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991.
K. Köprücü 《Aquaculture Nutrition》2012,18(6):662-672
In the present study, it was examined whether variability in chemical composition of different cottonseed (Nazilli‐M39, Nazilli‐84 and Çukurova‐1518) meals (CSMs) and sunflower (Sanbro, Isera and Coban) meals (SFMs) had any effects on digestibility when fed to grass carp. Protein and energy digestibility of CSMs (83.2–86.8%; 88.7–92.5%) and SFMs (78.9–83.1%; 88.4–92%) had a coefficient of variation of 1.96% (CSMs) and 1.52% (SFMs) for protein and 1.93% (CSMs) and 1.82% (SFMs) for energy digestibility. Sum of amino acids digestibility of CSMs (83.1–86.5%) and SFMs (78.9–83.4%) had a coefficient of variation of 1.85% and 2.47%, respectively. Protein and energy digestibility of CSMs and SFMs was significantly positive affected by a range of compositional features including protein or sum of amino acids and phosphorus content, and significantly negative affected by fiber and carbohydrate contents in the test ingredients. This suggested that fiber and carbohydrate contents of CSMs and SFMs may also be influencing the nutritional value of its own protein or sum of amino acids. In conclusion, the relationship between plant protein meals protein content and its digestible value provides a good support for the development of a system of grain segregation by protein content and ingredient pricing according to that protein content. 相似文献
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994.
Thermographic assessment of scab disease on apple leaves 总被引:1,自引:0,他引:1
Phytopathogenic fungi may affect both the cuticular and the stomatal conductance of plant tissue resulting in significant
modifications of leaf temperature. Venturia inaequalis colonizes apple leaves below the cuticle (subcuticularly) causing scab disease. The suitability of digital infrared thermography
for sensing and quantifying apple scab was assessed by investigating the effects of V. inaequalis on the water balance of apple leaves in relation to the disease stage and the severity of scab. Transpiration was measured
by infrared thermo-imaging to evaluate spatial heterogeneity of the leaves in response to localized infections. Fungal development
was assessed microscopically. Subcuticular growth of the pathogen caused localized decreases in leaf temperature before symptoms
appeared that significantly increased the maximum temperature difference (MTD) of leaves. The MTD increased with scab development
and was strongly correlated to the size of infection sites (r2linear = 0.85) and overall disease severity (% diseased leaf area, r2square = 0.71). In later stages of the disease, the MTD decreased because of leaf senescence. Thermographic measurements revealed
differences in disease severity resulting from disease stage, resistance of host tissue and differences in the aggressiveness
of V. inaequalis isolates. Subcuticular growth of the pathogen was beyond the area of conidia production, therefore, the area of leaf with
increased transpiration was larger than the scab lesions; the proportion decreased from >70% in the early stages to <20% for
mature lesions. Leaf transpiration was increased by all stages of scab development, therefore, MTD may be used not only for
the differentiation between diseased and non-diseased leaves, but also for disease quantification, e.g. in screening systems
and monitoring in precision agriculture. 相似文献
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997.
Ferbal Özkan-Yılmaz Arzu Özlüer-Hunt Suna Gül Gündüz Mehmet Berköz Serap Yalın 《Fish physiology and biochemistry》2014,40(2):355-363
In this study was evaluated potential protective effect of organic selenium (Se) on heavy metal stress induced by lead (Pb) in Cyprinus carpio. For this reason, C. carpio was exposed to sublethal concentration of Pb (1.5 mg/L Pb(NO3)2) for 14 days. The fish were fed a basal (control; measured 0.55 mg/kg Se) diet or a basal diet supplemented with 2.50 mg/kg (measured 2.92 mg/kg Se) organic Se (Sel-Plex®) during the experiment period. The variations in glutathione peroxidase (GSH-Px), glutathione S-transferase (GST) activities, and levels of reduced glutathione (GSH) with malondialdehyde (MDA) in liver and brain tissues of C. carpio were investigated in experimental groups. GSH levels in liver and brain tissues were significantly decreased by exposure to Pb. GST activity was significantly increased (p < 0.05) in liver tissue, but decreased in brain of treated fish by exposure to Pb. Also, GSH-Px activity was significantly increased in liver tissue, but decreased in brain of Pb-treated fish. Levels of MDA were increased in liver and brain of Pb-treated fish. The organic Se treatment for Pb-intoxicated animals improved activities of GSH-Px, GST and levels of MDA within normal limits. Supplemented Se could be able to improve Pb-induced oxidative stress by decreasing lipid peroxidation and regulating antioxidant defense system in tissues. 相似文献
998.
