索引     

施卫省  彭争  李洋 《热带作物学报》2013,34(1):29-30

采用大田试验,对“水冬瓜果油”包膜尿素与土壤水分耦合效应进行研究.结果表明:在相同灌水量和肥料施用量情况下,施包膜尿素比普通尿素可以推迟叶绿素SPAD下降时间40 d,平均产量增加为12.7 t/hm2.,平均水分利用率可提高3.4 kg/hm2· mm,其中灌水2600 m3/hm2,施包膜氮肥150 kg/hm2,增产最高,包膜尿素与水耦合效果最好.  相似文献   

不同材料包膜尿素对玉米生长及其缓释效应的研究   总被引：1，自引：0，他引：1  

王晓晶  王艳  王小波 《天津农业科学》2007,13(2):35-37

主要通过玉米盆栽试验研究了4种多年筛选的包膜肥料对玉米的生长及其氮素释放的影响。通过测定土壤中的速效N、脲酶、玉米生物量、氮肥利用率等,对包膜肥料进行评价。CRF-16的玉米生物产量最高,比ck提高了30.67%。CRF-16N肥利用率最高,与其它包膜肥料差异显著,比ck高19.1个百分点。在玉米生长前期,包膜肥料抑制脲酶活性;到了玉米生长旺盛期,脲酶活性增加,促进了氮的释放。在玉米生长中后期,4种包膜肥料不同程度地增加了土壤碱解氮的含量,这与氮素前期抑制释放而中后期大量释放有关。  相似文献   

强化蛋氨酸硒对刺参富硒效果的初步研究     

周玮  胡晓洁  王祖峰  鲁晓倩  刘剑波  曹芹  张津源 《大连海洋大学学报》2015,(3)

为了研究投喂蛋氨酸硒对刺参Apostichopus japonicus成参(40.00 g±5.62 g)的富硒效果,用添加蛋氨酸硒为0(对照)、0.2、0.4、0.6、0.8、1.0 mg/kg(饲料)的富硒饲料分别投喂刺参,试验共进行60 d,试验结束时测定成参个体的生长情况和富硒效果。结果表明:在本试验条件下,随着饲料中蛋氨酸硒添加浓度的增加,刺参的特定生长率、出皮率和体壁硒含量均呈现升高的趋势;试验结束时,刺参的体长特定生长率从试验开始时的0.11%/d提高到0.34%/d,体质量特定生长率从试验开始时的0.18%/d提高到0.46%/d;加工个体的出皮率从50.38%提高到61.14%,煮后出皮率从19.40%提高到24.69%;干品率从25.95%提高到30.88%;体壁硒含量从1.65 mg/kg提高到2.56 mg/kg。研究表明,饲料中添加适量蛋氨酸硒能够明显提高仿刺参的生长率、出皮率和体壁硒含量。  相似文献   

蛋氨酸铜对西门塔尔牛发情周期生殖激素分泌的影响     

王聪  黄应祥  岳文斌  刘强  王浩  董群 《家畜生态学报》2007,28(4):40-43

选用16头18月龄,体况良好,体重380±26 kg的西门塔尔牛育成母牛,采用完全随机区组设计分为4组,以蛋氨酸铜为铜源,研究日粮加铜(0、8、16和24 mg/kg)对发情周期生殖激素分泌规律的影响.结果表明:8 mg/kg组和16 mg/kg组显著提高了发情周期LH、FSH、P4和E2水平(P＜0.05);24 mg/kg组有所提高,但不显著(P＞0.05).说明添加蛋氨酸铜8～16 mg/kg对发情周期生殖激素分泌有显著促进作用.考虑基础日粮的含铜量,建议日粮铜水平为:13.87～21.87 mg/kg.  相似文献   

Choline supplementation to low methionine diets increase phospholipids in Atlantic salmon,while taurine supplementation had no effects on phospholipid status,but improved taurine status          下载免费PDF全文

