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31.
Viruses may predispose the respiratory tract to the development of secondary bacterial pneumonia by impairing functions of alveolar macrophages. The effects of bovine respiratory syncytial virus (BRSV) on selected functions of bovine pulmonary alveolar macrophages (PAM) were examined in vitro. Alveolar macrophages were obtained from nonsedated cattle, using a polypropylene tube passed intranasally into the lung. The PAM lavaged from the lung were allowed to adhere to glass coverslips or plastic tissue culture plates, and were exposed to BRSV for 2 hours. Control and BRSV-inoculated PAM were compared at intervals over a 72-hour period for their abilities to phagocytize and kill Staphylococcus epidermidis, rosette with and phagocytize antibody-coated sheep RBC (SRBC), phagocytize latex particles, and influence lysosomal enzyme activity. Challenge exposure with BRSV did not affect the ability of PAM to adhere and did not affect cell viability. There were numerical differences between control and BRSV-inoculated cell populations in phagocytosis and killing of S epidermidis, but these were not significant (P greater than 0.05). There was less than 5% difference in the abilities of control and BRSV-challenged PAM to phagocytize latex beads. When Fc-receptor-mediated phagocytosis of antibody-coated SRBC was compared with controls, BRSV-challenged PAM had significantly (P less than 0.05) impaired phagocytic function, which was maximal 72 hours after BRSV inoculation; the phagocytic impairment occurred in spite of normal Fc-receptor function, as determined by rosetting with antibody-coated SRBC.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
32.
Meloidogyne enterolobii (syn. M. mayaguensis) has been reported to cause severe damage in commercial guava orchards and other plants in Central and South American countries. Considering the risk of introduction and dissemination of this pest in the European region, M. enterolobii was placed on the EPPO A2 list in 2010. The use of non-host fruit species is a recommended strategy to manage root-knot nematodes in infested guava orchards. This study screened 89 plant genotypes from 25 fruit plants of economic importance, plus two susceptible controls (guava and tomato) for its host status to M. enterolobii. Three to eight months after inoculation, nematode reproduction factor (RF) was used to characterize host suitability of fruit crops to this nematode. Ten banana genotypes, six Barbados cherries, one fig, two grape rootstocks and six melons were rated as good hosts for this nematode. Sixteen fruit plants behaved either as non-hosts or poor hosts to M. enterolobii, including assaí, atemoya, avocado, cashew nut, citrus, coconut, grape, jabuticaba, mango, mulberry, papaya, passion fruit, sapodilla, soursop, starfruit and strawberry. For the future, field experiments in areas infested by this nematode are essential to confirm the greenhouse results. These non-host fruit species can replace in the future eradicated guava trees in fields severely infested by this nematode and become an economic option for growers where M. enterolobii is considered a serious problem.  相似文献   
33.
The porcine respiratory disease complex (PRDC) is an increasingly important cause of decreased swine productivity and is characterized by slow growth, decreased feed efficiency, anorexia, cough, and dyspnea. Mycoplasma hyopneumoniae is among the most prevalent and important infectious agents associated with PRDC. Understanding of mycoplasmal pneumonia has been hindered by inadequate diagnostic methods. Many of the currently available tests are relatively insensitive or nonspecific when used in a diagnostic laboratory setting or are too costly or difficult for routine diagnostic use. Several polymerase chain reaction (PCR) assays have been described, but they are not sensitive enough to detect the microorganisms in live pigs, from either nasal or tracheal swabs. A nested PCR using 2 species-specific sets of primers from the 16S ribosomal DNA gave positive results with as little as 80 microorganisms and did not cross-react with other mycoplasma species or with other microorganisms commonly found in the respiratory tract of pigs. This assay was better suited for detection of M. hyopneumoniae from nasal swabs than was conventional PCR. Nasal swab samples were taken at different time periods following experimental challenge of 10 susceptible pigs. Only 2 of the 55 swabs examined gave a positive result with conventional PCR, whereas 30 of the 55 swabs gave a positive result using the nested PCR. Twenty of 40 (50%) nasal swabs from pigs experiencing a respiratory disease outbreak where M. hyopneumoniae had been diagnosed also gave a positive result with the nested PCR. To confirm that the amplified product was specific, 4 nested PCR products were purified, sequences were determined and aligned, and they were confirmed to be from M. hyopneumoniae.  相似文献   
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35.
This study was aimed at determining the effect of raw full-fat soybean in the digestion/absorption of broilers and to evaluate the role of soybean agglutinin (SBA) in the pathogenesis of the runting and stunting syndrome of broilers. Six broiler groups were fed with six experimental diets for 42 days in which the defatted soybean meal of the basal diet was substituted with increasing raw full-fat soybean percentages ranging from 0 to 100%. The results suggested that SBA included in the raw full-fat soybean can play a role in the pathogenesis of the runting and stunting syndrome in broilers since binding and incorporation of SBA to enterocytes were associated with hyperplasia and dysplasia of the intestinal epithelium, as suggested by the progressive increases (P < 0.001) of mitosis/crypt in the duodenum and in the midintestine, as well as by intestinal villi atrophy (P < 0.001) in the duodenum and the midintestine. Indigestion and malabsorption of proteins induced progressive low weight gain (P < 0.001) up to 50% with 100% of raw full-fat soybean in the diet at 42 days. Xanthophylls in serum and skin yellowness were enhanced linearly in the broilers fed 42 days with increasing percentages of raw full-fat soybean in the diet. Increased xanthophylls absorption and decreased protein absorption can be caused by pathological changes in the epithelial intestine triggered by SBA binding and internalization.  相似文献   
36.
