高精料对泌乳奶山羊瘤胃上皮氧化应激和胆固醇代谢的影响

为了研究长期或短期饲喂高精料日粮对泌乳期奶山羊瘤胃上皮组织氧化应激和胆固醇代谢的影响,实验选用17只健康的经产泌乳中期关中奶山羊,随机分为3组:饲喂低精料组(对照组,LC,n=5);长期饲喂高精料组(HL, n=7),19周饲喂期;短期饲喂高精料组(HS,n=5),4周饲喂期。实验结束后采集瘤胃组织,用PBS反复清洗,于液氮中速冻后置于-80 ℃冰箱保存。结果显示,与对照组相比,HL和HS组山羊瘤胃上皮组织中细胞周期相关基因CDK2和CDK4 mRNA表达水平显著升高(P<0.05),且HS组p-ERK1/2蛋白表达显著升高(P<0.05),但GPR41和GPR43蛋白表达无显著变化(P>0.05);HL和HS组山羊瘤胃上皮组织促细胞凋亡基因Casepase9 mRNA表达显著升高(P<0.05),HS组抗凋亡Bcl-2/Bax mRNA表达比例呈下降趋势(0.050.05);HS组瘤胃上皮组织中胆固醇含量下降达显著水平(P<0.05),且HL组呈下降趋势(0.05+ ATPase mRNA表达显著升高(P<0.05),NHE2蛋白表达升高但未达显著差异水平(P>0.05)。与HL组相比,HS组山羊瘤胃上皮组织中总抗氧化能力T-AOC显著升高(P<0.05);且胆固醇含量显著下降(P<0.05)。以上结果说明,短期饲喂高精料日粮可加快泌乳期奶山羊瘤胃上皮组织的更新,提高组织总抗氧化能力;而长期饲喂高精料日粮未引起细胞增殖相关蛋白和总抗氧化能力的显著变化;饲喂高精料日粮可以加快瘤胃上皮组织对VFA的转运。此外,饲喂高精料日粮引起瘤胃上皮组织内胆固醇含量降低,胆固醇酰基转移酶基因表达的显著上调,提示其对瘤胃上皮组织更新的潜在影响。     

视网膜色素上皮细胞光氧化损伤及原花青素B2的保护作用

蓝光可诱导视网膜色素上皮(RPE)细胞发生光损伤,是年龄相关性眼病的主要发病机制之一。随着年龄增长,脂褐素在RPE细胞中沉积,蓝光能诱导RPE细胞中的脂褐素产生活性氧自由基(ROS),导致光氧化损伤。为了进一步研究蓝光诱导RPE细胞损伤的机制,采用累积了脂褐素主要成分N-亚视-N-视黄基-乙醇胺(A2E)的ARPE-19细胞作为RPE细胞光氧化损伤模型,对细胞活性、ROS、内质网应激(ER stress)蛋白及caspases进行检测,结果显示蓝光可降低RPE细胞活性,增加了ROS生成量,并且与内质网应激(ER stress)反应以及caspase-9和caspase-3的活化相关。此外,经原花青素B2处理后,RPE细胞活性显著提高,并且过氧化物歧化酶(SOD)活力及还原型谷胱甘肽(GSH)含量显著增加。这些结果表明,葡萄原花青素B2可能通过提高细胞内抗氧化酶活力降低氧化应激反应,从而抑制蓝光诱导RPE细胞损伤。     

西藏地区牦牛瘤胃中兼性厌氧纤维素降解菌的分离鉴定

本研究旨在从西藏地区牦牛瘤胃中分离出具有分解纤维素能力的兼性厌氧菌,为青贮饲料微生物添加剂的研制提供支持。试验采集了西藏那曲地区成年牦牛的新鲜瘤胃液,经刚果红染色初筛,滤纸降解复筛,获得分解纤维素能力强的菌株,对菌株生长速率及酶活力进行测定,经形态学、生理生化特性和16S rRNA序列分析对菌株进行鉴定,并分析了菌株对水稻秸秆的降解效果。试验分离出一株兼性厌氧纤维素降解菌,属于肠球菌属,即粪肠球菌(Enterococcus faecalis) JF85。菌株JF85在15~55 ℃,pH 3.0~7.0及3.0%和6.5% NaCl培养基中生长良好。接种JF85,36 h后可获得最大内切葡聚糖酶活力(0.41 U/mL)和滤纸酶活力(0.13 U/mL)。在模拟发酵试验中,接种菌株JF85,14 d后水稻秸秆干物质、纤维素和半纤维素含量与对照组相比显著降低(P<0.05);在发酵第7天,JF85处理组显示最高的可溶性碳水化合物含量,整个发酵过程中木质素含量变化不显著(P>0.05)。菌株JF85具有分解纤维素、耐酸、耐盐特性,在青贮饲料生产中具有较好的应用前景。     