M. Espe  J.‐E. Zerrahn  E. Holen  I. Rønnestad  E. Veiseth‐Kent  A. Aksnes 《Aquaculture Nutrition》2016,22(4):776-785

Phosphatidylcholine is synthesized endogenously through the enzyme phosphatidylethanolamine–methyl transferase. As endogenous choline synthesis requires methyl groups from S‐adenosylmethionine (SAM), the endogenous synthesis of choline may depend on SAM availability. SAM availability depends on methionine and ATP. SAM is also a precursor for cysteine and may affect taurine and glutathione concentrations. To investigate whether choline synthesis or transsulphuration is prioritized and the interactions between taurine and choline supplementation when methionine availability is low, juvenile Atlantic salmon were fed low methionine diets with and without taurine and choline supplementation. There were no differences in growth or protein accretion following treatments. Fish fed the low methionine diets did not develop a fatty liver, but choline supplementation increased the concentration of total phospholipids in liver and muscle. Taurine supplementation increased taurine concentrations in liver and muscle, but no interactions with choline were present. Liver SAM was unaffected by treatments. Two of three tanks fed the low methionine diet without choline and taurine supplementation had a higher gene expression of p38MAPK (mitogen activated phosphokinase). Choline supplementation to low methionine diets thus may have beneficial effect on the metabolic health and lipid transport to extra‐hepatic tissues. Taurine supplementation had no effect on phospholipids status, but increased taurine concentration in tissues and as such may affect oxidation status when methionine availability is low.  相似文献   

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     

Marit Espe  Vibeke Vikes  Trn Helgy Thomsen  Anne‐Catrin Adam  Takaya Saito  Kaja H. Skjrven 《Aquaculture Nutrition》2020,26(2):477-489

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.  相似文献   

Fishmeal levels can be successfully reduced in white shrimp (Litopenaeus vannamei) if supplemented with DL‐Methionine (DL‐Met) or DL‐Methionyl‐DL‐Methionine (Met‐Met)          下载免费PDF全文

A. Lemme  P. Yin  C. Figueiredo‐Silva  Y.‐J. Liu  S.‐W. Xie  J. Niu  L.‐X. Tian 《Aquaculture Nutrition》2018,24(3):1144-1152

The main objective of this study was to evaluate the effect of methionine supplementation when reducing fishmeal levels in diets for white shrimp (Litopenaeus vannamei). Tested diets consisted of a positive control with 260 g/kg fishmeal (D1), two negative controls with 100 g/kg fishmeal and no amino acid (AA) supplementation (D2) or supplemented with lysine but not methionine (D3), and four additional diets with 100g/kg fishmeal supplemented with increasing levels of DL‐Met (1.0, 2.0 or 3.0 g/kg) (D4, D5, D6) or Met‐Met (1.0 g/kg) (D7). Each diet was fed to four groups of 30 shrimp for 8 weeks at a daily rate of 70 g/kg body weight. Reduction in fishmeal from 260 g/kg down to 100 g/kg did not significantly affect survival rate, feed conversion ratio (FCR), protein efficiency ratio (PER) or protein retention efficiency (PR%) of white shrimp. However, growth performance (final body weight, FBW; weight gain, WG; specific growth rate, SGR) was reduced when dietary fishmeal level was reduced from 260 g/kg (D1) to 100 g/kg without methionine supplementation (D2). The growth performance (FBW, WG and SGR) of shrimp was significantly increased by supplementation of the 100 g/kg fishmeal diet with increasing levels of DL‐Met (p < .05). Same performance as positive control (D1) was achieved with diets containing 100 g/kg fishmeal and supplemented with 3.0 g/kg DL‐Met or 1.0 g/kg Met‐Met. The highest values of growth performance (FBW, WG and SGR) were found in shrimp fed D6 and D7 diets, which were significantly higher than those of shrimp fed D2 and D3 diets (p < .05) but without statistical differences with shrimp fed D1, D4 and D5 diets (p > .05). The highest values of whole‐body and muscle protein contents were found in shrimp fed D1 diet, which were significantly higher than those of shrimp fed all other diets (p < .05). The highest value of intestinal tract proteolytic enzyme activity was found in shrimp fed Met‐Met‐supplemented diet (D7) and followed by the positive control diet (D1) and 3 g/kg DL‐Met‐supplemented diet (D6) (p < .05). The highest values of apparent digestibility coefficients (ADCs) of dry matter and crude protein were found in Met‐Met‐supplemented diet (D7) and followed by the positive control diet (D1) (p < .05). Shrimp fed the D1 diet showed the highest value of total essential amino acid (EAA) and was significantly higher than shrimp fed D2–D3 (p < .05) but without significant difference with shrimp fed D4–D7 (p > .05). In conclusion, results showed that same performance can be achieved with diets containing 260 or 100 g/kg fishmeal supplemented with 3.0 g/kg DL‐Met or 1.0 g/kg Met‐Met. Moreover, supplementation of limiting methionine in low‐fishmeal diets seems to improve the digestive proteolytic activity, improving digestibility of dry matter and protein, and eventually to promote growth of juvenile white shrimp in fishmeal reduction diets.  相似文献   

