Acute and sublethal toxicity of novaluron, a novel chitin synthesis inhibitor, to Leptinotarsa decemlineata (Coleoptera: Chrysomelidae)

The acute and sublethal toxicities of novaluron, a novel chitin synthesis inhibitor, to a laboratory-reared insecticide-susceptible strain of Colorado potato beetle, Leptinotarsa decemlineata (Say), were determined. Novaluron exhibited excellent residual (120 h LC(50) = 0.42 mg litre(-1)) and good direct contact (120 h LC(50) = 27 mg litre(-1)) activity against second-instar larvae (L2). Hatch of eggs exposed by direct contact to novaluron solutions > or =100 mg litre(-1) was significantly reduced, as was the ability of emerged first-instar larvae to moult. L2 from eggs exposed to > or =100 mg litre(-1) novaluron weighed significantly less (P < 0.0001) than those from untreated eggs. However, L2 from eggs treated with 1 mg litre(-1) novaluron weighed significantly more (P < or = 0.05) than those from untreated eggs, suggesting novaluron can have a hormetic effect on L decemlineata larval development. Leptinotarsa decemlineata mating pairs fed foliage treated with novaluron at 25 or 75 g AI ha(-1) produced approximately 25% fewer egg masses and eggs per mass. Hatch of eggs on treated foliage was almost completely suppressed, and longevity of male beetles was reduced by approximately 50% when fed foliage treated with novaluron at 75 g AI ha(-1).     

Effects of Lactobacilli and lactose on Salmonella typhimurium colonisation and microbial fermentation in the crop of the young turkey

1. Three experiments were performed to examine the effects of Lactobacilli and lactose on microbial fermentation and Salmonella enterica serovar Typhimurium colonisation in the crop of the young turkey. 2. The following carboxylic acids were detected in the crop ingesta: formic, acetic, butyric, lactic, valeric, caproic, oxalic, phenyl acetic, succinic and fumaric; propionic, isobutyric and isovaleric acids were not detectable. 3. At the beginning of the night, there were considerable quantities of ingesta in the crop of young turkeys. During the scotophase, there were progressive reductions in the contents and pH. Moreover, there were linear increases in the concentration of lactic, valeric and caproic acids (by approximately 7-fold over 8 h). Much smaller changes in crop pH were observed in the study where dietary treatments of Lactobacilli were not included. 4. Chronic addition of lactose or Lactobacilli to the diet exerted modest effects on the carboxylic acid concentration in the crop contents but did not consistently influence colonisation of the crop by Salmonella enterica serovar Typhimurium. 5. Young turkeys confine eating to the hours of illumination (photophase) with a peak in consumption prior to the subjective dusk.     

The occurrence and distribution of Salmonella enteritidis and other serovars on California egg laying premises: a comparison of two sampling methods and two culturing techniques

Between the summer of 1998 and the winter of 2000, Salmonella analysis was performed on 2128 single and 532 pooled manure drag swabs obtained from 133 California commercial egg laying farms. The isolation of Salmonella from all rows and from all flocks using single or pooled swabs was 80% and 92%, respectively. Hence, there was no statistical difference between single vs. pooled swabs in terms of identifying Salmonella on a row or flock basis. A total of 14 serogroups comprising 44 serotypes were isolated from 123 of 133 farms. When the top 10 serotypes were considered, there was no significant difference in the range of serotypes isolated by the two culturing methods. The overall S. enteritidis prevalence for California flocks was 10.5% (14/133). The overall row prevalence for S. enteritidis for all the farms was 1.1% (24/2128), and the overall pool prevalence was 2.4% (13/532). Sixty percent (12/20) of the S. enteritidis isolates from the positive farms were phage type 4, and 40% (8/20) represented five other phage types (1, 6B, 7, 8, and 28).     

Bartonella quintana in Ethiopian lice

Head and clothing lice from Jimma, Ethiopia were investigated for pathogenic bacteria. Genomic DNA from pools of lice was subjected to PCR analysis for Bartonella spp., Borrelia spp. Coxiella burnetii, Rickettsia spp. and Yersinia pestis. All 102 lice pools were negative for the afore mentioned pathogens, with the exception of Bartonella species found among 6 of 65 (9.2%) head lice pools and1 of 33 clothing lice pools. Identification was achieved by sequencing the ribosomal intragenic transcribed spacer region (ITS), revealing all to be Bartonella quintana. Although established as a clothing louse-borne infection, typically causing chronic bacteraemia, trench fever, bacillary angiomatosis and endocarditis, this has only been rarely reported among head lice. The higher numbers of infected head lice pools compared with clothing lice suggests their competence for maintaining this infection within Ethiopia.     

Susceptibility of <Emphasis Type="Italic">Megachile rotundata</Emphasis> to insecticides used in wild blueberry production in Atlantic Canada

The alfalfa leafcutting bee, Megachile rotundata (Fabricius), is a valuable wild and managed pollinator of lowbush blueberry (syn. ‘wild blueberry’, Vaccinium angustifolium Ait.), in Atlantic Canada. As some insecticides may present a hazard to pollinators, we assessed the susceptibility of M. rotundata to insecticides used or projected for future use in lowbush blueberry pest management. In topical direct contact bioassays, adults were susceptible to phosmet, spinosad, spinetoram, and deltamethrin. Based on findings from these laboratory studies, it appears that when used at recommended or projected application rates, each of these compounds poses a hazard to M. rotundata by direct contact. In a second experiment, eggs and larvae were collected in the field and their pollen provisions were treated with deltamethrin, flubendiamide, and spinetoram at field relevant concentrations. Larvae treated with deltamethrin and spinetoram in the laboratory either died before spinning a cocoon or, in the case of spinetoram, occasionally pupated without spinning a cocoon. Flubendiamide was not toxic to adult M. rotundata by direct contact and had no effect on larval survivorship, or time to complete cocoon spinning. Emergence after overwintering was relatively poor overall, but there was no effect of treatment. Based on these results, flubendiamide appears safe to use in the presence of M. rotundata, whereas the other insecticides we tested may pose a hazard.     

