietary bile acid supplementation,significantly lower in group HBA than in the control group(P<0.05).The n-6 PUFA contents in groups HLBA and HL were significantly lower compared to other groups.In the groups with moderate lipid level,the contents of C20∶0,C16∶1 n-7,C18∶1 n-9,C18∶2 n-6,C20∶4 n-6,C18∶3 n-3,C18∶4 n-3,C20∶5 n-3 and C22∶6 n-3 in the liver tended to decrease with increasing bile acid levels.The serum activities of glutathione peroxidase and superoxide dismutase tended to increase with increasing bile acid levels,and were significantly higher in high-lipid groups than in the control group(P<0.05).However,the glutathione reductase activity showed an opposite pattern.The relative mRNA expression in liver of the control group was significantly higher than that in other groups,while the gene expression of peroxiredoxin 1 in group BA was significantly higher than that in the control.The bile acid supplementation in high-lipid diets significantly increased the hepatic gene expression of catalase.In conclusion,the dietary bile acid supplementation reduced the contents of a series of long-chain fatty acids in both diet and fish tissues,and the effects of dietary bile acid on serum activity of anti-oxidative proteins were different from those on the hepatic expression of anti-oxidative genes.