Note on the ecology and distribution of fresh water snails in the Bauchi and Plateau States, Nigeria

In Nigeria, little information is available on the distribution and ecology of fresh water snails as vectors of helminths. The authors have enumerated five species, the frequency of occurrence of which is exposed and discussed. No environmental factors seem to affect their distribution. Investigations are still continuing.     

Trematode cataract in fresh water fish

Abstract— —The occurrence of cataract in fresh-water fish has recently been the cause for increasing concern amongst anglers who have been catching a steadily falling number of fish in several regions. It has been known for over 100 years that certain fish may become infested with a trematode (or fluke) which has a remarkable predilection for the lens. The life cycle begins in the intestine of the seagull where the adult trematode produces ova which are excreted on to the waters of reservoirs and lakes. The ova hatch out into miracidia which in turn invade water snails to form a sporocystic stage. Cercariae emerge from the snail and swim free to burrow into the body of a fish and find their way to the crystalline lens. The cycle is completed by the consumption of the fish by the gull in which the adult trematode once more develops. The purpose of this communication is to demonstrate the histological changes produced in the lens by the trematode. Résumé— —L'augmentation de l'incidence de la cataracte du Poisson d'eau douce a été récemment la cause de l'inquiétude croissante des pécheurs qui prennent une quantité sans cesse diminuée de Poisson dam différentes régions. Il est connu depuis plus de cent ans que certains poissons peuvent être infectés par les trématodes (ou douves) qui se logent avec une nette prédilection dans le cristallin. Le biocycle débute dam l'intestin de la mouette ou le trématode adulte pond des oeufs qui sont excrétés dans les eau des réservoirs et des lacs. Les oeufs donnent naissance am miracidies qui à leur tour envahissent les escargots d'eau et s'y transforment en sporocystes. La cercaire se libère de l'escargot et nage librement pour se loger dans le corps d'un Poisson et se frayer un chemim jusqu'au cristallin. Le cycle est achevé par l'ingestion du Poisson par la mouette chez laquelle le trématode adulte continue à se développer. Le but de cet article est de décrire les lésions histologiques du cristallin produites par le trématode. Zusammenfassung— —Das Auftreten von Katarakten bei Süsswasserfischen gab vor kurzem Anlass für steigende Besorgnis unter Anglern, die in mehreren Gebieten nur eine ständig abnehmende Zahl von Fischen fingen. Es ist seit über 100 Jahren bekannt, dass bestimmte Fische von Trematoden (Saugwürmer) befallen werden können, die eine merkliche Bevorzugung der Augenlinse zeigen. Der Lebenszyklus beginnt im Darm der Seemöwe, wo die envachsenen Trematoden Eier legen, die auf Wasserflächen von Staubecken und Seen ausgeschieden werden. Aus den Eiern gehen Mirazidien hervor, die ihrerseits Wasserschnecken befallen und dort ein sporozystisches Stadium bilden. Aus den Schnecken gehen dann Zerkarien hervor, die frei umherschwimmen und nach dem Eindringen in den Körper eines Fisches den Weg in die Augenlinse finden. Der Zyklus wird dadurch gesch-lossen, dass die Möwe den Fisch frisst und dass sich in dem Vogel abermals die erwachsenen Trematoden entwickeln. Der Zweck dieser Mitteilung besteht in der Beschreibung der histologischen Veranderungen, die von den Trematoden in der Linse hervorgerufen werden.     

Surveillance and control of rabies in La Reunion,Mayotte, and Madagascar

Mayotte and La Reunion islands are currently free of animal rabies and surveillance is performed by the French Human and Veterinary Public Health Services. However, dog rabies is still enzootic in Madagascar with 4 to 10 confirmed human cases each year. The number of antirabies medical centres in Madagascar is still scarce to provide easy access to the local population for post-exposure rabies prophylaxis. Furthermore, stray dog populations are considerable and attempts to control rabies by mass campaigns of dog vaccination have not received sufficient attention from the national health authorities. To address these challenges, an expanded program to control rabies needs to be initiated by the Malagasy authorities.     

