A 6‐week growth trial was conducted to investigate the effect of dietary supplementation with maggot meal (MGM) and soybean meal (SBM) on the growth performance and antioxidant responses of gibel carp (GC) and darkbarbel catfish (DC). The basal diet was formulated to contain 114 g kg−1 fish meal (FM) and 200 g kg−1 SBM. The basal diet was supplemented with either 280 g kg−1 FM (Control), 390 g kg−1 MGM or 450 g kg−1 SBM to obtain three isonitrogenous (crude protein: 380 g kg−1) and isocaloric (gross energy: 16 kJ g−1) diets. For GC, a significant decrease in specific growth rate (SGR) was only observed in fish fed the SBM diet compared with the control (P < 0.05). Principal components analysis (PCA) of GC showed a higher similarity in antioxidant response to dietary supplementation with MGM and SBM proteins between liver and intestine, but the DC did not. The present results suggest that supplementing 390 g kg−1 MGM protein to basal diet cause an enhancement of the antioxidant capacity in GC, but supplementing 390 g kg−1 MGM and 450 g kg−1 SBM proteins to basal diets resulted in a significant attenuation of the antioxidant capacity in DC. 相似文献
This study aimed to investigate the optimum dietary carbohydrate/lipid (CHO/L) ratio for fingerling blunt snout bream Megalobrama amblycephala (average initial weight: 6.61 ± 0.03 g). Six isonitrogenous and isoenergetic diets were formulated to contain various CHO/L ratios ranging from 1.62 to 24.20. Each diet was tested in four replicates for 10 weeks. Specific growth rate (SGR), feed conversion ratio and nitrogen and energy retention all improved significantly (P <0.05) as dietary CHO/L ratios decreased from 24.20 to 5.64 but showed little difference (P >0.05) as dietary CHO/L ratios ranged from 2.45 to 5.64. Hepatosomatic index increased significantly (P <0.05) as dietary CHO/L ratios increased, whereas intraperitoneal fat ratio showed an opposite trend (P <0.05). Opposite to moisture content, lipid content of whole body and carcass all increased significantly (P <0.05) as dietary CHO/L ratios decreased. Liver lipid content showed little difference (P >0.05) among all the treatments, while liver glycogen content increased significantly (P <0.05) with increasing CHO/L ratios. High dietary carbohydrate enhanced the activities of liver hexokinase, pyruvate kinase and glucose‐6‐phosphate dehydrogenase but did not induce hyperglycaemia. Based on the second‐order polynomial regression analysis of SGR, the optimal dietary carbohydrate and lipid contents for fingerling blunt snout bream were 291.7 and 81.4g kg−1, respectively, with a corresponding dietary CHO/L ratio of 3.58. 相似文献
This study was conducted to evaluate the effects of dietary thiamin on the physiological status of the juvenile grouper, Epinephelus coioides. Graded levels of thiamin (0.08, 0.50, 2.12, 3.15, 4.63, 12.37 mg thiamin kg−1 diet) were fed to grouper juveniles (mean weight: 16.97 ± 0.14 g) for 10 weeks. Although fish fed the thiamin-deficient (TD)
diet showed no obvious symptoms of thiamin deficiency or increased mortality, those fed the lowest doses of thiamin (0.08
and 0.50 mg thiamin kg−1 diet) had significantly decreased transketolase activity in the liver. In addition, the level of liver thiobarbituric acid
reactive substances in fish fed the TD diet was 33–67% higher than that in fish with the thiamin-supplemented diet. There
were no significant differences in superoxide dismutase activity between the different groups of fish. 相似文献
Different effects of single and repeated application of various rates of phosphogypsum to a crusty meadow chernozemic high-sodium
solonetz with soda salinization formed in the zone of insufficient moistening in the forest-steppe zone of Western Siberia
(the Ishim-Irtysh interfluve area) with the mean annual precipitation of 325 mm are revealed. Repeated phosphogypsum application
provided a higher saturation of the soil exchange complex with exchangeable calcium, deeper desalinization of the soil profile,
and more intensive removal of the exchange products beyond the 1-m-thick layer as compared to a single phosphogypsum application.
