A survey on prevalence rate of aflatoxigenic species of Aspergillus and residues of aflatoxins by ELISA method in cold-water cultural fish (rainbow trout) feeds in Tehran and West Azarbayjan provinces-Iran

Aflatoxins are one kind of fungal toxins produced by species of toxigenic Aspergillus (A. flavus and A. parasiticus) and in other words they are secondary metabolites which are considered as one of the threatening factors of food consumer's health. In this research 96 samples of cold-water cultural fish feed, rainbow trout, during the seasons of spring and summer of 2007 (every fifteenth of the month) were randomized (by simple and stratified random) to determine: 1. The prevalence rate of aflatoxigenic species of Aspergillus in stored feed of cold-water cultural fish in West Azarbayjan cultural fish farms in both seasons (spring and summer); 2. The residues of total aflatoxin in stored feed of fish in cultural fish farms of West Azarbayjan in both seasons by ELISA method; and 3. The residues of that toxin in feed produced in aquatic feed factories in Tehran and West Azarbyjan provinces with the same method. In order to study prevalence rate of toxigenic species of Aspergillus, pour-plate culture method by general medium such as Malt Extract Agar (M.E.A.) and Sabouraud-Dextrose Agar (S.D.A.) and by standard No.997 of Iranian Standard Institute were used. The produced colonies were examined microscopically. To determine the aflatoxins residues, ELISA method using Agra-Quant kit of Romer Lab company, were applied. The results of this survey indicated that only 8.3% of the samples were infected by A. flavus. A. parasiticus was not observed. There were no significant differences between the prevalence rate of AFT and seasons/months, either (P<0.05). Evaluating mean of aflatoxin rate showed that the rates of this variable are lower than the tolerance levels designated by the joint FAO/WHO expert committee (The mean of AFT in all data was lower than 11 ppb). Furthermore, mean of total AFT residues rates of stored feed of various cultural center of West Azarbayjan and Tehran factories were comparable in spring and summer, and no significant differences were observed (P<0.05). But there were significant differences between the total aflatoxin rates in the feed of West Azarbayjan factory and spring and summer (P<0.05), and AFT residues in spring (8.6 ppb) were higher than summer (6.1 ppb). Prevalence rates of AFT in Tehran feed factories (9.2 ppb) are higher than W. Azarbayjan (7.4 ppb). In other words, location was considered as a decisive factor in total AFT rates of samples. Moreover, the results indicated that there was significant difference between total aflatoxin rates of feed and cultural centers (P<0.05). The mean of AFT rates in embankment dam cultural fish farms (6.75 ppb) and multi-functions cultural fish farms (6.25 ppb) was higher than individual cultural pond (4.67 ppb). In conclusion, the finally results of this survey indicated that the lower rates of Aspergillus is not effective on the presence of total aflatoxin rates in trout feed. Due to low levels of aflatoxin rates (lower than 20 ppb), the produced feed of cold-cultural fishes, Rainbow Trout, in Tehran and West Azarbayjan provinces, in spring and summer of 2007, were safe and healthy both for fish and their consumers.

Study the methods of connecting jacket to the seabed and choosing the best method for Persian Gulf according to soil characteristics

Offshore structures with numerous applications in different environments throughout the world and used at different depths. Due to the expansion of marine industries, including offshore oil industry in Iran , particularly in the Persian Gulf region, in order to more accurately model these structures and to prevent incidents such as the Overturning of the platform serious damage to the South Pars Phase ١٣ was platforms, the use New Technic is essential technologies. One of the methods that are used in the construction of offshore wind turbines, using a pre-pile. In this method, a template is constructed with the dimensions specified in the workshop. After making templates using special vessels for placement in the desired location on the sea bed is carried, then the template is placed on the sea bed, Then, using a hammer for Pile Driving Operation Started Vibration hammer and fit the template of 3 or 4 piles of crushed within this template on the seabed . The next step piling, templates have been removed from the site And Jacket placed on piles. The system was installed on the deck on piles and Consequently Deck Load pile inserted on .It should be noted that the design of these types of platforms, base diameter of the pile diameter independent of the choice as one of the major advantages of this system is. This thesis examines a Template Fixed Platform in the oil Soroush Using the Pre-Piling and the Common Piling systems in the Persian Gulf were studied and the effect of different design compared to the Pre-Piling Platforms Persian Gulf were evaluated. The results suggest that Pre-Piling system compared with conventional systems piling in the Persian Gulf, as a more appropriate model structure and behavior Top Model economic efficiency is selected. It should be noted that all calculations and analyzes were performed using Software Abaqus.