Intensive culture of fresh water fish

Recently, eel recirculation systems have provoked increasing attention in intensive fish culture, especially concerning animal welfare. "Aquaculture", "Intensive Culture", and "Recirculation Systems" are often confused with each other. This study, first of all, differentiates among these terms. The economic relevance of aquaculture in the Federal Republic of Germany is demonstrated by figures. A tendency towards intensive methods can only be seen in trout and eel culture. The problems of recirculation systems are explained comprehensively. Particular emphasis is laid on the conflict between theoretical suitability of intensive fish production and the absence of commercially working systems. At present, intensive fish culture does not pose a serious animal welfare problem in Germany. However, it is necessary to define the biological requirements of fish concerning their optimal accommodation in aquaculture facilities. According to the Law for the Protection of Animals, these requirements have to be laid down in an ordinance. Only then control is possible as to whether aquaculture systems fulfill fish welfare demands.     

益水素在淡水养殖中的应用效果

1试验目的在内陆淡水养殖青鱼和四大家鱼中,由于水质的原因常造成饵料系数高、成活率低、尾重轻、产量低,直接导致了养殖效益低下。本试验通过利用微生态制剂-益水素来改善淡水养殖的水体环境,从而验证其在提高成活率、尾重、产量,降低饵料系数,提高水产养殖效益等方面的实际应     

淡水鱼饲料模式化配方分析

我国的淡水鱼类营养与饲料技术从20世纪70年代开始至今.已经经历了30多年的发展历程,目前水产饲料的总产量已超过1 000万吨,在饲料总量中的比例超过了10%.总体分析,我国淡水鱼类营养与饲料学的基础研究和技术研究还处于一个发展的初级阶段,研究的力量也非常薄弱,主要表现为基础研究成果对应用技术研究和生产技术的支撑作用还较为有限,目前我国淡水养殖有近100个种类,重要养殖种类有20多个,而制定出营养标准的种类还不到10个.     

吡喹酮治疗淡水鱼绦虫病

随着水产养殖业的发展 ,近年来 ,江苏地区淡水鱼的绦虫病发生比较严重 ,尤其越冬鱼种受害甚深 ,严重时死亡率可达90 %以上。但对该病的药物防治比较滞后 ,缺乏对新型药物的试验研究。我们曾在 1997年 9月及 1999年 10月在宜兴市 2个严重发生绦虫病的水产养殖场试用吡喹酮防治 ,取得显著效果 ,现报告如下。1　发病情况养殖户蒋某 ,1997年 9月发现鳊鱼大量减食 ,致使投入饲料量减少 ,仅为原投料量的 40 %～ 6 0 % ,并不断有鱼死亡 ,损失可观。曾使用敌百虫或无锡、广州等地产鱼类驱虫药物均无效。捕鱼检查 ,鱼体瘦 ,成鱼每尾平均减重 0 12 5…     

菜籽饼粕在淡水鱼类饲料中的应用

<正>油菜籽经过溶剂浸出、机械压榨提取油脂后的残留物分别称为菜籽粕(rapeseed meal,RSM)和菜籽饼(rapeseed cake,RSC)。我国每年油菜种植面积大约600万hm2,油菜籽加工产品单一,主要有油、菜籽饼粕和油脚,其中油约占35%,饼粕约占60%,油脚约占5%。     

浅谈黄河口毛蟹养殖技术

黄河口毛蟹是淡水渔业中的珍品,已被列入山东省发展高效渔业的名优品种。黄河三角洲地区,地处黄河入海口,由于土地盐碱化严重,大部分土地无法种植;其次,由于水资源相对充足,土地和淡水呈弱碱性,适合毛蟹生长,因此发展毛蟹养殖必将给黄河三角洲地区带来可观的经济效益。1毛蟹的生态习性1.1毛蟹在淡水中生长,在海水中繁殖。它的一生依次经历蚤状幼体、大眼幼体(蟹苗)、仔蟹(豆蟹)、幼蟹(稚蟹)、蟹种(扣蟹)、黄蟹,绿蟹、抱卵蟹及软壳蟹等阶段、通过长期的自然选择作用,形成了毛蟹适应自然环境的多种生态习性,为毛蟹的生存和发展创造了条件,毛蟹…     

Potential of coconut water to enhance fresh semen quality and fertility in rabbits

Tropical Animal Health and Production - Coconut water as a natural diluent was evaluated on rabbit semen quality, conception and litter size in artificially inseminated does. A total of 10 bucks...     