Antonia Concetta Elia Valentina Ciccotelli Nicole Pacini Ambrosius Josef Martin Dörr Marilena Gili Mauro Natali Laura Gasco Marino Prearo Maria Cesarina Abete 《Fish physiology and biochemistry》2014,40(4):1055-1068
Oxytetracycline (OTC) is employed in fish farms to contest or prevent bacterial infections. We simulated an OTC treatment at therapeutic level (75 mg kg?1) and at higher doses (150, 300 mg kg?1) for 10 days. A withdrawal period of 10 days was considered for treated carp, carrying out the same chemical and biochemical analyses (total glutathione, superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione S-transferase and malondialdehyde). The aim was to obtain data related to the carryover in muscle and on variations in the antioxidant indicators in liver and kidney. The OTC residual levels in muscle showed a dose–response relationship. After 10 days of treatment at the recommended dose (75 mg kg?1), the mean value in muscle was 295 μg kg?1. After 10 withdrawal days, residues in all treated groups were not entirely eliminated by fish. Residues of recommended 75 mg kg?1 OTC dose were lower than the maximum permitted by EEC regulation: 100 μg kg?1. Disturbance in the antioxidant systems in liver and kidney was recorded in (150, 300 mg kg?1) carp, as well as during the withdrawal period. A lowered superoxide dismutase activity and higher levels of catalase, glutathione peroxidase, glutathione reductase and glutathione were evaluated in liver, while in kidney only higher malondialdehyde and glutathione S-transferase concentrations were recorded for 300 mg kg?1 dose. The therapeutic OTC dose exerted lower effects, and only in liver, enhancement of GPx and GR activities was recorded. After the withdrawal period, altered antioxidant responses in tissues were restored for all three OTC doses. 相似文献
999.
J. Pohjankukka S. Tuominen J. Pitkänen T. Pahikkala J. Heikkonen 《Scandinavian Journal of Forest Research》2018,33(7):681-694
Digital maps of forest resources are a crucial factor in successful forestry applications. Since manual measurement of this data on large areas is infeasible, maps must be constructed using a sample field data set and a prediction model constructed from remote sensing materials, of which airborne laser scanning (ALS) data and aerial images are currently widely used in management planning inventories. ALS data is suitable for the prediction of variables related to the size and volume of trees, whereas optical imagery helps in improving distinction between tree species. We studied the prediction of forest attributes using field data from National Forest Inventory complemented with ad hoc field plots in combination with ALS and aerial imagery data in Aland province, Finland. We applied feature selection with genetic algorithm and greedy forward selection and compared multiple linear and nonlinear estimators. Maximally around 40 features from a total of 154 were required to achieve the best prediction performances. Tree height was predicted with normalized root mean squared error value of 0.1 and tree volume with a value around 0.25. Predicting the volumes of spruce and broadleaved trees was the most challenging due to small proportions of these tree species in the study area. 相似文献
1000.
Sofia Bäcklund Joachim Strengbom Göran Thor 《Scandinavian Journal of Forest Research》2018,33(3):245-254
Managed forest stands are typically younger and structurally less diverse than natural forests. Introduction of non-native tree species might increase the structural changes to managed forest stands, but detailed analyses of tree- and stand-structures of native and non-native managed forests are often lacking. Improved knowledge of non-native forest structure could help clarify their multiple values (e.g. habitat for native biodiversity, bioenergy opportunities). We studied the structural differences between the introduced, non-native Pinus contorta and the native Pinus sylvestris and Picea abies over young forest stand ages (13–34 years old) in managed forests in northern Sweden. We found that P. contorta stands had greater mean basal areas, tree heights, diameters at breast height, and surface area of living branches than the two native species in young stands. The surface area of dead attached branches was also greater in P. contorta than P. abies. Although this indicates greater habitat availability for branch-living organisms, it also contributes to the overall more shaded conditions in stands of P. contorta. Only one older 87 years old P. contorta stand was available, and future studies will tell how structural differences between P. contorta and native tree species develop over the full forestry cycle. 相似文献