Dietary methionine affects growth and the expression of key genes involved in hepatic lipogenesis and glucose metabolism in cobia (Rachycentron canadum)     

Shuyan Chi  Yuanfa He  Yong Zhu  Beiping Tan  Xiaohui Dong  Qihui Yang  Hongyu Liu  Shuang Zhang 《Aquaculture Nutrition》2020,26(1):123-133

Juvenile cobia (Rachycentron canadum), a carnivorous fish, was chosen to examine the effects of methionine (Met) supplementation of low fishmeal diets on growth and the expression of key genes related to hepatic lipogenesis and glucose metabolism. Seven isonitrogenous and isolipidic diets were formulated to contain 7.2, 9.0, 10.0, 12.4, 14.1, 16.3 and 18.6 g/kg dietary Met levels. Healthy cobia (initial average weight ± SE = 9.79 ± 0.04 g) were randomly assigned into seven groups in triplicate with 40 individuals per sea cage for 8 weeks. The results showed that the weight gain rate (WGR) of fish increased as the dietary Met was increased up to 12.4 g/kg and then decreased. The expression of insulin‐like growth factor‐I (IGF‐I) and target of rapamycin (TOR) genes was inhibited by the Met‐deficient diets. The mRNA levels of fatty acid synthase (FAS) and sterol regulatory element‐binding protein‐1 (SREBP1) genes increased with increasing dietary Met until 12.4 g/kg after which the former remained constant, whereas the latter decreased from 12.4 to 18.6 g/kg Met. The mRNA levels of pyruvate kinase (PK) increased as the dietary Met levels increased, reaching a peak at 12.4 g/kg, and then decreased with further increases in Met. However, the mRNA levels of phosphoenolpyruvate carboxykinase (PEPCK) decreased as the dietary Met was increased up to 12.4 g/kg and then remained constant from 12.4 to 18.6 g/kg Met. In conclusion, based on the straight broken‐line analysis of WGR against dietary Met levels, the optimal dietary Met requirement for juvenile cobia was estimated to be 12.4 g/kg (26.9 g/kg dietary protein). A diet with the optimal level of Met induces fish growth and is associated with increased IGF‐I and TOR.  相似文献   

硬质合金涂层刀具车削Ti6Al4V磨损实验研究     

闫军宇  杜茂华  程正  栾建举 《农业装备与车辆工程》2021,(1):17-20

使用两种涂层硬质合金刀具在云南机床厂生产的CY6140普通卧式车床上对Ti6Al4V钛合金棒料进行干切削,当达到一定的切削长度时,使用工业显微镜观察、测量并记录了刀具前后刀面的磨损形貌及磨损量的值.一旦达到刀具磨钝标准时就停止切削.通过分析刀具的磨损形貌以及两种涂层刀具磨损的曲线图可知,在切削Ti6Al4V材料时,SP...  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：21，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   

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

Fagbenro 《Aquaculture Nutrition》1999,5(3):199-204

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.  相似文献   

蛋氨酸锌在山羊体内存留与分布   总被引：2，自引：0，他引：2  

李丽立  张彬 《湖南农业大学学报(自然科学版)》1998,24(6):461-464

为揭示蛋氨酸锌在山羊体内存留与分布的规律,将１０浆体重为９ｋｇ左右的健康浏阳黑公山羊分成两组,分别饲喂＾６５Ｚｎ－Ｍｅｒ与＾６５ＺｎＳＯ４两种不同来源的同位素锌,研究螯合盐中锌在山羊体内的分布与存留。结果表明：在试验前期体内富集的锌,蛋氨酸锌组为４８．１ｍｇ,硫酸锌组为３５．４０ｍｇ,前者比后者多富集１３．０１ｍｇ,存留率分别为４０．３７％与２９．５０％。各组织器官中锌的存留量分别为２．３６,１．  相似文献   

聚合物包膜尿素氮释放特性及其对高羊茅草坪生长的影响     

谷佳林  许俊香  徐秋明  边秀举  李会彬  曹兵 《园艺学报》2009,36(3):385-390

 通过静态水溶试验和草坪施肥试验, 研究了高分子聚合物包膜尿素( PCU) 的养分释放特性及春季一次性施用对高羊茅草坪生长的影响。结果表明, 由于肥料所处环境温度不同导致实验室静态水溶法测定PCU养分释放速度快于其在田间的实际释放速度。田间试验中一次性施用该肥料可以满足高羊茅草坪整个春季生长对氮素养分的需要; 与尿素和市场上的草坪肥料相比, 草坪质量无显著差异, 且草坪生长速度均匀, 草屑量相对较少, 起到了减少草坪修剪次数降低养护强度的作用。  相似文献   

