Influence of methionine and dithioerythritol on sperm motility, lipid peroxidation and antioxidant capacities during liquid storage of ram semen

The aim of this study was to investigate the effects of methionine and dithioerythritol, added to the Tris extender, on ram sperm motility and LPO (lipid peroxidation) and antioxidant capacities during liquid storage up to 72 h at 5 °C. Ejaculates collected from five Merino rams, were evaluated and pooled at 37 °C. This study included two experiments. In experiment 1, each pooled ejaculate was divided into four equal aliquots and diluted (37 °C) with the base extender, containing 0 (control), 1, 2 and 4 mM methionine, at a final concentration of approximately 4 × 10⁸ sperms/ml (single step dilution), in a 15-ml plastic centrifuge tube. In experiment 2, dithioerythritol, at concentrations of 0 (control), 0.5, 1 and 2 mM, was used as an additive in the extender, and the procedure explained above was applied for the division of aliquots and the dilution of semen. Diluted semen samples were kept in glass tubes and cooled from 37 to 5 °C in a cold cabinet, and maintained at 5 °C. Sperm motility and LPO and total glutathione (GSH) and glutathione peroxidase (GPx) capacities were determined at 5 °C for periods of 0, 24, 48 and 72 h of liquid storage.The extender supplemented with 1 mM methionine led to higher motility percentages (77.0 ± 1.2%), in comparison to the control group (66.0 ± 4.9%), during 72 h of liquid storage (P < 0.05). As regards dithioerythritol, it did not statistically improve the motility rates for any of the storage times at 5 °C. In biochemical assays, differences in LPO levels between the groups with antioxidants and the control groups were not statistically significant. Compared to the control group, no significant difference was observed in GSH and GPx activities following the addition of methionine, during 72 h of storage. Total GSH and GPx activities did not increase significantly upon supplementation with 0.5 and 1 mM of dithioerythritol, compared to the control group, at any of the time points (P > 0.05). Dithioerythritol at 2 mM led (P < 0.01) to elevating GSH activity, compared to the control group, during 72 h of liquid storage. GPx activity was approximately 10 times higher for 2 mM of dithioerythritol (P < 0.001), compared to that of the control group at all time points.The question regarding the sustainability of sperm survival, LPO and antioxidant capacities following liquid storage of semen remains unanswered. Further studies are required for a better understanding of the biochemical changes and to obtain more information on the determination of lipid peroxidation and antioxidant capacities during cooled storage of ram semen.     

不同硒源及浓度对偏关苜蓿种子萌发及物质转化的影响

为探究不同硒源及浓度对'偏关'苜蓿(Medicago sativa'Pianguan')种子萌发及物质转化的影响,本研究以'偏关'苜蓿种子为材料,采用不同浓度亚硒酸钠(0,0.3,0.6,1.2,2.4,4.8,9.6mg·L-1)及蛋氨酸硒(0,1,5,10,20,40 mg·L-1)在人工气候培养箱中进行发芽试验....     

液态蛋氨酸羟基类似物(HMB)在奶牛生产中的应用研究进展

液态蛋氨酸羟基类似物(HMB)是一种有效的反刍动物用活性蛋氨酸源,具有提高产奶量、改善乳成分、促进脂肪代谢和降低饲料成本等多种作用.本文对HM在奶牛生产中的应用效果、HMB的作用机理、影响HMB作用的因素及HMB应用过程中存在的问题进行了论述,认为HMB是泌乳奶牛有效的蛋氨酸源,可在瘤胃和瓣胃上皮细胞及小肠吸收并转化为蛋氨酸被机体利用,添加HMB可降低日粮CP水平,减少N排泄量,有利于动物健康和环境保护.     

