Eimeria tenella: anticoccidial action of drugs in birds with surgically closed ceca.

Surgical ligation of chick ceca was used to study the role of absorption and extraintestinal transport in the action of anticoccidial drugs. The administration of drugs in the feed was started after ligation of one of the paried ceca. Birds were inoculated orally with oocysts of Eimeria tenella before cecal ligation or were given bilateral cecal injections of sporozoites after ligation. Cecal lesions caused by the coccidia were evaluated and compared on day 6 postinoculation. Lesions in ligated and unligated ceca were reduced by feeding robenidine (33 ppm), arprinocid (70 ppm), zoalene (125 ppm), aklomide (250 ppm), clopidol (125 ppm), nicarbazin (125 ppm), monensin (120 ppm), salinomycin (60 ppm), and lasalocid (75 ppm). The lesions were more severe in the ligated cecum than in the intact cecum, whether in nonmedicated or medicated birds, but the differences were statistically significant only upon treatment with amprolium, aklomide, robenidine, and clopidol. Generally, however, all drugs except amprolium, significantly reduced the lesions in the ligated cecum in comparison with the control, nonmedicated ligated cecum. Therefore, we concluded that the systemic absorption of most anticoccidial drugs contributes significantly to their efficacy against coccidia in the intestinal mucosa.     

Eimeria tenella: experimental studies on the development of resistance to amprolium, clopidol and methyl benzoquate.

The development of resistance by the Houghton strain of Eimeria tenella to the anticoccidial drugs amprolium, clopidol and methyl benzoquate has been studied. Resistance to amprolium and clopidol developed more readily in experiments where a large number of coccidia were exposed to the drug, either by increasing the number of oocysts in the inoculum or by increasing the number of birds in the group. When 45 birds were given 2.0 X 10(6) oocysts, resistance to amprolium and clopidol appeared after 6 and 7 passages respectively. In previous experiments, under similar conditions, resistance to robenidine developed after 6 passages, suggesting little difference between these three drugs. Resistance to amprolium and clopidol arose gradually as the concentration of drug was increased, but resistance to methyl benzoquate appeared in a single step from sensitivity to high-level resistance. Both amprolium and clopidol-resistant lines showed an 8-fold reduction in drug sensitivity. Attempts to measure the degree of resistance by calculation of the ED50 were unsuccessful.     

Effect of immunization of channel catfish with inactivated trophonts on serum and cutaneous antibody titers and survival against Ichthyophthirius multifiliis

Two trials were conducted to determine the effect of immunization of channel catfish with inactivated trophonts on serum and cutaneous antibody titers and survival against Ichthyophthirius multifiliis Fouquet (Ich). In trial I, catfish were immunized intraperitoneally (IP) with: 1) 1% formalin-inactivated trophonts, 2) 3% formalin-inactivated trophonts and 3) freeze-thawed trophonts. Positive and negative control catfish were immunized with live theronts and 5% bovine serum albumin (BSA), respectively. At day 14, 28 and 50 post-immunizations, no statistical difference was noted in serum or cutaneous anti-Ich antibody titers to formalin-inactivated trophonts or freeze-thawed trophonts. The survival of catfish challenged with live theronts ranged from 33.3% to 43.3% for the formalin-inactivated or freeze-thawed trophonts at 50 d post-immunization. The survival of catfish immunized with live theront and BSA was 93.3 and 0%, respectively. In trial II, catfish were IP immunized with sonicated trophonts at doses of 1) 5 trophonts or 10.2 microg protein g(-1) fish, 2) 10 trophonts or 20.4 microg protein g(-1) fish, 3) 20 trophonts or 40.8 microg protein g(-1) fish, and 4) 5% BSA as the control. Fish immunized with 10 or 20 trophonts g(-1) fish showed highest serum (1/210 to 1/480) and cutaneous antibody titers (1/48 to 1/52), respectively, at 22 d post-immunization and survival (63.3-60.0%). The fish immunized with 5 trophonts g(-1) fish had titers of 1/52 and 1/12 for serum and cutaneous antibody and survival of 23.3%. BSA immunized catfish had background titers and a survival of 6.7%. There was a significant correlation between doses of sonicated trophonts used to immunize and catfish survival (correlation coefficient = 0.859, p < 0.01). These results indicate that doses of sonicated trophonts, but not formalin-inactivated or freeze-thawed trophonts provided both serum and cutaneous antibody responses and survival to live trophont challenge.     

