Effects of supplementary feeds with different protein levels on growth and economic performances of Nile tilapia (Oreochromis niloticus) cultured in a rain-fed rice–fish ecosystem     

M. A. R. Mridha  M. A. Hossain  M. Nahiduzzaman  M. S. Uddin 《Journal Of Applied Aquaculture》2017,29(2):152-166

This study investigated the effects of supplementary feeds with different crude protein (CP) levels on the growth and economic performances of sex-reversed Nile tilapia (Oreochromis niloticus) reared in a rain-fed rice–fish ecosystem for a period of 120 days. There were four treatments—namely, traditional feed (21% CP), formulated feed (26% CP), commercial feed (30% CP), and control (no feed was used)—with three replicates per treatment. Fish (30.04 g) were stocked in ditches at a rate of 0.5 fish m^?2 considering the total area and fed one of the tested feeds twice daily at the rate of 2%–5% of body weight. Water-quality parameters of the ditches were monitored fortnightly, and these parameters were found suitable for fish farming. Organic matter, total nitrogen, and available phosphorous in soil were increased significantly (P < 0.05) in the feed treatments after fish cultivation. Highly significant weight gain and SGR were observed with fish fed the commercial feed as compared with other treatments. The highest benefit-cost ratio (2.15) was found in the control, followed by formulated feed (1.90), but in the case of numerical net return, it was the opposite. However, commercial feed showed the lowest benefit-cost ratio (1.67) due to higher feed cost than other supplementary feeds. Therefore, this study suggests that fish fed with a formulated feed (26% CP) produced significantly higher net economic return in the rice–fish farming system.  相似文献   

Nutritional Qualities of the Low-Value Bivalve Mollusks Paphia malabarica and Villorita cyprinoides at the Estuarine Waters of the Southwestern Coast of India     

Minju Joy 《Journal Of Aquatic Food Product Technology》2017,26(1):54-70

The bivalve mollusks Paphia malabarica and Villorita cyprinoides collected from the estuarine system located in the southwest coastal waters of India were evaluated for their nutritional composition. A balanced essential to nonessential amino acid ratio (> 1.0) with a greater quantity of sulfur-containing amino acids in these species demonstrated that they could provide well-balanced protein depositions. The n-3/n-6 polyunsaturated fatty acid ratio in P. malabarica was found to be greater than 2, and, therefore, can be considered as a healthy diet. The C₂₀–C₂₂ long-chain polyunsaturated n-3 fatty acids (for example, docosahexaenoic acid and eicosapentaenoic acid) accounted for more than 23% of the total fatty acid content in P. malabarica as compared to about 7% in V. cyprinoides. P. malabarica showed greater hypocholesterolemic/hypercholesterolemic ratio (1.7) and lesser atherogenicity (0.7), thrombogenicity (0.3) indices when contrasted with those in V. cyprinoides, thereby indicating the nutritional superiority of the former. A greater content of vitamin D₃ (> 150 IU), along with significant quantities of calcium and phosphorus (> 500 mg/100 g) in the clams, signified their importance in preventing osteoporosis. This study demonstrated the importance of bivalves, in particular, P. malabarica as a valued species for human consumption.  相似文献   

Decoding Australia's China threat narrative during 2016–2021     

Kerry Liu 《Asia Pacific viewpoint》2023,64(1):126-141

Australia–China relations began to sour in 2016, and the China threat narrative began to dominate since then. Unlike previous studies which either use a qualitative approach or cross-sectional dataset for empirical analysis, this study creatively creates high-frequency weekly and monthly time series datasets using the Google Trends search results during January 2016–February 2021. Based on a series of time series modellings, this study examines the roles of various actors, including China's own policies, the Australian Strategic Policy Institute and Clive Hamilton, various factors, including Chinese purchase of Australian housing, Chinese investment in Australia, Chinese students in Australia and China's rise and various media outlets, including the Australian Broadcasting Corporation, Australian Financial Review, Sydney Morning Herald, Daily Telegraph and Herald Sun, in contributing to Australia's China threat narrative. This study makes significant contributions to academia in methods by bringing a new quantitative approach to international relations studies and to policy-makers as well by quantifying the roles of various actors, factors and media outlets in Australia's China policy debate.  相似文献   

