Outbreak of enteric microsporidiosis of hatchery‐bred juvenile groupers,Epinephelus spp., associated with a new intranuclear microporidian in China

A new enteric microsporidian was found to be associated with the mass mortality of hatchery‐bred juvenile groupers, Epinephelus spp., in China. The outbreak usually occurred during the rainy season between May and November when water temperature ranged from 26 to 30 °C and salinity from 28 to 34 ppt, although this microsporidian can be detected year round. External clinical signs included severe emaciation, white faeces syndrome, anorexia, sinking to the bottom of culture ponds and mass mortality (up to 90%). Upon necropsy, severe intestinal oedema and thin and transparent intestinal wall could be observed. The mature spores are tiny, measuring 1.3–1.5 (1.35 ± 0.13) × 1.6–2.4 (2.16 ± 0.31) μm and can be found in the cytoplasm and the nucleoplasm of most enteric epithelial cells of host. Epidemiological investigation showed that this species was distributed throughout most of the culture area of grouper fingerlings in Fujian, Guangdong, Hainan and Guangxi provinces in China, with maximum prevalence of 95%. Molecular analysis based on the partial small subunit rRNA sequence (1045 bp) placed this species within the Enterocytozoonidae, but sequence identities to other species were below 90%. The exact taxonomic position warrants study of the ultrastructural characteristics of the developmental stages.     

Role of the Helix aspersa snail as a vector of Phytophthora citrophthora causing branch cankers on clementine trees in Spain

This study investigated the suspected role of invertebrate vectors in the transmission of phytophthora branch canker, a severe disease of clementine cultivars in Spain, caused by Phytophthora citrophthora . Ants ( Lasius grandis ) and snails ( Helix aspersa and Rumina decollata ) were collected in spring and autumn 2005 from 15 commercial citrus fields which were severely affected by the disease. Isolations made from L. grandis and R. decollata bodies did not yield positive results. However, P. citrophthora was isolated from 5·0% of bodies of H. aspersa and 4·8% of samples of their faeces. In one assay, after snails were allowed to feed for 5 h on citrus branches which had been artificially infected with P. citrophthora , the pathogen was isolated from 79% of their faeces. In another experiment, snails were infested by placing them in contact with a substrate colonized by P. citrophthora and then transferred to the base of potted 4-year-old trees of cvs Clemenules, Fortune and Nova in the glasshouse. One day after their release, infested snails were widely distributed throughout the tree canopies and 10 days later bark discoloration and gum exudations were observed on the trees. Phytophthora citrophthora was readily isolated from tissues showing symptoms.     

冬季圈养和放归普氏野马成年雄性应激状态研究

于2006年冬季采用非损伤性的粪样激素R IA法,测定了新疆圈养和放归成年雄性普氏野马的糖皮质激素代谢产物含量,获得了各组成年雄性野马的生理应激状态。结果表明:野马各组间糖皮质激素代谢产物的含量存在显著差异,其中,放归雄马与头马组间(T=7.193,P=0.000)、放归头马和圈舍头马组间(T=7.496,P=0.000)、圈舍雄马和放归雄马组间(T=8.06,P=0.000)激素含量均存在极显著差异,圈舍头马与雄马组间激素含量差异显著(T=2.976,P=0.019)。各组间野马生理应激水平表现为:圈养雄马>圈养头马>野外头马>野外雄马。同时,初步分析了圈养和放归条件下普氏野马成年雄性的可能应激源,并由此从生理应激角度探讨了圈养和放归野马的科学管护问题。     

Testing the potential for improving quality of sediments impacted by mussel farms using bioturbating polychaete worms

Biodeposits from farmed mussels severely influence the biogeochemistry of sediments by increasing the levels of organic matter (OM). Mitigation of such negative impacts is important for the development of sustainable aquaculture operations. As a step towards developing methods for remediation of coastal sediments affected by mussel farming, the effects of the polychaete, Hediste diversicolor was evaluated experimentally. In a series of field‐ and laboratory experiments we tested hypotheses about the effects of polychaetes on sediment oxygen consumption, nutrient fluxes and sulphide pools under different polychaete densities and sedimentation regimes. The experimental results support the idea that polychaetes can mitigate negative effects on the benthic environment beneath mussel farms. H. diversicolor oxidized the sediment and generally enhanced the oxygen consumption, and thus the decomposition of OM. The accumulation of pore water sulphides were reduced and fluxes of nutrients across the sediment‐water interface increased. Additional calculations suggest that the effects of polychaetes were mainly indirect and driven by increased microbial activity due to the borrowing activity of the polychaetes. Trends of increasing decomposition with increasing polychaete density suggest that the decomposition could be further enhanced by higher densities. Overall, we concluded that H. diversicolor is a potentially strong candidate for remediation of mussel farm sediments. The results show that sediments inhabited by H. diversicolor have high assimilative capacity of OM and oxygen conditions are significantly improved following the addition of polychaetes at naturally occurring densities. However, technological developments are needed in order to allow the approach to be used in practice.     