Further observations on the epidemiology and spread of epizootic haematopoietic necrosis virus (EHNV) in farmed rainbow trout Oncorhynchus mykiss in southeastern Australia and a recommended sampling strategy for surveillance

Epizootic haematopoietic necrosis virus (EHNV) is an iridovirus confined to Australia and is known only from rainbow trout Oncorhynchus mykiss and redfin perch Perca fluviatilis. Outbreaks of disease caused by EHNV in trout populations have invariably been of low severity, affecting only 0+ post-hatchery phase fingerlings < 125 mm in length. To date the virus has been demonstrated in very few live in-contact fish, and anti-EHNV antibodies have not been found in survivors of outbreaks, suggesting low infectivity but high case fatality rates in trout. During an on-going study on an endemically infected farm (Farm A) in the Murrumbidgee River catchment of southeastern New South Wales, EHNV infection was demonstrated in 4 to 6 wk old trout fingerlings in the hatchery as well as in 1+ to 2+ grower fish. During a separate investigation of mortalities in 1+ to 2+ trout on Farm B in the Shoalhaven River catchment in southeastern New South Wales, EHNV infection was demonstrated in both fingerlings and adult fish in association with nocardiosis. A 0.7% prevalence of antibodies against EHNV was detected by ELISA in the serum of grower fish at this time, providing the first evidence that EHNV might not kill all infected trout. EHNV infection on Farm B occurred after transfer of fingerlings from Farm C in the Murrumbidgee river catchment. When investigated, there were no obvious signs of diseases on Farm C. 'Routine' mortalities were collected over 10 d on Farm C and EHNV was detected in 2.1% of 190 fish. Tracing investigations of sources of supply of fingerlings to Farm B also led to investigation of Farm D in Victoria, where the prevalence of anti-EHNV antibodies in 3+ to 4+ fish was 1.3%. The results of this study indicate that EHNV may be found in trout in all age classes, need not be associated with clinically detectable disease in the population, can be transferred with shipments of live fish, can be detected in a small proportion of 'routine' mortalities and may be associated with specific antibodies in a small proportion of older fish. Sampling to detect EHNV for certification purposes should be based on examination of 'routine' mortalities rather than random samples of live fish. Antigen-capture ELISA can be used as a cost effective screening test to detect EHNV on a farm provided that sampling rates conform with statistical principles.     

Ichthyophthirius (Ciliophora): population studies suggest reproduction in host epithelium

Evidence that Ichthyophthirius multifiliis trophonts may reproduce within the epithelium of the host was obtained from experimental infections of channel catfish. Mean number of parasites spontaneously leaving the fish increased from 0 on day 3 postexposure (PE) to 66.5 per fish on day 7 PE. Mean population density in fin, however, increased five-fold from day 3 to day 5 PE in the absence of opportunity for reinfection. At day 3 PE, 100% of parasite loci in fin and gill arches contained solitary trophonts. At day 4 PE, 10% of loci in fin contained clusters of two trophonts; at day 7 PE, 69% contained clusters of two or more trophonts. The first clusters of four trophonts in fin were observed day 5 PE and of eight trophonts, day 8 PE. Trophonts in clusters were flattened against one another.     

The effect of exposure to imidacloprid on Asian longhorned beetle (Coleoptera: Cerambycidae) survival and reproduction

The effect of imidacloprid delivery method and application rate on survival of adult Asian longhorned beetles, Anoplophora glabripennis (Motschulsky), was studied, along with the effect of repeated daily ingestion of imidacloprid on the survival and reproductive capacity of adult females. Beetles exposed repeatedly to 50 ppm imidacloprid died in < 2-3 wk, whether dosed orally each day, or through contact exposure. Beetles given 1 microl of 50 ppm imidacloprid daily for two, three, four, or five consecutive days died sooner with increasing consecutive days: the beetles treated for 5 d all died within 15 d, while 80% of beetles treated for only 2 d lived > 8 wk. For females given 1 microl daily, across a range of doses from 2 to 50 ppm imidacloprid, the total number of viable eggs laid was reduced with increasing dosage, but percentage egg viability was not affected. Survival of females at dosages of 10 or 30 ppm/d was not significantly reduced compared with controls but these females laid 23-38% fewer viable eggs, suggesting a sublethal effect of imidacloprid. Female beetles given 1 microl/d of 40 or 50 ppm imidacloprid died more quickly than controls and viable egg production was reduced 82-93%, because of a combination of lethal and sublethal effects of intoxication.     

