The effects of replacement of whole‐plant corn with oat and common vetch on the fermentation quality,chemical composition and aerobic stability of total mixed ration silage in Tibet

The objective of this experiment was to evaluate the effects of replacement of whole‐plant corn with oat and common vetch on the fermentation quality, chemical composition and aerobic stability of total mixed ration (TMR) silage in Tibet. Four TMR that varied in the forage sources on dry matter basis were used: (i) 52% whole‐plant corn (Control); (ii) 43% oat + 12% common vetch (OC3.6); (iii) 38% oat + 18% common vetch (OC2.2); and (iv) 33% oat + 23% common vetch (OC1.5). Silos were opened on day 45 and then subjected to an aerobic stability test for 12 days. The results showed that all silages were well preserved with low pH and NH₃‐N, and high lactic acid and V‐scores. With the increasing proportion of common vetch, crude protein, ether extract increased (P < 0.05), and neutral detergent fiber and acid detergent fiber decreased (P < 0.05). Under aerobic conditions, treated silages were more stable than the control silage as indicated by lower (P < 0.05) pH and yeast population. It was concluded that replacement of whole‐plant corn with oat and common vetch had no unfavorable effects on the fermentation quality and improved crude protein content and aerobic stability of TMR silage. OC2.2 silage was the best among three treated TMR silages.     

从世遗标准看广东客家乡村景观的文化遗产价值

在认知粤东北传统客家乡村景观遗产分布、构成及现状的基础上,运用世界遗产杰出普世价值的评估标准,分析归纳了它作为文化景观的遗产价值;主要体现在三个方面:1)两千年中原文化南迁历史的活体见证;2)客家传统文化及民俗风貌的独特展示;3)岭南山区人居环境营造的杰出范例。     

Effects of feeding rates on growth and production of Nile tilapia, common carp and silver carp polycultured in fertilized ponds

Abstract In an attempt to identify appropriate feeding rates for multispecies of fish raised in fertilized earthen ponds, the present work was conducted over a 19‐week experimental period to establish the growth performance, production and body composition of Nile tilapia, common carp and silver carp fed 0.0%, 0.5%, 1.0%, 3.0%, 5.0% biomass and to apparent satiation (treatments). Twelve ponds were stocked with a similar number and weight of each fish species. Two ponds were assigned to each of the treatments, and a 25% protein pelleted fish feed was used to feed fish at the specified rate of feeding. At the end of the experiment, growth, weight gain, survival, yield and body composition of fish groups were affected by the treatments. The economic effectiveness also varied among treatments. The most conspicuous attribute of the feeding rates was its lack of influence on growth (g day^?1), weight gain (g per fish), yield (kg ha^?1) or body composition of silver carp. The results of whole‐body proximate analysis indicated that various feeding rates had either an irregular pattern or no effects on the protein and ash gain per 100 g of fish body weight (bw) gain. The most notable exceptions were significant (P < 0.05) increases in body fat and gross energy gains in Nile tilapia, common carp and silver carp accompanied by decreases in percentages of moisture (but not in silver carp) as feeding rate increased. Among the six different feeding levels, feeding to apparent satiation (feed amount was equivalent to 2.67% of fish bw day^?1) appeared to be optimal, as it significantly (P < 0.05) supported the highest fish production, income and net profit compared with all other treatments except for the 3% feeding level, for which the differences in those measurements were comparable.     

The conservation of the endangered Mediterranean common dolphin (Delphinus delphis): Current knowledge and research priorities

