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171.
Tropical Animal Health and Production - This study aimed to estimate the genetic parameters of milk (305-day milk yield (MY305)), growth (weaning weight (WW), yearling weight (YW), and weight at...  相似文献   
172.
Flavobacterium columnare is an important pathogen of freshwater fish, implicated in skin and gill disease, often causing high mortality. An outbreak of skin disease in fingerling and adult Nile tilapia, Oreochromis niloticus (L.), cultivated in a recirculation system, was investigated. Four strains were isolated and characterized by biochemical reactions, enzyme production, fatty acid profile and analysis of the 16S-23S rDNA intergenic spacer region. All strains were identified as F. columnare. Experimental infection assays with one of these strains (BZ-5-02) were conducted and pathogenicity (by intramuscular route) was demonstrated in Nile tilapia and channel catfish, Ictalurus punctatus (Rafinesque). This is the first report of characterization of Brazilian strains of F. columnare.  相似文献   
173.
Accessions of Gossypium spp., some of them never previously tested, were evaluated for resistance to a local isolate of Meloidogyne incognita race 3 in greenhouse experiments. Nematode infection was characterized based on the galling and egg mass indexes and the reproduction factors (RF). Root‐knot nematode reproduction among the newly tested accessions varied from highly susceptible (AS0188, AS0189) to moderately resistant (MT123 no. 3), and some accessions showed highly reduced nematode reproduction (CIR1343, CIR1348, Fai Mui). Histological observations of two resistant accessions (G. barbadense CIR1348 and G. hirsutum TX‐25, respectively) showed that resistance occurs through a two‐stage mechanism in the first accession and through a single‐stage mechanism in the second. Parasitism is blocked early after second‐stage juvenile (J2) penetration or during its initial tissue migration (CIR1348) and the development of later‐stage juveniles into female adults is suppressed at a later stage (TX‐25 and CIR1348). Fluorescence and bright light microscopy showed that root cells surrounding nematodes exhibit a hypersensitivity‐like reaction, with the accumulation of presumably phenolic compounds and the presence of necrotic cells that limit the development of nematodes and the formation of giant cells. Underdeveloped giant cells with degenerated cytoplasmic content were found in small numbers in CIR1348 and in large numbers in TX‐25, along with deformed nematodes. The full characterization of the defence mechanisms of novel sources of resistance to the root‐knot nematode in cotton constitutes a first step towards their use in crop improvement.  相似文献   
174.
Objectives To investigate the effects of levomepromazine and different desflurane concentrations upon electrocardiographic variables. Animals Twenty adult mongrel dogs of both sexes weighing 6–28 kg. Methods Dogs were divided into two groups of 10 animals. Group 1 received 1 mg kg?1 IV of levomepromazine and 15 minutes later anesthesia was induced with propofol (3 mg kg?1 IV). Desflurane end‐tidal concentration was set at 1.6 MAC. After 30 minutes at this concentration, measurements were taken and the end‐tidal concentration was reduced to 1.4 MAC. Thereafter, it was reduced to 1.2 and then 1.0 MAC at 15‐minute intervals. The same procedure was followed for group 2, except that levomepromazine was replaced with 0.2 mL kg?1 of 0.9% saline solution and more propofol was needed for induction (7 mg kg?1). The animals' body temperature was maintained between 38.3 and 39 °C using a heating pad. The electrocardiographic tracing was obtained from lead II throughout the experimental period. The measurements were taken immediately before the administration of levomepromazine or placebo (T1), 15 minutes after pre‐medication (T2) and 30 minutes after the establishment of 1.6 MAC (T3). The other measurements were made at the concentrations of 1.4, 1.2, and 1.0 MAC, respectively (T4?6). The numerical data were submitted to analysis of variance plus F‐test (p < 0.05). Results The dogs that received levomepromazine had a decrease in heart rate. However, in both groups it increased with desflurane administration. Levomepromazine, in association with desflurane, did not induce significant electrocardiographic changes, and all mean values (except P‐wave duration) were within the reference range for this species. Conclusions and clinical relevance This study documented that levomepromazine, in association with desflurane, does not induce significant changes in electrocardiographic variables, suggesting that this drug combination has minimal effect on myocardial conduction.  相似文献   
175.
After one clinical case that evidenced the outbreak, a complete screening by intradermal tuberculin test was performed in one goat herd in Brazil. The herd was composed by 500 animals and 83 of them (16.6%) showed to be reactive to the comparative double cervical intradermal test. Four months after the test, all the 83 reactive animals were slaughtered and blood samples were collected from 45 of them, for serological assays. From those 45, 32 were randomly chosen for necropsy and histopathological and bacteriological procedures were conducted. Histopathology evidenced at least one characteristic lesion of tuberculosis in each animal, with typical granulommas where acid-fast bacilli (AFB) could be observed. Bacteriology was positive for Mycobacterium bovis in 22 samples (68.7%), therefore confirming the etiology of the outbreak. Sera of 45 animals plus 20 other from a certified free tuberculosis farm were tested in an ELISA using the recombinant M.bovis protein MPB70 as capture antigens. From those, 43 were reactive to the test, with high ODs results, considering a cut-off point established by ROC curve analyzing results (cut-off = 0.8; mean = 0.55; range: 0.157–1.357). These results suggest that MPB70-ELISA can be considered as a reliable tool to diagnose tuberculosis in goat herds, since this assay was capable to correctly detect 95.6% of the animals here examined.  相似文献   
176.
The topical antiinflammatory activity of three extracts at increasing polarity (n-hexane, chloroform, and methanol) from the leaves of Rosmarinus officinalis L. (Labiatae) has been tested using the croton oil ear test in mice. Both the n-hexane and the chloroform (CE-1) extracts from the leaves showed a dose-dependent activity, the last one possessing an antiinflammatory potency similar to that of indomethacin, the nonsteroidal antiinflammatory drug used as a reference drug (ID50 = 83 and 93 microg/cm2, respectively). The bioassay-oriented fractionation of CE-1 led to the identification of tritepenes, ursolic acid, oleanolic acid, and micromeric acid as the main antiinflammatory principles. Furthermore, the CE-1 extract obtained from the residue of the steam distillation of the leaves (extract A) showed the same antiinflammatory potency of CE-1, suggesting this waste product as a source of antiinflammatory products.  相似文献   
177.
One of the current challenges of global fish farming is developing plant‐based proteins as a feasible substitute for fishmeal in the formulation of aquafeeds. Substitution levels of fishmeal with hydrolyzed soybean meal (HSM) in diets for silver catfish (Rhamdia quelen) were evaluated for growth, protein metabolism and antioxidant activity. The experiment was carried out in a recirculation system of 20 tanks of 250 L. A total of 300 silver catfish juveniles were used to compose five treatments and four replicates per treatment. Levels of soybean hydrolysate (0%, 5%, 10%, 15% and 20%) were tested in diets (39% protein and 3,500 Kcal) for 60 days. Silver catfish growth was higher at all inclusion levels of HSM when compared to the control diet. No change was shown for body protein deposition. The production of nitrogenous compounds in the liver and muscle was also unaffected by any of the diets. The diet containing 20% HSM promoted an increase in the amounts of non‐protein thiols in the gills and brain. The HSM substitution levels of up to 20% of fishmeal in the diet increases growth and contributes to silver catfish antioxidant activity.  相似文献   
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