Host cellular components adhering to the tegument of schistosomes from cattle, buffalo, hippopotamus and lechwe

The teguments of adult Schistosoma mattheei from cattle and buffalo, S. hippopotami from hippopotamus and S. margrebowiei from lechwe were examined by means of scanning electron microscopy for cells possibly engaged in immunological action. Leukocytes were observed on the teguments of the schistosomes from all 4 host species. Although certain of these cells seemed to be fused to the surface membrane of the worms, they did not display pseudopodia. The tegument of certain schistosomes from buffalo exhibited cells the size of platelets with dendritic structures connected to the tegument of the parasite. The results seem to indicate that, as with laboratory hosts, naturally infected domestic and wild hosts are unable to mount an effective cellular response against the tegument of live adult shistosomes. The possible role of platelets in immunology against schistosomes is mentioned.     

Transfusion-associated Babesia gibsoni infection in a dog

A 2.5-year-old spayed female German Shepherd Dog was referred for evaluation of progressive anemia, lethargy, and weight loss. Seventeen days earlier, the dog had received a whole blood transfusion to manage hemorrhage after ovariohysterectomy. Mild fever, splenomegaly, and thrombocytopenia were also identified. Von Willebrand disease and Babesia gibsoni infection were diagnosed. Because of the serologic cross-reactivity of B gibsoni and B canis in the immunofluorescent antibody assay for IgG antibodies against these organisms, polymerase chain reaction amplification of parasite DNA was required to identify the infecting Babesia sp. The source of the B gibsoni infection was traced to an apparently healthy American Pit Bull Terrier blood donor. Despite resolution of clinical signs in the dog of this report, a series of antiparasitic treatments failed to eliminate the B gibsoni infection. Screening of potential blood donor dogs for Babesia spp is becoming increasingly important in the United States.     

Reproductive and Metabolic Responses of Early‐lactating Dairy Cows Fed Different Dietary Protein Sources

Optimal reproduction is very closely tied with optimal nutrition, and early‐lactation diets in cows are critical to successful reproduction and monitoring is important. To evaluate the effects of different dietary protein sources on metabolic parameters and reproductive activity, a total of 36 Italian Friesian early‐lactating dairy cows were assigned for 16 weeks to three dietary treatments as follow: the control diet contained soya bean meal (SBM) as the main protein source, whereas the experimental diets contained faba bean (FB) or pea seeds (PS) as alternative protein sources. Diets were formulated to be isocaloric and isonitrogenous. Cow blood samples were collected, and plasma were analysed for metabolites, biological enzymes, β‐hydroxybutyrate (BHBA) and non‐esterified fatty acids (NEFA). Feeding alternative protein sources had no effects on most metabolic blood profile, except for blood cholesterol, triglycerides and urea. Results from reproductive parameters indicated that cows fed FB diet had a lower insemination index, but a shorter calving to conception period and an improved conception rate and artificial insemination outcome, when compared to cows fed SBM or PS diets. It can be concluded that replacing conventional dietary SBM with alternative protein sources, especially FB, resulted in improved reproductive performances and metabolic parameters in early‐lactating dairy cows.     

Effect of Roller Mill Extraction Rate on the Chapatti-Making Quality of Canadian Flours

The effect of roller mill extraction rate on the chapatti-making potential of Canadian wheat from six different classes was assessed. Objective measurement of texture including pliability, puncturability, and tearing force, in conjunction with color, discerned significant differences due to flour extraction rate as well as wheat class. The 85% extraction yield was determined by sensory panelists to yield the best chapatti. Analyses of objective measurements, HunterLab values L*, a*, and b*, in conjunction with sensory assessments, suggested that the optimum chapatti have a brightness (L*) of 75–79, redness (a*) of 1.5–4.0, and a yellowness (b*) >17. Sensory scoring compared with objective measurement indicated that a tearing force of <4.0 kg was necessary to achieve optimum panelist evaluation of tearing and chewability. The primary reasons for a fair rating were attributable to either a too white and nonwheaty taste for the low extraction flours or, in the case of the 95% extraction material, dark chapattis with a slightly off flavor. No chapatti prepared from any of the wheat classes or varying extraction rate flours resulted in an unacceptable rating. Evidence suggests that removal of low-extraction mill-streams, up to 40%, from a 85% extraction yield flour did not have a detrimental effect on chapatti quality.     

