نشریه تحقیقات منابع طبیعی تجدید شونده
سال دهم شماره 2 (پیاپی 32، پاییز و زمستان 1398)

The purpose of this study was to investigate the effect of organic and inorganic selenium in the diet of rainbow trout on changing of malondialdehyde (MDA) and some liver antioxidant enzymes including aspartate transaminase (AST) and glutathione peroxidase (GPX). For this purpose, 810 rainbow trout fry with an average weight of 50.6±2.2 g were randomly fed with supplemented diets: 0 (control), 0.15, 0.30, 0.45, and 0.60 mg of organic (selenium-enriched yeast) and inorganic (sodium selenite) selenium per kg of feed with 3 replicates for 60 days. At the end of the experiment, the results showed that the amount of GPX enzyme activity in fish fed with 0.60 mg of organic selenium per kg diet reached a maximum of 5.49±0.62 IU/L, which was significantly different with other treatments (p<0.05). Addition of different sources of selenium to the diet caused a decreasing trend in AST enzyme, although the addition of organic selenium more than 0.45 mg kg was significantly reduced this enzyme and its lowest value was obtained in 0.60 mg kg of organic selenium (49.30±1.84 IU/L) (p<0.05). The lowest MDA level was observed in 0.60 mg kg of organic selenium (19.10 ± 0.76 μmol/L) compared to the other treatments (p <0.05), but the level of MDA among fish fed with inorganic selenium was only reduced in 0.60 mg kg of inorganic selenium and other treatments showed no significant difference (p> 0.05). Overall, considering the importance of selenium in GPX enzyme activity and based on the results, adding of organic selenium, especially at 0.60 mg/kg feed, had a greater effect on enhancing the antioxidant ability of rainbow trout compared to sodium selenite.

 The purpose of this study was to investigate the effect of cyproheptadine on dietary survival and growth in rainbow trout Oncorhynchus mykiss. In this study, 300 rainbow trout children were divided into four groups with initial mean weight of 4.87 g for two months with diet containing cyproheptadine including 0 (control), 2, 4, and 6 mg/kg. The results showed that cyprohep had no positive effect on the growth parameters including final weight, percentage of weight gain, specific growth, protein yield and average daily growth and most of the measured parameters had no significant difference (p> 0.05). Therefore, the results showed that the use of cyproheptadine in feed did not improve the growth and nutrition performance of rainbow trout and it is not recommended to improve rearing conditions.

Ecotourism is an activity that takes place in order to human use the beauties of natural ecosystems, especially ranges and forests. This activity, while creating economic prosperity, can destroy natural resources if not properly planned. In this research, using the opinions of experts, residents and tourists of the studied watershed, the relationship between the success rate of tourism projects and their effects on the basin was evaluated. The study population included 554 natives, tourists and experts. The research variables were analyzed using Kruskal–Wallis test and Spearman coefficient. The results showed that there is a great correlation between the implementation of tourism projects and the protection status of the watershed and the living conditions of the residents with the protection status of the watershed and the successful implementation of projects and suitable conditions of indigenous residents can have a direct, positive and many effects on forests protection.

Plantain tree is one of the species that is often planted in the riverside in different areas; therefore, this tree has important effects for increasing the stability and reducing erosion of soil by rivers with their roots. The science of using plants roots for soil stabilization for the soil reinforcement, called bio-engineering. The amount of soil conservation by plants depends on their biotechnological characteristics. One of these characteristics is the rate of root distribution in the soil or the Root Area Ratio (RAR). This study was carried out to estimate the amount of RAR of plantain in the riverside of the Cranelo River Kalibar County in East Azerbaijan Province. This study showed that the RAR of plantain is decreasing with depth increase and there are about 67.4% RAR in depth of 30 cm. According to the information obtained from this research, the use of plantain trees in riverside was determined.

The purpose of this study was to investigate the anatomical and biometrical characteristics of the Platanus Sycamore tree (Plane tree) in the longitudinal and transverse axis of the stem. For this purpose, a completely healthy Plane tree with an approximate age of 12 years located in Amol city was randomly selected and cut. Two discs 5 cm thick from diameter at breast height and close to the crown of the tree was prepared. Then test specimens with dimensions of 3 × 2 × 2 cm consecutively in the transverse direction of the discs from the brain to the skin and the case were examined. Fiber biometry, fiber length, fiber lumen diameter, cell wall thickness and fiber diameter were evaluated. The results showed that longitudinal and transverse axis of the trunk significantly affect fiber on biometric features. The length of fibers, fiber lumen diameter, cell wall thickness and fiber diameter in the radial axis of the pith towards the skin increased and in the long axis of the lumber toward the crown decreased. Anatomical characteristics of sycamore Three transverse, tangential and radial cross sections showed that this wood is a diffuse porous hardwood species, distinct growth ring, Simple perforation plates with scalariform and opposite Intervessel pittings.

The purpose of this study was to investigate the causes of wilt of hand-planted Haloxylon in terms of vegetation and soil characteristics in Ardestan plain in an area of 583.94 hectare. Samples were taken from three one-hectare, juicy, semi-withered and withered areas in three replications. In order to determine the effect of each factor on the wilt of Haloxylon, the data were analyzed by factorial method based on completely randomized block design. The results showed that there were significant differences in abundance, age of soil, soil pH, SAR and Ec limitations, soluble magnesium deficiency at 99% and soluble sodium at 95% probability level. It seems that due to physiological conditions and adaptability of the species, soil factors are tolerable for this species. Therefore, it is recommended that the native populations of the area be harvested on a regular basis from the elderly populations on condition of expert supervision to control the density and age of the paddy fields as well as to prevent pests.