Efficacy of quinine against ichthyophthiriasis in common carp Cyprinus carpio

Ichthyophthiriasis, caused by Ichthyophthirius multifiliis, is an economically important worldwide parasitic disease that infects all freshwater fish. Since the banning of malachite green for use in food fish, there has been a great need for alternative therapeutants. The goal of this study was to investigate the efficacy of quinine against I. multifiliis. Parasite developmental stages from our laboratory-established life cycle in rainbow trout Oncorhynchus mykiss were exposed to quinine in vitro, and a dual fluorescent staining technique was used to allow a clear distinction between viable and damaged parasites. Furthermore, the effect of quinine was assessed in vivo by oral administration and intraperitoneal injections in common carp Cyprinus carpio. The results of the in vitro experiments proved quinine to be effective against the parasite. Quinine injected at a dosage of 60 mg kg(-1) body weight resulted in a significantly lower number of trophonts. In contrast, in-feed trials did not show a significant reduction of trophonts after treatment commencing 1 d after infection with concentrations of up to 20 g quinine kg(-1) feed for 3 d. After a 14-d treatment at concentrations of up to 10 g quinine kg(-1) feed prior to theront exposure, there was also no significant difference in parasite numbers between treated and control groups. The results of oral versus parenteral application of quinine indicate that the substance is not completely absorbed from the intestinal tract of common carp. However, medicated feed containing higher concentrations of quinine was less readily accepted by the fish, presumably due to the bitter taste.     

Promotion of Growth in Mungbean (Phaseolus aureus Roxb.) by Selenium is Associated with Stimulation of Carbohydrate Metabolism

The mungbean plants were grown hydroponically in the absence (control) or presence of 0.1, 0.25, 0.50 and 0.75 ppm selenium (as sodium selenate) for 10 days. The growth of shoots and roots increased with application of selenium with greater extent in shoots. With 0.5 and 0.75 ppm Se levels, the shoot growth was stimulated by 24% to 27% over control, respectively, while the roots showed a corresponding increase of 18-19%, respectively. The shoot-to-root ratio was enhanced significantly with Se application and maximum effects occurred at 0.75 ppm Se. A significant increase was observed in chlorophyll and cellular respiration ability with 0.5 and 0.75 ppm selenium. The increase in growth by selenium was accompanied by elevation of starch, sucrose and reducing sugars. The activity of starch hydrolysing enzymes--amylases and sucrose hydrolysing enzyme--invertase was stimulated significantly with selenium. This was associated with elevation of activities of sucrose synthesising enzymes--sucrose synthase and sucrose phosphate synthase. It was concluded that increase in growth of shoots and roots by application of Se was possibly the result of up-regulation of enzymes of carbohydrate metabolism thus providing energy substrates for enhanced growth.     

Effect of lectins on the invasion of Ichthyophthirius theront to channel catfish tissue.

This study determined the effects of lectin binding to theronts of Ichthyophthirius multifiliis on theront immobilization, invasion, trophont development and survival in channel catfish Ictalurus punctatus excised fins in vitro. Soybean agglutinin (SBA), lentil agglutinin (LCA), gorse agglutinin (UEA-I) and wheat germ agglutinin (WGA) were used to treat theronts. Percentages of theronts immobilized by 4 lectins ranged from 12.0 to 19.4% at a concentration of 1000 microg ml(-1). These lectins bound more than half of the theronts at a concentration of 50 microg ml(-1). More theronts were labeled by SBA and WGA than by lectin LCA at concentrations of 50 and 100 microg ml(-1), respectively. The binding of these lectins to theronts indicated that monosaccharides (D-galactose, L-fucose, D-mannose and D-glucose) and amino sugar derivatives (N-acetylgalactosamine and N-acetylglucosamine) were present on the surface of theronts. Invasion was reduced significantly for theronts treated with LCA, UEA-I and WGA. No difference in invasion was found between control and SBA bound theronts (p > 0.05). The binding of lectin LCA, UEA-I and WGA to theronts significantly reduced the development of trophonts (p < 0.05). The mean volumes of trophonts labeled with these 3 lectins were smaller than volumes in control trophonts from 8 to 48 h after exposure. Survival was lower in trophonts labeled with lectins than in control trophonts at 48 h after exposure.     

