State of the antioxidant enzyme complex of tissues of the Black Sea mollusc Mytilus galloprovincialis under conditions of natural oxidative stress

The state of the antioxidant (AO) system (AOS) and the content of products of lipid peroxidation (LPO) in hepatopancreas, gill, and foot of the Black Sea mollusc Mytilus galloprovincialis Lam. were studied in norm and under conditions of natural oxidative stress (spawning). It has been established that under conditions of spawning, the AO-protection of hepatopancreas cells is predominantly oriented to inactivation of high concentrations of peroxide compounds with participation of glutathione peroxidase and catalase. In the foot tissue, on the contrary, the main role in AO-processes is played by enzymatic inhibition of superoxide anionradical with aid of superoxide dismutase. The highest level of oxidative stress in the spawning state is revealed in the mollusc gill, which is indicated by the maximal increase of the content of TBK-active products.     

Tissue specificity of metabolism in the bivalve mollusc <Emphasis Type="Italic">Anadara inaequivalvis</Emphasis> Br. under conditions of experimental anoxia

Peculiarities of the course of metabolic processes in tissues of the bivalve mollusc Anadara inaequivalvis Br. were studied under conditions of experimental anoxia. In the absence of oxygen, in gill and foot the protein catabolism processes were found to be enhanced; this led to a decrease of the protein content and to an increase of the free amino acid and urea levels. Predominantly hydrolyzed were low molecular peptides, which was indicated by a decrease of the cathepsin D activity on the background of a rise of the γ-glutamyltranspeptidase activity. Anoxia was accompanied by enhancement of the succinate thiokinase and fumarate reductase reactions controlled by alanine and aspartate aminotransferases. This prevented accumulation of toxic lactate in tissues and allowed obtaining an additional macroerg resource. Metabolic processes in the mollusc hepatopancreas were oriented to production of amino acids.     

Antioxidant enzyme complex of tissues of the bivalve <Emphasis Type="Italic">Mytilus galloprovincialis</Emphasis> Lam. under normal and oxidative-stress conditions: A review

The results of studies of tissue specifics of the enzymatic antioxidant complex of the bivalve Mytilus galloprovincialis Lam. are summarized. It is shown that the highest oxidative load is experienced by gills. The antioxidant complex of gills largely depends on environmental conditions than on the mollusk’s state, which allows this tissue to be used for ecological diagnostics. A decrease in the content of carotenoids in tissue s suppressed the activities of the key enzymes of antiradical defense—superoxide dismutase (SOD) and catalase—and is accompanied by a decrease in the reduced glutathione (GSH) pool. The state of the antioxidant complex of molluscan tissues under conditions of natural (spawning) and artificial (exposure to a cationic surfactant) oxidative stress was studied.     

急性低氧/复氧胁迫对克氏原螯虾抗氧化-能量代谢的影响

为研究低氧/复氧胁迫对克氏原螯虾(Procambarus clarkii)抗氧化及能量代谢的影响,将克氏原螯虾暴露于(1.0±0.1) mg/L急性低氧胁迫和后续(6.8±0.2) mg/L复氧环境中,于低氧胁迫1h、6h及复氧1h、12h分别采集肝胰腺、鳃和血淋巴,研究低氧/复氧胁迫下克氏原螯虾抗氧化-能量代谢酶的活力变化,分析鳃和肝胰腺组织的超微结构改变。在低氧胁迫下,肝胰腺和血淋巴中SOD酶活力显著下降(P<0.05);复氧以后,肝胰腺、血淋巴及鳃组织中SOD酶活力均出现了显著上升(P<0.05)。SOD酶活力变化可能与复氧过程中超氧阴离子自由基的过量产生有关。在复氧12h后,血淋巴和鳃组织中MDA含量均出现了显著性增加(P<0.01),提示机体细胞在复氧胁迫下产生了脂质过氧化。在低氧胁迫下,肝胰腺、鳃和血淋巴中ACP、AKP酶活力显著上升(P<0.05);在复氧12h后,肝胰腺和鳃组织中ACP酶活力显著降低(P<0.01)。显示低氧/复氧胁迫影响了机体的非特异性免疫应答。在急性低氧胁迫下,肝胰腺、血淋巴与鳃组织中的LDH含量和总ATPase活力均显...     

Content of carotenoids and the state of tissue antioxidant enzymatic complex in bivalve mollusc Anadara inaequivalvis Br.

