Use of treated mine water for rainbow trout (Oncorhynchus mykiss) culture: a production scale assessment

In previous proof-of-concept work, it was shown that the use of treated coal mine water for rainbow trout (Oncorhynchus mykiss) culture in a cage was technically feasible, though only a 50-fish bioassay was grown and no work on production-related issues was conducted. To further advance the use of treated mine water, an under-utilized water resource throughout Mid Appalachia, work was conducted to assess the effects of using treated coal mine water for the intensive production of rainbow trout in a flow-through system. During this study, comprehensive water quality data were collected to supplement fish weight and length data taken during routine monthly sampling events. The 8000 fish grew well in the raceway system over the 9 months of production, where a feed conversion ratio of 1.4 and a condition factor of 5.1 × 10⁻⁴ were measured with stocking and harvest densities of 26.4 and 50.2 kg/m³, respectively. Further, total net production was 3275 kg (7220 lb) with 98.6% survival. Throughout the study, dissolved ion concentrations (Fe, Al, Mg, Ca, and SO₄) often exceeded recommended tolerance limits. Further, elevated ammonia nitrogen concentrations generated from a component of the mine water-treatment process were identified as a potential limiting factor for aquaculture development. However, when the non-ideal effects of high ionic strength and the speciation of dissolved metal–ligand complexes were taken into account, the concentrations of free metal ions were within recommended tolerance limits.     

Exploring Patterns of Exotic Earthworm Distribution in a Temperate Hardwood Forest in South-Central New York, USA

Exotic earthworms invading forests in Canada and northeastern United States that were naturally devoid of large detritivores cause major changes in ecosystem function. To assess their long-term impacts, studies are needed to elucidate the factors that control the patterns of earthworm invasion at the landscape level. We analyzed the distribution patterns of exotic earthworms in a northern hardwood forest in south-central New York (USA), as explained by landscape variables thought to be important in determining earthworm distribution. Forest type, slope angle, elevation, and the distance to agricultural clearings and wet refugia were significant predictors of earthworm presence, whereas local wetness index and the distance to streams and roads were not. Forest type and distance to agricultural clearings were the two most significant predictors. Our data suggest that areas close to agricultural clearings, dominated by mixed hardwoods, and located towards valley bottoms or on gentle slopes are very likely to support communities of exotic earthworms. Steeper slopes, areas dominated by American beech or eastern hemlock, and locations in the core of extensive forest landscapes have lower probabilities of invasion by exotic earthworms. When applied to a nearby area, our statistical model correctly predicted earthworm presence for 67% of 377 sampling points. Most of the mistakes were incorrect predictions of earthworm absence, suggesting that our statistical model slightly underestimated earthworm presence, possibly because of the pervasive influence of active agricultural fields adjacent to the test site.     

In vitro inhibition of Eimeria tenella invasion by indigenous chicken Lactobacillus species

The aim of this study was to determine the effects of indigenous chicken Lactobacillus species isolates from different parts of the gastrointestinal tract on Eimeria tenella invasion in vitro and to characterise the nature of inhibition, if any. The effects of competitive exclusion, steric interference and bacterial extracellular factors on E. tenella invasion were examined in an MDBK cell model. Several Lactobacillus species were initially isolated from chickens and identified by biochemical characteristics and 16S-rRNA. All Lactobacillus species isolates tested, significantly inhibited E. tenella invasion. Steric interference did not affect parasite invasion. Extracellular metabolic factors secreted by Lactobacillus species isolates into the surrounding media were shown to inhibit parasite invasion and these factors appeared to be heat stable. These results show that the natural microflora of poultry can provide a source of E. tenella-inhibiting Lactobacillus species in vitro, and thus may contribute to the control of Eimeria infection.     

Growth of bream, Abramis brama (L.), in Irish canals and implications for management

The growth rates of bream, Abramis brama (L.), were determined in three Irish Canals: the Royal and Grand Canals, and the Barrow Line. Compared with growth patterns for other Irish and European waters, the growth of bream was fast in the Royal Canal, but slow to moderate for the Grand Canal and the Barrow Line. Significant differences in bream growth in terms of both length and weight were found between the three canal systems, and between canal levels, particularly in the Grand Canal. Associations between growth, and (1) alkalinity, (2) total fish biomass and (3) the ratio of bream biomass to total fish biomass were also found. However, it was considered that these three factors alone were not sufficient to explain the differences in growth. Productivity was implicated as the main factor controlling bream growth because fish species diversity was greater and total fish biomass was generally higher in levels of the Grand Canal with faster growing bream populations. The division between 'fast' and 'slow' growing bream also corresponded with a change in the aquatic weed community. There is evidence to suggest that there was a corresponding change in macro-invertebrate community structure and density. Angler usage as another factor in promoting growth is discussed. The implications for the future management and development of these canals are outlined.     

Mineralisation of atrazine, metolachlor and their respective metabolites in vegetated filter strip and cultivated soil

In vegetated filter strips (VFS) the presence of perennial vegetation, rhizodeposition of labile organic substrates and the accumulation of an organic residue thatch layer may enhance microbial numbers and activity, thereby increasing the potential for mineralisation of herbicides and herbicide metabolites retained during run-off events. The objective of this laboratory experiment was to compare the mineralisation of atrazine and metolachlor with that of their respective metabolites in VFS and cultivated soil. With the exception of total bacteria, propagule density of the microbial groups, endogenous soil enzymes and microbial diversity were higher in the VFS soil. This correlated with increased mineralisation of metolachlor and its metabolites in the VFS soil and indicates potential for VFS to curtail the subsequent transport of these compounds. In contrast, the mineralisation of atrazine and the majority of its metabolites was substantially reduced in VFS soil relative to cultivated soil. Consequently, the potential for subsequent transport of atrazine and many of its metabolites may be greater in VFS soil than in cultivated soil if reduced mineralisation is not offset by increased sorption in the VFS.     

