饲料花生四烯酸含量对子二代中华鲟成活与生长、抗氧化能力、组织花生四烯酸代谢酶活性及肠道菌群组成的影响

Effects of Dietary Arachidonic Acid Content on Survival and Growth,Antioxidant Capacity,Arachidonic Acid Metabolic Enzyme Activities and Intestinal Microbial Composition of F_(2) Generation Chinese Sturgeon

本试验旨在探究饲料花生四烯酸(ARA)含量对子二代中华鲟成活与生长、抗氧化能力、组织ARA代谢酶活性及肠道菌群组成的影响。通过在基础饲料中添加0、0.5%、1.0%和2.0%的ARA纯化油(ARA占总脂肪酸的44.88%),制成4种等氮等能的试验饲料,饲料ARA含量分别为0.18%、0.53%、0.96%和1.89%。用4种试验饲料投喂初始体质量为(4.17±0.22)kg的子二代中华鲟22周,每种饲料投喂3个重复,每个重复18尾鱼。结果表明:试验鱼的增重率与成活率不受饲料ARA含量的显著影响(P>0.05)。肝脏超氧化物歧化酶(SOD)、过氧化氢酶(CAT)与谷胱甘肽硫转移酶(GST)活性随饲料ARA含量的升高而升高,丙二醛(MDA)含量随饲料ARA含量的升高而下降。血清SOD、CAT、GST活性与MDA含量不受饲料ARA含量的显著影响(P>0.05)。性腺中,1.89%ARA组环氧合酶-2(COX-2)与细胞色素氧化酶P_(450)(CYP _(450))活性显著高于0.18%与0.53%ARA组(P<0.05),与0.96%ARA组无显著差异(P>0.05);0.96%ARA组环氧合酶-1(COX-1)活性显著高于0.18%与0.53%ARA组(P<0.05);1.96%ARA组脂氧合酶(LOX)活性显著高于0.18%ARA组(P<0.05)。肝脏中,COX-1、COX-2与LOX活性均以1.89%ARA组最高,与0.96%ARA组无显著差异(P>0.05);0.18%ARA组CYP _(450)活性显著低于0.96%与1.89%ARA组(P<0.05)。0.18%ARA组Chao1指数、ACE指数、Shannon指数与Observed-species数量显著高于0.53%ARA组(P<0.05),与0.96%及1.89%ARA组无显著差异(P>0.05)。Simpson指数与PD-whole tree指数不受饲料ARA含量的显著影响(P>0.05)。上述结果表明,饲料中添加1.0%的ARA纯化油使饲料ARA含量为0.96%时对子二代中华鲟的生长与存活无显著影响,但能增强鱼体的抗氧化能力、组织中ARA代谢酶活性及调控肠道菌群多样性。

The effects of arachidonic acid(ARA)on survival and growth,antioxidant capacity,tissue ARA metabolic enzyme activities and intestinal microbial composition of the F_(2) generation Chinese sturgeon were evaluated in this experiment.Four isonitrogenous and isoenergetic experimental diets were formulated by adding 0,0.5%,1.0%and 2.0%purified ARA oil(43%ARA in total fatty acids)in the basal diet,and dietary arachidonic acid content was 0.18%,0.53%,0.96%and 1.89%,respectively.The F_(2) generation Chinese sturgeon with an initial body weight of(4.17±0.22)kg were fed for 22 weeks with 3 replicates per diet treatment,and 18 fish per replicate.The results showed that the weight gain rate and survival rate were not significantly affected by dietary ARA content(P>0.05).The activities of superoxide dismutase(SOD),catalase(CAT),glutathione S-transferase(GST)in the liver were increased with dietary ARA content increasing,while the content of malonic aldehyde(MDA)in the liver was decreased with dietary ARA content increasing.The activities of SOD,CAT,GST and the content of MDA in the serum were not significantly affected by dietary ARA content(P>0.05).In the gonad,the activities of cyclooxygenase-2(COX-2)and cytochrome P_(450)(CYP _(450))of the 1.89%ARA group were significantly higher than those of the 0.18%and 0.53%ARA groups(P<0.05),but there were no significant differences between the 1.89%and 0.96%ARA groups(P>0.05);the cyclooxygenase-1(COX-1)activity of the 0.96%ARA group was significantly higher than that of the 0.18%and 0.53%ARA groups(P<0.05);the lipoxygenase(LOX)activity of the 1.89%ARA group was significantly higher than that of the 0.18%ARA group(P<0.05).In the liver,the activities of COX-1,COX-2 and LOX were the highest in the 1.89%ARA group,and there were no significant differences between the 0.96%and 1.89%ARA groups(P>0.05);the CYP _(450) activity of the 0.18%ARA group was significantly lower than that of the 0.96%and 1.89%groups(P<0.05).The Chao1 index,ACE index,Shannon index and Observed-species number of the 0.18%ARA group were significantly higher than those of the 0.53%ARA group(P<0.05),and there were no significant differences among the 0.18%,0.96%and 1.89%ARA groups(P>0.05).The Simpson index and PD-whole tree index were not significantly affected by dietary ARA content(P>0.05).These results indicates that dietary with 1.0%ARA has no significant effects on the growth and survival of F_(2) Chinese sturgeon,but can enhance the antioxidant capacity,tissue ARA metabolic enzyme activities and regulate the diversity of intestinal microbes.