This work deals with studies on the content of carotenoids, the state of antioxidant (AO) enzymatic complex, and the intensity of lipid peroxidation in tissues (hepatopancreas, gill, and foot) of the Black Sea bivalve mollusc Anadara inaequivalvis. Tissues with a high content of the pigment have been established to have a low activity of the key AO enzymes: superoxide dismutase, catalase, and glutathione reductase, as well as an elevated content of reduced glutathione (R ² = 0.81–0.97). The differences of the recorded activities between the tissues reached 1.7–2.9 times (p < 0.05–0.01). At increased concentrations (more than 2.5 mg · 100 g^?1 tissue), carotenoids show an insignificant pro-oxidant effect manifested in a rise of glutathione peroxidase activity. The competitive interrelations between these molecular complexes for the same kinds of reactive oxygen species (O₂, OH^·, and ¹O₂) are discussed.     

Superoxide radical production in response to environmental hypoxia in cultured shrimp

Markers of oxidative stress in response to hypoxia and reoxygenation were assessed in Pacific white shrimp (Litopenaeus vannamei). Adult shrimp were either exposed to hypoxia (1 mg O(2)/L) for 6, 12, or 24 h followed by 1-h reoxygenation, or exposed to hypoxia for 24 h followed by 1- to 6-h reoxygenation. In all cases, shrimp maintained at constant normoxia were used as controls. Spectrophotometric techniques were applied to analyze lactate concentration, superoxide radical (O(2)(*-)) production, lipid peroxidation (TBARS), and antioxidant capacity status in muscle, hepatopancreas, and gill samples. Results indicate differences among tissues, even under control conditions. O(2)(*-) production and TBARS levels were higher in hepatopancreas than in gill or muscle. No effect of exposure to hypoxia was found. However, reoxygenation following exposure to hypoxia was found to affect the oxidative metabolism of muscle and hepatopancreas from cultured shrimp. Lactate concentration and O(2)(*-) production increased while antioxidant capacity decreased in hepatopancreas and muscle in the first hours of reoxygenation. This could translate into tissue damage, which may significantly jeopardize the commercial aquaculture product.     

Peculiarities of antioxidant defense system organization of the Black Sea mollusks Mytilus

Antioxidant (AO) system and lipid peroxidation (LP) in tissues of two species of the Black Sea bivalve mollusks Mytilus galloprovincialis and Anadara inaequivalvis were investigated. The activity of superoxide dismutase (SOD, 1.15.1.1), catalase (1.11.1.6), glutathione peroxidase (GP, 1.11.1.9), glutathione reductase (GR, 1.6.4.2), concentrations of reduced glutathione (GSH) and TBA-reactive products were determined in the foot, hepatopancreas and gills of mature mollusks. The characteristics of AO complex and LP products connected with tissue and species specificity of mollusks were found. Hepatopancreas of mussels has been found to have higher values of all characteristics investigated, except GP. The gills and the foot of anadara have been found to be involved in AO defense along with hepatopancreas: maximum activity of GR, catalase and SOD was found in the gills and the highest activity of GP and maximum level of GSH was observed in the foot. Anadara has been shown to have higher antioxidant potential and lower level of oxidative stress because the LP intensity in all tissues examined of the hemoglobin-containing mollusk was twice lower in comparison with the mussel.     

Comparative characteristics of the antioxidant glutathione complex in the black sea molluscs Mytilus galloprovincialis Lam. and Anadara inaequivalvis Br.

The peculiarities in distribution of lipid peroxidation (LPO) products, glutathione (GSH) level, and antioxidant enzymes-glutathione peroxidase (GP) and glutathione reductase (GR)—were studied in tissues of Black Sea bivalve molluscs, Anadata inaequivalvis Br. (anadara) and Mytilus galloprovincialis Lam. (mussel, black morph), as well as their comparative characteristics were presented. The differences were established in organization of the glutathione anti-oxidant system and the LPO intensity in tissues of these mollusc species. In all anadara tissues the intensity of LPO processes was lower than that in Mytilus galloprovincialis. The GP activity in hepatopancreas and gills of mussels was significantly higher than that of anadara. On the contrary, in the foot the GP activity and GSH content in anadara considerably exceeded those in mussel. The revealed differences might reflect the peculiarities in functioning of the glutathione complex and the ratio of its activity with LPO level in tissues of anadara and mussel, as well as be of interest for understanding mechanisms of mollusc adaptation to their habitat conditions.     

