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1.
This study was carried out to evaluate the effects of water temperature (WT) and dietary protein levels on growth, body composition and blood biochemistry of GIFT tilapia (Oreochromis niloticus; initial average body weight: 38.75 ± 0.61g, n = 20). The fish were fed with six diets contained graded levels of protein (209.6, 251.0, 302.4, 354.3, 401.9 and 456.8 g/kg) and raised in each of WT (22°C, 28°C and 34°C) for 8 weeks. Results showed that the growth, feed utilization and protein efficiency were significantly increased with the increase of dietary protein level and followed by the latter platform at each WT. The fish raised at 28 and 34°C showed similar growth performance, and their values were significantly higher than the fish raised at 22°C (p < 0.05). The lipid contents in whole body were decreases with the increase of dietary protein level at each WT. However, the whole‐body protein, ash and moisture contents were not affected by dietary protein level or WT (p > 0.05). The values of serum biochemical indices (ALP, ALT, AST and TCHO) were all decreased with the increase of dietary protein. The optimal dietary protein requirement for GIFT tilapia to achieve maximal growth performance is 374.4, 301.7 and 304.9 g protein/kg diet at 22, 28 and 34°C, respectively.  相似文献   
2.
刘梅  练青平  倪蒙  郭爱环  原居林 《水产学报》2021,45(12):2011-2028
为探究养殖过程中池塘内循环流水养殖模式(inner-pond raceway aquaculture, IPRA)对大口黑鲈生长性能、抗氧化酶、消化酶、消化道组织结构及菌落结构的影响。将池塘内循环流水养殖的4条水槽设置为流水组2条和对照组2条,进行为期153 d的养殖实验,分别在养殖中期和末期测量相关生长、生化指标及观察组织形态结构,并采用Illumina Miseq测序平台对消化道中的微生物进行分析。结果显示:①养殖中期,流水组的增重率、特定生长率和肥满度低于对照静水组;至养殖末期,流水组的增重率、特定生长率和肥满度持续下降,但成活率一直高于静水组。②养殖中期,流水组肝脏SOD和CAT显著高于静水组,流水组MDA显著低于静水组,流水组消化酶活性显著高于静水组;至养殖末期,抗氧化酶和消化酶均不同程度下降,但流水组SOD仍显著高于静水组,MDA显著低于静水组。③流水组大口黑鲈肠绒毛高度及密度均明显高于静水组,且养殖中期分泌消化酶较多,运动加强了肠道消化吸收功能。④养殖中期,流水养殖使大口黑鲈肠胃菌群的物种多样性和均匀度明显增高,至养殖末期,流水组的肠胃多样性和均匀度指数不断下降;养殖中期流水组和静水组胃分别为柔膜菌门和蓝细菌,静水组肠主要优势菌依次为变形菌门和厚壁菌门,流水组肠主要优势菌分别为厚壁菌门和变形菌门;至养殖后期时,流水组和静水组胃肠优势菌群均为柔膜菌门;而养殖水体的优势菌为变形菌门和放线菌门。研究表明,IPRA模式下的持续运动会降低其生长指标,但能够提高其成活率,增强其免疫和消化能力,改善肠胃菌群结构,尤其是处于生长期效果更明显,而至养殖末期运动状态可能会打破肠道菌群平衡,引发疾病,应加强养殖管理。  相似文献   
3.
为了维持长期培养植物愈伤组组织的高再生率,以应用于体细胞无性系进行变异筛选。本研究以继代15年的沟叶结缕草[Zoysia matrella (L.) Merr.]胚性愈伤组织为材料,用不同浓度的表油菜素内酯(EBL)处理,研究油菜素甾醇(BR)对其生长和再生的影响,选出可提高长期离体培养愈伤组织生长及再生效率的最优EBL浓度。同时,测定EBL处理的愈伤组织和再生植株中过氧化氢酶(CAT)、过氧化物酶(POD)、超氧岐化酶(SOD)活性和丙二醛(MDA)含量等生理指标变化,探究BR调控沟叶结缕草体细胞胚发生过程中抗氧化系统的作用机理。结果表明,0.02 μmol·L-1EBL对愈伤组织生长和再生的促进作用最明显,直径增长率和再生率分别为131.11%和43.8%,且愈伤组织胚性维持最佳。高浓度的EBL(>0.10 μmol·L-1)抑制愈伤组织的胚性维持和再生。EBL处理激活了植物体内的抗氧化反应系统,继代生长中POD活性降低;再生过程中,CAT、POD、SOD活性均增强;继代和再生过程中MDA含量均降低,表明BR途径能激活愈伤组织的抗氧化系统的响应,加强继代和再生过程中的抗氧化反应,从而调控体细胞胚胎发生过程中的生理生化进程。本研究为缓解长期培养的愈伤组织再生率随着培养时间增长而下降的难题提供了解决方案。  相似文献   
4.
