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171.
This study investigates the effects of date palm extracts [DPE] (Phoenix dactylifera L. Arecaceae) on growth, immune function and antioxidant system in common carp fingerlings (Cyprinus carpio). One hundred and twenty fish (4.06 ± 0.13 g) were divided into six groups fed on control diet or diets containing 200 mL kg?1 DPE for 8 weeks. At the end of feeding trial, the expression of different genes was measured. Selected genes were grouped into three categories: growth factor genes in brain and liver [growth hormone (GH), insulin‐like growth factors I and II (IGF‐I and IGF‐II), antioxidant‐related genes in liver [glutathione S‐transferase‐alpha (GST‐α), glutathione reductase (GR) and glutathione peroxidase genes (GPX)] and immune‐related genes in head kidney [interleukin‐8 (IL‐8), interleukin‐10 (IL‐10) and transforming growth factor‐beta (TGF‐β) genes]. The relative expression of the growth‐related genes in fish fed DPE showed no significant increase compared to control group (> 0.05). On the other hand, DPE altered the expression of genes encoding antioxidants enzymes in liver of fingerlings which was statistically significant with respect to the control samples in case GPX (< 0.05). Also, DPE caused remarkable increases in the expression of the immune‐related genes (IL‐8, IL‐10 and TGF‐β) analysed on head kidney of common carp fingerlings compared to the control group (< 0.05). In conclusion, it can be suggested that administration of DPE in early stages of common carp culture can promote immune efficacy and increase the antioxidant activity.  相似文献   
172.
In this study, we prepared silver nanoparticles immobilized onto silica sand beads as an antibacterial material against pathogenic luminous Vibrio sp. Persian1. Silica beads were modified with 3‐aminopropyltriethoxysilane (APTES), cyanuric chlorid and tetraethylene pentamine, and silver nanoparticles were generated in various concentrations (0.5, 1, and 2 mM g?1 of silica beads) of AgNO3 on the surface using chemical reduction. Ag/TEPA‐Den‐SiO2 samples were characterized by TEM, FE‐SEM/EDS, FT‐IR and ICP OES and their antibacterial activity assayed by zone of inhibition and test tube tests against pathogenic Vibrio sp. The results of the zone inhibitory test revealed that all the Ag/TEPA‐Den‐SiO2 samples had an antibacterial effect against luminous Vibrio sp. Persian1. In addition, the tube test results showed 100% killing of bacteria in 2 h contact period. Ag/TEPA‐Den‐SiO2 samples maintained their antibacterial activity after 14‐day immersion in seawater by slow release of silver ions. These results suggest that Ag/TEPA‐Den‐SiO2 substrates could be effective antibacterial materials for disinfection of seawater used to culture Penaeid shrimp larvae.  相似文献   
173.
The biogenic amine contents in fillets of three freshwater fish of kutum (Rutilus frisii), common carp (Cyprinus carpio), and Caspian salmon (Salmon caspius) were monitored during storage at 4°C for 20 days. The amounts of biogenic amines were determined at regular intervals using high performance liquid chromatography after derivatization with benzoyl chloride. Significant differences in the levels of selected biogenic amines among the fish samples were found (p < 0.05) during storage times. While the amount of putrescine, cadaverine, histamine, and tyramine in the fish fillets increased during the storage time, the changes in spermine and spermidine contents of the fish species were minor and both showed low and inverse correlations with storage time. For each of the three fish species, the sensory acceptability limit was found to be 4–8 days. The quality and biogenic amine indices of fish samples showed high correlation with storage time (r > 0.9). The principal component analysis of the results indicated that the formation of biogenic amines displays a certain behavioral pattern in all fish samples.  相似文献   
174.
This experiment was conducted to illustrate the effect of dietary taurine levels on Persian sturgeon, Acipenser persicus (mean weight of ~35 g) fed plant‐based diet. A basal diet containing low level of fishmeal (19%) was formulated containing 0.05% endogenous taurine (control diet). To this diet were added five levels of exogenous taurine: 0.25 (0.25T), 0.5 (0.5T), 0.8 (0.8T), 1.2 (1.2T) and 1.6% (1.6T). These diets were fed to the experimental fish for 42 days. Results showed that growth performance decreased and food conversion ratio increased as dietary taurine increased, although no significant difference was observed between the control and 0.25T treatments. Increased dietary taurine led to increased carcass moisture and decreased carcass lipid percentages. Feed intake was significantly and negatively correlated with dietary taurine. Carcass taurine content significantly increased with dietary taurine elevation up to 1.2% and then decreased. Hepatic taurine content showed a significant increase in 0.25T treatment and then decreased along with dietary taurine elevation and reached the control values at 1.6% taurine level. Dietary taurine elevation led to more hepatic damages compared to the control. In conclusion, although within the range reported for other studied fish, the tested taurine levels in this study might be supra‐optimal causing adverse effects in Persian sturgeon and further study with lower taurine levels is encouraged.  相似文献   
175.