Heart diseases in birds are frequent and generate significant production disorders. Morphometry is a valuable tool to provide fundamental information about heart conditions. Few studies have addressed morphological aspects of the heart of ratite birds, such as the Greater rhea. The present study aimed to analyse rhea heart morphometry, comparing young and adult subjects, in order to provide relevant information for the diagnosis of heart disease in this species. Hearts of young (n = 10) and adult (n = 10) female rheas were used in this research. Heart length and width and sternum length were measured using a caliper. Heart length and width and sternum length in adults were approximately three times greater than in young individuals. The left ventricular wall (LVW) was thicker than the right ventricular wall (RVW) at all ages, and the RVW was thicker in adults when compared to young subjects. The basal and middle RVW regions thicken with advancing age, and the thickness of the interventricular septum (ISW) occupies an intermediate position between the LVW and RVW. In general, an increase in rhea heart thickness and size relative to age is observed. The morphometric variations between young and adult rhea hearts observed in the present study may serve as a comparative subsidy for the diagnosis of cardiac abnormalities observed in this species.  相似文献   
37.
38.
The aim of the present study was to determine and to compare through an indirect enzyme linked immunosorbent assay (ELISA) test, the presence of anti-Neospora caninum antibodies in city and farm dogs, as well as in farm cows, and the relationship among them. The correlation between anti-N. caninum antibodies in farm dogs and cattle was also assessed. The research was conducted in the dairy region of Tizayuca, Hidalgo, Mexico. The frequency of anti-N. caninum antibodies was significantly higher in farm dogs (n = 14) (51%) when compared to those from the city (n = 6) (20%) (P < 0.05), suggesting that farm dogs have a higher risk of exposure to the parasite. There was no significant difference in seropositivity between males (n = 11) (39%) and females (n = 9) (33%) (P > 0.05). The frequency of anti-N. caninum antibodies in farm cattle was significantly higher in farms with dogs (n = 158) (58%) when compared to those with no dogs (n = 43) (35%) (P < 0.05). These results suggest the possible transmission of the parasite from dogs to cattle.  相似文献   
39.
Wheat is used in shrimp feed as protein and energy sources, as well as a nutritive binder that promotes water stability. However, wheat may be contaminated with deoxynivalenol (DON or vomitoxin) when wet weather conditions prevail during the growing season. Deoxynivalenol‐contaminated wheat was added to shrimp diet to obtain DON levels of 0.2, 0.5, and 1.0 ppm. Pelleted diets were fed 3 times daily until satiation to Pacific white shrimp Liropenaeus vanna‐mei. Biological performance (live weight, weekly growth increment, feed conversion ratio, and survival) was determined biweekly for 16 wk. Histological characteristics of shrimp were determined on samples obtained after 8 and 16 wk of growth. The DON levels in ground wheat, feed mash, pellets, and freeze‐dried shrimp were determined using thin layer and high performance liquid chromatography. Deoxynivalenol levels of 0.2, 0.5, and 1.0 ppm in the diet significantly reduced shrimp body weight and/or growth rate. However, the effects of 0.2 and 0.5 ppm DON were manifested at later stages of shrimp growth, and 0.2 ppm DON significantly affected only growth rate and not body weight (P > 0.05). Feed conversion ratio and survival of shrimp fed diets containing 0.2, 0.5, and 1.0 ppm DON were not significantly different from those of shrimp fed the control diet (0.0 ppm DON). After 16 wk of growth, no DON was detected in freeze‐dried shrimp, and no consistent difference was observed in the histological organ profiles of shrimp fed diets containing various levels of DON. Because low levels of DON in the diet can significantly reduce body weight and growth rate of shrimp, feed ingredients should be monitored for DON.  相似文献   
40.
A system was developed to recover pulmonary alveolar macrophages (PAM) from living cattle and to evaluate the function of these cells by measuring bacterial phagocytosis and killing. For the collection of PAM, single-tube and telescoped double-tube pulmonary lavage devices were compared. The total recovery, using these systems, was 70 +/- 10.7% of infused fluid, yielding approximately 87% PAM. The total number of cells per collection was approximately 5 times higher with the single-tube device (6.87 +/- 0.78 x 10(7) cell/ml) than with the telescoped double-tube device (1.3 +/- 0.1 X 10(7) cells/ml). Phagocytosis and intracellular killing of Staphylococcus epidermidis and Staphylococcus aureus by PAM in media suspension and by plastic-adherent PAM were evaluated. In addition, different bacteria-to-macrophage ratios were assessed, as well as the intracellular killing of S epidermidis at periodic intervals. Results showed that over a 3-hour period, similar numbers of both bacteria were phagocytized, but intracellular killing of S epidermidis was more efficient than intracellular killing of S aureus. It also was found (i) that suspended PAM and adherent PAM phagocytized similar numbers of bacteria; (ii) that when the bacteria-to-cell ratio was 10:1, the numbers of phagocytized bacteria and intracellular killing were higher than when the ratio was 1:10; and (iii) that killing of S epidermidis by adherent PAM was directly proportional to incubation time. The time that PAM are in culture affects the phagocytosis and killing of intracellular bacteria, as shown by increased phagocytosis and by intracellular killing of S epidermidis by PAM in suspension for 48 hours or plastic adherent for 60 hours after collection.  相似文献   
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