Effect of calcium chloride, zinc chloride, and water infusion on metmyoglobin reducing activity and fresh lamb color

Calcium chloride (CaCl2), zinc chloride (ZnCl2), or water infusions were used to investigate the biochemical factors that affect fresh lamb color, and to examine the role of metmyoglobin-reducing activity in regulating this important quality attribute. Immediately after exsanguination, lamb carcasses (n = 6 per treatment) were infused (10% of BW) with 0.3 M CaCl2, 0.05 M ZnCl2, or water via a catheter inserted into the left carotid artery. The right LM was excised at 24-h postmortem and divided into two halves. The caudal portion was cut into 2.5-cm-thick chops and displayed for 6 d under 1,076 lx of white fluorescent lighting at 2 degrees C, whereas the cranial half was vacuum-packaged and stored at 2 degrees C for 3 wk before retail display. Objective color measurements and samples for biochemical analysis were taken at 0, 1, 3, and 6 d of display. In infused carcasses, pH decline was more rapid (P < 0.05) than in untreated controls, and it was greatest for CaCl2-infused carcasses. Calcium chloride-infused carcasses had lower (P < 0.01) NAD and higher (P < 0.001) NADPH concentrations than water- and ZnCl2-infused or untreated control carcasses. The negative effects of calcium infusion on fresh lamb color, higher (P < 0.01) metmyoglobin accumulation rate, and lower (P < 0.01) L*, a*, and b* color measurements could be explained by the lower amounts of unbound water (P < 0.01), shorter sarcomere length (P < 0.01), lower NAD concentrations (P < 0.01), and higher lipid peroxidation (P < 0.01). Zinc and water-infusions produced less (P < 0.01) lipid oxidation and improved the color and color stability of fresh lamb (P < 0.001). Rate of lipid oxidation in LM chops was greater (P < 0.01) after 3 wk of vacuum-packaged storage than 24-h postmortem. Metmyoglobin-reducing activities (sarcoplasmic and myofibrillar) were decreased in response to infusion treatments (P < 0.001), and ZnCl2 infusion resulted in the lowest metmyoglobin-reducing activities (P < 0.001). A significant association between the myofibrillar metmyoglobin-reducing activity and lipid peroxidation was observed, but metmyoglobin-reducing activities were not associated with any improvement in lamb color. Strategies to increase the antioxidant levels in lamb are very important to improve lamb quality, especially during vacuum-packaging storage.     

南美白对虾淡水池塘养殖高产试验

采取人工调兑淡水盐度，合理投喂颗粒饲料和调节水质、综合预防虾病等措施，在面积为1667m^2、2201m^2、2734m^2的三口淡水池塘中养殖南美白对虾，经123d的饲养管理，平均每667m^2产虾298．1-344．4kg、产值8942．9—10332．0元，纯利润3829．5—4206．8元，投入产出比1：1．69—1：1．75。商品虾平均体长11．5—13．1cm，成活率80．4％—89．4％。     

用体外法对麸皮调水的鲜啤酒糟发酵品质研究

用麸皮调节水分的鲜啤酒糟分别发酵0、30、60、90、120d后制样,作为体外法发酵底物进行体外培养,探讨混合培养物的pH值、挥发性脂肪酸浓度、干物质、有机物、中性洗涤纤维降解率随时间的动态变化。结果表明,不同贮存时间的样品对体外混合培养液pH值影响差异不显著,不同混贮时间pH均值都高于6.2;VFA随混贮时间延长呈先降后升的趋势;发酵60d的样品体外培养后的干物质、有机物质和中性洗涤纤维降解率均值都显著高于其它组。     

Leptospira exposure in the human environment in France: A survey in feral rodents and in fresh water

This paper confirms the important role of rodents to be maintenance hosts of leptospires. Their role is related to renal carriage and shedding of leptospires into urine, thus contaminating fresh water. Serological and carriage of feral rodents trapped in France were determined by MAT and hap1PCR specific for pathogenic leptospires. In same areas, fresh water samples were analyzed by hap1PCR. The overall seroprevalence was 44% in 649 rodents and was similar regardless of the species. Seroprevalence for leptospirosis is about 20-53% according to species. hap1PCR (516 kidneys) showed that renal carriage was higher in brown rats (34.7%) and muskrats (15.8%) than in coypus (3.3%). hap1PCR demonstrates a significative difference (P-value > 10(-12)) for the renal carriage between the different species: muskrats and rats are more efficient maintenance hosts than coypu but all infect water. Moreover 5/38 water samples associated with human cases were hap1PCR positive and 1/113 in controlled waters.