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171.
Arginine activity in broiler diets can be supplied by L-arginine (Arg), guanidinoacetic acid (GAA) and L-citrulline (Cit), all of which are commercially available. This study was conducted to assess the effects of Arg source and level on broiler performance, nutrient digestibility and carcass parameters. Day-old Ross 308 cockerels (n = 768) were assigned to one of eight dietary treatments using a completely randomized design: normal protein (NP), low protein deficient in Arg (LP) and LP with two levels of either Arg (0.238% and 0.476%), GAA (0.309% and 0.618%) or Cit (0.238 and 0.476%). The LP was 5 percentage points lower in protein level than the NP. Wheat, sorghum, soya bean meal, canola meal, and meat and bone meal-based diets were fed over three feeding phases to 6 replicate floor pens with 16 birds each. Compared to NP, birds fed LP had reduced feed intake (FI, p < 0.001), reduced body weight gain (BWG, p < 0.001) and increased feed conversion ratio (FCR, p < 0.001) from day 0 to day 35. Additions of Arg or Cit to the LP at both levels resulted in increased BWG and reduced FCR (p < 0.05). Birds fed LP with GAA added had lower FCR (p < 0.05) but not higher BWG (p > 0.05) compared with the LP observed from day 0 to day 35. Supplementation of Arg, Cit and the low level of GAA to LP resulted in increased carcass yield, bone length, diameter and ash (p < 0.05) but did not increase ileal energy or nitrogen digestibility (p > 0.05). The findings indicate that Cit is an efficacious source of Arg activity in Arg-deficient diets.  相似文献   
172.
本试验旨在研究妊娠早期饲粮中添加N-氨甲酰谷氨酸(NCG)对母羊胚胎存活及相关血液指标的影响,并对其作用机制进行初步探讨。选择发情正常、健康状况良好的湖羊50只,随机分为2组(对照组和NCG试验组),每组25只母羊,自配种当天开始给母羊分别饲喂基础饲粮(对照组)和基础饲粮+0.11%NCG(NCG组),饲喂期38 d。测定妊娠第19和38天母羊血浆游离氨基酸、总一氧化氮合酶(TNOS)、内皮型一氧化氮合酶(eNOS)、诱导型一氧化氮合酶(iNOS)、一氧化氮(NO)、雌二醇、孕酮的浓度;38 d时每组各屠宰7只妊娠母羊,测定妊娠母羊的黄体数和活胎儿数等指标。结果显示,与对照组相比,妊娠第38天时,NCG组每只母羊总胎儿数增加了79.72%(P<0.05),活胎儿数增加了79.72%(P<0.05),胎儿形成指数增加了0.26(P<0.05),胎水体积增加了72.89%(P<0.05),活胎儿总重提高了71.13% (P<0.05);NCG组妊娠第19天的甘氨酸、蛋氨酸、赖氨酸、精氨酸、NO、iNOS、eNOS和孕酮的浓度显著高于对照组(P<0.05),NCG组妊娠第19天的瓜氨酸和脯氨酸极显著高于对照组(P<0.01);NCG组妊娠第38天的精氨酸、脯氨酸和NO显著高于对照组(P<0.05),NCG组妊娠第38天的iNOS和eNOS的浓度极显著高于对照组(P<0.01)。由此,妊娠早期饲粮中添加NCG提高了胚胎和胎儿的存活,增加了妊娠母羊第38天的总胎儿数和活胎儿数,改善了母羊的繁殖性能,其作用机制可能是NCG促进了母羊内源性精氨酸的合成,提高了母羊血浆精氨酸、NO和孕酮含量,改善了子宫内环境和营养供给,使之有利于胚胎着床和妊娠维持。  相似文献   
173.
尿素是农业生产中施用量最多的氮肥之一,也是植物体内重要的代谢中间产物。普遍认为,植物主要吸收土壤中经土壤微生物转化产生铵态氮和硝态氮,直接吸收尿素和内部水解作用并不显著, 但这一观点正受到挑战,因为植物拥有专用的尿素转运蛋白,能够利用尿素作为唯一氮源。本文通过概述尿素在不同生命系统中存在的基础生理意义及MIPs和DUR3系统在调控尿素吸收、转运以及库/源间氮循环过程的作用,讨论了脲酶在促进尿素氮的同化、信号传导,精氨酸途径和酰胺途径在维持C/N代谢平衡和激素信号网络调节机制,以及植物尿素代谢及稳态调节机制在农业运用方面的展望。通过阐述植物体内局部尿素浓度与整体的氮素状态信号的反馈调节调控氮素的吸收和再利用的复杂调控网络,为提高作物氮的吸收、利用及再分配和农作物遗传改良奠定理论基础。  相似文献   
174.
对产碱假单胞菌产精氨酸脱亚胺酶的发酵条件进行了优化,结果表明,产碱假单胞菌产ADI的最佳发酵条件为:10 g·L-1蔗糖为碳源,6 g·L-1蛋白胨为氮源,10 g·L-1精氨酸诱导物,4%的接种量和30%的装液量,发酵温度29℃,发酵时间24 h,摇床转速为150 r·min-1,发酵液的初始p H8.5。在此条件下,产碱假单胞菌产ADI的酶活最高。  相似文献   
175.
