Effects of additive iron on growth,tissue distribution,haematology and immunology of gilthead sea bream, <Emphasis Type="Italic">Sparus aurata</Emphasis>

The comparative effects of iron-supplemented levels on growth, tissue distribution, haematology and immunology of gilthead sea bream, Sparus aurata (2 g) were investigated, using four organic (50, 100, 200, 300 mg ORG/kg diet) and one inorganic iron source (200 INOR mg/kg diet). Fish were treated for 12 weeks with the experimental diets and maintained at a water temperature of 19–22°C. Growth (final weight and specific growth rate), tissue distribution (spleen, liver and muscle), haematological parameters (red blood cells, haematocrit, haemoglobin and mean corpuscular haemoglobin concentration) and non-specific immune indexes (respiratory burst activity and antibacterial activity of serum) were analysed. No significant differences were found in growth and iron tissue distribution among the tested groups. Red blood cell counting was statistically higher in fish given 50 ORG, 100 ORG, 200 ORG and 200 INOR feeds. However, haematocrit, haemoglobin and mean corpuscular haemoglobin concentration were not significantly affected by increasing dietary iron. Fish receiving the 100 ORG diet had the best performance with respect to the respiratory burst activity and significantly higher values for antibacterial activity of serum were obtained in fish fed with the 300 ORG diet. The present findings provided no clear evidence of the optimum iron concentration. However, there was adequate indication that iron supplementation enhanced the performance of gilthead sea bream, mainly from a haematological and immunological point of view.     

MAGNETIC RESONANCE IMAGING APPEARANCE OF SUSPECTED ISCHEMIC MYELOPATHY IN DOGS

Ischemia and infarction of the spinal cord is a known cause of acute spinal injury in dogs. Currently, the diagnosis of spinal cord infarction in small animals is based on history, clinical signs, and the exclusion of other differentials with radiography and myelography. It is a diagnosis only confirmed through necropsy examination of the spinal cord. The aim of this paper is to describe the Magnetic resonance imaging (MRI) findings of the spinal cord of dogs with suspected spinal cord infarcts to utilize this technology for antemortem support of this diagnosis. This retrospective study evaluated the spinal MR examinations of 11 dogs with acute onset of asymmetric nonpainful myelopathies. All patients except one (imaged at 2 months) were imaged within 1 week of clinical signs and managed conservatively with minimal medical and no surgical intervention. They were followed clinically for a minimum of 4 months after discharge. MR findings in all dogs were characterized by focal, intramedullary, hyperintense lesions on T2-weighted images with variable contrast enhancement similar to what is reported in humans. Though it could not be used to diagnose spinal cord infarction definitively, MRI was useful in excluding extramedullary spinal lesions and supporting intramedullary infarction as a cause of the acute neurologic signs. Together with the history and clinical examination findings, MRI is supportive of a diagnosis of spinal cord infarction.     

Evaluation of PCR,IEF and ELISA techniques for the detection and identification of potato cyst nematodes from field soil samples in England and Wales

Effective management of potato cyst nematodes (PCNs) requires simple, rapid and accurate identification and quantification of field populations. Soil samples from a survey of 484 fields in potato rotations in England and Wales were used to compare the identification and quantification of PCNs using IEF, PCR, ELISA and bait plant tests. The cyst counts and bait plant test revealed that 64.3% of field samples contained PCNs. Bait plant tests increased the detection rate of PCNs in field samples by 4–6.4%. This means that some infestations are cryptic and would not normally be detected by standard counts. IEF, PCR and ELISA methods distinguished between Globodera rostochiensis and G pallida and were able to register mixed populations; however they were not in full agreement. All methods suggested that G pallida is the dominant species in the field samples tested. The PCR results indicated that 66% of field samples contained pure G pallida, 8% contained pure G rostochiensis and 26% contained mixtures of the two species. Estimates of the relative process times taken per sample in the PCR, IEF and ELISA techniques are given. © 2001 Society of Chemical Industry     

Resistance to foliage-feeding insects in conifers: implications for pest management

