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11.
The effects of constant light (24L:00D), no light (00L:24D) and two light–dark periods (18L:06D;12L:12D) on the growth, stress and haematological variables were assessed in juvenile great sturgeon, Huso huso . During the 8-week experimental period, juveniles (22.5 ± 0.6 g) were kept under a 150 lx light intensity in fibreglass tanks (0.8 m2, 500 L). Differences in growth were insignificant during the experiment, but lactate levels were higher in the 00L:24D and 24L:00D photoperiods compared with 12L:12D and 18L:06D photoperiods. Cortisol levels did not show differences among the various photoperiods. At the end of the experimental period, fish reared under a 12L:12D photoperiod had higher haemoglobin values and erythrocyte numbers than in the other photoperiods, while no differences were found between groups with regard to haematocrit values or leucocyte numbers. The highest survival rate (89%) was observed in the 12L:12D period in which the levels of lactate and cortisol as stress indicators were minimal. The results indicate that various photoperiods cause different stress levels in juvenile great sturgeon and have no significant effects on growth, at least in short time periods.  相似文献   
12.
Efficacy of Thymus vulgaris essential oils was assessed on growth, immune response and disease resistance of rainbow trout (Oncorhynchus mykiss). Fish weighing 10 g were fed with dietary supplemented of the oils at 0.5, 1.0 and 2.0 ml/kg feed for 2 months. Fish fed with the oils at 0.5 ml/kg feed demonstrated a better weight gain and specific growth rate, compared to other treatments (p < .05). Fish fed with 1.0 ml the oils showed the highest up‐regulation of complement component 3 (C3) and (cluster of differentiation 4) (CD4) genes expression (p < .05), while lysozyme gene expression level significantly increased in fish fed with 2.0 ml of the oils. In addition, at the end of the experiment, the expression of C3 and CD4 genes were significantly up‐regulated in fish fed with 1.0 and 2.0 ml of the oils, while IL‐1ß and lysozyme genes expression levels were significantly decreased in fish fed 2.0 ml oils, towards the end of the trial (p < .05). There was a fluctuation in the levels of Alanine aminotransferase, Aspartate aminotransferase and Alkaline phosphatase in all treatments during the experiment. When treated fish were challenged with Aeromonas hydrophila, the highest survival rate was observed in 0.5 ml/kg treatment, followed by 2 and 1 mg/kg treatments. Overall, these findings demonstrated that dietary administration of T. vulgaris oils especially at 0.5 mg/kg feed can be considered as a potential component for enhancing of the growth, immune responses and disease resistance of trout against motile Aeromonas septicemia caused by A. hydrophila.  相似文献   
13.
Journal of Crop Science and Biotechnology - Field bindweed is a deep-rooted and drought-tolerant perennial weed that can hardly be controlled once it has become established in wheat. Field...  相似文献   
14.
Genetic Resources and Crop Evolution - The collection and characterization of apricot germplasm is an important step for its utilization, conservation, and breeding programs. In the present study,...  相似文献   
15.
Koi herpesvirus (KHV) is the aetiological agent of an emerging disease (KHVD) associated with mass mortalities in koi and common carp and reported from at least 30 countries. We report the first detection of KHV from koi in Iran using clinical, histopathological and molecular studies. KHV‐infected fish showed reduced swimming activity, sunken eyes and increased mucus production on skin and fins. On post‐mortem examination, gill necrosis was observed in the majority of fish. Histopathologically, the gill showed diffuse necrosis of the branchial epithelial cells. Margination of chromatin was detected in gills, kidney, heart, spleen, intestine and brain. In addition, sequence analyses of the TK gene, ORF 136 and marker I and II, demonstrates that Iranian KHV isolates were identical and classified as variant A1 of TUSMT1 (J strain) and displayed the I++II+ allele of this Asian genotype.  相似文献   
16.
Journal of Crop Science and Biotechnology - It is exceptionally difficult to have productive farming without the use of herbicides. It has been found that they create difficulties in the growth and...  相似文献   
17.