Ichthyophthirius (Ciliophora): Population Studies Suggest Reproduction in Host Epithelium1

Evidence that Ichthyophthirius multifiliis trophonts may reproduce within the epithelium of the host was obtained from experimental infections of channel catfish. Mean number of parasites spontaneously leaving the fish increased from 0 on day 3 postexposure (PE) to 66.5 per fish on day 7 PE. Mean population density in fin, however, increased five-fold from day 3 to day 5 PE in the absence of opportunity for reinfection. At day 3 PE, 100% of parasite loci in fin and gill arches contained solitary trophonts. At day 4 PE, 10% of loci in fin contained clusters of two trophonts; at day 7 PE, 69% contained clusters of two or more trophonts. The first clusters of four trophonts in fin were observed day 5 PE and of eight trophonts, day 8 PE. Trophonts in clusters were flattened against one another.     

Prolonged in vitro cultivation of Ichthyophthirius multifiliis using an EPC cell line as substrate

The ciliate Ichthyophthirius multifiliis, which normally requires a fish host to develop from the theront stage to the trophont stage, was cultivated in vitro for part of its life cycle. Experiments were conducted using a laboratory strain of the parasite originally isolated from rainbow trout Oncorhynchus mykiss in a Danish trout farm. Theronts escaping from tomontocysts were kept in water, cell culture media (E-MEM or L-15), or cultures of EPC (Epithelioma Papulosum Cyprini) cells in plastic tissue culture dishes (Nunc multidish plates). In addition, a 2-compartment system, with water separated from tissue culture media by a monolayer of EPC cells on an Anopore Tissue Culture Insert (mimicking the fish epidermis) was tested as an experimental habitat for the parasite. Theronts transformed into trophonts in all treatments except in water alone. However, development was accelerated in wells containing EPC cells, and survival and growth of trophonts were significantly increased compared to water or tissue culture media alone. Further, the 2-compartment system allowed superior performance of the parasites (attachment of parasites to cells and growth from 36 to 46 microm). In all experiments it was found that the presence of host factors (mucus and serum) stimulated parasite development.     

Suppressive effect of an inducible nitric oxide inhibitor, ONO-1714, on AOM-induced rat colon carcinogenesis.

The expression of inducible nitric oxide synthase (iNOS) is markedly elevated in rat colon cancers induced by azoxymethane (AOM). In addition, iNOS can be detected in most adenomas and dysplastic aberrant crypt foci (ACF), suggesting that iNOS plays an important role in colon carcinogenesis. In the present study, the effect of an iNOS inhibitor, ONO-1714 ((1S,5S,6R,7R)-7-chloro-3-imino-5-methyl-2-azabicyclo[4.1.0] heptane hydrochloride), on AOM-induced rat colon carcinogenesis was investigated. Male F344 rats were treated with 15 mg/kg body weight of AOM once a week, for 2 weeks. ONO-1714 was given to the rats at doses of 10, 20, 50, and 100 ppm in diet for 4 weeks from the day before the first carcinogen treatment. The number of AOM-induced ACF in the rats receiving 10, 20, 50 and 100 ppm ONO-1714 were 94, 73 (P < 0.05), 71 (P < 0.005), and 53% (P < 0.0005), respectively, of the control value. Moreover, the mean number of aberrant crypts per focus was significantly lowered in 100 ppm ONO-1714 group (P < 0.05). Then, the effects of long-term treatment (32 weeks) with 50 and 100 ppm ONO-1714 on AOM-induced colorectal tumor development were examined. Although incidences and multiplicities of colon tumors did not significantly differ among the groups, number of tumors developing in the middle part of colon were reduced with both 50 and 100 ppm doses (P < 0.05). Furthermore, colon tumor volume tended to be decreased by ONO-1714 treatment, and the number of colon tumors more than 3mm in diameter was significantly lowered in the 100 ppm ONO-1714 group (P < 0.01). These results suggest that iNOS plays roles in both early and late stages of colon carcinogenesis.     