The ecological implications of insect resistance in conifers are rarely discussed. It is however a fairly straightforward plant-insect interaction and should be treated as such, making use of the increasing amount of information in this field. Work on tree breeding is usually carried out by silviculturalists who, not surprisingly, rarely consider the insect component of the environment in which the treess are growing. In all fairness, it must be stated that many entomologists, fail to consider the plant component of the interaction. Clonal forestry will almost certainly result in the loss of genetic variability. The use of clonal material has already been cited as a possible source for the diminution of the resistance against pests and diseases and if particular resistance mechanisms against forest pests are sought in the future the reduction in genetic material caused by clonal selection could have serious consequences. The ethics of clonal forestry have been questioned as have the ethics of biotechnological advances in the area of recombinant DNA molecules. The potential of both these techniques should be publicized and brought to the attention of the general public and the scientific community at large and evaluated. To improve our forest environment and to protect the environment as a whole, entomologists, geneticists, physiologists and silviculturalists must work together to produce better trees that require little, if any, chemical aid, be it insecticides, herbicides, fungicides or fertilizers. An increasing awareness of the environmental problems generated by large-scale insecticide applications to forest plantations, coupled with an increasingly chemophobic work-force and the difficulty in obtaining pesticide registration for use in forest environments, means that the forest industry world-wide must look to the use of integrated control measures with more diligence than has been shown in the past. Many recent outbreaks of pests and diseases have been linked with particular seed origins of tree crops. Host plant resistance as part of a suite of other proposed integrated control tools is thus an obvious candidate for development. Despite this, scientists concerned with tree improvement continue to select largely for silvicultural traits rather than for resistance to pests and disease. The different avenues open to plant breeders are examined and the potential of breeding trees resistant to insect attack highlighted. Using resistant trees as part of an integrated pest management system has five very important properties. Firstly, there is no additional pest control cost to the grower, secondly, it operates at all levels of insect incidence and not just when the pest is at high population levels, thirdly, it reduces the insect population cumulatively, fourthly it avoids toxic residues and environmental pollution and, finally, it usually interacts well with the other integrated pest management strategies in existence.     

Analysis of feline,canine and equine hemograms using the QBC VetAutoread

Blood samples form 120 consecutive clinical cases (40 cats, 40 dogs and 40 horses) were analyzed on the QBC VetAutoread analyzer and the results compared with those obtained by a Baker 9000 electronic resistance cell counter and a 100-cell manual differential leukocyte (WBC) count. Packed cell volume (PCV), hemoglobin (Hb) concentration, mean cell hemoglobin concentration (MCHC), and platelet, total WBC, granulocytes, and lymphocyte plus monocyte (L+M) counts were determined. Indistinct separation of red blood cell and granulocytes layers on the QBC VetAutoread was observed in samples from five cats (12.5%), two dogs (5%), and one horse. Significantly different (P=0.002) median values for the two methods were obtained for PCV, Hb concentration, MCHC and platelet count in cats; PCV, MCHC, WBC, count and granulocytes count in dogs; and PCV, Hb concentration, MCHC and WBC, granulocytes and platelet counts in horses. Results from the QBC VetAutoread should not be interpreted using reference ranges established using other equipment. Results were abnormal on a limited number of samples; however, when correlation coefficients were low, marked discrepancy existed between values within as well as outside of reference ranges. Spearman rank correlation coefficients were excellent (r=0.93) for PCV and Hb concentration in dogs, and Hb concentration and WBC count in horses. Correlation was good (r=0.80-0.92) for PCV and Hb concentration in cats, WBC count in dogs, and PCV, granulocytes count and platelet count in horses. For remaining parameters, correlation was fair to poor (r=0.79). Acceptable correlations (r>0.80) were achieved between the two test systems for all equine values except MCHC and L+M count, but only for PCV and HB concentration in feline and canine blood samples.     

Experimental Exposure of Pigs to Infectious Bovine Rhinotracheitis (IBR) Virus

Thirteen specific-pathogen-free pigs were used in an experiment to determine the pathogenicity of IBR virus for pigs. Three pigs were used as controls, eight were exposed to IBR virus by either the intravenous, subcutaneous, intratracheal, or intranasal route, and two pigs served as contact controls. The clinical response consisted of a temperature rise, depression and variable lymphocytosis. The major tissue alterations were interstitial pneumonitis, and peribronchiolitis with round cell aggregates and giant cell formation. IBR virus was not recovered from any of the pigs. A serologic response was detected in only the pig injected intravenously.     

A simple technique for mass cultivation of Campylobacter fetus.

Studies using 86 media for maximum growth of Campylobacter fetus for antigen production showed that a diphasic medium (solid base with liquid overlay) was most suitable. The solid base was double strength cystine heart agar. The liquid overlay was thioglycollate medium of Brewer (135-C) without agar. This medium yielded maximum growth of C. fetus in six days with good motility, less clumping and less filament formation than all other media tried.     

Laboratory studies with antifeedants against larvae of Boarmia (Ascotis) selenaria on alfalfa

The antifeedant effect of five organotin compounds (fentin acetate, fentin hydroxide, fentin chloride, cyhexatin and fenbutatin oxide) and of three other compounds known to possess antifeeding activity (guazatine triacetate, 4′-chloroacetophenone isobutyrylhydrazone and thiram) was investigated by feeding treated alfalfa to larvae of Boarmia selenaria. The three fentins and cyhexatin were highly active at 0.1 g litre^?1, the order of activity at this concentration being fentin chloride > fentin hydroxide > fentin acetate ? cyhexatin, whereas the other compounds were practically inactive at either this or a somewhat higher concentration (0.5 g litre^?1). Guazatine triacetate had a concentration-independent antifeedant effect at much higher concentrations (5–20 g litre^?1).