Epidemiology of brown rot (Monilinia fructigena) on apple: infection of fruits by conidia     

X.-M. Xu  & J.D. Robinson 《Plant pathology》2000,49(2):201-206

Effects of fruit maturity, wound age, temperature and the duration of wetness periods on infection of apple fruits by conidia of the brown rot fungus, Monilinia fructigena , were studied. Inoculation of fruits on potted apple trees and harvested mature fruits showed that wounding was essential for infection by M. fructigena . On potted trees, there was a significant difference between the susceptibility of cvs Cox and Gala and this difference depended on wound age. The incidence of brown rot was affected greatly by fruit maturity and wound age. Wounds on younger fruits were more resistant to infection than those on older fruits, whilst the older the wound, the more resistant it was to infection. Furthermore, the degree of wound age-related resistance was greater on younger fruits than on older fruits. These relationships were well described by regression models. The effect of the duration of wetness periods was very small: increasing the duration of wetness periods reduced the incidence of brown rot on older wounds. For detached fruits, all those wounded were rotted after inoculation, except for those in two treatments under 20°C on fruits with wounds which were 8 days old. The incubation period of the fungus was generally very short. Wound age was the single most important factor influencing the length of the incubation period; the incubation period increased as wound age increased.  相似文献   

Effects of temperature on the incubation and latent periods of hawthorn powdery mildew (Podosphaera clandestina)     

X-M. Xu†  J. D. Robinson 《Plant pathology》2000,49(6):791-797

The effects of temperature on the length of the incubation and latent periods of hawthorn powdery mildew, caused by Podosphaera clandestina , were studied. At constant temperatures over the range 10–28°C, the incubation period ranged from 5 to 14 days and the latent period from 5 to 16 days; no visible colonies had developed at 30°C after 15 days. The relationships between temperature and the rates of fungus development within the incubation and latent periods were well described by a nonlinear model. The resulting curves were asymmetrically bell-shaped with an optimum temperature of approximately 23°C. The lengths of the incubation and latent periods under fluctuating temperatures were also determined, and were used to evaluate the models developed from constant temperature experiments for their accuracy of prediction. The incubation and latent periods under fluctuating temperature regimes were predicted using a rate-summation scheme with a time step of 24 min, by integrating the respective incubation and latent rate functions obtained under constant temperatures. The predicted incubation or latent periods agreed well with the observed values. Under constant temperature the interval between the times when symptoms and sporulation on the same leaflet were first observed was very short, on average <1 day, and was not significantly correlated with temperature. However, this interval was negatively correlated with mean temperature under fluctuating regimes.  相似文献   

Aflatoxins from Moldy Corn Cause No Reductions in Channel Catfish Ictalurus punctatus Performance     

Bruce B.  Manning  Menghe H.  Li Edwin H.  Robinson 《Journal of the World Aquaculture Society》2005,36(1):59-67

Aflatoxins are a group of mycotoxins produced by the mold organisms Aspergillus flavus and A. parasiticus on feed grains and oil seeds such as corn, peanuts, and cottonseed. Research conducted in aquaria, about 15 yr ago, demonstrated that channel catfish Ictalurus punctatus are very tolerant to dietary aflatoxin B₁ (AFB₁) from a purified source. To evaluate the effect of feeding diets containing aflatoxin from a natural source, moldy corn (MC) naturally contaminated with a high concentration (550 pg/kg) of total aflatoxins was incorporated into practical diets. The diets were fed to Juvenile catfish in two experiments. Experiment 1 consisted of feeding catfish (mean body weight 7.1 g/fish) four diets containing 20% or 40% of two lots of corn; one with no apparent mold contamination, which was designated as clean corn (CC), or the previously described MC. Each diet was fed twice daily to five 100-L aquaria of 20 fish each for 12 wk. Experiment 2 consisted of three diets containing either 50% CC or MC, or a combination of 25% CC and 25% MC prepared by the cooker-extrusion method. Each diet was fed once daily for 130 d to five replicate 0.04-ha ponds of catfish fingerlings. Results of these experiments indicate that feeding diets containing aflatoxin from moldy corn does not affect channel catfish weight gain, feed consumption, feed efficiency, survival, hematocrit, or hepatosomatic ratio. No liver abnormalities were observed upon gross examination. Levels of aflatoxin were reduced approximately 63% in the diets used in experiment 2 after exposure to the high temperature (ca. 120 C) of the cooker-extrusion process used to manufacture commercial catfish diets.  相似文献   

