首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 140 毫秒
1.
国内外口蹄疫的流行情况及防制   总被引:2,自引:0,他引:2  
口蹄疫是一种高度传染性疾病,以传播迅速和发病率高而被国际兽医局列为法定报告动物疫病之首。该病不但严重危害畜牧业和经济,还对国家声誉、国际关系也有很大影响。本文在查阅近几年国内外有关口蹄疫文献的基础上,对其流行情况、防制策略等方面进行了总结,为该病的预防和控制提供参考和依据。  相似文献   

2.
Abstract  Catch composition, relative abundance and diversity of fish catches in open access and three old fisheries closures were compared and contrasted with previous ecological studies. There was less variation in catch community composition among the fishing grounds than the closures, suggesting that fishing has homogenised catch composition. The trap survey found that some parrotfish [ Leptoscarus vaigiensis (Quoy &Gaimard), Calotomus carolinus (Valenciennes) and Scarus ghobban Forsskål] were relatively more common and that some important predators of macro-invertebrates [ Balistapus undulatus (Mungo Park) and Cheilinus chlorourus (Bloch)] were less common in the fishing grounds than closures. Unexpectedly, and in contrast to visual census results, cumulative number of species in catch surveys was higher in open access than closures sites. This may result from fishers covering more area and habitat or a reduction in the catch of competitively subordinate and rare species by aggressive, early-caught fish that can dominate bait. Comparisons of ecological visual census surveys and fisheries-dependent methods indicated that small differences in catch composition can reflect larger ecological differences and that baiting methods can underestimate biodiversity. Ecological impacts of fishing and large-scale changes in marine ecosystems must be considerable given the many fisheries-dependent assessments report modest changes.  相似文献   

3.
随着人们对甲壳动物生理生态学研究的逐步深入,尤其是与免疫应答密切联系的血液生理学领域被广泛关注.抽取和固定血淋巴,成为进行血液学研究必不可少的步骤.那么如何更好地抽取和固定血淋巴呢,本文以虾蟹为例做了总结,以供参考.  相似文献   

4.
渔业管理理论与中国实践的回顾与展望   总被引:2,自引:1,他引:2  
黄硕琳  唐议 《水产学报》2019,43(1):211-231
渔业管理一直是世界各渔业国家所面临的难题。本文首先分析了中国渔业的特点,指出中国的渔业管理比世界上任何国家都更为复杂、更为困难,描述了中国渔业管理的历史沿革和中国渔业政策的发展脉络,指出在中国的渔业发展中渔业政策对渔业生产始终起着指导和推动的作用,认为中国初步形成了以《中华人民共和国渔业法》为基本框架,层次结构完备,措施有力,不断完善和强化的渔业管理制度。然后,介绍了渔业管理的主要理论,梳理了中国学者对渔业管理研究的主要文献,指出中国通过水产养殖支撑不断增长的水产品消费需求,成功解决了水产品需求与资源环境约束之间的矛盾,对减少捕捞野生渔业资源发挥了重大作用。文章归纳了中国渔业管理的主要制度和措施,并对其效果进行综合评述,认为几十年来,特别是改革开放以来,中国不断引进先进的渔业管理理念,促进养殖业、捕捞业、加工流通业、增殖渔业、休闲渔业等五大产业蓬勃发展,渔业生态环境修复力度不断加大,依法治渔能力显著提升;但是由于中国渔业的特点和渔业的复杂性和不确定性,中国渔业仍存在着一些明显的问题。最后,本文根据相关的渔业发展规划,展望了中国的渔业管理将朝着渔业资源总量控制、强化资源保护及生态修复的方向发展。  相似文献   

5.
大黄鱼常见疾病的防治   总被引:1,自引:0,他引:1  
本文在对大黄鱼(Pseudosciaena crocea)的疾病种类、主要症状、病理变化等调查研究的基础上,提出了大黄鱼的主要病害和防治方法。  相似文献   

6.
北极微生物的分离及抗菌抗肿瘤活性筛选   总被引:3,自引:0,他引:3  
采用多种培养基对北极地区(海洋沉积物、湖泊沉积物及土壤)微生物进行分离,并采用琼脂平板打孔法和MTT法进行了抗菌、抗肿瘤活性菌株的筛选.共分离极地微生物151株,筛选结果显示,12.4%的菌株有抗菌活性,6.2%菌株有抗肿瘤活性,其中3株同时具有抗菌、抗肿瘤活性,表明极地有良好的微生物药用资源.  相似文献   