Non-edible parts of crustaceans could be a rich source of valuable bioactive compounds such as the carotenoid astaxanthin and peptides, which have well-recognized beneficial effects. These compounds are widely used in nutraceuticals and pharmaceuticals, and their market is rapidly growing, suggesting the need to find alternative sources. The aim of this work was to set up a pilot-scale protocol for the reutilization of by-products of processed shrimp, in order to address the utilization of this valuable biomass for nutraceutical and pharmaceuticals application, through the extraction of astaxanthin-enriched oil and antioxidant-rich protein hydrolysates. Astaxanthin (AST) was obtained using “green extraction methods,” such as using fish oil and different fatty acid ethyl esters as solvents and through supercritical fluid extraction (SFE), whereas bioactive peptides were obtained by protease hydrolysis. Both astaxanthin and bioactive peptides exhibited bioactive properties in vitro in cellular model systems, such as antioxidant and angiotensin I converting enzyme (ACE) inhibitory activities (IA). The results show higher astaxanthin yields in ethyl esters fatty acids (TFA) extraction and significant enrichment by short-path distillation (SPD) up to 114.80 ± 1.23 µg/mL. Peptide fractions of <3 kDa and 3–5 kDa exhibited greater antioxidant activity while the fraction 5–10 kDa exhibited a better ACE-IA. Lower-molecular-weight bioactive peptides and astaxanthin extracted using supercritical fluids showed protective effects against oxidative damage in 142BR and in 3T3 cell lines. These results suggest that “green” extraction methods allow us to obtain high-quality bioactive compounds from large volumes of shrimp waste for nutraceutical and pharmaceutical applications.  相似文献   
5.
稻米食味品质形成及其响应氮素调控作用的研究进展   总被引:1,自引:0,他引:1  
稻米食味品质是消费者评价稻米优劣的关键品质,决定了大米的档次与市场定位。本文阐述了直链淀粉含量、胶稠度、淀粉晶体结构、淀粉颗粒粒径分布、支链淀粉链长分布、淀粉溶解及膨胀特性、热力学特性、糊化特性及回生特性等稻米食味品质评价体系,从稻米淀粉合成相关酶(AGPase)、颗粒结合淀粉合成酶(GBSS)、可溶性淀粉合成酶(SSS)、淀粉分支酶(SBE)、淀粉脱分支酶(DBE)及蛋白组分概述了稻米食味品质的遗传调控。着重综述影响蛋白质含量的重要栽培因素——氮肥施用量、施用时期及氮肥形态对稻米食味品质形成的调控途径,对水稻食味品质的遗传研究及栽培调优进行了探讨与展望,可为水稻优良品种选育与生产、稻米在市场中的竞争力提升提供参考。  相似文献   
6.
【目的】研究叶面喷施不同浓度氨基酸硒肥,对新疆吐鲁番秋季露地甜瓜早衰生理的影响,筛选出秋季露地甜瓜早衰延缓和调控技术中氨基酸硒肥的最佳施用浓度和频次。【方法】在吐鲁番秋季露地栽培条件下,以露地甜瓜主栽品种'西州密17号'为试材,从初花期开始设置叶面喷施不同浓度氨基酸硒肥处理,以清水为对照,分析不同浓度氨基酸硒肥对甜瓜叶片的叶绿素、可溶性蛋白含量、丙二醛和抗氧化酶活性的变化规律及与叶片早衰的关系。【结果】相对于清水对照处理,每隔7 d喷施2 000~2 500倍的氨基酸硒肥6~7次,可以有效延缓叶片在衰老期叶绿素相对含量、可溶性蛋白含量的下降速度,降低MDA的升高,明显提高了抗氧化酶的活性。【结论】喷施2 000~2 500倍氨基酸硒肥是延缓甜瓜叶片衰老比较理想的调控措施。  相似文献   
7.
