Distribution of ‘Candidatus Phytoplasma prunorum’ and its vector Cacopsylla pruni in European fruit‐growing areas: a review

European stone fruit yellows (ESFY) is an EU‐listed I/AII disease affecting Prunus spp. caused by ‘Candidatus Phytoplasma prunorum’. This paper reports the results from a systematic literature review approach that sought to determine the geographic distribution of ‘Ca. Phytoplasma prunorum’ in European fruit‐growing areas. Evidence for the presence of the phytoplasma was found for 15 of the 27 EU countries. It is prevalent in the most important stone fruit production areas of Central and Southern Europe, where it causes substantial impact in apricots (Prunus armeniaca), Japanese plums (P. salicina) and peaches (P. persica). In Northern European areas where these hosts are not produced, it is occasionally found on tolerant species (P. domestica). However, because surveys of the disease status of tolerant hosts are not performed, it remains unclear whether the pathogen is absent in Northern Europe or survives in tolerant cultivated or wild hosts. No reports of ESFY were found from the southernmost part of Europe: Portugal, Spain (Andalucia, Castile–La Mancha), Italy (Sicily, Puglia), Greece (Crete), Cyprus and Malta. This may be explained by the absence of the favoured wild hosts of the vector. Moreover, it remains unclear if the vector finds suitable conditions for aestivation and overwintering in these regions.     

Food intake, growth rate, food conversion and food choice in broilers fed on diets high in rapeseed meal and pea meal, with observations on sensory evaluation of the resulting poultry meat

1. Experiments were done to measure the effects of 100 and 200 g/kg of either pea meal or low glucosinolate, low erucic acid rapeseed meal on food intake and growth, food choice and meat organoleptic quality in broiler chickens. 2. The test diets were formulated to be iso-energetic and iso-nitrogenous with a soy-wheat control diet. In all diets, lysine was fixed at 11.0 g/kg and all other indispensable amino acids were present in excess of requirements. 3. Food intake was little affected by the inclusion of 100 g/kg of pea meal in the diet but 200 g/kg of peas caused a decrease. Rapeseed produced a decrease in food intake at both dietary concentrations. 4. Weight gain was similarly affected, but food conversion from d 0 to d 42 was little affected by the inclusion of either peas or rapeseed. 5. Absolute breast muscle weight was affected by diet but there was no significant difference in breast weight as a proportion of total body weight. 6. From d 7 onwards, selection against the pea-containing diet approached statistical significance. Between d 7 and d 14, birds ate almost twice as much of the control as of the pea-containing diet. Birds offered a rapeseed meal diet ate similar amounts of that and the control diet. 7. The breast meat from birds given 200 g rapeseed/kg was the only meat identified as different but no strong aversion was expressed by the tasting panel.     

Expression of erythropoietin in cats treated with a recombinant adeno-associated viral vector

OBJECTIVE: To characterize the biological effects of IM administration of a recombinant adeno-associated virus serotype 2 (rAAV2) vector containing feline erythropoietin (fEPO) cDNA and determine whether readministration of the vector or removal of muscle tissue at the injection sites alters those effects. ANIMALS: 10 healthy 7-week-old specific pathogen-free cats. PROCEDURE: Cats received 1 X 10(7) infective units (iU; n = 3), 1 X 10(8) iU (3), or 1 X 10(9) iU (2) of rAAV2-fEPO vector IM (day 0). Two control cats received an rAAV2 vector containing the LacZ gene (1 X 10(9) iU, IM). In all cats, hematologic variables and serum fEPO concentration were measured at intervals; anti-rAAV2 antibody titer was measured on day 227. In cats that did not respond to treatment, the rAAV2-fEPO vector was readministered. Injection sites were subsequently surgically removed. RESULTS: Compared with control cats, cats treated with 1 X 10(9) iU of rAAV2-fEPO vector had increased Hct and serum fEPO concentrations. One of these cats developed pure RBC aplasia; its Hct normalized following injection site excision. Cats receiving lower doses of vector had no response; on retreatment, 1 of those cats developed sustained erythrocytosis that persisted despite injection site removal and the others did not respond or responded transiently. Antibodies against rAAV2 were detected in all vector-treated cats. CONCLUSIONS AND CLINICAL RELEVANCE: Gene therapy may be an effective treatment for cats with hypoproliferative anemia. However, rAAV2-fEPO vector administration may result in pure RBC aplasia or pathologic erythrocytosis, and injection site removal does not consistently abolish the biological response.     

Alleviation of acute heat stress by food withdrawal or darkness

1. Growing 33-d-old broiler fowl were exposed to air temperatures of 35 to 40 degrees C for a period of 4 h each day for 5 d. 2. The birds were fed on diets providing widely differing proportions and intakes of energy as protein, carbohydrate and fat. 3. Three lighting and feeding treatments were superimposed on the 4-h heat stress period. The treatments were: LF (control) lights and food throughout, NL (no light) extinguished throughout the hot period, NF (no food) food withdrawn 2 h before the hot period and replaced immediately after it. 4. Diet had no significant effect on rate of increase of rectal temperature (TR) during heat stress. 5. The NL and NF treatments significantly reduced the rate of increase of TR and the TR attained after 4 h of heat exposure.     

Effects of feeding by crop intubation on energy metabolism and physical activity in domestic cockerels.

1. Heat production and physical activity were measured in cockerels given the same amount of food either conventionally or by direct intubation into the crop. 2. The thermogenic effect of feeding (heat increment per unit weight of food) was about 30% less with tube-feeding. 3. The difference in heat increment of feeding, and therefore in efficiency of energy utilisation, was entirely attributable to the circumvention of feeding activity by intubation.     