Qualitative composition of carotenoids, catalase and superoxide dismutase activities in tissues of the bivalve mollusc Anadara inaequivalvis (Bruguiere, 1789)

Using high performance liquid chromatography, UV-VIS spectra and mass-spectra (FAB MS), 7 carotenoid species were identified in tissues of the bivalve mollusc Anadara inaequivalvis (Bruguiere, 1789): trans- and cis-pectenolon, alloxanthin, pectenol A, β-carotene, zeaxanthin, and diatoxanthin. Their quantitative ratio in hepatopancreas, gills and foot of animals were determined. A negative correlation (R ² is about 0.9) was revealed between tissues content of a series of carotenoids (trans- and cis-pectenolon, zeaxanthin, alloxanthin, and diatoxanthin) and activity of antioxidant enzymes (catalase and superoxide dismutase). The existence of competitive interrelations between these molecular systems is proposed and underlying causes are discussed.     

Effect of salicylic acid potentiates cadmium-induced oxidative damage in <Emphasis Type="Italic">Oryza sativa</Emphasis> L. leaves

In the present investigation, we studied the possible potentiating effect of salicylic acid (SA) under Cd toxicity in Oryza sativa L. leaves. Cd treatments for 24 h reduced the shoot length, dry biomass and total chlorophyll content followed by high Cd accumulation in shoots. About 16 h presoaking with SA resulted in partial protection against Cd, as observed by minor changes in length, biomass and total chlorophyll. SA priming resulted in low Cd accumulation. Enhanced thiobarbituric acid reactive substances (TBARS), hydrogen peroxide (H₂O₂) and superoxide anion (O₂ ⁻) content were seen when Cd was applied alone, while under SA priming the extent of TBARS, H₂O₂ and O₂ ⁻ were significantly low, suggesting SA-regulated protection against oxidative stress. The antioxidant enzymes like Catalase (CAT), guaiacol peroxidase (GPx), glutathione reductase (GR) and superoxide dismutase (SOD) showed varied activities under Cd alone. CAT activity increased after Cd treatment, followed by a decline in GPX and GR activity. SOD also declined at the highest concentrations with an initial increase. Under SA-priming conditions, the efficiency of the antioxidant enzymes was significantly elevated. GPx and SOD activity showed significant increase in activity. The ascorbate activity increased after Cd treatment, followed by a decline in glutathione under SA-free condition. SA priming showed gradual increase in these non-enzymic antioxidants. Our results indicate that Cd-induced oxidative stress can be regulated by SA.     

重金属离子对凡纳滨对虾肝胰脏、鳃丝和血液SOD活力的影响

研究了3种重金属离子(Cu²⁺、Zn²⁺、Cd²⁺)在96 h内对凡纳滨对虾(Litopenaeus vannamei)对肝胰脏、鳃丝和血液超氧化物歧化酶(SOD)活力的影响.结果表明,凡纳滨对虾SOD活力在3种重金属离子作用下随取样时间变化显著(P＜0.0),Cu²⁺在实验浓度范围内(0.1～1 mg·L^-1),肝胰脏、鳃丝和血液的SOD活力随时间延长呈一峰值变化,Zn²⁺在10 mg·L^-1时对肝胰脏表现为显著抑制作用,Cd²⁺在0. mg·L^-1时对肝胰脏和鳃丝起显著抑制作用,0.2 mg·L^-1对鳃丝SOD活力无显著变化(P＞0.0),其他浓度Zn²⁺(＜10 mg·L^-1)、Cd²⁺(＜0.2 mg·L^-1)对各组织器官SOD活力的影响随时间延长均呈现先升高后下降的趋势.3种重金属离子对凡纳滨对虾肝胰脏、鳃丝、血液SOD活力的影响呈现明显的剂量-时间效应关系.其SOD活力大小顺序为肝胰脏＞鳃丝＞血液,3种重金属离子对凡纳滨对虾伤害大小顺序为Cd²⁺＞Cu²⁺＞Zn²⁺.     

Antioxidant enzyme complex of tissues of the bivalve Mytilus galloprovincialis Lam. under normal and oxidative-stress conditions: a review

The results of studies of tissue specifics of the enzymatic antioxidant complex of the bivalve Mytilus galloprovincialis Lam. are summarized. It is shown that the highest oxidative load is experienced by gills. The antioxidant complex of gills largely depends on environmental conditions than on the mollusk's state, which allows this tissue to be used for ecological diagnostics. A decrease in the content of carotenoids in tissue s suppressed the activities of the key enzymes of antiradical defense-superoxide dismutase (SOD) and catalase-and is accompanied by a decrease in the reduced glutathione (GSH) pool. The state of the antioxidant complex of molluscan tissues under conditions of natural (spawning) and artificial (exposure to a cationic surfactant) oxidative stress was studied.     