Studies on leaf spot and shoot blight of Eucalyptus caused by Cylindrocladium quinqueseptatum

In glasshouse experiments, Cylindrocladium quinqueseptatum, which was associated with outbreaks of leaf spot and shoot blight in a young plantation of Eucalpytus microcorys in north Queensland during the 1982 and 1983 autumns, was pathogenic on seedlings of E. microcorys and caused varying degrees of leaf spot and shoot blight in ten species of Eucalyptus from major taxonomic groupings of the genus, When the outbreaks occurred, the weather was unusually showery with minimum temperatures above 16°C. In vitro studies showed that free water was essential for conidial germination, which occurred between 14–32°C. The optimum for mycelial growth was 28.5°C. In vivo studies showed that leaf penetration. by germinated conidia was via the stomata. Mancozeb was more effective at controlling the disease than benomyl, captan or copper oxychloride. The potential importance of C. quinqueseptatum and options for control in young Eucalyptus plantations are discussed.     

Detection of low numbers of poliovirus 1 in oysters: collaborative study

A collaborative study was performed to evaluate a method for determining numbers of poliovirus 1 in oysters. Commonly available laboratory equipment and materials were used. Raw oysters in the shell were shipped to each investigator along with 12 tubes of unknown concentrations of virus. Six 100 g duplicate oyster samples were analyzed by 5 collaborating laboratories. Each analyst used a prescribed procedure for diluting the inocula. Two samples contained approximately 100 plaque-forming units (pfu)/100 g, 2 samples contained approximately 50 pfu/100 g, and the other 2 contained approximately 25 pfu/100 g. Recoveries varied from 35 to 55% at inocula levels of 30-100 pfu/100 g. The limit of detectability was hypothesized to be 14 pfu in a 100 g sample when the recovery was 35%. The method has been adopted official first action.     

木豆杂种优势利用研究进展

自1974年发现木豆雄性不育株以来,国际上不断对木豆核雄性不育(GMS)和核质互作雄性不育(CGMS)基因及其种质资源进行研究和挖掘,最终实现了木豆杂种优势的成功利用。本文系统总结了过去30多年来,国际上木豆杂种优势机理、表现及授粉方式等基础研究,GMS、CGMS不育系及其配套制种体系研究,杂种优势强度研究,以及木豆杂交种生产技术研究进展。提出了木豆杂种优势利用的具体研究方向和展望。     

Adsorption and desorption of atrazine, desethylatrazine, deisopropylatrazine, and hydroxyatrazine in vegetated filter strip and cultivated soil

Adsorption and desorption of atrazine and its metabolites in vegetated filter strip soil (VFS) has not been evaluated, yet these data are needed to predict the transport of these compounds through the VFS. Adsorption and desorption parameters for atrazine, desethylatrazine (DEA), deisopropylatrazine (DIA), and hydroxyatrazine (HA) were compared between a cultivated Houston Black clay (CS) and an adjacent 12-year-old VFS established in a mixed stand of bermudagrass [Cynodon dactylon (L.) Pers.] and buffalograss [Buchloe dactyloides (Nutt. Engelm)]. Adsorption and desorption isotherms were determined by batch equilibrium. The evaluated chemical and physical properties of the VFS and CS were similar with the exception of a 1.7-fold increase in the organic carbon content of the VFS. Adsorption and desorption coefficients for atrazine were at least 59% higher in VFS than in CS. The adsorption coefficient for HA was 48% higher in VFS compared with CS, but desorption was not statistically different between soils. Adsorption and desorption coefficients for DEA and DIA were not statistically different between soils. The predicted order of mobility in CS is HA < atrazine = DIA = DEA. In VFS, the predicted order of mobility is HA < atrazine = DIA < DEA. These data indicate that the higher organic carbon in VFS will likely retard the transport of atrazine and HA to surface and ground waters; however, the transport rates of DEA and DIA will be similar between soils.     

Piloting interprofessional education interventions with veterinary and veterinary nursing students

Interprofessional education (IPE) has received little attention in veterinary education even though members of the veterinary and nursing professions work closely together. The present study investigates veterinary and veterinary nursing students' and practitioners' experiences with interprofessional issues and the potential benefits of IPE. Based on stakeholder consultations, two teaching interventions were modified or developed for use with veterinary and veterinary nursing students: Talking Walls, which aimed to increase individuals' understanding of each other's roles, and an Emergency-Case Role-Play Scenario, which aimed to improve teamwork. These interventions were piloted with volunteer veterinary and veterinary nursing students who were recruited through convenience sampling. A questionnaire (the Readiness for Interprofessional Learning Scale [RIPLS]) was modified for use in veterinary education and used to investigate changes in attitudes toward IPE over time (pre-intervention, immediately post-intervention, and four to five months afterward). The results showed an immediate and significant positive change in attitude after the intervention, highlighting the students' willingness to learn collaboratively, their ability to recognize the benefits of IPE, a decreased sense of professional isolation, and reduced hierarchical views. Although nearly half of the students felt concerned about learning with students from another profession before the intervention, the majority (97%) enjoyed learning together. However, the positive change in attitude was not evident four to five months after the intervention, though attitudes remained above pre-intervention levels. The results of the pilot study were encouraging and emphasize the relevance and importance of veterinary IPE as well as the need for further investigation to explore methods of sustaining a change in attitude over time.