The use of liposomally-entrapped gentamicin in the treatment of bovine Staphylococcus aureus mastitis.

The effect of incorporation of gentamicin in liposomes on intracellular killing of Staphylococcus aureus was studied in vitro in cultured bovine mammary macrophages, and in experimental bovine mastitis. Liposomes were prepared by reverse-phase evaporation and ranged in size from 0.1 to 1.0 micron in diameter (mean 0.51 micron), with an encapsulation efficiency of gentamicin of 27.4%. Liposomes were taken up by in vitro cultured macrophages but intracellular killing of S. aureus over 12 h was not significantly enhanced when treatment with liposomally-entrapped gentamicin was compared to free gentamicin. Treatment of experimentally-induced S. aureus mastitis in five lactating Holstein cows (20 quarters) failed to show significant differences in bacterial counts when treatment with liposomally-entrapped gentamicin was compared to treatment with free gentamicin or blank liposomes plus free gentamicin. Gentamicin concentrations exceeded the in vitro determined minimum inhibitory concentration for 48 h when quarters were treated with 50 mg gentamicin on two occasions 24 h apart.     

Incidence of pecking damage in growing bantams in relation to food form, group size, stocking density, dietary tryptophan concentration and dietary protein source

1. This paper reports 4 experiments with groups of 10 to 20 growing bantams in multi-unit brooders, which investigated effects of certain environmental and dietary factors on development of feather pecking damage to 6 weeks of age. Damage was assessed according to a subjective scoring system. 2. A test of food form (pellets, mash, mash diluted with 100 g/kg powdered cellulose) confirmed that pecking damage tends to be greater with pellets than with mash but there was no significant difference between the low damage scores associated with undiluted and diluted mash treatments. 3. A test of group size (10, 20 birds) and stocking density (744, 372, 186 cm2/bird) showed that variation in pecking damage was associated with group size x density interactions. 4. A test of dietary supplementation with L-tryptophan (0, 10, 20 g/kg) showed suppression of pecking damage with the higher (20 g/kg) dose, compared with the control (0 g/kg) treatment. 5. A test of dietary protein source (plant, mainly animal, mainly semipurified) showed no difference in pecking damage scores between treatments.     

Book reviews

Avian Endocrinology. Edited by P.J. Sharp, 1993. 408 pp., Bristol, The Society for Endocrinology. Endocrine Updates Series. Price £39.50.

Poultry Feed from Waste: Processing and Use. Edited by A.R.Y. El Boushy and A.F.B. van der Poel, 438 pp., 85 illustrations, 152 tables, 829 references. London UK, Chapman & Hall. £95 ISBN 0412 58280 5.     

In vitro effects of the active metabolite of leflunomide, A77 1726, on feline herpesvirus-1

OBJECTIVE: To determine whether the active metabolite of leflunomide, A77 1726 (A77), inhibits replication of feline herpesvirus-1 (FHV-1) in cell culture. STUDY POPULATION: Crandell Rees feline kidney (CRFK) cell cultures. PROCEDURES: Cell cultures were inoculated with FHV-1 and treated simultaneously with concentrations of A77 ranging from 0 to 200microM. The antiviral effect of A77 was determined by use of conventional plaque reduction assays. The effect of A77 on viral load was determined via real-time PCR analysis, and transmission electron microscopy was used to evaluate the effect of A77 on viral morphology. To determine whether the antiviral effect was attributable to alterations in CRFK cell viability and number, CRFK cells were treated with various concentrations of A77 and stained with Annexin V and propidium iodide to assess apoptosis and a mitochondrial function assay was used to determine cell viability. RESULTS: Concentrations of A77 > or = 20microM were associated with substantial reduction in plaque number and viral load. Concentrations > or = 100microM were associated with complete suppression of plaque formation. At low concentrations of A77, clusters of intracytoplasmic virus particles that appeared to lack tegument and an external membrane were detected. Treatment of uninfected CRFK cell monolayers with A77 was associated with reduction in mitochondrial function with minimal evidence of apoptosis. CONCLUSIONS AND CLINICAL RELEVANCE: Leflunomide may be an alternative to current calcineurin-based immunosuppressive protocols used in feline organ transplantation because of its antiherpesviral activity.     

Suppression of wheat early growth in standing stubble

Early growth and development are often lower when wheat is sown into standing stubble. A study was conducted to determine whether this difference in early growth could be explained by the effects of stubble on soil temperature in the vicinity of the young plant. The roles of nitrogen nutrition and soil strength were also assessed. Three crops were monitored (1990–1992), with the wheat being sown into either standing wheat stubble after a no-till fallow (NT), or into no-tilled plots from which the stubble had been removed by burning (NB). Measurements were made of wheat growth and development, soil and plant N, soil temperature and penetration resistance. The site was on a black earth near Warialda in the northern wheatbelt of New South Wales, Australia. In 1992 wheat was also grown under simulated stubble to isolate the shading and soil temperature effects of stubble from other factors. A significant (P<0.05) relationship was found between average soil temperature and above ground dry matter (DM) at 65 days after sowing (DAS) but not at 107 DAS. This relationship accounted for differences in DM production at 65 DAS between NT and NB treatments in 1991 and 1992, but not in 1990. In that year the lower DM production in NT plots was associated with poorer N nutrition, and possibly disease. Laboratory incubations indicate that immobilisation of N as stubble decomposed could have contributed to this. Burning stubble produced no immediate increase in soil N availability, so that it is unlikely that N contained in stubble contributed to the difference. Soil strength differences between treatments and phytotoxic effects are unlikely to have contributed to growth differences in this soil.