Transgenic cotton (<Emphasis Type="Italic">Gossypium hirsutum</Emphasis> L.) seedlings expressing a tobacco glutathione <Emphasis Type="Italic">S</Emphasis>-transferase fail to provide improved stress tolerance

Transgenic cotton (Gossypium hirsutum L.) lines expressing the tobacco glutathione S-transferase (GST) Nt107 were evaluated for tolerance to chilling, salinity, and herbicides, antioxidant enzyme activity, antioxidant compound levels, and lipid peroxidation. Although transgenic seedlings exhibited ten-fold and five-fold higher GST activity under normal and salt-stress conditions, respectively, germinating seedlings did not show improved tolerance to salinity, chilling conditions, or herbicides. Glutathione peroxidase (GPX) activity in transgenic seedlings was 30% to 60% higher under normal conditions, but was not different than GPX activity in wild-type seedlings under salt-stress conditions. Glutathione reductase, superoxide dismutase, ascorbate peroxidase, and monodehydroascorbate reductase activities were not increased in transgenic seedlings under salt-stress conditions, while dehydroascorbate reductase activity was decreased in transgenic seedlings under salt-stress conditions. Transgenic seedlings had 50% more oxidized glutathione when exposed to salt stress. Ascorbate levels were not increased in transgenic seedlings under salt-stress conditions. Malondialdehyde content in transgenic seedlings was nearly double that of wild-type seedlings under normal conditions and did not increase under salt-stress conditions. These results show that expression of Nt107 in cotton does not provide adequate protection against oxidative stress and suggests that the endogenous antioxidant system in cotton may be disrupted by the expression of the tobacco GST.     

Purification and Characterization of Lactate Dehydrogenase in the Foot Muscle and Hepatopancreas of <Emphasis Type="Italic">Otala lactea</Emphasis>

Lactate dehydrogenase (LDH) has a crucial role in maintaining ATP production as the terminal enzyme in anaerobic glycolysis. This study will determine the effect of posttranslational modifications (PTMs) on the activity of LDH in the foot muscle and hepatopancreas of an estivating snail, Otala lactea. LDH in foot muscle of O. lactea was purified to homogeneity and partially purified in hepatopancreas in a two-step and three-step process, respectively. The kinetic properties and stability of these isoforms were determined where there was a significant difference in K_m and I₅₀ values with pyruvate and urea separately in foot muscle; however, hepatopancreas exhibited significant differences in K_m and I₅₀ in salt between control and stress. Interestingly, hepatopancreas has a higher affinity for pyruvate in the control state whereas foot muscle has a higher affinity for its substrate in the estivated state. PTMs of each isoform were identified using immunoblotting and dot blots, which prove to be significantly higher in the control state. Overall, foot muscle LDH enters a low phosphorylation state during estivation allowing more efficiency in consuming pyruvate with higher thermal stability but less structural stability. Hepatopancreas LDH becomes dephosphorylated in the estivating snail that decreases the efficiency of the enzyme in the forward direction; however, the snail has an increased tolerance to the presence of salt when water becomes scarce. Such tissue-specific regulations indicate the organism’s ability to reduce energy consumption when undergoing metabolic depression.     

Effects of 24-epibrassinolide on seed germination, seedling growth, lipid peroxidation, proline content and antioxidative system of rice (Oryza sativa L.) under salinity stress

The effects of 24-epibrassinolide (24-epiBL) on seedling growth, antioxidative system, lipid peroxidation, proline and soluble protein content were investigated in seedlings of the salt-sensitive rice cultivar IR-28. Seedling growth of rice plants was improved by 24-epiBL treatment under salt stress conditions. When seedlings treated with 24-epiBL were subjected to 120 mM NaCl stress, the activities of superoxide dismutase (EC 1.15.1.1), catalase (EC 1.11.1.6) and glutathione reductase (EC 1.6.4.2) did not show significant difference, whereas the activity of ascorbate peroxidase (EC 1.11.1.11) significantly increased. Increased activity of peroxidase (EC 1.11.1.7) under NaCl stress showed remarkable decrease in the 24-epiBL+NaCl-applied group. Lipid peroxidation level significantly increased under salt stress but decreased with 24-epiBL application revealing that less oxidative damage occurred in this group (24-epiBL+NaCl). In addition, increased proline content in the NaCl-applied group was decreased by 24-epiBL application in the 24-epiBL+NaCl-applied group. Soluble protein content was increased by 24-epiBL application even under NaCl stress, being also higher than control conditions (no 24-epiBL or NaCl treatment). 24-epiBL treatment considerably alleviated oxidative damage that occurred under NaCl-stressed conditions and improved seedling growth in part under salt stress in sensitive IR-28 seedlings.     