消旋蛋氨酸与液体蛋氨酸羟基类似物在肉仔鸡上的相对生物学效价比较

本试验采用生长试验结合数学模型探讨了消旋蛋氨酸(DL-methionine,DLM)和液体蛋氨酸羟基类似物-游离酸(methionine hydroxy analogue-free acid,MHA-FA)的相对生物学效价。选取990只7日龄体重相近且健康的雄性肉仔鸡(Avian)随机分为11个处理,每个处理6个重复,每个重复15只鸡。基础日粮设计为蛋氨酸缺乏但其他营养素均满足动物需要,各处理水平分别为:对照组、DLM(0.03%、0.06%、0.10%、0.15%和0.21%)、液体MHA-FA(0.034%、0.068%、0.114%、0.171%、0.239%)。结果表明:7～42日龄,添加蛋氨酸源显著改善了肉仔鸡的增重和饲料转化效率(P<0.05);在等摩尔基础上,液体MHA-FA的相对生物学效价是DLM的59.9%(增重)和74.2%(饲料效率)。     

蛋氨酸碘对5种养殖鱼类的急性毒性和抑菌作用

进行了蛋氨酸碘对5种养殖鱼类的急性毒性和抑菌作用的研究,以期为在水产养殖上安全有效地使用蛋氨酸碘防治水生动物疾病和避免鱼类中毒提供科学依据.实验采用静水试验法检测蛋氨酸碘对鲫(Carassius aura-tus)、鲢(Hypophthalmichthys molitrix)、团头鲂(Megalobrama amblycephala)、中华倒刺鲃(Spinibarbus sinensis)和草鱼(Ctenopharyngodon idellus)的急性毒性,其48 h半数致死浓度(LC50)分别为11.70、10.50、11.50、12.40、14.60mg/L,安全浓度(SC)分别为1.13、1.03、1.13、1.13、1.38mg/L;采用试管稀释法进行了蛋氨酸碘对嗜水气单胞菌(Aeromonas hydrophila)、温和气单胞菌(Aeromonas sobria)及荧光假单胞菌(Pseudomonas fluorescens)3种鱼类常见致病菌的抑菌试验,最低抑菌浓度(MIC)分别为0.01562、0.06250、0.03125μL/mL,最低杀菌浓度(MBC)为0.06250、0.25000、0.06250μL/mL.试验结果表明,蛋氨酸碘具有较好的抑菌和杀菌作用.     

Oxidative modification of low density lipoprotein induced byhyperhomocysteinaemia following application of methionine

AIM:To observe the oxidative modification of low density lipoprotein iinduced by hyper homocysteinaemia following application of methionine. RESULTS:Following application of methionine, the levels of hyperhomocysteine, ox-LDL and TBARS in group M and group M+Ch were significntly higher than those of group C and group Ch (P＜0.01). The oxidative modification of low density lipoprotein induced by homocysteine in vitro were significantly increased with the concentrations of LDL and homocysteine (P＜0.01).     

饲粮中不同赖氨酸和蛋氨酸水平对猪生长肥育效果的研究

本文研究了具有不同赖氨酸、蛋氨酸水平的四种饲粮组合对杂种去势仔猪前、中期增重和饲料利用效率的影响。结果表明,在含16.02%与14.01%两种粗蛋白质水平的基础饲粮中单一添加0.1%赖氨酸,对生长肥育猪前、中期增重和饲料利用效率均无明显效益;而在含14.01%粗蛋白质的基础饲粮中添加赖氨酸与蛋氨酸各0.1%,可有效节省基础饲粮中2%的饲料蛋白质,并且平均增重可提高6.69%(P>0.01)。     

蛋氨酸锌对吉戎兔体内锌、铜、铁沉积率的影响

随机选取60日龄健康吉戎兔72只,分成4个处理,每个处理3个重复,每个重复6只吉戎兔。饲养45d,每处理基础日粮相同,对照组为处理Ⅰ不添加蛋氨酸锌(Zn-Met),试验组为处理Ⅱ、Ⅲ和Ⅳ分别添加40、80、120mg·kg-1蛋氨酸锌。结果表明,随蛋氨酸锌添加量增加,组织中锌、铜和铁含量有增加趋势,但添加到Zn-Met80mg·kg-1以后这种趋势减缓并有所下降。本试验中,添加蛋氨基酸锌增加组织中锌的含量,有促进铜和铁的吸收作用。     

蛋白质饲料鱼粉、豆粕的掺假鉴定及分析

对蛋白质饲料鱼粉和豆粕的掺假鉴定方法进行了概述.分析结果表明,蛋氨酸和赖氨酸含量可作为鉴定这两种饲料掺假与否的指标.