LATERAL COLLATERAL LIGAMENT AVULSION OF THE HUMERORADIAL JOINT IN A HORSE   总被引：1，自引：0，他引：1  

John B.  Chopin  BVSc  John D.  Wright  MVSc  Lisa  Melville  BVSc  Wayne F.  Robinson  BVSc  PhD 《Veterinary radiology & ultrasound》1997,38(1):50-54

This report describes traumatic avulsion of the lateral collateral ligament of the humeroradial joint in a horse. The history and diagnostic procedures are included with relevant radiographs and ultrasonographs. The poor prognosis associated with this injury is due to degenerative joint disease.  相似文献   

Clinical signs, diagnosis, and treatment of alkalemia in dogs: 20 cases (1982-1984)     

E P Robinson  R M Hardy 《Journal of the American Veterinary Medical Association》1988,192(7):943-949

Alkalemia (pH greater than 7.50) was measured in 20 dogs admitted over a 3-year period for various clinical disorders. Alkalemia was detected in only 2.08% of all dogs in which blood pH and blood-gas estimations were made. Thirteen dogs had metabolic alkalosis (HCO3- greater than 24 mEq/L, PCO2 greater than 30 mm of Hg), of which 8 had uncompensated metabolic alkalosis, and of which 5 had partially compensated metabolic alkalosis. Seven dogs had respiratory alkalosis (PCO2 less than 30 mm of Hg, HCO3- less than 24 mEq/L); 4 of these had uncompensated respiratory alkalosis and 3 had partially compensated respiratory alkalosis. Ten dogs had double or triple acid-base abnormalities. Dogs with metabolic alkalosis had a preponderance of clinical signs associated with gastrointestinal disorders (10 dogs). Overzealous administration of sodium bicarbonate or diuretics, in addition to anorexia, polyuria, or hyperbilirubinemia may have contributed to metabolic alkalosis in 8 of the dogs. Most of the dogs in this group had low serum K+ and Cl- values. Two dogs with metabolic alkalosis had PCO2 values greater than 60 mm of Hg, and 1 of these had arterial hypoxemia (PaO2 less than 80 mm of Hg). Treatments included replacement of fluid and electrolytes (Na+, K+, and Cl-), and surgery as indicated (8 dogs). Six dogs with respiratory alkalosis had a variety of airway, pulmonary, or cardiac disorders, and 3 of these had arterial hypoxemia. Two other dogs were excessively ventilated during surgery, and 1 dog had apparent postoperative pain that may have contributed to the respiratory alkalosis.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

The Effect of Constant and Fluctuating Temperatures on the Confinement-induced Plasma Cortisol Stress Response in Channel Catfish lctalurus punctatus     

Kenneth B.  Davis Bill A.  Simco Menghe H.  Li Edwin  Robinson 《Journal of the World Aquaculture Society》2001,32(4):422-425

Abstract.— Initial and confinement-induced changes of plasma cortisol were measured in channel catfish Ictalurus punctatus acclimated to upper and lower constant temperatures for each season, a spring/fall diurnal pattern between 15 and 26 C, and a summer diurnal pattern between 24 and 35 C. In diurnal treatments, temperature changes were achieved in 10 h and held constant for 2 h before reversing the temperature. Fish held in the spring/fall pattern or at a constant temperature of 15 or 26 C revealed no plasma cortisol concentration differences due to acclimation temperature, but hormone concentrations in all groups increased by about 4.5 fold following a 2-h confinement. Fish held on a summer pattern had differences in both the initial cortisol samples and those measured after confinement. Acclimation to a constant 35 C resulted in significantly higher initial cortisol concentrations, but these levels did not increase following confinement. The inability of the fish held at 35 C to respond to the confinement was thought to be due to the constant thermal stress, resulting in an inadequate interrenal reserve. Physiological consequences due to the diurnal physiochemi-cal cycling in ponds needs further attention.  相似文献   

Evaluation of Various Concentrations of Dietary Protein and Animal Protein for Pond-Raised Channel Catfish Ictalurus punctatus Fed to Satiation or at a Restricted Rate     

Edwin H.  Robinson  Menghe H.  Li  Bruce B.  Manning 《Journal of the World Aquaculture Society》2000,31(4):503-510

