牛至油和过瘤胃蛋氨酸不同组合对奶牛产奶性能和氮排泄的影响

本试验旨在研究牛至油(Oo)和过瘤胃蛋氨酸(RPMet)的不同添加量组合对奶牛产奶性能与氮排泄的影响。选取年龄、体重、胎次、产奶量、乳成分及泌乳期(90±15) d相近的荷斯坦奶牛40头随机分为10个组,每组4头。对照(C)组饲喂基础日粮,试验组饲喂不同添加水平的Oo和RPMet,Oo添加水平分别为11.5(L)、13.0(M)、14.5(H) g·(d·头)^-1;RPMet添加水平分别为22.5(L)、25.0(M)、27.5(H) g·(d·头)^-1,共组成9个不同的添加量组合,分别为LL、ML、HL、LM、MM、HM、LH、MH、HH(第1个字母为Oo添加水平,第2个字母为RPMet添加水平)。预试期15 d,正试期60 d。结果表明:产奶量方面,LL、HL、HM、MH、HH组产奶量极显著高于对照组(P<0.01),以MH组最高。乳成分方面,MH、HM组乳脂率极显著提高(P<0.01);HM、HH组乳蛋白率极显著提高(P<0.01),各试验组在乳体细胞数均极显著低于对照组(P<0.01)。在氮排泄方面,LL、ML、LM、MM、HM、LH、MH、HH组氮排泄极显著低于对照组(P<0.01),以MH组最低。综合考虑上述指标,在本试验条件下,以MH组[Oo 13.0 g·(d·头)^-1、RPMet 27.5 g·(d·头)^-1]组合效果最好。     

添喂色氨酸、过瘤胃色氨酸对奶牛泌乳性能、血浆指标和乳中褪黑素含量的影响

本研究旨在探究在饲粮中添喂色氨酸(Trp)、过瘤胃色氨酸(RPTrp)对奶牛泌乳性能、血浆指标和乳中褪黑素(MLT)含量的影响。选取30头3~5岁、2~3胎次、泌乳天数为(180±46)d的健康荷斯坦奶牛,随机分为3组,分别为对照组、试验Ⅰ组和试验Ⅱ组,每组10头。对照组饲喂全混合日粮,试验Ⅰ、Ⅱ组在对照组基础上分别添喂100 g/(d·头)色氨酸和220 g/(d·头)过瘤胃色氨酸(L-色氨酸含量≥45%)。预试期7 d,正试期60 d。结果表明:1)试验Ⅰ、Ⅱ组产奶量相比于对照组分别提高了11.78%(P0.05)和17.19%(P0.01);试验Ⅰ、Ⅱ组乳糖产量极显著高于对照组(P0.01)。2)试验Ⅰ、Ⅱ组在14:00和22:00血浆中生长激素(GH)含量极显著高于对照组(P0.01);14:00时,试验Ⅱ组血浆色氨酸含量极显著高于对照组(P0.01),各组血浆褪黑素含量无显著差异(P0.05);22:00时试验Ⅱ组血浆色氨酸含量极显著高于对照组(P0.01),试验Ⅱ组血浆褪黑素含量显著高于对照组(P0.05);试验Ⅰ组在14:00和22:00血浆色氨酸、5-羟色胺(5-HT)和褪黑素的含量与对照组均无显著差异(P0.05)。3)05:00时试验Ⅱ组乳中褪黑素含量极显著高于对照组(P0.01);18:00时各组乳中褪黑素含量无显著差异(P0.05)。4)试验Ⅰ组血浆总抗氧化能力(T-AOC)极显著高于对照组(P0.01);试验Ⅱ组血浆谷胱甘肽过氧化物酶(GSH-Px)活性极显著高于对照组(P0.01);试验Ⅰ、Ⅱ组血浆超氧化物歧化酶(SOD)活性极显著高于对照组(P0.01);试验Ⅱ组血浆丙二醛(MDA)含量极显著低于对照组(P0.01)。结果提示,添喂色氨酸[100 g/(d·头)]、过瘤胃色氨酸[220 g/(d·头)]能够提高泌乳期奶牛产奶量、血浆GH含量及抗氧化能力,其中以添喂过瘤胃色氨酸效果较好;添喂过瘤胃色氨酸[220 g/(d·头)]可提高血浆色氨酸含量及夜间血浆褪黑素含量,从而提高夜间奶牛乳中褪黑素含量。     