不同粗饲料日粮对西门塔尔繁殖母牛瘤胃发酵和血液指标的影响

[目的] 分析不同粗饲料日粮对西门塔尔繁殖母牛瘤胃液pH值、瘤胃挥发性脂肪酸含量及血液指标的影响。[方法] 选择体重相近的西门塔尔繁殖母牛18头,按同质原则分为3组,每组6头。日粮1组粗饲料为干玉米秸秆,日粮2组粗饲料为全株玉米青贮,日粮3组粗饲料为全株玉米青贮+干玉米秸秆。预试期14 d,正试期42 d。采集试验牛的瘤胃液和血液样本,进行瘤胃液pH值、挥发性脂肪酸（volatile fatty acid,VFA）含量及血液指标测定。[结果] 3组繁殖母牛的瘤胃液pH值差异不显著（P> 0.05）。全株玉米青贮组的瘤胃内乙酸含量显著（P<0.05）高于干玉米秸秆组,全株玉米青贮组和全株玉米青贮+干玉米秸秆组的瘤胃内丙酸含量显著（P<0.05）高于干玉米秸秆组,全株玉米青贮组的瘤胃内正丁酸和异丁酸含量显著（P<0.05）高于其他组。干玉米秸秆组的血清SOD活力和T-AOC活力显著（P<0.05）低于其他组,GSH-Px活力显著（P<0.05）低于全株玉米青贮+干玉米秸秆组。干玉米秸秆组血清中的铁（Fe）和锌（Zn）含量显著（P<0.05）低于全株玉米青贮组,干玉米秸秆组和全株玉米青贮组血清中的硒（Se）含量显著（P<0.05）高于全株玉米青贮+干玉米秸秆组。干玉米秸秆组血清中VD和VE含量显著（P<0.05）低于其他组。[结论] 饲喂以全株玉米青贮或者全株玉米青贮+干玉米秸秆为粗饲料的日粮,西门塔尔繁殖母牛的瘤胃发酵和血液生化指标优于饲喂以干玉米秸秆为主要粗饲料的日粮。结合饲养成本和农区粗饲料供给情况,生产中推荐全株玉米青贮+干玉米秸秆的粗饲料饲喂模式。     

发酵五味子药渣对断奶仔猪小肠黏膜的形态及免疫的影响

选用90头DLY(杜×长×大)断奶仔猪(28日龄),随机分为5组:空白对照组,饲喂基础日粮;阳性对照组(0.5%SC组),饲喂基础日粮+0.5%北五味子;0.1%FSD组,饲喂基础日粮+0.1%发酵五味子药渣;0.3%FSD组,饲喂基础日粮+0.3%发酵五味子药渣;0.5%FSD组,饲喂基础日粮+0.5%发酵五味子药渣。每天记录5组猪的腹泻情况以及采食量,计算腹泻率和料肉比,并于试验第7、14、21天,分别采集空白对照组、0.5%SC组、5%FSD组仔猪的十二指肠、空肠、回肠中段组织以及空肠黏膜,测定肠绒毛高度,隐窝深度,肠上皮内杯状细胞、淋巴细胞数量,以及空肠黏膜分泌型免疫球蛋白A(SIgA)含量。结果表明:0.1%FSD组、0.3%FSD组、0.5%FSD组仔猪的腹泻率分别比空白对照组低13.87%、30.82%、41.72%;料肉比分别比空白对照组仔猪低1.7%、4.02%、8.6%;与空白对照组相比,0.5%SC和0.5%FSD组仔猪的小肠绒毛较完整;0.5%FSD组仔猪的十二指肠、空肠、回肠绒毛高度显著增加(P0.05),隐窝深度显著降低(P0.05),绒毛高度与隐窝深度比值(V/C)提高;0.5%FSD组仔猪肠上皮内杯状细胞及淋巴细胞数量均高于空白对照组,肠黏膜SIgA含量极显著高于空白对照组(P0.01),0.5%FSD组与0.5%SC组各项指标的差异均没有统计学意义。     

Effects of dietary concentrate level and chromium-methionine supplementation on ruminal fermentation,and ruminal bacterial and fatty acid composition in Tan lambs北大核心CSCD

This study evaluated the effects of dietary concentrate level and chromium methionine(Cr-Met)supplementation on ruminal fermentation and fatty acid composition, and ruminal bacteria abundance in Tan lambs. Forty male Tan lambs [(21.00±1.23) kg body weight, 5 months of age] were randomly assigned to four treatment groups with 10 lambs in each treatment. The treatments were: a low-concentrate (LC) diet (concentrate:forage, 35:65) without Cr-Met supplementation; a high-concentrate (HC) diet (concentrate:forage, 55:45) without Cr-Met supplementation; groups fed the HC diet with 0.75 or 1.50 g·d-1·lamb-1 Cr-Met (HCM and HCH, respectively). Ruminal fluid was collected on day 65 with an oral stomach tube about 3 h after the morning feed and samples used for fermentation analysis, fatty acid composition determination and bacterial DNA extraction. It was found that: 1) Ruminal pH, acetate proportion and acetate:propionate were greater (P<0.05) with the LC diet whereas microbial crude protein, propionate and valerate proportions were greater (P<0.05) with the HC diet. The acetate:propionate was greater (P<0.05) in the HCM group than in the HC group. 2) For the HC diet, the DNA abundances of Butyrivibrio fibrisolvens vaccenic acid subgroup (Butyrivibrio VA) and Ruminococcus flavefaciens were decreased (P<0.05), compared with the LC diet, whereas the DNA abundance of Anaerovibrio lipolytica was increased (P<0.05). For lambs fed the HC diet, DNA abundances of B. fibrisolvens stearic acid subgroup, Butyrivibrio VA, Butyrivibrio proteoclasticus, and A. lipolytica showed a linear decrease (P<0.05) with increasing Cr-Met supplementation level; However, the DNA abundance of R. flavefaciens showed a linear increase (P<0.05). 3) Compared with the LC group, the concentrations of t11 C18:1, trans C18:1, c9t11 CLA, t10c12 CLA, C18:2n6, and C18:3n3 were decreased by the HC diet without Cr-Met supplementation whereas the concentration of C18:0 was increased. There was a linear increase in t11 C18:1 and trans C18:1 with increasing Cr-Met supplementation level in lambs fed the HC diet. The results suggest that the HC diet inhibited the growth of ruminal bacteria involved in the ruminal biohydrogenation process, and the addition of Cr-Met had a potentially positive effect on conjugated linoleic acid (CLA) synthesis in body tissue. © 2022, Editorial Office of Acta Prataculturae Sinica. All rights reserved.