1. Diets containing a freeze‐dried tannin extract from faba beans (Vicia faba L.) at concentrations of 0, 8 and 16 g/kg were fed to growing chicks and rats.
2. Chicks fed on the tannin‐containing diets exhibited a high mortality and significant decreases in body‐weight as well as lower food intakes and higher food intake:weight gain ratios (P<0.01). In rats there was no mortality but the growth and food intake were adversely affected (P< 0.05).
3. Histological changes occurred in the ileal mucosa of chicks. Atrophy and shortening of villi with distortion of their architecture were observed. Similar histological disorders but less pronounced were also found in rats.
4. Histopathology of the liver of both chicks and rats showed an hydropic degeneration of hepatocytes, clearly more severe in the former than in the latter. 相似文献
This work has evaluated the effects of thermally dried (TDS) or composted (CDS) dewatered sewage sludge on β-glucosidase activity,
total (TCH) and extractable (ECH) carbohydrate content, microbial biomass carbon and basal respiration of soils from limestone
quarries under laboratory conditions. Two doses (low and high) of the dewatered sludge (DS) or of the respective TDS or CDS
were applied to a clayey and a sandy soil, both coming from working quarries. The soil mixtures and the controls (soils with
no added sludge) were incubated for 9 months at 25°C and 30% of field capacity. The addition of sludge increased all the studied
soil parameters, and the increase depended on the amount of sludge. Except in the case of TCH and ECH, the enhancing effect
decreased with time, but at the end of incubation, parameters of the treated soils were higher than those of the control.
The rank order of the initial stimulating effect was soil–TDS ≥ soil–DS ≥ soil–CDS, and probably, this order depended on the
proportion of stable organic matter, which was the lowest in the TDS. Values of metabolic quotient (qCO2) were higher at the lower dose, and they did not change during incubation in the CDS-treated soils. Both TCH and ECH were
the parameters with the greatest significant sludge and dose effects. Basal respiration, microbial biomass carbon and β-glucosidase
activity were the best measured parameters in distinguishing the long-term effects of the three sludge types over the soils. 相似文献
Seven different methods of administering ivermectin to gazelles were compared: subcutaneous injection, direct oral administration, administration in individual feeds, administration in a herd feed, direct oral administration of a second ivermectin formulation, administration in individual water supplies, and administration in the herd's water supply. The first five treatments were effective, as monitored by faecal egg count reduction tests, and administration in individual feeds or in a herd feed avoided the need to capture the animals, with the attendant risk of mortality. Of the factors associated with the recipients (species, sex, age and inbreeding coefficient) age was the only significant factor for the efficacy of the treatment. Oral or subcutaneous, individual or collective, and direct or indirect administrations were equally satisfactory for the treatment of all the parasite groups studied. Only when parasitic problems were due to Nematodirus species did direct administration to individual animals appear to be preferable. 相似文献
Initial results demonstrating the feasibility of a multiplexed liquid array immunoassay for foot-and-mouth disease viral antigen detection and simultaneous serotype differentiation are presented. Serotype-specific antibodies from rabbit and guinea pig hyperimmunesera were isolated and prepared for use in a multiplexed, bead-based assay. The performance of all of the available antibodies as both capture and detector reagents was evaluated in the multiplexed system to establish a combination exhibiting the highest homotypic responses and lowest heterotypic reactions. The multiplexed assay was evaluated against inactivated cell culture supernatant samples of the same subtype as the virus used to raise the capture and detector antibodies. Distinct serotype differentiation was observed, except in the case of serotype SAT1. Subsequently, cell culture supernatant samples from a larger pool of viral subtypes were analyzed. Distinct serotype differentiation was obtained when analyzing cell culture supernatant samples from viral serotypes C, Asia, and SAT3, irrespective of the subtype. However, limitations of the current antibody pairs were realized in some inconclusive results obtained when analyzing samples from a broader range of O, A, and SAT2 subtypes. The results obtained in this initial study will be used to further optimize the assay using polyvalent or monoclonal antibodies and move toward the analysis of clinical samples. 相似文献
Ecophysiological simulation models provide a quantitative method to predict the effects of management practices, plant characteristics and environmental factors on crop and weed growth and competition. The INTERCOM interplant competition model was parameterised, calibrated by monoculture data for three cowpea (Vigna unguiculata) genotypes that differed in growth habit, common sunflower (Helianthus annuus) and common purslane (Portulaca oleracea), and used to simulate competition of cowpea cover crops with sunflower or purslane. The simulation results were compared with observations from field competition experiments in 2003 and 2004. INTERCOM more accurately simulated actual field data for the competition of cowpea genotypes and sunflower than companion field experiments for the competition of cowpea and purslane. The validated simulation model of cowpea and sunflower at two densities was used to study the effects of cowpea growth habit on final biomass production of cowpea and sunflower. The model suggested that erect growth habit was more competitive than semi‐erect and prostrate growth habit, when cowpea genotypes were grown with sunflower. Cowpea leaf area distribution was important to higher cowpea biomass production, while cowpea height growth was important to reduce sunflower biomass. Our simulation approach is suggested as a method for crop breeders to gauge the likely success of selection for competitive crops before undertaking expensive long‐term breeding experiments. 相似文献
Objective To determine the regional incidence and effectiveness of treatment of failure of passive transfer (FPT) in foals. Design A study of disease incidence. Animals Eighty-eight foals and 57 mares from four studs in the practice area of the Rural Veterinary Centre were tested. Procedure Foals were tested for their serum IgG and total serum protein (TSP) concentration within the first 72 hours of life. Colostrum was collected from mares and specific gravity determined. FPT and partial failure of passive transfer (PFPT) of immunoglobulins was diagnosed when serum IgG concentrations were < 4 g/L and 4 to 8 g/L respectively. Owners of foals diagnosed with FPT were offered treatment with 1 to 2 L plasma (TSP > 70 g/L); 9 (64%) of the affected foals were treated. Results Fourteen foals (16%) had FPT whereas 15 (17%) had PFPT. There were significant differences between the mean TSP concentration in foals with FPT (42.6 ± 4.2 g/L), PFPT (48.1 ± 3.9 g/L) and those acquiring adequate passive immunity (58.9 ± 5.5 g/L) (P < 0.01). Sixteen (29%) mares had pre-suck colostral specific gravity < 1.060 and 12 (71%) foals raised by these mares had FPT or PFPT. The incidence of severe disease (categorised by a sepsis score > 11, positive culture of bacteria from blood or disease requiring hospitalisation) in all foals in the first 2 months of life was 10%. However, none of the nine foals with FPT that received plasma experienced severe disease. In contrast, foals with PFPT had an increased susceptibility to severe disease (P < 0.001) when compared with normal foals. Conclusion Treatment of foals with FPT may reduce the subsequent incidence of severe disease. Pre-suck colostral specific gravity and foal TSP may be used to predict the likelihood of FPT and PFPT. Even though the number of foals studied is small the results highlight the importance of optimal management practices in reducing the incidence of FPT and disease associated with this process. 相似文献