动物营养中胆碱同其它甲基供体间的关系   总被引：19，自引：2，他引：19  

王宏  霍启光 《动物营养学报》1999,(2)

本文概述了胆碱、甜菜碱和蛋氨酸三种甲基供体的特性与共性;它们之间的代谢关系;饲养实践中的添加效应以及相互替代值。作者认为,日粮中必须含有一定数量的胆碱和蛋氨酸,分别用于合成磷脂和蛋白质。甜菜碱作为一种有效的甲基供体和抗应激剂,有明显的饲用效果。所谓甜菜碱替代蛋氨酸并非指生化途径可以替代,而只是反应在生产指标方面的相同或相近的效应,这种替代效应还受动物本身和日粮类型等因素的影响。  相似文献   

分娩前饲喂包被氯化钙对母猪产程和死胎的影响     

汪刘  杨志鹏  王苗苗  彭健  谭家健  孙海清  魏宏逵 《动物营养学报》2022,(1)

本试验旨在研究分娩前饲喂包被氯化钙对母猪产程和死胎的影响。选取913头妊娠109 d丹系长×大和大×长二元杂交母猪,根据体况和胎次接近的原则分成3组。对照组于妊娠109 d至分娩当天每天饲喂基础饲粮,试验Ⅰ组和试验Ⅱ组在基础饲粮的基础上分别额外饲喂25和50 g/d包被氯化钙。饲养试验从妊娠109 d到分娩当天。试验过程中每天进行粪便评分,于分娩当天记录试验母猪产程、产仔数和死胎数,并采集尿液和血液分别用于测定尿液pH和血清钙离子浓度。结果表明:1)总产仔数和分娩前饲喂包被氯化钙对母猪死胎数无显著交互作用(P>0.05);试验Ⅰ组和试验Ⅱ组死胎数分别为0.31和0.28头,显著低于对照组的0.44头(P<0.05),但试验Ⅰ组和试验Ⅱ组无显著差异(P>0.05)。2)试验Ⅰ组母猪产程相较于对照组显著缩短(P<0.05),而试验Ⅱ组产程相较于对照组无显著差异(P>0.05);3组母猪胎盘排出时间之间无显著差异(P>0.05)。3)3组母猪妊娠109 d和分娩当天尿液pH之间无显著差异(P>0.05);妊娠110 d到妊娠113 d,对照组和试验Ⅰ组尿液pH无显著差异(P>0.05),试验Ⅱ组尿液pH显著低于对照组和试验Ⅰ组(P<0.05)。与对照组相比,试验组母猪血清钙离子浓度显著提高(P<0.05),妊娠112 d和分娩当天粪便评分显著降低(P<0.05);3组母猪便秘率之间无显著差异(P>0.05)。综上所述,母猪妊娠109 d至分娩前饲喂25 g/d包被氯化钙可显著缩短产程,减少死胎,而且该效果不受母猪总产仔数的影响,该调控效果与其提高血液钙离子浓度有关。  相似文献   

聚水阻渗措施对矮砧密植苹果园土壤水分、硝态氮及果树细根的影响     

陈东凯  骆汉  谢永生  吕佼容 《水土保持学报》2023,37(6):298-304

为提高土壤水肥利用效率，探索适宜渭北地区苹果园发展的聚水阻渗措施。通过大田试验，以矮砧密植苹果园为研究对象，分析不同聚水阻渗措施对土壤水分、硝态氮和果树细根的影响。结果表明：在垂直方向，防渗层、起垄+防渗层、起垄+覆膜+防渗层处理均可有效提高0—40 cm土层土壤含水量、硝态氮含量和细根根长密度，其中，起垄+防渗层和起垄+覆膜+防渗层处理土壤含水量和细根根长密度高于防渗层处理，硝态氮含量则低于防渗层处理。在50—100 cm土层，3种处理措施均降低土壤硝态氮含量，有效缓解硝态氮淋溶累积。在水平方向上，起垄+防渗层和起垄+覆膜+防渗层处理使定植带内(树下、株间)土壤含水量与根长密度平均分别提高15.1%,5.0%,硝态氮含量降低8.6%,防渗层与清耕处理相比无显著差异。在施肥沟内(中间点),3种处理措施使土壤水分含量和细根根长密度增加，土壤硝态氮含量降低，以起垄+覆膜+防渗层处理效果最好，使土壤含水量和细根根长密度分别增加48.6%,48.3%,硝态氮含量降低17.4%。在所有处理措施中，起垄+覆膜+加防渗层处理对果园土壤环境和果树根系的调控效果最佳，研究结果为渭北地区矮砧密植苹果园聚水...  相似文献