Use of full-fat winged bean Psophocarpus tetragonolobus seed meal as a protein feedstuff in fish-meal free diets for African catfish Clarias gariepinus

Mature winged bean Psophocarpus tetragonolobus seeds were quick-cooked and the full-fat meal derived was used to completely replace menhaden fish meal as a dietary protein source for the African catfish Clarias gariepinus . Five dry practical diets (400 g crude protein kg⁻¹ and 17.5 kJ gross energy g⁻¹ dry diet) containing menhaden fish meal (diet 1) or winged bean meal with or without graded levels of supplemental L -methionine (diets 2, 3, 4 and 5; 0, 5, 10 and 15 g kg⁻¹, respectively) were fed to catfish fingerlings (5.8  +  1.2 g) for 70 days. Weight gain, growth rate, feed conversion and protein utilization by catfish fed a winged bean meal diet without L -methionine supplementation (diet 2) was inferior ( P  > 0.05) to that in catfish fed the other diets, where performance differed nonsignificantly. Carcass protein of catfish was lower ( P  < 0.05) while liver protein was higher ( P  < 0.05) in catfish fed the winged bean meal diet without methionine supplementation. Results suggest that winged bean meal cannot replace fish meal as a protein source in catfish diets except with a minimum supplementation with 5 g L -methionine kg⁻¹ diet.     

低温胁迫对甘薯S-腺苷甲硫氨酸合成酶mRNA表达水平的影响

S-腺苷甲硫氨酸合成酶（s-adenosylmethionine synthetase SAMS）是植物代谢中的一个关键酶,它催化甲硫氨酸与ATP生物合成S-腺苷甲硫氨酸（SAM）。SAM是生物合成乙烯以及多胺的前体,参与了植物的转甲基、转氨丙基、转硫反应等多种重要的生理过程。Frank等研究发现,SAM可以与RNA结合参与基因表达调控。近年来研究表明,乙烯和多胺都参与了植物抗逆反应,     

母种鸡补充不同硒源对后代肉鸡硒沉积、抗氧化指标及生长性能的影响

选用39周龄岭南黄品种肉用母种鸡240只,按照饲养试验要求分成2组,每组3个重复,分别饲喂添加0.30 mg?kg-1硒水平的亚硒酸钠和DL-硒代蛋氨酸日粮;种蛋按重复分别孵化后,初生雏鸡各选60只,共计360只,饲喂不加硒的相同日粮56 d,研究母种鸡补充不同硒源对后代肉鸡硒沉积、抗氧化指标及生长性能的影响.结果表明:与亚硒酸钠组比,硒代蛋氨酸组显著提高了初生雏鸡、肉成鸡肝、肾和肌肉组织、雏鸡胸腺、肉成鸡血清及种蛋的硒含量(P0.01);提高了初生雏鸡肌肉GSH-Px、SOD和肾脏SOD活力(P0.05)、肌肉和肝脏T-AOC及肾脏GSH水平(P0.01),降低了肌肉和胰脏MDA含量(P0.05);增强了肉成鸡血清和肌肉GSH-Px活力(P0.01)、血清SOD活力、胰和肌肉T-AOC(P0.05);降低了后代肉鸡死亡率和料质量比(P0.05).上述结果提示,母种鸡补充DL-硒代蛋氨酸同比亚硒酸钠能提高种蛋及后代肉鸡组织硒含量,增强后代机体抗氧化功能,降低其死亡率,有利于生长并提高饲料转化率.     