Methods of detection of Chlamydia psittaci in domesticated and wild birds

OBJECTIVE: To study the occurrence of Chlamydia psittaci in domesticated and wild birds and compare the sensitivity of molecular detection with cell culture isolation. DESIGN: Study of cell culture isolation and PCR detection of C psittaci in avian samples. PROCEDURE: Samples were obtained from 485 birds. Domesticated birds were selected at random from pet shops, private aviaries and zoos, while wild birds were captured locally, sampled, and immediately released. Swabs were collected from choanal slit, conjunctiva and cloaca of each bird and pooled. Samples were divided into equal portions for use in PCR dot-blot and cell culture detection. PCR and dot-blot detection was based on the ompB gene. RESULTS: Prevalence of infection varied markedly between flocks of captive birds. It was highest where there were frequent changes in the flock members or where there were many birds confined in small areas. C psittaci was not detected in wild birds or water birds. The sensitivity of cell culture compared to PCR dot-blot detection was 68%. All samples positive by cell culture were also positive by PCR. CONCLUSIONS: PCR-dot blot detection of C psittaci in birds appears to be more sensitive than cell culture isolation in this study. C psittaci infection of birds may occur in clinically normal captive birds.     

Electrical conductivity in the precambrian lithosphere of western canada

The subcrustal lithosphere underlying the southern Archean Churchill Province (ACP) in western Canada is at least one order of magnitude more electrically conductive than the lithosphere beneath adjacent Paleoproterozoic crust. The measured electrical properties of the lithosphere underlying most of the Paleoproterozoic crust can be explained by the conductivity of olivine. Mantle xenolith and geological mapping evidence indicate that the lithosphere beneath the southern ACP was substantially modified as a result of being trapped between two nearly synchronous Paleoproterozoic subduction zones. Tectonically induced metasomatism thus may have enhanced the subcrustal lithosphere conductivity of the southern ACP.     

造纸废渣和养分的改良对北部硬阔叶林土壤表面CO2通量的影响

Safe and economical disposal of paper mill sludge is a key consideration for forest products industry. A study was conducted to examine the effects of amendments of sludge and nutrients on soil surface CO₂ flux (R_s) in northern hardwood forests and to quantify the relat among R₅, soil temperature, and moisture in these stands. The experiment was a randomized complete block design that included sludge-amended, fertilized, and control treatments in sugar maple (Acer saccharum Marsh) dominated hardwood forests in the Upper Peninsula of Michigan, USA. Results showed that R_s was positively correlated to soil temperature (R²=0.80, p<0.001), but was poorly correlated to soil moisture. Soil moisture positively affected the R_s only in the sludge-amended treatment. The R_s was significantly greater in the sludge-amended treatment than in the fertilized (p=0.033) and the control (p=0.048) treatments. The maximum R_s in the sludge-amended treatment was 8.8 μmol CO₂·m⁻²·s⁻¹, 91% and 126% greater than those in the fertilized (4.6 μmol CO₂·m⁻²·s⁻¹) and control (3.9 μmol CO₂·m⁻²·s⁻¹) treatments, respectively. The R_s did not differ significantly between the fertilized and control treatments. The difference in R_s between sludge-amended and the other treatments decreased with time following treatment. Foundation item: The research was funded by a NCASI grant to S.T. Gower. Wang CK was supported by Innovated Talent Program of Northeast Forestry University (2004–07) Biography: WANG Chuan-kuan (1963-), male, Professor in the Ecology Program, College of Forestry, Northeast Forestry University, Harbin 150040, China. Responsible editor: Chai Ruihai     

Epidemiological and clinical investigations into big liver and spleen disease of broiler breeder hens

SUMMARY The epidemiological and clinical features of big liver and spleen disease (BLS) in flocks on two broiler breeder farms were investigated by serology and gross pathology. The most common necropsy findings on farm 1 were splenomegaly and hepatomegaly, with kidney enlargement in some birds. In one flock (farm 1), a decline in egg production began at 40 weeks of age and lasted for 9 weeks. Seroconversion to BLS antigen was first detected at 45 weeks (3.1% of birds) and increased to 72% at 50 weeks, which coincided with clinical recovery in the flock. Antigen was detected before antibody at 44 weeks and persisted at low incidence (<15%). Farm egg production statistics and serology indicated that the disease affected all flocks on the farm. In three of eight flocks, seroconversion was detected in birds before peak production. The birds in the remaining sheds did not seroconvert or become sick until after peak production. On the second farm, sampling began within a flock already experiencing BLS. Clinical signs and pathology were similar to those seen in flocks on farm 1. However, the lesions that were seen in the pancreas in 15% of birds have not been reported previously. BLS antibody was detected in 78%, and circulating antigen in 14%, of sick birds.