The effect of muscular loading on carbohydrate and fat metabolism in the current year's brood of Salmo irideus trout]

In trout fingerlings with a mean weight 1.1 g and body length 4.3 cm, kept in a water stream at the velocity of 0.2 m/sec for 1-3 hours, the content of glycogen in muscles, liver and brain decreases whereas the content of unsaturated fatty acids and glucose in the blood as well as the level of lactate in muscles increase. After 5-hour swimming of the fingerlings carbohydrate metabolism and the content of unsaturated fatty acids return to the initial levels; the content of fat in the liver significantly decreases. Presumably trout fingerlings exhibit high capacity for adaptation to the given muscular activity and do not show fatigue.     

The effect of sodium and calcium concentrations on the hatching of eggs and the survival of the yolk sac fry of brown trout, Salmo trutta L. at low pH

The effect of various external concentrations of sodium and calcium on the survival and hatching of brown trout, Salmo trutta , eggs at pH 4.5 was tested. A calcium concentration of approximately 10 ppm (500 μE l⁻¹) enables freshly fertilized eggs to survive whereas eyed ova are tolerant of deionized water acidified by sulphuric acid with no other ions added. Concentrations of sodium and calcium of 1 ppm (44 and 50 μE l⁻¹, respectively) are sufficient to ensure the successful hatching of eyed ova and subsequent survival of the alevins. At pH 4.5 hatching is prolonged by the alevins passing through a temporary encapsulated stage.     

Physical and chemical effects on viability of the Myxobolus cerebralis triactinomyxon

Various chemical and physical methods for destroying the triactinomyxon (TAM) stage of the myxozoan parasite Myxobolus cerebralis were tested. The fluorescent stains propidium iodide and fluorescein diacetate were used as indicators of viability. Physical variables tested included freezing, drying, high temperature, sonication, and pressure of 6.2 x 10(7) Pa (9000 psi). Chemicals evaluated included chlorine bleach, povidone-iodine, and hydrogen peroxide. Freezing or drying for 1 h was effective in killing TAMs, but pressure was not. Temperatures above 75 degrees C for at least 5 min were also effective. Sonication with a laboratory instrument cleaner for 10 to 13 min killed and ruptured TAMs, resulting in <1.9% recovery. However, among the surviving TAMs, 39 to 58% were still viable. Chlorine concentrations of 130 ppm for 10 min were also effective at temperatures ranging from ice-water to room temperature and total hardness ranging from 10 to 500 mg l(-1). Lethal concentrations of hydrogen peroxide and povidone-iodine (10% solution) were quite high: 10% for 10 min, and 50% (5000 ppm active iodine) for 60 min, respectively. The stain results indicating TAM death were verified in 2 tests in which rainbow trout Oncorhynchus mykiss were exposed to TAMs that had been either frozen for 1 h or treated with 66 ppm chlorine as sodium hypochlorite for 1 min. None of the fish exposed to the treated TAMs became infected. These results should provide disinfection guidelines to prevent transfer of M. cerebralis TAMs to uninfected areas and provide information on the risks of parasite transfer under various treatment scenarios.     

