银鲳卵黄发生期间组织中抗氧化水平的变化及饲料n-3 LC-PUFA对其的影响

研究了银鲳(Papus argenteus)肝及卵巢组织中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性、总抗氧化能力(T-AOC)及丙二醛(MDA)含量在整个卵黄发生过程中的变化情况,并分析了饲料n-3 LC-PUFA对卵黄发生期间组织中抗氧化水平的影响。分别以100%鱼油(FO组)、70%鱼油和30%大豆油(FSO组)、30%鱼油和70%大豆油(SFO组)、100%大豆油(SO组)为脂肪源,配制了4组等氮、等能及等脂的试验饲料。以1年龄雌性银鲳为试验对象,每组饲料设3重复,试验周期185 d。研究结果表明,肝与卵巢组织SOD、CAT活性、T-AOC水平及MDA含量在卵黄发生过程中均呈现逐渐升高的趋势,且卵黄发生后期各指标水平均显著高于卵黄发生前期(P0.05)。肝SOD(除SO饲料组外)、CAT活性、T-AOC水平及MDA含量在卵黄发生中期与前期之间未表现出显著性差异(P0.05),而卵黄发生中期FO与FSO饲料组卵巢SOD、CAT活性及T-AOC水平则均显著高于卵黄发生前期(P0.05)。FSO饲料组肝与卵巢SOD、CAT活性在卵黄发生过程中均为最高值,且在卵黄发生中、后期均显著高于SO饲料组(P0.05),但与FO饲料组无显著性差异(P0.05)。各饲料组间肝与卵巢T-AOC水平在卵黄发生前期均未表现出显著性差异(P0.05),而在卵黄发生后期,FO与FSO饲料组肝与卵巢T-AOC水平均显著高于SO饲料组(P0.05),但FO与FSO饲料组间无显著性差异(P0.05)。肝与卵巢中MDA含量随着饲料n-3 LC-PUFA含量的升高而呈现出升高趋势,且这种升高趋势在肝组织中表现更为明显,卵巢组织MDA含量在卵黄发生中、后期仅FO饲料组表现出显著性升高趋势(P0.05),其他各饲料组在卵黄发生各期均未表现出显著性差异(P0.05)。统计分析表明,银鲳卵黄发生过程中组织中抗氧化水平逐渐升高,适宜的饲料n-3 LC-PUFA含量(4.01%,FSO饲料组)可明显改善银鲳卵黄发生中期与后期组织中的抗氧化水平。双因素方差分析结果表明,试验饲料与卵黄发生时期对银鲳组织抗氧化水平均具有极显著性影响(P0.01),且两者对肝T-AOC水平与MDA含量存在显著性的交互作用(P0.05)。

Changes intissue antioxidant levels in silver pomfret (Pampus argenteus) during vitellogenesis and the response to dietary n-3 long-chain polyunsaturated fatty acids

Changes in hepatic and ovarian superoxide dismutase (SOD) and catalase (CAT) activities, total antioxidant capacity (T-AOC) and malonyldialdehyde (MDA) contents in silver pomfret (Pampus argenteus) during vitellogenesis and the responses of their levels to dietary n-3 long-chain polyunsaturated fatty acids (LC-PUFA) were investigated. Four iso-nitrogenous, iso-energetic and iso-lipidic experimental diets were formulated:(1) 100% fish oil (FO); (2) 70% fish oil and 30% soybean oil (FSO); (3) 30% fish oil and 70% soybean oil (SFO); and (4) 100% soybean oil (SO). Female silver pomfrets (1 year old) were assigned to one of the four diets (with three replicates each) for 185 d. The results showed that there was an increase in SOD and CAT activities, T-AOC levels and MDA contents in the liver and ovary during vitellogenesis, and that the levels of all the indices in the post-vitellogenesis stage were significantly higher than those in thepre-vitellogenesis stage (P<0.05). No significant differences in hepatic SOD (except in the SO diet group) and CAT activities, T-AOC levels and MDA contents were found between the vitellogenesis and pre-vitellogenesis stages (P>0.05). However, ovarian SOD and CAT activities, and T-AOC levels in the FO and FSO diet groups at the vitellogenesis stage, were significantly higher than those at thepre-vitellogenesis stage (P<0.05). The highest levels of hepatic and ovarian SOD and CAT activities during vitellogenesis were found in the FSO diet group. At the post-vitellogenesis stage, hepatic and ovarian SOD and CAT activities in the FSO group were significantly higher than those in the SO group, respectively (P<0.05); however, there was no significant difference between the FSO and FO groups (P>0.05). No significant difference was found in hepatic and ovarian T-AOC levels among the diet groups at the pre-vitellogenesis stage (P>0.05); however, at the post-vitellogenesis stage, the hepatic and ovarian T-AOC levels in the FO and FSO groups were significantly higher than those in the SO group (P<0.05), while there was no significant difference between the FO and FSO groups (P>0.05). The MDA contents in the liver and ovary increased with increasing dietary n-3 LC-PUFA, and this trend was more apparent in the liver tissue. There was no significant difference in ovarian MDA contents among the diet groups during vitellogenesis (P>0.05), except for the FO group, which showed a significant increase at the vitellogenesis and post-vitellogenesis stages (P<0.05). Statistical analysis showed that tissue antioxidant levels increased gradually during vitellogenesis, and the optimum dietary n-3 LC-PUFA content (4.01%, FSO group) could promote the tissue antioxidant levels in silver pomfret at the vitellogenesis and post-vitellogenesis stages. The results of two-way ANOVA indicated that statistically significant effects of both diets and stages were observed for the tissue antioxidant levels (P<0.01). Meanwhile, the significant effects of interactions of diets and stages on the hepatic T-AOC levels and MDA content were also recorded (P<0.05).