1. Preservation of endangered species is now recognized as a relevant component of regional and global conservation actions achieved through the maintenance of the remaining populations in a favourable conservation status. The Mediterranean common dolphin (Delphinus delphis) is listed as an Endangered subpopulation in the International Union for Conservation of Nature Red List, with declining numbers in some of the areas where it has been studied for numerous years. Prey depletion, fisheries bycatch, pollution, health risks, and climate change are among the recognized threats that the species is facing in the region.
2. The existing national, regional, and international legislation pertinent to Mediterranean countries should aid greater science–policy–management integration and support innovative research and monitoring towards effective conservation. The challenges inherent in studying the pelagic D. delphis should not preclude the use of long-term, year-round, multiplatform surveys, side by side with the latest molecular tools, which aid our understanding of its populations' genetic diversity, resistance to diseases, and resilience in a semi-enclosed fast-changing sea.
3. Addressing the multiplicity of problems confronting the species requires collaborative effort at all levels to share and merge resources, data, and expertise more efficiently. In this review, we provide an overview of the current knowledge on the Mediterranean common dolphin, the main threats, and knowledge gaps that are priorities for addressing its conservation, while providing clear recommendations for effectively safeguarding the species and its habitat at both local and regional levels.

     

鲤鱼血淋巴细胞培养及染色体制备条件探索

从鲤鱼侧线鳞处静脉采血于含有肝素的一次性注射器中，采用RPMI1640全培养基进行体外淋巴细胞培养。通过对采血后细胞培养时间、秋水仙素浓度及加入时间、低渗时间及温度等条件的摸索，建立了较成熟的培养鱼类血淋巴细胞的实验方法。     

地被植物在郑州都市区园林绿化中的组成结构及管理对策研究

采用实地调查统计的方法对郑州市各大公园及路边广场的地被植物及其特点、选择标准、养护管理等进行了研究分析。结果表明:当前地被植物品种单一,种植面积较小,且多单独种植,混合应用较少,较多地段没有地被植物覆盖,后期管理粗放。建议充分利用每种地被植物不同时期的观赏特点,种植时合理搭配,及时管理,以大大提高观赏价值,从而提高地被植物的造景水平。     

三种鲤对暴发性鱼病抗病力的差异

本文报道三种鲤对嗜水气单胞菌引起暴发性鱼病的抗病力试验结果。当菌液浓度为６．０×１０￣８ＣＦＵ／ｍｌ，采用１０￣０、１０￣（－１）、１０￣（－２）、１０￣（－３）四个稀释度、０．３ｍｌ／尾注射剂量时，建鲤、野鲤和镜鲤的半数致死量（ＬＤ＿（５０））分别为１０￣（－１．３７５）、１０￣（－０．９７６）、１０￣（－０．５６２）。这三种鲤的半数致死量差异显著（Ｆ＞Ｆ＿（０．０５））。从四个方面研究了抗病机理：白细胞吞噬功能和补体替代途径（Ｃ＿３旁路）杀菌能力，镜鲤较强于野鲤和建鲤，但无显著差异（Ｆ＜Ｆ０．０５）；红细胞Ｃ＿（３ｂ）受体花环率和补体总量（单位／ｍｌ），是建鲤＞野鲤＞镜鲤，差异极显著（Ｆ＞Ｆ０．０１）。本研究结果还表明建鲤的红细胞Ｃ＿（３ｂ）受体花环率和补体总量稍高，但对暴发性鱼病病原（嗜水气单胞菌）较易感染。以上结果证明，不同品系鲤鱼对暴发性鱼病有种内特异性。     

船体网箱饲养的鲤鱼水霉病发病条件及防治药物筛选

本文研究了水霉病的发病条件，病原分离和防治药物，结果表明：水霉病主要发生在１￣４月份，水温和机械损伤是水霉病发生的主要条件，孔雀石绿对水霉菌抑菌，杀菌效果最佳，其安全浓度为０．１３ｐｐｍ。生产中与甲醛，敌百虫和食盐结合使用，效果更佳。     

鲤鱼脱脂方法的研究

分别采用水漂洗、有机溶剂浸提、脂肪酶酶解的方法对鲤鱼鱼肉进行脱脂。试验结果表明,水漂洗法中,清水漂洗效果最优;有机溶剂浸提法中,异丙醇脱脂效果最佳,并对其采用正交试验方案对异丙醇脱脂工艺进行优化,得到最佳试验条件是:脱水时间30 m in,脱脂时间110 m in,温度为75℃,溶剂添加量为50 g;脂肪酶脱脂试验得出最佳条件是加酶量40 U/m l,酶作用时间50 m in。3种方法中,脂肪酶脱脂效果最佳。