广东鲂全人工繁殖的研究

本文研究了广东鲂人工繁殖的鱼苗在池塘育成亲鱼的方法,用ＬＲＨ－Ａ２与ＤＯＭ混合催们效果最优,人工授精的关键是效应时间的掌握,本研究提出广东鲂最小性成熟年龄为２龄,属一年我次产卵鱼类,可进行一次２次性成熟产卵,胚胎发育程序与家鱼基本相似,胚胎发育最适水温范围约为２４－２８℃,临界水温上、下限分别为３１℃和２０℃。     

整体荧光原位杂交用于检测水稻特异DNA程序的研究

文章报道了整体荧光原位杂交应用于检测水稻特异ＤＮＡ的实验程序。利用该实验方法,以经地高辛（ＤＩＧ）标记的ｒＤＮＡ作为探针,成功地在水稻根尖和花药内部组织检测与探针互补的片段。对于实验方法,结果表明,整体荧光原位杂交的成功与否受到多种因素的影响,包括组织的种类、固定剂的种类以及固定后的处理方法（主要是酶解与否）等。检测根尖ＤＮＡ可以采用φ（福尔马林）＝１％固定加上酶解;检测花药（花粉发育处于单核期）     

三角高程测量的最佳时间

依据不同地貌,不同地表植以及不同时间观测所得出的同一边长征返高差之差和高程路线闭合差,分析并探讨了测距三角高程测量的精度与最佳观测时间问题,进而提出了一些观点。     

网销中果型鲜食番茄全产业链生产管理技术

为了提高中果型鲜食番茄生产经营者的积极性,保护全产业链各方利益,保证产业健康有序发展,从产前、产中、产后3个方面系统阐述了中果型鲜食番茄产地环境、GAP要求、品种选择、壮苗培育、田间管理、采摘收获、生产记录、产品包装、等级标准、存储条件、快递服务、售后服务及运营管理等全产业链生产管理技术,该技术推广应用后,可实现番茄的周年安全、稳定供应,得到了菜农的积极响应,农户不仅获得了番茄种植的收益,还参与视频直播,获得了网络销售的收益。     

全株玉米青贮饲料饲喂肉牛增重效果试验

试验选择10月龄左右,体重相近的西门塔尔公牛20头,随机分两组,每组10头,在精料补充水平相同的情况下,饲喂全株玉米青贮饲料和黄贮玉米青贮饲料进行对比分析,为全株玉米青贮饲料饲喂肉牛提供理论数据,并在今后同地区或相似地区的肉牛规模养殖场进行广泛推广。     

全膜双垄沟膜面气流场与种床覆土互作过程模拟研究

为进一步提升全膜双垄沟种床构建质量,合理膜面覆土及减少扬尘,探究膜面覆土与气流间互作规律,本文以甘肃省定西市临洮县境内52986号气象观测站点近30年的年平均风速1.32m/s、年平均极大风速18.07m/s、月平均极大风速26.5m/s为仿真数据来源,以正北方向为基准,以农户经验选择覆膜方向范围0°～90°的最小值、中间值、最大值为全膜双垄沟种床构建方向,分别建立T1（0°）、T2（45°）、T3（90°）3个种床模型,采用CFD-DEM气固耦合技术,得出不同风速、不同方向下全膜双垄沟种床覆土与气流场间的互作机制,综合空气流场、太阳辐射能、耕地利用率对全膜双垄沟种床构建的影响,对其构建方法进行优化,最后进行了田间验证试验。种床覆土表面流场分析表明：当空气流速恒定时,横腰带覆土表面空气最大流速由大到小依次是T3、T1、T2,大垄面覆土空气流速与标准空气流速差值由大到小依次是T3、T1、T2。种床覆土过程分析表明：当空气流速恒定时,种床及土壤颗粒对气流影响程度由大到小依次是T3、T1、T2,气流对颗粒影响程度由大到小依次是T3、T1、T2。由此可知T3模型种床及覆土表面气流速度最大,所受气流影响最大,膜面覆土移动距离最大,易形成扬尘,同时大垄面覆膜交接点极易渗入气流,引起大风揭膜现象,影响作物生长,危及经济效益。优化后的种床构建方法应遵循种床覆土位移最小、太阳辐射能最大、构建效率最快、南坡（向阳坡）耕地优先、南北走向耕地优先原则,优先采用模型依次是T1、T2、T3。田间试验结果表明：当空气流速为2.77m/s、风向北风时,平均种床合格率由大到小依次是T2、T1、T3,覆膜效率、耕地利用率、采光面积占有率由大到小依次是T1、T3、T2,试验结果与仿真模拟结果高度一致,验证了模型的可靠性。     