Conservation implications of isotopic variation in nails and blood with wetland quality in three species of Australian freshwater turtle     

Roxane J. Francis  Kate J. Brandis  Bruce C. Chessman  Eve Slavich  Richard T. Kingsford 《水产资源保护:海洋与淡水生态系统》2024,34(1):e4056

Effects of long-term application of various organic amendments on soil particulate organic matter storage and chemical stabilisation of vertisol soil     

Keke Hua  Zhibin Guo 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2018,68(6):505-514

Current understanding of the effects of long-term application of various organic amendments on soil particulate organic matter (POM) storage and chemical stabilisation remains limited. Therefore, we collected soil samples from the soil profile (0–100?cm) under six treatments in a 31-year long-term fertilisation experiment: no fertiliser (CK), mineral fertilisers (NPK), mineral fertilisers plus 3.8 or 7.5?t?ha^?1?year^?1 (fresh base) the amount of wheat straw (1/2SNPK and SNPK) and mineral fertilisers plus swine or cattle manure (PMNPK and CMNPK). Long-term incorporation of wheat straw and livestock manure amendments significantly (p?<?0.05) increased crop yield and sustainable yield index, and POM storage compared with CK and NPK treatments. The mole ratios of H/C in the POM under organic amendment treatments significantly (p?<?0.05) decreased by 13.8% and 37.1%, respectively, compared with the NPK treatment. Similarly, solid state NMR spectroscopy showed that the O–alkyl carbon content of POM was greatly decreased, whereas aromatic carbon contents and alkyl to O–alkyl carbon ratios were substantially increased under PMNPK and CMNPK treatments. In conclusion, we recommend long-term livestock manure application as a preferred strategy for enhancing POM quantity and quality (chemical stability), and crop yield of vertisol soil in northern China.  相似文献   

设施葡萄不同新梢间距处理对冠层光环境及果实品质的影响   总被引：1，自引：0，他引：1  

史祥宾  刘凤之  程存刚  王孝娣  冀晓昊  王宝亮  郑晓翠  王海波 《园艺学报》2018,45(3):436-446

选用6年生‘贝达’砧木嫁接的‘京蜜’葡萄为试材,在控制果实负载量相同的前提下,设置10、15和20 cm新梢间距处理,连续两年研究其3种新梢间距处理条件下葡萄冠层光环境及果实品质的差异。结果表明：树体冠层总孔隙度和开度为新梢间距20 cm处理 > 15 cm处理 > 10 cm处理,叶面积指数和光能截获率表现相反,新梢间距10 cm 处理 > 15 cm处理 > 20 cm处理。20 cm间距处理光能利用率低,10 cm处理叶面积指数过高,树体郁闭,15 cm处理叶面积指数合理,光能利用率高。果实单粒质量在新梢间距15 和20 cm处理间无显著差异,显著高于10 cm处理;果皮色泽以15 cm间距处理最佳,其次为20 cm处理,10 cm处理最差。果实内在品质,可溶性糖和维生素C含量以新梢间距15 cm处理 > 20 cm处理 > 10 cm处理,可滴定酸含量表现相反趋势,10 cm间距处理最高,15和20 cm处理间无显著差异。特征香气组分中具有玫瑰香味的芳樟醇与绿叶清香和果香的正己醛含量均以15 cm间距处理显著高于其他两个处理;清香和果香味的橙花醇、花香味的香叶醇、甜玫瑰香味的香茅醇及绿叶清香和果香味的2–己烯醛含量均以15和20 cm新梢间距处理显著高于10 cm处理。15 cm间距处理挥发性香气物质的含量较高,表现更浓的品种香气。综合认为,设施栽培中水平龙干树形配合高光效V形叶幕的‘京蜜’葡萄以新梢间距15 cm处理表现最佳。  相似文献   