The Effect of Salinity Pretreatment on Cd Accumulation and Cd-Induced Stress in <Emphasis Type="Italic">BADH</Emphasis><Emphasis Type="Italic">-</Emphasis>Transgenic and Nontransgenic Rice Seedlings

The influence of betaine aldehyde dehydrogenase (BADH) and salinity pretreatment on oxidative stress under cadmium (Cd) toxicity was investigated in rice cv. Xiushui 11 and its BADH-transgenic line Bxiushui 11. The results showed that plants previously treated with 4.25 and 8.5 mM NaCl, respectively, for 5 days each had higher Cd concentrations in both roots and shoots of the two rice genotypes compared with the controls. Malondialdehyde (MDA) content in both leaves and roots was increased by salinity pretreatment and was significantly lower in the salinity-pretreatment plants than in the controls when the plants were consequently exposed to Cd stress. Salinity pretreatment also increased proline content and the activities of superoxide dismutase (SOD) and peroxidase (POD) in both leaves and roots. It can be assumed that salinity pretreatment enhances the defensive ability of plants against oxidative stress through increasing activities of antioxidative enzymes. The BADH-transgenic line (Bxiushui 11) had lower Cd and MDA content, higher SOD and POD activities, and higher proline content than its wild type (Xiushui 11). The current results suggest that betaine, a product of BADH expression, improves the tolerance of rice plants to Cd stress through increasing the activities of antioxidative enzymes and osmoprotectant content.     

WGA reduces the level of oxidative stress in wheat seedlings under salinity

Protective effect of exogenous wheat germ agglutinin (WGA) on wheat seedling (Triticum aestivum L.) during salinity stress was studied. In particular, we examined the state of pro- and antioxidant systems as well as the level of peroxide oxidation of lipids and electrolyte leakage under control conditions and when stressed with NaCl. Generation of superoxide anions and activity of both superoxide dismutase (SOD) and peroxidase increased during saline stress. Accumulation of O₂ ^·− resulted in peroxide oxidation of lipids and electrolyte leakage in response to stress. The injurious effect of salinity on root growth of seedlings was manifested by a decreased mitotic index (MI) in apical root meristem. This study show that WGA pretreatment decreased salt-induced superoxide anion generation, SOD and peroxidase activities, levels of lipid peroxidation and electrolytes leakage as well as correlating with a reduction in the inhibition of root apical meristem mitotic activity in salt-treated plants. This suggests that exogenous WGA reduced the detrimental effects of salinity-induced oxidative stress in wheat seedlings. Thus WGA effects on a balance of reactive oxygen species (ROS) and activities of antioxidant enzymes may provide an important contribution to a range of the defense reactions induced by this lectin in wheat plants.     

Impact of metal accumulation pattern on the annual rhythmicity of antioxidants and their interrelationship to maintain the oxidative balance in mollusc

A chronological relationship between the annual profiles of oxidative stress markers, the key regulator of stress physiology has been sought in a terrestrial mollusc (Nerita articulata) under natural photothermal conditions. The hemolymph samples were collected at two different times in each month (from January to December) and the same was repeated for two consecutive years throughout an annual cycle. The fluctuations in the concentrations of certain heavy and trace metals (zinc, copper, cadmium, mercury, lead, and nickel) in both soil and hemolymph of Nerita are also estimated accordingly. Therefore, the present study aims to explore the rhythmic responses of oxidative stress marker to assess the impact of different trace and heavy metals on selected mollusc species. We tries to develop a realistic conceptual idea to analyze and predict the effect of changing environmental pollution on the possible shift in the rhythmicity of aforesaid antioxidants in terrestrial mollusc and their adaptive responses to thrive in such environment. Our results indicates that the amplitude of circannual rhythms of all the selected stress markers varied accordingly but the pattern of annual fluctuation is noted to be similar, and correlated with the metal accumulation. Therefore current information might help to frame the adaptive strategies for invertebrate species under similar toxic circumstances.     