High‐oil residue camelina meal,a viable source of protein at low levels in diets for juvenile salmonids

The oilseed Camelina sativa has been studied as a lipid source for farmed salmonids, but recommended inclusion as a protein source has not been determined. This study evaluated low inclusion of camelina high‐oil residue meal (HORM) at 20, 40 and 60 g/kg of the diet, to determine an adequate level for Atlantic salmon parr (Salmo salar) and rainbow trout (Oncorhynchus mykiss). Salmon and trout were fed experimental diets containing up to 60 g/kg HORM for 16 weeks. At 40 g/kg HORM, trout and salmon growth performance were similar to those fed a control diet. However, at 60 g/kg HORM, trout showed lower final weight, weight gain and feed intake than those fed the control diet. Rainbow trout fed 40 and 60 g/kg HORM showed significantly lower whole body ash (p = .005), slightly lower whole body protein levels and higher fat than the control. In salmon fed 60 g/kg HORM diets, whole body ash (p = .024), and the submucosal layer of the intestine was thicker than the control (p = .007). Current results indicate that up to 40 g/kg HORM can be included in diets for rainbow trout and salmon juveniles.     

Formation of Biogenic Amines and Associated Biochemical and Microbial Attributes of Whole Sutchi Catfish (Pangasianodon hypophthalmus) during Iced Storage

Sutchi catfish (Pangasianodon hypophthalmus) is a highly preferred farmed species that is produced in huge quantities. Meat from ice-stored (4 ± 2°C) whole Sutchi catfish was evaluated for formation of biogenic amines, such as putrescine, cadaverine, histamine (HIM), agmatine, tyramine, spermine, and spermidine, and compared with biochemical, microbial, and sensory attributes during 22 days. Analysis of content of biogenic amines in the meat was carried out by liquid chromatography with tandem mass spectrometry using a without derivatization method. Three amines, namely, tyramine, spermidine, and spermine, were only present on 0^th day of storage. Presence of cadaverine was noticed from 9^th day onwards, where the aerobic plate count (APC) reached 4.85 log CFU/g. Putrescine was detected on the 22^nd day of storage, where the APC crossed 7 log CFU/g. HIM was detected in lower quantities from 3^rd day onwards. A shelf life of 15 days was determined based on sensory and microbiological evaluation. Although the samples were biochemically acceptable throughout the storage period, APC exceeded the limit on day 19, and the gradual increase of H₂S-producing bacteria, Brochothrix thermosphacta, Aeromonas, and Enterobacteriaceae, was observed during storage.     

The effect of feeding commercial diets on the development of juvenile crucian carp (Carassius carassius,L.). Part 1: Skeletal deformations

The crucian carp (Carassius carassius, L.) is a cyprinid freshwater species, whose wild‐living populations have decreased in recent years due to an increasing competition of invasive species. Several initiatives were launched, attempting to reintroduce this fish back into its native open waters, which requires the use of crucian carp fry grown under controlled conditions. However, the use of popular commercial diets results in severe developmental abnormalities. The aim of this study was to analyse the impact of feeding natural feed (Chironomidae sp. larvae) or two popular commercial diets on the skeletal development of crucian carp juveniles. Whole‐mount staining and histological methods were used in the study. Skeletal tissues of fish fed both commercial diets were demineralized and displayed a variety of deformities, such as abnormal vertebral spines and vertebral fusion, as well as a new type of deformation, which involved the action of dorsal fin pterygiophores upon the spine. Finally, a novel analytical method was proposed, which utilizes LA‐ICP‐MS for the estimation of bone mineralization. The study proved that basic commercial diets are inadequate for the rearing of crucian carp juveniles.     

丽水莲都区大港头镇茶产业发展现状及对策建议

茶叶产业是丽水市莲都区大港头镇的农业主导产业,文章在分析大港头镇产业发展优势及存在问题基础上,提出构建茶叶绿色发展基地、推动茶业全产业链建设、注重茶旅融合、加大宣传推介、提升科技水平等方面对策建议,促进大港头镇茶产业转型升级,做优做强.