7.
饲料糖种类和水平对青鱼、鲫生长和体成分的影响   总被引:3,自引:1,他引:3       下载免费PDF全文
用分别含20%(低)、40%(高)葡萄糖和糊精的等氮(粗蛋白为35%干物质),等能(16.4 kJ/g)饲料分别饲养青鱼(Mylopharyngodn piceus)和鲫鱼(Carassius auratus)8周,研究饲料糖种类和水平对青鱼和鲫的生长、体成分的影响.青鱼和鲫鱼平均体质量分别为2.14 g和6.75 g.结果表明,两种鱼都是糊精组增重率、饲料效率、蛋白质效率显著高于葡萄糖组,提示两种鱼对糊精利用效率比葡萄糖高.饲料糖含量低时增重率、饲料效率、蛋白质效率相对高,提示两种鱼对脂肪作为能源的利用效率高于糖.两种鱼糊精组脂肪蓄积率显著高于葡萄糖组,体脂、肝脂、肌脂含量也高于葡萄糖组,提示糊精比葡萄糖更容易以脂肪形式积累在体内.青鱼对实验饲料的利用效率高于鲫鱼,推测这与能量代谢有关.[中国水产科学,2006,13(3):452-459]  相似文献   

8.
氨基酸微量元素螯合物的生产与应用   总被引:7,自引:0,他引:7       下载免费PDF全文
赵元凤 《水产学报》1997,21(3):263-268
研究了以动物蛋白质废弃物(毛发、蹄角、皮革下脚料等)为主要原料,工业化生产复合氨基酸微量元素螯合物和生产工艺、产品在工业生产中的质量控制方法以及产品在鲤、非鲫养殖中的应用效果。研究表明,按本工艺,蛋白原料水解近基酸的转化率高,且氨基酸的种类齐全。由于生产过程中采用了控制氨基酸配体与金属离子摩尔比的中间控制方法,确保了微量元素与氨基酸的螯合效果。养鲤试验表明,添加螯合盐的三个试验组分别比添加无机盐的  相似文献   

9.
李佳  吴东波 《畜禽业》2007,(4):8-11
本试验利用饲养试验方法,研究玉米-豆粕型日粮中添加植酸酶时不同磷水平和钙磷比对生长肥育猪血清指标和骨骼性能的影响。试验选用162头20kg左右的杜长大三元杂交猪进行2×3(磷水平×钙磷比)因子饲养试验,试验分2个阶段进行,前期为生长期体重在20-60kg,后期为肥育期体重为为60-100kg。结果表明:添加植酸酶日粮磷水平对血清磷含量和碱性磷酸酶的活性影响显著(P<0.05);钙磷比对血清钙和血清磷含量的影响显著(P<0.05);添加植酸酶日粮磷水平和钙磷比对生长肥育猪骨骼性能的影响不显著(P>0.05)。在添加植酸酶条件下,降低日粮磷水平不影响猪的正常生长发育。  相似文献   

10.
选择繁殖性能好的A家系(F6)和生长与存活好的B家系(F3),设计家系内自繁和家系间杂交,比较其自交组与杂交组子一代的生长与存活,评价杂交效应。由自交组F66(A♀×A♂)、F33(B♀×B♂)和杂交组F63(A♂×B♀)、F36(B♂×A♀)4个实验组组成,比较各实验组子一代在80、100、120、150日龄时的各生长指标杂种优势。研究表明,同一生长发育阶段的同一杂交群体的不同性状,表现的杂种优势大小有很大差异,而且同一杂交群体的同一性状在不同生长发育阶段表现的杂种优势大小同样有差异。自交组各阶段全甲宽、甲宽、甲长和体高的生长趋势比较一致,为F33F66;不同生长性状的生长速度方面,杂交组具有不同程度的总体杂种优势(-3.50%-19.47%)。结果显示,就存活而言,杂交组比自交组的存活率杂交优势明显,总体杂种优势率为24.8%,与存活相关的养殖产量的总体杂种优势率为15.99%,无论是生长性状还是存活,杂交使A家系获得的改良效果比B家系的好。A、B两个家系间存在的遗传差异获得杂种优势,是性状得到改良的基础。  相似文献   

11.
为利用杂种优势培育皱纹盘鲍(Haliotis discus hannai)优良新品种,本研究以4个不同养殖群体[黄岛(HD)、荣成(RC)、日本(JP)、大连(DL)]的皱纹盘鲍为亲本,设计4×4完全双列杂交,建立了4个自交家系和12个正反杂交家系,在利用微卫星标记进行亲子鉴定的基础上,对各家系的F1在1、5、13、17月龄时的生长性状、杂种优势率、生长速度和存活情况进行比较,分析杂交效应。结果表明,在各个生长阶段均有部分杂交家系与自交家系相比表现出显著的生长优势;HDRC、HDDL和JPDL家系的生长速度较高;HDDL、HDJP、RCDL、JPRC及RCHD家系有着较高的存活率;在杂种优势方面,HDRC、HDDL与DLHD家系在各生长参数与生长速度上有明显的杂种优势,HDDL、RCDL、DLHD家系在存活率上表现出明显的杂种优势。本研究筛选出的具有优势的交配组合,可作为皱纹盘鲍生产上种苗来源的参考,也为利用杂种优势培育皱纹盘鲍新品种提供了基础资料。  相似文献   