The soil reclamation results in the soil profile’s differentiation into three zones with respect to the salt content: the
desalinization, transit, and accumulation zones. The greater the ameliorant rate, the higher the soil desalinization upon
a single application of phosphogypsum. Upon the repeated phosphogypsum application, the zones of desalinization and salt transit
are thicker irrespectively of the ameliorant rate. Despite the additional salt application, the degree of salinization in
the upper 2 m does not increase. Data of the long-term investigations show that a single gypsum application exerts a favorable
and long-term ameliorative effect. In the solonetz repeatedly ameliorated with phosphogypsum at the rates of 8 and 16 t/ha,
the amount of the reacted phosphogypsum considerably exceeds the applied calculated rate and is almost equal to that upon
a single application of phosphogypsum at the double rate (32 t/ha). It has been shown that not only the repeatedly applied
phosphogypsum but also the soil calcium participates in the exchange reactions. This makes it possible to apply smaller rates
of the ameliorant or calculate its rate for the upper 10-cm-thick layer. 相似文献
This study presents the main results about the removal of the antibiotic cefotaxime (CTX) under simulated sunlight radiation using heterogeneous photocatalysis with titanium dioxide (TiO2) and zinc oxide (ZnO) in aqueous solutions. The effects of pH and catalyst initial load on pollutant removal were assessed considering the response surface methodology and a central composite circumscribed experimental design, which allowed to determine the optimized conditions that lead to a higher substrate elimination. Experimental results indicated that evaluated parameters have a significant effect on antibiotic removal in both TiO2 and ZnO suspensions. In addition, the role of photogenerated holes, hydroxyl, and superoxide anion radicals on CTX degradation was evaluated to clarify the reaction mechanism. Finally, analysis of the dissolved organic carbon content in solutions and the antibacterial activity of treated samples showed that photocatalytic treatments were able to reduce a considerable portion of the organic matter present in the systems and its antimicrobial activity. 相似文献
Low-molecular-weight organic acids play an important role in the mobilization of soil phosphorus (P). The molybdate blue colorimetric
method, based on the formation of P molybdenum blue compound, is commonly used for analysis of phosphate in soil and environmental
samples. However, some organic acids can act as a ligand to bond with molybdenum acid, which subsequently interfere with the
colorimetric reaction. The recoveries of P were inhibited by the addition of oxalic (>2 mM) and citric acids (>3 mM) both
in standard P solutions and soil extracts, but formic and maleic acids did not interfere with the P determination. The inhibition
of oxalic and citric acids on P recovery remained even at higher level of P (up to 100 μg P 100 ml−1) though such interferences decreased by increasing P concentration. Comparison between oxalic and citric acids revealed the
more pronounced interference by the addition of oxalic acid. The results suggested that the interference of organic acids
with P determination is related to the types of organic acids and the ratio of organic acid ligands to P anions in the solutions.