Monogeneans are of great interest to the ecologists because of their simple life cycle and are considered as one of the important and sensitive parasites to any changes in water quality. The monogenean gill parasite, Diplozoon kashmirensis of the Carassius carassius was examined with the aim to evaluate the infection level and the factors influencing the infection. Our results showed that highest prevalence (34.22%) of D. kashmirensis was in the lake having high trophic status and least prevalence (10.90%) in the lake having least trophic status. Infection levels were significantly higher at the basins/sites having deteriorated water quality in comparison to the basins/sites having better water quality. The combined effect of pollutants and eutrophication showed decrease in intensity of D. kashmirensis in one of the polluted/hypertrophied site in the hypertrophic lake (Anchar Lake), while as synergistic effect (i.e. increase) on prevalence and intensity was observed in one of the polluted/hypertrophied site in the eutrophic lake (Dal Lake). Sex was not an important factor influencing the D. kashmirensis in three lakes. The study showed that condition factor was significantly higher in the hypertrophic lake and in an uninfected fish. In addition microhabitat influenced the Diplozoon infection. Most preferable site for the D. kashmirensis was middle sector of the gill. Furthermore, the gill parasite showed significantly positive correlation (r(p)=0.6, P<0.05) with water temperature in the hypertrophic lake, thus showing the impact of water temperature on this parasite. It was concluded that intra lake differences, season, condition factor, microhabitat and water temperature influenced the infection of D. kashmirensis. It seems from the data that eutrophic and hypertrophic habitats were favourable for the D. kashmirensis. The D. kashmirensis showed both antagonistic and synergistic response to the combined effect of pollution and eutrophication.  相似文献   
18.
The aim of the present study was to investigate the anaesthetic efficacy and biochemical effects of 1,8‐cineole (cineole) in rainbow trout (Oncorhynchus mykiss). The fish were exposed to 200, 300, 400, 500, 600 and 800 μl/L cineole and time of induction of anaesthesia and recovery from anaesthesia were recorded. Thereafter, the fish haematological and biochemical responses to anaesthesia with different concentrations of cineole were studies. Moreover, the haematological and biochemical response of fish anaesthetized for 300 s with either cineole (283 μl/L) or eugenol (25 μl/L) were compared. Cineole at the concentrations of 200–800 μl/L induced stages 2, 3 and 4 anaesthesia within 109‐29.3, 226‐59 and 418‐117 s respectively. Increase in anaesthesia induction time led to higher stress responses and enzymes’ activity characterized by elevation in red blood cell (RBC), white blood cell (WBC), blood haematocrit and haemoglobin, and plasma cortisol, glucose and lactate levels, and aspartate aminotransferase (AST), alkaline phosphatase (ALP), lactate dehydrogenase and creatine phosphokinase (CPK) activities. However, cineole concentrations had no significant effects on plasma alanine aminotransferase (ALT) activity and ions levels. Comparison of cineole with eugenol showed that cineole showed less change in blood RBC and plasma AST, ALP, CPK, cortisol and glucose levels compared to eugenol. In conclusion, cineole is efficient to anaesthetize trout at concentrations of 200–800 μl/L. Increase in cineole concentration shortens anaesthesia induction time, stress response and probably tissue damage. The concentrations of 600–800 μl/L cineol is recommended for rapid sampling as it causes the least stress and enzymatic responses. The present results suggest that cineole causes slightly lower side effects in trout compared to eugenol.  相似文献   
19.
  【目的】  基于微量元素在水稻营养和代谢中的重要作用,研究叶面喷施 (Fe EDTA 0.1%, Zn EDTA 0.05%, B 0.02%, Cu EDTA 0.05%, and Mn EDTA 0.05%) 对水稻品种 Shiroodi 产量的影响,明确叶面喷施微量元素的最佳次数和时期。  【方法】  为了准确评估液体肥料 (Fe-EDTA 0.1%, Zn-EDTA 0.05%, B 0.02%, Cu-EDTA 0.05%, and Mn-EDTA 0.05%) 对水稻品种Shiroodi产量的影响,和喷施微量元素肥料1~7次 (T1~T7) ,第一次喷施在移栽后9天进行,之后每隔7天喷施一次。  【结果】   喷施微量元素显著增加了植株干重、籽粒产量、千粒重和收获指数,而且试验年份与喷施微量元素处理对籽粒含锌量、叶片叶绿素b含量和千粒重有显著交互作用。T4处理籽粒产量为4257 kg/hm2,而 T0只有3499 kg/hm2,增产幅度约为 20%。产量和产量构成因子的提高源于喷施微量元素肥料处理增加了每株分蘖数、穗长和穗粒数。  【结论】   叶面喷施有效地提高了水稻对微量元素的吸收利用,喷施4次效果最好。  相似文献   
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