A factorial experiment was conducted to evaluate effect of dietary protein (28% or 32%), animal protein (0, 3, or 6%), and feeding rate (satiation or >90 kg/ha per d) on production characteristics, processing yield, and body composition of pond-raised channel catfish Ictalurus punctatus . Fingerling channel catfish (average weight: 55 g/fish) were stocked into 60, 0.04-ha ponds at a rate of 18,530 fish/ha. Five ponds were used for each dietary treatment. Fish were fed once daily to satiation or no more than 90 kg/ha per d for 147 d. Fish fed at a rate of >90 kg/ha per d consumed about 85% of the amount of feed consumed by fish fed to satiation. Dietary protein did not affect the total amount of feed fed, amount of feed consumed per fish, weight gain, feed conversion efficiency, or fillet protein. Animal protein had no effect on the total amount of feed fed, amount of feed consumed per fish, weight gain, or fillet protein and ash. Fish fed a diet containing 6% animal protein converted feed more efficiently than fish fed diets containing 0% and 3% animal protein. Fish fed to satiation daily consumed more feed, gained more weight, converted the feed less efficiently, and had a higher carcass yield, a higher level of visceral fat as compared to fish fed at a rate of >90 kg/ha per d. Feeding rate had no effect on fillet protein. Results from this study indicated that both a 28% and a 32% protein diet with or without animal protein provided the same growth rate of channel catfish raised in ponds from fingerlings to marketable size if feed is not restricted below a maximum rate of 90 kg/ha per d. Even though there were some interactions among the three factors evaluated, dietary protein levels of 28% to 32% and animal protein levels of 0% to 6% do not appear to markedly affect carcass yield and fillet proximate composition of pond-raised channel catfish.  相似文献   

Comparison of Channel Catfish,Ictalurus punctatus,and Blue Catfish,Ictalurus furcatus,Fed Diets Containing Various Levels of Protein in Production Ponds     

Menghe H. Li  Edwin H. Robinson  Craig S. Tucker  Daniel F. Oberle  Brian G Bosworth 《Journal of the World Aquaculture Society》2008,39(5):646-655

A comparative study was conducted on growth and protein requirements of channel catfish, Ictalurus punctatus, and blue catfish, Ictalurus furcatus. Four diets containing 24, 28, 32, or 36% protein were fed to both channel (initial weight 6.9 g/fish) and blue (6.6 g/fish) catfish for two growing seasons. There were significant interactions between dietary protein and fish species for weight gain and feed conversion ratio (FCR). No significant differences were observed in weight gain of channel catfish fed various protein diets, whereas higher protein diets (32 and 36%) resulted in better weight gain in blue catfish than lower protein diets (24 and 28%). No consistent differences were observed in the FCR of channel catfish fed various levels of dietary protein, whereas significantly higher FCRs were noted in blue catfish fed the 24 and 28% protein diets compared with fish fed 32 and 36% protein diets. Regardless of dietary protein levels, blue catfish had higher carcass, nugget, and total meat yield, and higher fillet moisture and protein, but lower fillet yield and fillet fat. Regardless of fish species, fish fed the 36% protein diet had higher carcass, fillet, and total meat yield than fish fed the 28 and 32% protein diets, which in turn had higher yields than fish fed the 24% protein diet. It appears that blue catfish can be successfully cultured by feeding a 32% protein diet.  相似文献   

Dermatosis associated with Listrophorus gibbus in the rabbit     

A. Patel  K. J. E. Robinson 《The Journal of small animal practice》1993,34(8):409-411

A dermatosis associated with Listrophorus gibbus, a pelage mite, is described in the rabbit. The case details of four domestic rabbits are described including diagnostic investigations, treatment, and successful recovery.  相似文献   

Immunohistochemical detection of porcine reproductive and respiratory syndrome virus using colloidal gold.   总被引：11，自引：2，他引：9       下载免费PDF全文

R Magar  R Larochelle  Y Robinson    C Dubuc 《Canadian journal of veterinary research》1993,57(4):300-304

Two cytopathic agents were isolated on porcine alveolar macrophages following inoculation with homogenates of lung tissues from pigs showing respiratory problems. These isolates were identified as porcine reproductive and respiratory syndrome (PRRS) virus isolates by indirect immunofluorescence using a PRRS virus (PRRSV) specific monoclonal antibody (MAb) and were designated as LHVA-92-1 and LHVA-92-2. Immunogold electron microscopy using a porcine PRRS positive serum pool and protein A-gold resulted in an intense labelling of aggregates of viral particles. Dark specific cytoplasmic staining of porcine alveolar macrophages infected with both virus isolates could be observed by immunogold silver staining (IGSS) using the specific MAb. This method proved effective in detecting PRRSV antigens in several ethanol-fixed tissues of piglets intranasally inoculated with the supernatants of macrophages infected with each isolate. Immunogold silver staining was also successfully used for the detection of PRRSV antigens on sections of formalin-fixed paraffin-embedded lung tissues and on frozen sections of lungs. The present results indicate that colloidal gold may be useful for the identification and immunohistochemical detection of PRRSV in tissues.  相似文献