Thus, analysis of P using the molybdate blue colorimetric method should be undertaken cautiously in the presence of relative
strong ligands like oxalic and citric acids. 相似文献
Most of Pinus brutia (Ten.) Holmboe forests are grazed, as silvopastoralism is well adapted in the Mediterranean environment. However, little
attention has been paid to the demographic dynamic of the understorey vegetation even though it is strongly affected by the
absorbed radiation. The purpose of this study was to examine the adaptation of herbaceous plant species under a Pinus brutia canopy, in Northern Greece. Monocultures of four plant groups (annual and perennial grasses, annual and perennial legumes)
were sown in experimental areas of 50%, 70% and 100% light intensity. The density of annual and perennial grasses and perennial
legumes were decreased by the shade cast by the Pinus brutia canopy. Population density of the annual legumes was little affected by light intensity: the annual grasses Bromus mollis L. and Lolium rigidum Gaudin; the perennial grasses Dactylis glomerata L. var. palestine, Festuca arundinacea and Agropyron cristatum (L.) Gaertn; the perennial legume Medicago sativa L. var. romana; the annual legumes Medicago lupulina L. and all the tested varieties of Trifolium subterraneum adapted well to the 50% light intensity habitat. 相似文献
Agrobacterium tumefaciens‐mediated transformation (ATMT) is being increasingly recognized as an effective insertional mutagenesis tool in studies of filamentous fungi for gene discovery and functional analysis. We developed and optimized ATMT for 2 Colletotrichum species, Colletotrichum gloeosporioides and Colletotrichum acutatum, the causative agents of Colletotrichum leaf disease in rubber trees in Southern China. A. tumefaciens strain AGL‐1 carrying an ILV1 gene and a green fluorescent protein gene were used to transform the conidia of these 2 Colletotrichum species. The transformation efficiency was correlated with the co‐cultivation duration and bacterial cell concentrations, which reached 300–400 transformants per 1 × 106 conidia after optimization. Southern blot analysis indicated that about 60.0% of the C. gloeosporioides transformants and 46.2% of the C. acutatum transformants had a single copy of T‐DNA in their genomes. Fungal genomic DNA segments flanking the T‐DNA were identified in the transformants through thermal asymmetrical interlaced polymerase chain reaction followed by sequencing. The flanking sequences from 4 C. acutatum and 7 C. gloeosporioides transformants showed moderate or weak homology to the NCBI database entries. Some sequences matching those reported virulence‐related genes. The results suggest that the T‐DNA inserted mutants banks constructed are useful for the discovery of new or important genes and to elucidate their function in the 2 Colletotrichum species. 相似文献
We present some applied data concerning the torsional behavior of glued-laminated wood beams under several loading programs.
These data can contribute to adequate modeling of such behavior. We review the theory of the structure and rheology of the
wood material and the torsion of beams, particularly those that are anisotropic, and we describe the test device and the experimental
environment that led to the data in question. We show the failure characteristics of the studied beams in monotonous torsion
and the influence of the loading amplitude in cyclic torsion on their behavior.
Received: May 21, 2001 / Accepted: January 9, 2002
Correspondence to:M. Araar 相似文献
The dynamics of carbon (C) and nitrogen (N), derived from the decomposition of windrowed harvest residues, was examined in the establishment phase of a second rotation (2R) hoop pine (Araucaria cunninghamii Aiton ex A. Cunn) plantation in subtropical Queensland, Australia. Following harvesting and site preparation, when residues were formed into windrows, in situ N mineralisation was measured in positions along the three tree-planting rows formed between the windrows. The position above the windrow had a higher nitrification rate than the other positions, averaging about 18 kg N ha−1/month compared with 12 and 9 Kg N ha−1 for the positions between and below the windrow positions, respectively. This position also had consistently greater soil moisture.
Macroplots were formed extending 5 m above and 10 m below a windrow. Windrowed residues within the macroplots were replaced by 15N-labelled material comprising hoop pine foliage, branch and stem. Hoop pine trees were planted within each macroplot with foliar samples taken at 12 and 24 months. Differences in foliar 15N enrichment between positions within macroplots were <1‰. Soil samples were taken from positions along the macroplots at 6-monthly intervals. Samples revealed an initial release of labile C and N but soil δ15N showed that residue-derived N was largely immobilised within the windrows for the 30-month sampling period. Whilst the use of windrows may act as a barrier to the down-slope movement of water, the residue N within the windrows may not be available to the trees of the following rotation for a considerable period following planting. Trees closest to the windrows may be able to introduce roots under the windrows thereby gaining access to the available N, but trees in the central tree planting row are unlikely to derive any significant benefit from the decomposition of windrowed residues. 相似文献