寄主植物对不同基因型麦长管蚜解毒酶活性的影响   总被引：1，自引：0，他引：1  

李时荣  葛朝虹  刘德广  崔晓宁  黄贤亮  王达 《西北农业学报》2018,27(2):283-293

为阐明麦长管蚜[Sitobion avenae(Fabricius)]取食不同寄主植物时体内解毒酶活性的变化,并探索寄主适应性的生理生化基础,以8种基因型麦长管蚜为研究对象,测定其1代或连续3代取食小麦、大麦、燕麦和黑麦草后,体内3种解毒酶[乙酰胆碱酯酶(AChE)、羧酸酯酶(CarE)和谷胱甘肽-S-转移酶(GST)]的活性。结果表明,麦长管蚜在4种麦类植物上饲养1代后,大麦对AChE和GST的诱导效果最显著,燕麦对CarE的诱导效果最显著。4种植物相比,大麦对麦长管蚜基因型1、2、3和8的AChE,基因型2、4、5、6和8的CarE,以及基因型1、3、5和6的GST的诱导效果较为显著。比较各寄主植物上第1代和第3代蚜虫的酶活性,发现4种寄主均对第1代蚜虫的CarE活性具有明显诱导效果;大麦对第1代蚜虫GST活性的诱导效果显著,但小麦、燕麦和黑麦草均对第3代蚜虫GST的诱导效果显著。因此,不同寄主植物对麦长管蚜体内3种解毒酶的诱导作用存在显著差异,且这种诱导作用与蚜虫的遗传背景、繁衍世代数及二者的交互作用均密切相关。  相似文献   

海南4个地区暹罗炭疽菌群体遗传结构分析     

蒋仕强  李杨  周国英  刘君昂  万智  蒋越西  李河 《热带作物学报》2016,37(11):2204-2209

对分离自海南4个地区13种寄主植物上暹罗炭疽菌的ITS-CAL-GAPDH 3基因序列进行群体遗传结构分析。95条暹罗炭疽菌多基因序列可定义为16个单倍型,其中,单倍型H5为主要单倍型,分布于所有寄主植物。AMOVA分析显示,遗传变异主要发生在种群内;病菌未经历过大规模的种群扩张过程。研究结果表明,暹罗炭疽菌种群具有丰富的遗传多样性。  相似文献   

漆酶基因异源表达及其酶活性的研究进展     

刘晓庆  那日  郭九峰 《安徽农业科学》2016,(1):18-21

近年来由于漆酶在生物漂白和农作物秸秆利用等方面具有广阔的应用前景,对漆酶的研究越来越受到国内外学者的重视。然而,自然界漆酶的产量和酶活较低,难以适应工业化生产需求。此外,漆酶的产酶效率低,成本高。实现漆酶的异源高效表达是解决这一问题的有效途径。目前,国内外已有多种来源的漆酶基因被成功克隆,并在不同的宿主细胞中实现异源表达,但迄今为止漆酶基因异源表达结果仍然不理想,离真正实现漆酶的高效表达还有一定距离。  相似文献   

Comparison of New Ultrasonic Digestion Approaches for Plant Matrices in the Analysis of Trace Metals by Inductively Coupled Plasma–Optical Emission Spectroscopy Analysis: Contrast with USEPA Method 3050B     

Golam Ahmed  David Takuwa  Inonge T. Chibua  Zibisani Bagai  Lebogang Morekisi  Hilary Shoniwa 《Communications in Soil Science and Plant Analysis》2016,47(4):512-520

An ultrasonic method using two approaches, A and B, along with a reference Environmental Protection Agency (EPA) Method 3050B [i.e., a mixture of 30 mL of nitric acid–hydrochloric acid–hydrogen peroxide–water (HNO₃-HCl-H₂O₂-H₂O)] were contrasted for leaching of a plant matrix. The trace metals were arsenic, cadmium, cobalt, chromium, copper, mercury, manganese, nickel, lead, selenium, and zinc (As, Cd, Co, Cr, Cu, Hg, Mn, Ni, Pb, Se and Zn) and quantified by ICP-OES followed by an investigation into residue formation and the impact of digestion time. Approach B was the most accurate and precise with percent recoveries ranging between 99 and 120%, whereas ultrasonic approach A and the USEPA method 3050B gave similar results with poor accuracies and precisions. In the optimization of the digestion time using approach B, the total metal recovery was fairly the same over a period of 120 min except for Cr and Cu, which showed slight variations.  相似文献