Toxicity and behavioral effects of nootkatone, 1,10-dihydronootkatone, and tetrahydronootkatone to the formosan subterranean termite (Isoptera: Rhinotermitidae)

Toxicity and behavioral effects of nootkatone and two of its derivatives, 1,10-dihydronootkatone and tetrahydronootkatone, to Coptotermes formosanus Shiraki were investigated on workers from two different colonies by using topical application assays, repellency assays, and sand barrier assays. The acute toxicity of the nootkatones on workers from both colonies increased as the saturation of the molecule increased, but the difference was significant for only one colony. The results of the repellency assays showed a similar trend of efficiency; the threshold concentration for significant repellency was four-fold higher in nootkatone treatments (50 ppm) than in the reduced derivatives 1,10-dihydronootkatone or tetrahydronootkatone (12.5 ppm). In sand barrier assays, a concentration of 100 ppm of any of the three chemicals significantly reduced termite survival, tunnel building, and food consumption after a 12-d exposure. Termites preexposed to 100 ppm nootkatone-treated sand and placed in containers without nootkatone for 15 d continued to exhibit abnormal feeding and digging behaviors; survivorship, tunneling, and feeding activities were significantly reduced by 83.5, 63.2, and 95.4%, respectively. Termites pretreated for 12 d at concentrations of 50 and 75 ppm nootkatone and tetrahydronootkatone returned to normal digging activity after they were removed from the treatments, but their feeding activity was significantly reduced.     

农药助剂对茚虫威防治番茄潜叶蛾的减量增效作用

为评价农药助剂对15%茚虫威悬浮剂防治番茄潜叶蛾Tuta absoluta(Meyrick)的减量增效作用,分别向减量10%、20%、30%的15%茚虫威悬浮剂药液中添加500 ppm的有机硅silwet 408、矿物油、芦荟精油助剂,测定其对番茄潜叶蛾的田间防效。结果显示：相同浓度下,添加农药助剂后的防效均显著高于15%茚虫威悬浮剂的防效,相对常规用量通过添加有机硅Silwet 408、矿物油或芦荟精油可使农药减量10%～20%。田间应用将15%茚虫威悬浮剂按照常规用量减量10%～20%,通过添加有机硅Silwet 408、矿物油或芦荟精油可有效防治番茄潜叶蛾。     

Jodmangel bei Wiederkäuern

Effects of a supplemental Aspergillus niger‐phytase on digestibility and utilization of dietary phosphorus (P) were studied in three experiments with rainbow trout. P concentration in the diets was 4.8 and 5.8 g/kg DM, respectively. The P contained in the diet originated solely from plants, mainly soy‐products. Digestibility of P was studied using the stripping method and hydrochloride insoluble ash as marker. Utilization was studied in growth trials by use of the comparative body analysis.

At a water temperature of 15°C, both digestibility and utilization of P were increased from 25 to 57% and from 17 to 49%, respectively when 1000 U/kg phytase were supplemented. Feed consumption and gain of trout were significantly increased. At a water temperature of 10°C, utilization of P was also increased from 6 to 25%. However, feed consumption and gain of trout were very low at this water temperature and not influenced by the supplemental phytase.     

不同异构体的氯氰菊酯对德国小蠊的毒力

氯氰菊酯的顺式或反式、或其混合体对德国小蠊的生物活性，在50～500PPm浓度范围内，击倒中浓度由原369ppm降至49～164ppm；高温稳定性中的击倒中时，由原10～18分降至4～10分。     

Changes of C-reactive protein levels in rainbow trout (Oncorhynchus mykiss) sera after exposure to anti-ectoparasitic chemicals used in aquaculture

Changes of serum C-reactive protein (CRP) levels in rainbow trout (Oncorhynchus mykiss) were studied after exposure to formalin, metriphonate or potassium permanganate, which are used in aquaculture as anti-ectoparasitic chemicals. The CRP level in normal trout sera is 88+/-5 microg ml(-1) according to sandwich enzyme-linked immunosorbent assay. CRP levels increased to a maximum at six or nine days after exposure to formalin for 3.5 h at 300 ppm or 9.5 h at 30 ppm, respectively; these levels are 4.3 and 18 times higher than normal. At 18 days after treatment, the CRP level had decreased to significantly below the normal level. After exposure to metriphonate (0.4 ppm for 30 min), the CRP level increased significantly to a maximum at three days after exposure (9.9 times higher than normal), then decreased to below normal. With exposure to potassium permanganate at 40 ppm for 45 min, fish showed significantly lower CRP levels than the normal level at 14 days after exposure. Fish reared at a water temperature of 16.5-19.5 degrees C showed significantly higher CRP levels than those reared at 13 degrees C. Measurement of CRP levels in trout serum can be used as a bioindicator of the health condition of the fish.