Bilateral ovarian adenocarcinoma in a mare causing haemoperitoneum and colic

Abstract

CASE HISTORY: A 13-year-old Thoroughbred mare was presented with a history of mild colic over 3 days. This colic had acutely exacerbated and was unresponsive to analgesic treatment, and was referred to Massey University Veterinary Teaching Hospital.

CLINICAL FINDINGS: On examination the heart rate was 100 beats per minute, and mucous membranes were pale and tacky. A large mass was detected on transrectal palpation in the caudal abdomen to the left of midline. Explorative laparotomy revealed severe haemoperitoneum and several masses that were associated with the reproductive tract. The mare was then subject to euthanasia. On post-mortem examination, adjacent and attached to each ovary were soft, lobulated dark red masses up to 200 mm in diameter. Similar masses were present in the omentum and on the peritoneal surface of the diaphragm and the serosa of the spleen and liver. Histopathology revealed that the neoplastic component of the masses comprised proliferating cuboidal to columnar cells forming disorganised acini and cords separated by dense collagenous stroma. Immunohistochemistry showed the neoplastic cells were positive for cytokeratin AE1/AE3 and vimentin, but negative for cytokeratin 7 and inhibin α.

DIAGNOSIS: Bilateral ovarian adenocarcinoma with transcoelomic metastasis and terminal decompensation due to rupture of a neoplastic mass and consequent haemoperitoneum.

CLINICAL RELEVANCE: To the authors' knowledge, bilateral ovarian adenocarcinoma has not been previously reported in a horse. Ovarian adenocarcinoma should be considered when horses present with haemoperitoneum and colic. Further research is required on the immunohistochemical differentiation of adenocarcinoma of ovarian and intestinal origin in the horse.     

Estimating Foliar Nitrogen Concentration of Heather (Calluna vulgaris) from Field and Laboratory Spectra

Regional botanical surveys supported by field experiments suggest that atmospheric nitrogen deposition threatens the balance between species and causes loss of biodiversity within plant communities. Methods are required to monitor the nitrogen status of vegetation at a landscape scale and therefore the potential for ecological change. Remote sensing has the potential to monitor a number of plant biophysical and chemical variables, but its application to monitor the nitrogen status of native vegetation remains limited and untested. Using field spectroscopy, canopy reflectance measurements were taken from two heathland field sites and heather (Calluna vulgaris) plants grown in a greenhouse. The nitrogen concentration was determined through destructive sampling and chemical analysis. Stepwise multiple regression analysis was used to identify the wavebands most associated with nitrogen concentration and despite high variation in the selected wavebands between the three datasets, most of these wavebands were associated with nitrogen and protein absorption features within the spectral region 1,990–2,170 nm. Results highlight the potential of remote sensing as a bio-monitoring technique to estimate foliar nitrogen status in native plants.     

Response to dietary phosphorus deficiency is affected by genetic background in growing pigs

Concern over the environmental effect of P excretion from pig production has led to reduced dietary P supplementation. To examine how genetics influence P utilization, 94 gilts sired by 2 genetic lines (PIC337 and PIC280) were housed individually and fed either a P-adequate diet (PA) or a 20% P-deficient diet (PD) for 14 wk. Initially and monthly, blood samples were collected and BW recorded after an overnight fast. Growth performance and plasma indicators of P status were determined monthly. At the end of the trial, carcass traits, meat quality, bone strength, and ash percentage were determined. Pigs fed the PD diet had decreased (P < 0.05) plasma P concentrations and poorer G:F (P < 0.05) over the length of the trial. After 4 wk on trial, pigs fed the PD diet had increased (P < 0.05) plasma 1,25(OH)(2)D(3) and decreased (P < 0.05) plasma parathyroid hormone compared with those fed the PA diet. At the end of the trial, pigs fed the PD diet had decreased (P < 0.05) BW, HCW, and percentage fat-free lean and tended to have decreased LM area (P = 0.06) and marbling (P = 0.09) and greater (P = 0.12) 10th-rib backfat than pigs fed the PA diet. Additionally, animals fed the PD diet had weaker bones and also decreased (P < 0.05) ash percentage and increased (P < 0.05) concentrations of 1alpha-hydroxylase and parathyroid hormone receptor mRNA in kidney tissue. Regardless of dietary treatment, PIC337-sired pigs consumed more feed and gained more BW than their PIC280-sired counterparts (P < 0.05) during the study. The PIC337-sired pigs also had greater (P < 0.05) HCW, larger (P < 0.01) LM area, and tended to have (P = 0.07) greater dressing percentage. Meat from the PIC337-sired pigs also tended to have greater (P = 0.12) concentrations of lactate but decreased (P = 0.07) concentrations of total glucose units 24 h postslaughter. Although plasma 1,25(OH)(2)D(3) concentrations were elevated (P < 0.05) in all the animals fed the PD diet, this elevation due to P deficiency tended (P = 0.09) to be greater in the PIC337-sired pigs after 12 wk on the treatment. The PIC337-sired pigs had stronger (P < 0.01) bones with greater ash percentage than the PIC280-sired pigs. The difference in the strength of the radii between the PIC337-sired pigs fed the PA and PD diets was greater than their PIC280-sired counterparts, which resulted in sire line x treatment interactions (P < 0.05). These data indicate differing mechanisms of P utilization between these genetic lines. Elucidating these mechanisms may lead to strategies to increase efficiency of growth in a more environmentally friendly manner.