Effective management of the nutrients and enzyme activity in the soil is necessary for maximum crop growth and productivity. However, the excessive use of chemical fertilizers (CFs) not only adversely affects the soil nutrient status and soil physicochemical properties but also aids pollution to the ecosystem. The objective of present study was to investigate the effect of single as well as combined applications of phosphate-solubilizing bacteria and agrochemicals on important soil enzyme activities and their impact on the growth of kasumbha (safflower). Pseudomonas putida (P. putida;106 cells/mL) was applied as seed inoculation prior to sowing, and CFs were applied as full, half, and quarter doses during sowing to modulate the growth of kasumbha host plants. P. putida in combination with half dose of CFs (PH) increased the soil urease and phosphatase activities, while P. putida combined with quarter dose of CFs (PQ) augmented the soil invertase activities. Moreover, the PQ treatment exhibited the maximum colony-forming units of P. putida. Leaf chlorophyll, carotenoids, protein contents, and root lengths were increased by PH treatment. Whereas, shoot length and leaf area were improved by PH and PQ treatments, respectively. Leaf protease activity was enhanced by P. putida in combination with full dose of CFs and PQ treatments, while leaf phosphate contents were significantly improved by PQ treatment. It can be concluded that P. putida in combination with half as well as quarter doses of CFs is a promising approach for the improvement of soil enzyme activities and growth of kasumbha and replacing 50% of the use of CFs.  相似文献   
8.
The major constraint in the promotion of organic farming, a safe and sustainable alternative, is lack of availability of quality organic resources in sufficient quantities. The quality of resources can be ascertained by monitoring its nutrient release pattern, which has not yet been attempted. A controlled condition pot experiment was conducted at ICAR-Central Tuber Crops Research Institute, Thiruvananthapuram, India, in completely randomized design to study the nutrient dynamics of various organic and inorganic resources, commonly used in cassava production, at monthly intervals up to six months. The release of almost all nutrients and activity of soil enzymes were higher at the middle (3 or 4?months) of the incubation period. The pH showed an increasing trend and electrical conductivity, organic C and Fe content declined from initial. Averaging over stages, organic practice favored the activity of soil enzymes and release of almost all nutrients over conventional system significantly, except N.  相似文献   
9.
马源  张德罡 《草业学报》2020,29(11):172-182
了解根际土壤养分碳、氮和磷的转化和循环利用是解决草地农业生态系统可持续利用性和提高草地生产力的根本问题。草地根际过程能够反映土壤碳、氮和磷等养分的周转速率,影响植物、土壤微生物对养分的竞争和捕获,维持根际微环境中各组分的养分平衡,同时与作物相比,草地土壤中养分元素碳、氮和磷的耦合性更强。因此,根际微生态系统结构与功能在维持养分转化和循环等方面具有重要作用。大量文献报道,调控根际微环境改变的关键因素是植物与土壤进行物质交换和信息传递的关键物质-根际分泌物,同时根际分泌物也是介导根际微生物和根际酶活性的关键物质。当草地环境发生改变时,该区域的根际分泌物、根际酶活性和根际土壤的微生物的组成和多样性也将发生根本性改变,从而导致该区域土壤养分的供应量和有效性发生改变,最终影响草地生产力和养分的有效利用效率。因此,深入探究草地根际过程对养分循环的调控机理,对于揭示草地植物与微生物间养分物质的分配利用和养分收益方面具有重要指导意义。综述了根际分泌物、根际酶和根际微生物参与养分循环的机制和互作机理,总结草地根际过程参与养分循环的机制,并对草学领域未来在根际微域的研究进行了一定的展望。  相似文献   
10.
为探究苜蓿生产过程中使用的杀菌剂对其传粉昆虫意大利蜜蜂(意蜂)的安全性,利用田间推荐使用浓度的菌核净、咪鲜胺和异菌脲处理意大利蜜蜂,分别测定蜜蜂体内3种保护酶:超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)和3种解毒酶:羧酸酯酶(CarE)、谷胱甘肽S-转移酶(GSTs)和细胞色素P450(P450)的活性。结果表明,不同浓度的3种杀菌剂均可诱导意蜂SOD和POD活性,其中咪鲜胺1500倍液(0.17 mg·L-1)处理的蜜蜂体内SOD和POD活性最高,分别为对照的1.82和5.40倍。3种杀菌剂对CAT、CarE和GSTs活性表现为低浓度诱导,高浓度抑制,对P450活性表现为抑制作用(咪鲜胺)或者诱导作用(菌核净和异菌脲)。随着处理时间的延长,3种杀菌剂1000倍液(0.40、0.25和0.50 mg·L-1)对意蜂体内3种保护酶的活性总体表现为诱导作用;而对3种解毒酶的影响各异,菌核净对3种解毒酶活性均为先激活后抑制;异菌脲对CarE和GSTs活性表现为先抑制后激活,对P450为诱导作用;咪鲜胺对CarE和GSTs表现为先激活后抑制,对P450表现为随时间逐渐降低的抑制作用。该结果表明意蜂可以通过调节体内保护酶和解毒酶活性,降低杀菌剂的负面影响,但对蜜蜂正常生理和代谢产生了影响。因此在生产中应当谨慎施用杀菌剂,保护蜜蜂安全授粉。  相似文献   
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