12.
Although the gills have been reported as a site for settlement by sea lice attached stages in experimental challenges, the prevalence and abundance of infection on gills have not been reported in farmed fish and have been reported only rarely in wild salmonids. Disproportionate attachment to the gills may be significant in evaluation of new therapeutants and this study asks whether the efficacy data from studies of therapeutants based on experimental challenge can be extrapolated to the fish farm arena. The distribution of chalimus on gills, body and fins of farmed first sea year Atlantic salmon were examined in two Scottish sea lochs, each on two occasions (30 fish on each sampling date), fish from one farm with infection with Lepeophtheirus salmonis only and the other farm with exclusively Caligus elongatus. The dorsal fin was the primary attachment site of L. salmonis (50% and 33% in two samples respectively) with 29% and 32% on other fins and 20% and 29% on the body and head. Only one of 56 chalimus (1.8%) and four of 75 chalimus (5.3%) were attached to the gills. In contrast, the chalimus distribution of C. elongatus was predominantly on fins other than the dorsal, including the tail, 74% and 71%, on two sampling occasions, respectively, with only 4.2% and 3.6% of chalimus located on the dorsal fin. The pectoral fins were the most common location with 32%, followed by the tail 23%, pelvic fins 14% and only 3% on the anal fin. None of 287 and 111 chalimus in two samples, respectively, of C. elongatus was attached to the gills. The low abundance of lice on the gills indicated that non‐destructive sampling methods adequately represented lice infection. In three experimental challenges with L. salmonis, the gills were a major attachment location with 19.9–36.3% of chalimus, 9.9–26.9% on the body, 22–27% on the dorsal fin and 19–23% on the other fins. These differences with natural challenge in L. salmonis reported here and also in the literature suggest that the importance of the gills for chalimus location in the experimental model is atypical and an artefact of reduced host swimming speed in tanks that permits copepodids to attach to the gills. In natural infection, the flow over the gills is high and reduced flow is required for copepodid settlement. Greatest reductions (96%) in chalimus bath treated with cypermethrin occurred on the gills with no significant reductions in those located on the dorsal and other fins. It is possible that the efficacy of therapeutants may be higher in chalimus attached to the gills because of the higher concentration encountered of bath therapeutant and extrapolation of efficacy to farms may be misleading and progression to field testing is essential.  相似文献   

13.
孔雀石绿是一种三苯甲烷类化合物,作为一种重要的化工原料、碱性染料、杀真菌剂、生物染色剂得到了广泛的应用.由于其毒性和可致癌性,已经被禁止用于水产品生产和运输过程中.综述了孔雀石绿污染物的治理和样品中其残留物的分离检测方法.  相似文献   

14.
奶牛酮病发病机理研究进展   总被引:2,自引:0,他引:2  
结合国内外目前研究状况较为详细的综述了奶牛酮病的病因与发病机理,并分析了奶牛酮病发生的生化机制。旨在对临床实践中很好的认识诊断和群体监控奶牛酮病提供较为系统的理论依据,保证奶牛群的高产和稳产,从而创造良好的经济效益。  相似文献   

15.
本文采用不同浓度的褐藻酸钠溶液和氯化钙溶液对贻贝肉被膜保鲜的镀膜与定型进行了研究探讨,分析了说明贻贝肉在镀膜过程中的重量变化情况,定型液浓度与定型时间和被膜液浓度与被膜厚度的关系以及定型液浓度与定型情况。  相似文献   

16.
Abstract— Plasma concentrations of insulin-like growth factor-I (IGF-I) and insulin-like growth factor binding proteins (IGFBPs) were compared between market sized sunshine and palmetto bass. Differences between male and female fish were examined and both hybrids were sampled before and after a low-water confinement stress. There was no difference in body weight between the hybrid types, however, females were significantly heavier than males in both hybrids. Plasma IGF-I concentrations were significantly higher in pre-stressed palmetto bass when compared with sunshine bass, and male palmetto bass had significantly higher IGF-I concentrations than females. Two hours after a 15-min low-water stress, a significant decrease in palmetto bass IGF-I occurred, but there was no change in sunshine bass IGF-I concentrations. Levels of a 33-kDa IGFBP were similar in pre-stressed palmetto bass when compared with sunshine bass; however, no differences due to gender were evident for either hybrid. Two hours after a 15-min low-water exposure, there was no change in the levels of a 33-kDa IGFBP in palmetto or sunshine bass. A more complete understanding of IGF-I, IGFBPs, and IGF-I receptors may be necessary to explain the role of IGF-I in regulating fish growth.  相似文献   