In situ polymerization coating and characteristics of coated NPK compound fertilizer     

WANG Zhenghui ZHU Boming 《东北农业大学学报(英文版)》2007,14(2):48-152

Controlled release NPK compound fertilizers were prepared by means of in situ polymerization of monomers on the surface of fertilizer granules at room temperature.Methacrylate,α-methyl acrylic acid,and ethylene dimethylacrylate were used as monomers,Dibenzoyl peroxide as initiator,and cobalt naphthenate,and triethyl amine as promoters.The structures of coating materials were characterized by IR spectra.The thermogravimetric analysis result indicated that the coating materials were of good thermal stability.The mean thickness of single coating measured with screw gauge was ca.140μm.The morphologies of uncoated and coated fertilizer granules analyzed by using scanning electron microscopy were changed from porosities and gullies to hills and plain. The release rate of coated compound fertilizers in water could be controlled by the hydrophicity and thickness of coating.The increase in coating hydrophicity caused the increase in release rate of fertilizer.The increase in thickness of coating slowed the release rate.  相似文献   

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   总被引：2，自引：1，他引：1  

迟淑艳  谭北平  董晓慧  杨奇慧  刘泓宇  许悦娜  黄红岩 《中国水产科学》2011,18(1):110-118

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.  相似文献   

包膜缓释尿素与普通尿素配施对双季超级稻产量及氮肥利用的影响   总被引：5，自引：1，他引：5       下载免费PDF全文

钱银飞  邵彩虹  邱才飞  陈先茂  谢江  邓国强  陈大洲  童金炳  伍守恒  彭春瑞 《中国土壤与肥料》2015,(5):27-32

以双季超级稻为材料,研究了不同包膜缓释尿素与普通尿素配施组合对其产量和氮肥利用等生物学性状的影响,结果表明:在全氮(早稻180 kg·hm-2,晚稻225 kg·hm-2)模式下,与全施普通尿素处理相比,全施包膜缓释尿素的处理双季超级稻的穗数降低,但每穗粒数和结实率显著提高,最终提高产量,提高了氮肥利用效率;节氮模式(早稻144 kg·hm-2,晚稻180 kg·hm-2)下,不同比例包膜缓释尿素与普通尿素组合的产量和氮肥利用效率均显著高于全氮模式;3种配比组合中以包膜缓释尿素∶普通尿素=3∶7组合的产量最高,氮肥吸收利用程度最高,应用效果最好。  相似文献   

沙壤土包膜尿素释放期与小麦适宜施用方式研究   总被引：8，自引：2，他引：8  

刘永哲  陈长青  尚健  王火焰  周健民  陈照明  刘晓伟 《植物营养与肥料学报》2016,22(4):905-912

【目的】在保水保肥性差、 氮素淋溶损失严重的姜堰高砂土地区,采用新型水基反应成膜技术的包膜尿素,研究可提高小麦产量以及氮肥利用率的肥料品种和施肥方法。【方法】本研究采用30、 60、 90 d三种控释期包膜尿素(PCU30、 PCU60、 PCU90)并各设置三种施肥方式处理: 播种行下方12 cm处一次基施、 播种行侧方3 cm深5 cm处一次基施、 播种行侧方10 cm深5 cm处一次基施(T1、 T2、 T3)。小麦成熟期测定各小麦秸秆和籽粒产量与干物质分配,测定氮素吸收量。【结果】三种包膜尿素中,施用PCU60增产效果最好,其侧施处理优于种下深施,其中T2处理的小麦产量最高,为8661 kg/hm2,比当地习惯施肥增产6.5%。PCU60 T2处理的氮肥利用率为53.7%,较习惯施肥提高17.3%,差异显著。PCU90各处理较习惯施肥均减产且收获期土壤硝态氮残留量高,不适合当地使用。【结论】在砂土基质下,PCU60在播种行侧方3 cm深5 cm处一次基施可替代尿素分次施用,降低劳动成本。  相似文献