蚕沙中黄酮和生物碱提取工艺研究

为了优化蚕沙中黄酮和生物碱的提取工艺,通过单因素试验和正交试验相结合的方法,比较了不同提取方法、提取溶剂、提取时间、提取温度等条件。结果表明:盐酸浓度对生物碱提取率有显著影响,提取温度和提取时间对生物碱提取率无显著影响;各因素对黄酮提取率均无显著影响。综合考虑,最佳生物碱和黄酮提取工艺条件为:0.01 mol/L盐酸,90℃水浴提取2次,每次1 h。该提取工艺稳定可靠,可用于蚕沙黄酮和生物碱的提取。     

我国畜牧业粪便废弃物的污染及其治理对策的探讨

我国集约化养殖业的迅速发展带来的大量畜禽粪便废弃物已经造成了严重的环境污染。对污染现状 ,及畜禽粪便中的主要污染成分氮、磷、矿物质元素、恶臭物质、生物病原和药物添加剂对环境的危害进行了综述 ,指出饲料配方不合理是畜禽粪便废弃物中主要污染成分含量过高的重要原因。探讨了污染治理对策 ,认为应该提高饲料原料质量 ,合理饲料配方 ,使用绿色添加剂 ,并改进饲料制造工艺 ,以提高饲料中营养物质的利用率 ,减少畜禽粪便排放量并降低其有害成分含量。应通过技术手段对畜禽粪便进行有效处理并加以综合利用 ,如经过适当处理后作为肥料、燃料和饲料加以利用 ,这对于减轻畜禽粪便污染 ,减少资源浪费 ,改善生态环境具有重要意义     

象山港网箱养殖鲈鱼残饵和排粪情况初步研究

通过对象山港典型网箱养殖区,养殖鲈鱼投饵、摄食情况的研究,推算残饵和排粪情况。结果表明,鲈鱼年平均摄食率以饵料湿重计为2.6%,以饵料干重计为0.6%。全年投入象山港养殖网箱中的饵料以湿重计为143335.5 t,平均每天投392.7 t,以干重计为31 045.5 t,平均每天投85 t。鲈鱼的排粪率以颗粒有机碳POC干重计平均为6.5%,象山港网箱养殖鱼类每天排粪量干重为7.5 t,全年为2 737.5 t。鲈鱼对饵料的平均利用率为71.8%,全年网箱养鱼的残饵量湿重为43 252.5 t,每天平均118.5 t;以干重计为9 548.4 t,平均每天为26.16 t。显示残饵和排粪量对养殖区底质和水质污染比较严重。     

Digestive physiology of captive giant anteaters (Myrmecophaga tridactyla): determinants of faecal dry matter content

Giant anteaters (Myrmecophaga tridactyla) are specialized insectivores and consume mainly ants and termites in the wild. In captivity, giant anteaters are either fed a complete diet, or a combination of a domestic carnivore diet with leaf eater pellets, or a traditional gruel‐type diet. Soft faeces are a frequently encountered problem with this type of feeding. In the present study, we analysed diet and faeces composition, calculated digestibility and measured mean retention time on various diets in eight giant anteaters (total of n = 64 experiments). The results suggest that the digestive physiology of giant anteaters is similar to that of domestic dogs and cats in terms of nutrient digestibility and digesta retention. When testing correlations between faecal dry matter content and other variables, no relationship with dietary crude fibre content or mean digesta retention time could be detected. However, acid insoluble ash intake was significantly and positively correlated with faecal dry matter content. The amount of acid insoluble ash excreted with the faeces was higher than that ingested with the diet offered, indicating that the giant anteaters ingested soil from their enclosure of up to 93 g per day. This finding is consistent with observation of faeces of wild giant anteaters that contain soil or sand most likely due to indiscriminate feeding. It also corresponds to reports that indigestible materials such as peat, soil, chitin or cellulose contribute to a firmer faecal consistency in various carnivore species. Therefore, offering giant anteaters the opportunity to voluntarily ingest soil from their enclosure might be beneficial.     

氟摄入对胃肠道及其粪钙排出的影响

本研究给 72只小鼠不同浓度的饮水加氟 ,剂量 2 5 /L～ 1 0 0 /L ,以了解氟对消化道的影响以及氟对粪钙排出的影响。在给氟 5 0d时 ,粪钙在不同加氟组间未见明显差别。给氟 90d时 ,胃肠粘膜观察到不同程度的灶性坏死脱落 ,十二指肠粘膜部分绒毛溶解 ,上皮变性坏死。表明一定剂量氟可对上消化道粘膜产生强烈刺激与损伤 ,从而引起厌食等消化道症状     

Colonization of broilers with Campylobacter in conventional broiler-chicken flocks

Eight of 16 conventional broiler-chicken flocks examined contained Campylobacter. All isolates were identified as C. jejuni except from 1 flock were C. coli was isolated. One herd consisting of 6 different houses where Campylobacter regularly has been isolated was continuously examined. It was not possible to isolate Campylobacter from newly hatched chickens or from environmental samples and cloacal swabs during the 2 first weeks of growth.