17.
鲍鱼冷风干燥和自然晾晒试验的比较分析   总被引:3,自引:0,他引:3  
研究皱纹盘鲍(Haliotis discus hannai Ino)在冷风干燥和自然晾晒两种干燥方式下的干燥速率、色泽、酸性粘多糖和总糖含量,以及微观结构变化的差异,并进行分析比较。在实验室内采用冷风干燥试验机和自然晾晒方式进行鲍鱼干燥试验。结果显示:当鲍鱼样品干基含水率从238%下降到16%以下时,冷风干燥所需时间约为122 h,是自然晾晒的70%;至干燥完成时冷风干燥鲍鱼多糖含量高于自然晾晒样品;冷风干燥样品通透性明显优于晾晒样品;两种干燥样品的微观结构差异性不明显。综合分析得出,与自然晾晒相比,冷风干燥方式具有干燥时间短,干燥过程易于控制,品质和卫生条件好,适合工业化生产等优点,是一种较佳的鲍鱼干制方法。  相似文献   

18.
A series of experiments were conducted to examine the effects of salinity (1–48 g/L) on the biological performance, as evaluated by growth and survival, of the Pacific white shrimp, Litopenaeus vannamei, and the Atlantic white shrimp, Litopenaeus setiferus, reared at temperatures of 20, 24 or 28 C. Poor growth and survival of L. vannamei was observed after 21–28 d of culture at low salinity (2 and 4 g/L) at 20 C. Raising salinity to 8 and up to 32 g/L significantly increased survival at this temperature, indicating that avoiding low temperatures is critical for survival of this species when reared at low salinity. A major improvement in the growth rate of L. vannamei was observed at 24 C, but it still was sub‐optimal compared to growth observed at 28 C. Irrespective of salinity, high survival rates were observed at both 24 and 28 C, but variable growth rates were recorded. Contrary to L. vannamei, the Atlantic white shrimp, L. setiferus, which was reared for 28 d at 24 C only, had better growth performance at 8 g/L compared to 2, 16 and 32 g/L. Under equal experimental conditions, L. setiferus had considerably lower weight gain and survival than L. vannamei.  相似文献   

19.
为研究翘嘴红鲌(Eryghroculter ilishaeformis)主要形态指标和雌雄个体的形态差异,2016年3月采集了67尾翘嘴红鲌,对其全长/体长、体高/体长、体宽/体长、尾柄长/体长、尾柄高/体长、眼间距/头长、头高/头长、头宽/头长、吻长/头长和丰满度10项标准化比例性状进行主成分分析、R-聚类分析和逐步判别分析,并建立了雌雄判别方程式。主成分分析和R-聚类分析结果显示,翘嘴红鲌主要形态指标可分为肥瘦程度特征、躯干部特征、尾部特征和头部特征4个方面。散布图结果显示雌雄个体在尾部形态上存在差异,同判别分析结果一致。通过逐步判别法从67尾翘嘴红鲌的10项标准化性状中筛选出体高/体长、体宽/体长、尾柄高/体长和丰满度4个比例性状,建立性别判别方程,对群体识别正确率达91.0%。经T检验,除体高/体长外,其他3个比例性状在两性群体间均存在显著或极显著差异,表明雌性相较于雄性体型较宽、较丰满,但尾柄较矮。上述差异性状及雌雄判别方程式可为翘嘴红鲌性别的鉴定提供方法和理论依据。  相似文献   

20.
黄鳝胃肠的生长抑素分泌细胞及超微结构   总被引:12,自引:1,他引:12  
舒妙安 《水产学报》2002,26(3):202-216
在肠卷石蜡法切片上,用ABC免疫组织化学方法,显示消化管全长的生长抑素分泌细胞(又称D细胞),结果只在胃体部显现,主要散在分布于胃腺中,个别出现在粘膜上皮。消化道内分泌细胞根据基部有否胞质突起,可分为4种类型,在黄鳝胃中均有,其中Ⅲ型数量最多,I、Ⅳ型次之,而Ⅱ型数量最少。由于产生生长抑素的D细胞在消化道内分泌细胞中作用多并且类型复杂,故黄鳝胃还是一个十分重要且复杂的内分泌器官。应用透射电镜,对黄鳝的胃肠作超薄切片观察显示在胃腺上皮细胞内含大量的微管泡系和一定量的酶原颗粒,表明其兼有泌酸及产生酶原的功能,属泌酸胃酶细胞。在肠上皮细胞游离面,含有大量微绒毛,但幼鳝比成鳝的长、密且整齐,提示幼鳝的肠上皮比成鳝有更强的吸收能力。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号