慢病毒介导shRNA干扰MAT2A与MAT2B基因抑制猪肌内脂肪细胞分化

【目的】腺苷甲硫氨酸转移酶(MAT)在ATP的作用下,催化生成体内重要的甲基供体S-腺苷甲硫氨酸(SAMe)。通过构建慢病毒介导的pLenti-H1干扰载体,探究腺苷甲硫氨酸转移酶MAT2A和MAT2B对猪肌内脂肪细胞分化的影响。【方法】无菌条件下采集3—7日龄小猪背最长肌,采用差速贴壁法分离猪肌内脂肪细胞。根据GenBank中猪MAT2A基因序列（Accession No.NM_001167650.1）和MAT2B基因序列（Accession No. NM_001142832.1）,获得其CDS序列。利用Invitrogen 公司在线软件BLOCK-iTTM RNAi Designer分别设计shRNA靶序列, 将合成的单链寡核苷酸退火形成双链,与经过Bam H I和Xho I (TaKaRa) 双酶切后的pLenti-Hl载体连接,转化,并提取质粒进行酶切和测序鉴定。采用X-tremeGENE-HP DNA转染试剂与测序成功的重组质粒以及包装质粒（CMV-Δ8.9和CMV-VSVG）共转染293T细胞,48 h后观察绿色荧光蛋白(GFP)的表达,并进行滴度测定。在猪原代脂肪细胞密度达到70%—80%时,侵染病毒;细胞密度融合时诱导分化。提取分化第8天的猪肌内脂肪细胞的RNA,按照反转录试剂盒操作说明进行反转录,合成cDNA第一链。采用primer primer 5软件设计MAT2A、MAT2B、PPARγ、aP2、CEBP/α、β-actin基因的定量引物,实时定量和Western blot试验检测MAT2A和MAT2B基因的干扰效率。油红O染色和实时定量鉴定MAT2A和MAT2B基因对猪肌内脂肪脂质积累的影响。【结果】酶切及测序证明重组慢病毒载体pLenti-Hl-MAT2A/MAT2B构建成功;包装的慢病毒sh-MAT2A和sh-MAT2B病毒滴度分别为6.7×10 ⁷和7×10 ⁷ pfu/mL,侵染肌内脂肪细胞72 h后,可出现90%的绿色荧光蛋白(GFP),表明所包装的病毒可满足侵染猪前体肌内脂肪细胞需要。实时定量结果显示其显著抑制了MAT2A和MAT2B的mRNA水平表达,其干扰效率分别在70%和60%以上;进一步采用Western blot试验及蛋白分析表明,干扰MAT2A基因后,MAT2A蛋白表达水平降低40%左右,差异达到极显著水平(P<0.01);干扰MAT2B基因后,MAT2B蛋白表达水平降低25%左右,差异达到显著水平(P<0.05)。油红O染色和吸光度定量结果显示,与sh-scramble对照组相比,干扰MAT2A和MAT2B基因后,脂滴聚积能力显著抑制猪肌内脂肪细胞脂质积累。实时定量结果显示,干扰MAT2A和MAT2B基因抑制成脂标志基因PPARγ,aP 2及CEBP/α的表达。 【结论】成功构建了猪MAT2A和MAT2B基因的慢病毒sh-MAT2A和sh-MAT2B干扰载体。获得的重组慢病毒感染细胞后,能有效降低猪肌内前体脂肪细胞内MAT2A和MAT2B基因的mRNA和蛋白水平表达;进一步试验证明,干扰MAT2A及MAT2B基因后,显著抑制猪肌内脂肪细胞的脂质积累以及成脂关键基因表达。     