This study investigates the effects of Coriander (C. sativum) on the growth, antioxidant, and immune‐associated genes and serum and mucosal immune parameters in zebrafish (D. rerio). The experimental fish were treated with 0 [control], 5, 10 and 20 g/kg coriander supplemented diets for 8 weeks. The results revealed that coriander remarkably increased mucosal immune parameters (the total Immunoglobulin, protease and lysozyme activity). The highest levels of the measured parameters were noticed in 20 g/kg CP treatment. Also, the zebrafish fed 20 g/kg coriander powder showed significantly higher expression gene for lysozyme and TNF‐alpha. The same results were noticed in case of IL‐1B gene expression. In case of sod gene expression there was no significant difference between treatments. However, regarding cat gene expression, significant difference was noticed between 20 g/kg CP treatment and other groups. In addition, no significant changes were observed between coriander fed zebrafish and control treatments regarding GH gene expression level, although IGF‐I remarkable up‐regulate in 20 g/kg coriander powder treatment compared other groups. In conclusion, it can be proposed that dietary Coriander powder can improve mucosal immune parameters and immune and antioxidant genes expression.  相似文献   
176.
177.
Agriculture is a major source of nitrogen usage and release to environment. Due to the effect of water movement on solute transport, investigating the effect of different management scenarios of irrigation and drainage could be useful for reducing nitrate loss and environmental pollution. This study is a scientific attempt to assess the ability of HYDRUS-2D model to simulate the effect of subsurface controlled drainage on nitrate loss of paddy fields. So, two physical models with difference in depth of subsurface controlled drainage (40 and 60 cm) were constructed. The tanks were filled with loam silty soil texture and then transplanted rice. 90 kg/ha potassium nitrate fertilizer was added in two stages of rice growth. Mid-season drainage was applied 26 days after transplantation. After 17 days, drains were closed again and applied flooded irrigation with 5-cm water stagnant layer above soil surface. During experiment, nitrate concentration of drain water was measured. HYDRUS-2D was calibrated with measured data in 60 cm drain depth and validated with 40 cm drain depth. HYDRUS-2D could simulate nitrate concentration with the coefficient of determination 0.95 and 0.89 in calibration and validation stages, respectively. The comparison between the volume of drain water and nitrate concentration from the drains in the depths of 40 and 60 cm indicated lower nitrate load in depth of 40 cm. The results obtained proved that the presence of hardpan layer in depth of 25 cm rather than the absence of it causes increase in 3 % of average nitrate concentration and reduce in 17 % of water discharge.  相似文献   
178.
以西昆仑山2个海拔样点的土样为对象,利用(LB和TSA)2种培养基,基于16S rRNA基因序列的系统发育,采用纯培养法对其可培养细菌多样性进行研究。2样点中共分离到91株细菌,分为25个属,52个种。厚壁菌门(Firmicutes)占总菌数的48.75%,放线菌门(Actinobacteria)占36.25%,γ-变...  相似文献   
179.
Our objective was to characterize the current reproductive performance and factors which may be related to it in the Fars province dairy herds in southern Iran. We collected retrospective data from four commercial herds in the region. All 256 cows with history of calving between 21 March 2004 and 20 March 2005 were followed until subsequent pregnancy, culling or death. Effects of risk factors on days open were investigated in a Cox proportional-hazards model. The overall median calving interval, dry period and days open were 388, 68, and 120 days, respectively. First-service conception risk and overall-service conception risk were 45 and 42%, respectively. Average numbers of insemination per pregnant and all cows were 2 and 2.1, respectively. Cows without incidence of any disorder during the lactation (but before conception, and including metabolic disorders) had 2.1-times greater hazard of conception than cows with incidence of disease. No significant association between calving interval, dry period, parity of dam, and sex and weight of calves with days open was observed.  相似文献   
180.
Drought is a problem of the expanding universe which seriously influences crop production and quality. Approximately one-third of the cultivated area of the world suffers from constantly inadequate supplies of water. The present study aimed to determine the effects of drought and rewatering on activities of antioxidant enzymes, chlorophyll, proline, and relative water contents (RWC). In this experiment, six maize hybrids (Sc260, Sc370, Sc500, Sc647, Sc700, and Sc704) were examined in a pot study during the maize-growing season of 2011. Results indicated that the growth of hybrids was retarded under drought stress conditions and regained growth speed during rewatering. RWC, chlorophyll, and carotenoid contents were markedly decreased by the water deficit and reached normal values during rewatering in Sc647, Sc704, and Sc700. Our findings also indicated significantly higher activity levels of peroxidase and catalase and proline content in water-stressed plants than in well-watered plants, which decreased when the plants were rewatered, showing an inverse relationship to gluthatione reductase activity. According to the results, the better upregulation of the protective mechanism in Sc704 and Sc647 probably induced higher drought resistance. We concluded that antioxidant enzyme activity could provide a useful tool for depicting drought tolerance in maize hybrids in arid and semiarid regions.  相似文献   
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