Responses of antioxidant defense system of <Emphasis Type="Italic">Helianthus annuus</Emphasis> to abscisic acid treatment under drought and waterlogging

The effect of abscisic acid (ABA) treatment on growth pigments and antioxidant defense system were investigated in seedlings of Helianthus annuus (cvs. Nantio F1 and Özdemirbey) subjected to drought and waterlogging stress. In addition, seedlings were sprayed with 10 M ABA three times every other day. Relative growth rate (RGR) was significantly reduced in both genotypes under drought stress, however, this growth inhibition was less in ABA-treated plants. Total chlorophyll content increased by drought stress in both genotypes. Ascorbate was not influenced by drought, while α-tocopherol increased in cv. Nantio F1. Ascorbate and α-tocopherol increased with drought stress in cv. Özdemirbey. ABA treatment decreased ascorbate and β-carotene contents while it increased α-tocopherol and xanthophylls contents under drought stress. The activity of superoxide dismutase (SOD) in both genotypes increased under drought stress-ABA combinations. Catalase (CAT) activity decreased under drought stress and drought-ABA combinations while it increased under waterlogging stress. Glutathione reductase (GR) activity decreased under drought stress but recovered with ABA treatment. The results suggested that ABA treatments have different effects on the components of antioxidant defense system in H. annuus genotypes and ABA may contribute drought-induced oxidative stress tolerance but not effects under waterlogging stress.     

饲料丙二醛对草鱼生长、肝胰脏及肠道结构和功能的影响

为了探讨丙二醛(MDA)对草鱼Ctenopharyngodon idellus(74.821.49) g生长、肝胰脏及肠道结构和功能的影响并初步对比MDA与其他油脂氧化产物的毒副作用, 本试验以新鲜豆油、低氧化程度的鱼油为饲料脂肪源, 制成豆油组(S组)、鱼油组(F组), 并在豆油组中喷涂不同浓度的MDA, 制成MDA水平为61.59 (M1组)、123.92 (M2组)、185.04 (M3组) mg/kg的5种等氮等能的试验饲料。经72d池塘网箱养殖后, 试验结果显示:(1)饲料中MDA及油脂其他氧化产物均可显著增加草鱼饲料系数(FCR) (P0.05), 显著降低特定生长率(SGR)、蛋白质沉积率(PRR)(P0.05), MDA还可显著降低草鱼脂肪沉积率(LRR) (P0.05); (2)饲料中MDA及油脂其他氧化产物均可显著降低血清总胆汁酸(TBA)含量(P0.05), 并使血清总胆固醇(TC)、甘油三酯(TG)、MDA含量及超氧化物歧化酶(SOD)酶活性显著上升(P0.05), 饲料中MDA还可显著增加血清丙氨酸氨基转移酶(ALT)含量(P0.05), 显著降低血清高密度脂蛋白与低密度脂蛋白之比(HDL/LDL)、白蛋白与球蛋白之比(A/G)比值(P0.05); (3)饲料中MDA及油脂及其他氧化产物会显著增加肝胰脏脂肪(P0.05), 且MDA还会显著增加肝胰脏SOD含量(P0.05), 导致草鱼肝胰脏氧化应激; (4)饲料中MDA会损伤肝胰脏细胞线粒体, 降低细胞核数量, 使肝胰脏细胞有明显纤维化趋势; (5)饲料MDA及鱼油其他氧化产物均会引起草鱼肠道黏膜杯状细胞数量增加, 损伤肠道微绒毛, 并会损伤肠道紧密连接结构, 增加肠道通透性, 导致血清内毒素及D-乳酸含量显著增加(P0.05)。上述结果表明: (1)饲料MDA会引起草鱼鱼体应激, 并通过干扰正常胆汁酸循环来干扰草鱼对脂肪的消化吸收, 最终导致草鱼生长性能下降; (2)MDA会引起肝胰脏氧化应激, 并可通过损伤肝胰脏细胞线粒体内部结构来损伤草鱼肝胰脏, 增加其发生脂肪性肝炎机率, 而鱼油其他氧化产物则是通过影响线粒体膜结构改变线粒体形态来损伤肝胰脏; (3)饲料MDA及鱼油其他氧化产物均会损伤草鱼肠道绒毛和微绒毛来降低其消化吸收能力, 还可损伤肠道紧密连接结构, 增加肠道通透性。