微胶囊蛋氨酸或晶体蛋氨酸对军曹鱼幼鱼相关酶活性的影响

比较研究了低鱼粉饲料中添加微胶囊蛋氨酸或晶体蛋氨酸对军曹鱼(Rachycentron canadum),消化酶和蛋白质代谢酶活性的影响.将鱼粉组和减少鱼粉后蛋氨酸缺乏组分别设为正、负对照组,试验组饲料在负对照组的基础上分别添加晶体蛋氨酸(MET)、羟基蛋氨酸(MHA)、邻苯二甲酸醋酸纤维素微胶囊蛋氨酸(CAP)、丙烯酸树脂微胶囊蛋氨酸(RES)和棕榈酸甘油酯微胶囊蛋氨酸(TPA),共7组等氮等脂饲料.每个处理设3个重复,每个重复放养20尾鱼,初始体质量(5.40±0.07)g,流水养殖8周,水温29～31℃.结果显示微胶囊蛋氨酸组的军曹鱼肠道胰蛋白酶活性显著高于正对照组和MET组(P＜0.05),MET和TPA组肝脏谷草转氨酶(GOT)活性显著高于正负对照组(P＜0.05);MET组军曹鱼幼鱼摄食后0.5 h肠道Na+、K+-ATP酶活性显著高于其他各组(P＜0.05),摄食3 h后正对照组和RES组Na+、K+-ATP酶活性上升,显著高于CAP和MHA组(P＜0.05),摄食8 h后正对照组和微胶囊蛋氨酸组显著高于MHA和MET组(P＜0.05).以上结果表明,军曹鱼低鱼粉饲料中添加晶体蛋氨酸即可增进氨基酸的代谢和蛋白质的合成,微胶囊有助于蛋氨酸在肠道中的缓慢释放,提高肠道内胰蛋白酶活性.     

Inhibition of Methionine Biosynthesis in Botrytis cinerea by the Anilinopyrimidine Fungicide Pyrimethanil

When mycelium of Botrytis cinerea was treated with low concentrations of the anilinopyrimidine fungicide pyrimethanil the total amount of free amino acids increased. Qualitative variations were also induced: alanine, glutamine, lysine, glycine, histidine, asparagine, arginine, threonine and moreover, α-aminobutyrate and β-alanine were accumulated; cyst(e)ine, valine, leucine and citrulline were reduced. When mycelium of B. cinerea was incubated with Na₂[³⁵S]O₄, pyrimethanil at 1·5 μM induced a decrease of [³⁵S]methionine and simultaneously an increase of [³⁵S]cystathionine. These data indicate that the anilinopyrimidine fungicide pyrimethanil inhibits the biosynthesis of methionine and suggest that the primary target could be the cystathionine β-lyase. © 1997 SCI.     

Atlantic salmon fed a nutrient package of surplus methionine,vitamin B12, folic acid and vitamin B6 improved growth and reduced the relative liver size,but when in excess growth reduced

Feeding plant‐based diet through smoltification of Atlantic salmon requires verification of the optimal level of 1C nutrients. Here, we fed Atlantic salmon plant‐based diets containing three different surplus amounts of the 1C nutrients; methionine, cobalamin (vitamin B12), pyridoxine (vitamin B6) and folic acid during 6 weeks in fresh water, through smoltification, followed by 3 months on‐growing period in salt water. The three diets were fed to fish dispersed in triplicate tanks throughout the experiment. Mean start body weight was 32 g. Dietary methionine levels in the diets were 6.7, 9.2 and 11.7 g/kg. Dietary B6 was 6.75, 8.45 and 11 mg/kg. Cobalamin was 0.16, 0.18 and 0.20 mg/kg. While dietary folic acid was 2.9, 4.8 and 6.3 mg/kg, diets are referred to as low, medium and high 1C diet. All other amino acids were similar between diets. The results showed no differences in growth or feed utilization in the fresh water period, but following the on‐growing salt water period, differences between diets occurred. The fish fed the medium 1C diet showed better growth, as compared to fish fed the low or high 1C diet (p = .009). The medium 1C fed fish showed a relative lower liver weight compared with fish fed low or high 1C diet (p = .025). Condition factor was better in fish fed the medium and high 1C diet as compared to those fed the low 1C diet (p = .0006). As expected, free methionine in liver, plasma and muscle increased by dietary methionine inclusion. Surplus vitamins only had minor effect on tissue concentrations. Based on these findings, we conclude that the micronutrient and methionine level presented in the medium 1C diet improved the growth, liver size and condition factor; however, more research is needed to evaluate the optimal requirement level for each of the 1C nutrients.