A 10‐week feeding experiment was conducted to evaluate the effects of replacing fish meal with soybean meal (SBM), with or without dietary arginine (Arg), on growth performance, immune indices and intestinal morphology of grouper, Epinephelus malabaricus. Nine experimental diets were formulated to contain 20%, 30% and 40% fish meal protein (FMP) replaced using SBM and 0, 0.5% and 1% dietary Arg supplementation. The results showed that weight gain (WG) of fish was significantly affected by the interaction of substitution level and Arg supplemental level. The maximum WG occurred at the 30% FMP substitution level and the 0.5% Arg supplemental level. The immune assay showed that the interaction between the two levels significantly influenced the production of serum nitric oxide but did not affect serum IgG concentration and alkaline phosphatase activity or the liver IGF‐1 gene expression. Significant interaction effects between the two levels were observed in muscle layer thickness (tML) and fold height (hF) in the proximal and mid‐intestine. High SBM level in diets reduced the tML and hF in the entire intestine. The results suggested that the interaction of 30% FMP substitution level and Arg supplemental level of 0.5% most benefitted growth performance, immune indices and intestinal structure of grouper.  相似文献   
176.
Dietary arginine requirement of Heteropneustes fossilis fry (3.0 ± 0.5 cm; 5.1 ± 0.3 g) was determined by feeding casein‐gelatin‐based isonitrogenous (400 g kg?1 crude protein) and isocaloric (17.97 kJ g?1) amino acid test diets containing graded levels of l ‐arginine (15, 17, 19, 21, 23 and 25 g kg?1 dry diet) for 12 weeks. Maximum absolute weight gain (AWG) (44.4), best feed conversion ratio (FCR) (1.22), highest protein retention efficiency (PRE%) (41%), energy retention efficiency (ERE%) (75%), best condition factor, hepatosomatic index and viscerosomatic index were noted at 21 g kg?1 arginine of the dry diet. Maximum body protein (189.8 g kg?1) was also obtained in fish fed above diet. Highest haematocrit value (35%), Hb concentration (9.54 g dL?1), RBC count (3.44 × 109 mL?1) and lowest Erythrocyte sedimentation rate (ESR) (1.93 mm h?1) were obtained at the above level of arginine in the diet. AWG, FCR, PRE% and ERE% data were analysed using broken‐line and an exponential fit to obtain more precise dietary arginine requirement. On the basis of broken‐line and exponential analyses of AWG, FCR, PRE and ERE data, inclusion of dietary arginine in the range of 20.4–22.6 g kg?1 dry diet, corresponding to 51–56.5 g kg?1 dietary protein, is recommended for formulating arginine‐balanced feeds for rearing H. fossilis fry.  相似文献   
177.
Streptococcosis causes serious economic losses to fish farms every year. A four‐week feeding trial was carried out to evaluate arginine (ARG) supplementation in the diet of Nile tilapia (Oreochromis niloticus) fingerlings challenged by Streptococcus agalactiae. Fish were fed with experimental diets containing five levels of supplementation with 1.39%, 1.76%, 1.97%, 2.18% or 2.39% analysed level of ARG. Each diet was randomly distributed in 30 tanks containing 20 fish/tank. After 30 days, no differences were observed in performance parameters, weight gain, daily weight gain, specific growth rate, feed intake or food conversion. After the performance assay, fingerlings were infected with 1.95 × 108 CFU/fish of Streptococcus agalactiae. Mortality was verified daily, and the respiratory burst of leucocytes and nitric oxide production were measured at 0 hr, 24 hr, 7 days and 15 days after infection. The survival rate of the fish is compared using the Kaplan–Meier method, with values of 4.29%, 14.8%, 10.8%, 17.2% and 33.3% for the 1.39, 1.76, 1.97, 2.18 and 2.39 treatments respectively. A reduction in the mortality rate and a boost in the immune responses was observed in all the supplementations of ARG in the diet; however, the best survival rates were obtained in the treatments with 2.39% ARG as well as the most efficient immune responses.  相似文献   
178.
An 8‐week growth trial was conducted to investigate the effects of dietary Arg levels (7.6, 12.3, 17.9, 22.4 and 28.6 g/kg diet) on growth performance, hepatopancreatic antioxidant capacity, intestinal morphology and growth‐related gene expressions of juvenile grass carp (Ctenopharyngodon idellus). The results showed that SGR in Arg22 and Arg28 groups was lower than in Arg12 and Arg17 groups (p < 0.05). Serum NO content in Arg7 group was lower than other groups. Hepatopancreatic GSH‐Px activity was higher in Arg17 group than in Arg7 group, while MDA content showed the opposite trend. Hepatopancreatic IGF‐1 expression tended to increase with Arg from 7.6 to 22.4 g/kg and then decreased in Arg28 group (p < 0.05), while IGFBP‐1 expression increased with Arg level. Muscle mRNA expressions of TOR and S6K1 showed quadratic trends as dietary Arg level increased, which were higher in Arg17 group than in Arg22 and Arg28 groups (p < 0.05). Higher mRNA expression levels of y+LAT1, y+LAT2 and PepT1, as well as higher villus height and villus width in foregut, were all observed in Arg17 group. The optimal dietary Arg level based on SGR by the quadratic model was 15.3 g/kg diet for juvenile grass carp, corresponding to 54.7 g/kg dietary protein.  相似文献   
179.
PGMS水稻在长短日照下Arg,Met的含量变化   总被引:1,自引:1,他引:1  
对光敏核不育水稻农垦58s进行长、短日照处理并测定叶片、叶鞘多胺合成前体Arg、met的含量。结果表明,长日不育株叶片中Arg含量显著高于短日可育株;Met含是出现最大值的时期长日不育株为减数分裂期,短日可育株为二次枝梗和颗花原基分化期;Met含是 体上是短日可育株高于长日不育株。  相似文献   
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