فهرست مطالب دکتر رضا نهاوندی

This experiment was conducted to evaluate the effect of different levels of supplementation of P. fortunei on the growth performance and digestive enzymatic activities of goldfish (Carassius auratus) for 8 weeks. Goldfish (with an average initial weight of 12±0.10g) were divided into four experimental treatments with three replicates (30 fish/ replicate) which contained control treatment (without paulownia extract) and three treatments were supplemented with paulownia extracts 1, 2, and 3 percent/kg diet. The results showed that the highest final weight, weight gain, specific growth rate, and condition factor were observed in fish fed with 3% paulownia extract. Significant differences were observed in the activity of digestive enzymes (proteases, amylase, and lipase). The highest proteases, amylase, and lipase activities were observed in paulownia extract at 3%. The results of this study showed that goldfish fed the diet containing paulownia extract had better growth performance and activity of digestive enzymes compared to other groups. Therefore the administration of paulownia extract at 3% is recommended to use in the goldfish diet.

Nutrients in wastewater enrich the environment and cause environmental problems in aquatic environments. Conventional wastewater treatment systems are not capable of removing phosphorus effectively.  The  entry  of  phosphorus  into  water  resources  leads  to  the  formation  of  an Eutrophication  phenomenon. Micro-algae have been more effective among the various methods used for the removing of nutrients from wastewater. Wastewater biological-treatment using algae to eliminate nitrogen and phosphor and produce oxygen for aerobic bacteria is a new trend that has drawn a great deal of attention. Using sunlight, microalgae consume nutrients in wastewater and convert them into useful biomasses. Wastewater biological-treatment using microalgae was studied. Treatment efficiency of micro-algae depends on the species, algae mass concentration, aeration level, and the optimal time to maximize algae activity on wastewater.

The effects of formic acid on growth performance, blood indices, and digestive enzyme activities of common carp (Cyprinus carpio) were examined over 60 days. The common carp (mean weight of 10±0.11g) were randomly allocated to four experimental treatments with three replications (25 pieces in each replication) including control treatment (no propionic acid) and three treatments which received formic acid (0.5, 1, 1.5 gr/ kilogram diet). The results indicated that growth parameters (final weight, weight gain, specific growth rate, condition factor, and FCR) were significantly different between the control and experimental treatments. The final weight, weight gain, specific growth rate, and condition factor in the propionic acid treatments had a significant increase compared to the control group (P < 0.05). The results of study showed that no significant difference in blood parameters were observed between treatments (P > 0.05). The highest lipase activity (21.73± 1.18 U/L) was observed in 1 g/kg propionic acid group (P < 0.05). Moreover, the highest protease (303.15± 4.16 U/L) and amylase activities (650.26± 10.05 U/L) were recorded in 1.5 g/kg propionic acid group (P < 0.05). According to obtained results, inclusion of propionic acid in common carp diet had a positive effect on the improvement of growth performance and digestive enzyme activities; therefore, a diet containing 1.5 g/kg propionic aid proposed to enhance growth performance and digestive enzyme activity of common carp.

With increasing environmental concerns from consumers, governments and communities around the world and organizations have sought to develop environmentally friendly programs such as green service and product development, green behavior and green technology. The aim of this study was to investigate the effects of IoT, green shopping intention and green operations on green behavior of employees in the hotel industry (Case study: Hayat Shargh Apartment Hotel). The present study is applied in terms of purpose and descriptive-correlation in terms of implementation method. The statistical population of this study was all employees of Hayat Shargh Apartment Hotel, whose number is 100 people. The statistical sample was calculated using Morgan table, 80 people and the random sampling method was simple. In order to collect data, Basana et al (2021) questionnaire was used. In order to determine the validity of the questionnaires, content validity and professors' approval., construct validity, convergent and divergent were used and the reliability of the questionnaires was assessed and confirmed using Cronbach's alpha coefficient. In this research, structural equation modeling methods using PLS software have been used to analyze the data. The results showed that the Internet of Things has a significant effect on green operations and green behavior of employees. The intention to buy green also had a significant effect on green operations and green behavior of employees. But the impact of green operations on staff green behavior was not confirmed.

Formic acid is simplest member of carboxylic acid family. The effects of formic acid on growth, blood indices, and immune parameters of goldfish fry were examined over 60 days. The goldfish fries (mean weight of 5.10±0.15g) were randomly allocated to four experimental treatments with three replications (25 pieces in each replication) including control treatment (no formic acid) and three treatments which received formic acid (10, 20, 30 gr/ kilogram diet). The results indicated that growth indices (final weight, weight gain, specific growth rate, condition factor, and FCR) were significantly different between the control and experimental treatments. The final weight, weight gain, specific growth rate, and status index in the formic acid treatments had a significant increase compared to the control group. In addition, adding formic acid to goldfish fry food ration improved blood factors and immunity in the fish. The results of study showed that inclusion of folic acid resulted an increase in hematocrit, hemoglobin, number of red blood cells, number of white blood cells, lysozyme, immunoglobin, and total immunoglobin compared to the control group. In general, adding folic acid to the food of goldfish fry improved growth parameters along with blood and immune parameters. According to obtained results, a diet containing 10 g/kg diet proposed to enhance growth performance and immunity of goldfish.

The effects of citric acid on the growth and blood indices of goldfish fry (Carassius auratus) were examined in a 60-day period. The goldfish fries (with initial weight of 7.10±0.16 g) were randomly categorized into four experimental treatments with three replications (25 fish/tank). The treatments included a control three groups of 1, 2, and 3 g citric acid per each kilogram of food ration. The results indicated that the growth parameters: The final weight, weight increase, specific growth rate, and condition factor in the citric acid groups had a significant increase compared to the control group (P<0.05). In addition, blood indices in the experimental treatment indicated that the red blood cell count and hemoglobin and hematocrit levels in the citric acid treatments had a significant increase compared to the control group (P<0.05). In general, adding citric acid at 2 g/kg of the diet of goldfish fry improved the growth parameters and blood indices. 

The Biofluc system is an efficient and effective nutrient replacement method that continuously recycles and refines these substances. The system is based on microbial growth in the breeding environment, which reduces or eliminates water changes in aquaculture systems. Recent years have seen the growth of biofloc-based aquaculture systems, as these systems are able to have the greatest environmental safety and even sustainable production in aquaculture while maintaining biosecurity. Bioflocks improve water quality by adding carbon, removing harmful nitrogenous substances, improving food use, and enhancing the efficiency of growth in aquaculture systems. Aquatic animals are naturally protected from pathogens by phytobiotics, which are plant derivatives that add natural compounds to their diets. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . .. . . .

This experiment was conducted to evaluate the effect of different levels of supplementation of Sargassum ilicifolium on the growth performance, blood parameters and digestive enzymatic activities of goldfish (Carassius auratus) for 60 days. Goldfish (with an average initial weight of 5.25±0.45g) were divided into four experimental treatments with three replicates (30 fish/replicate) inluding control treatment (without algae extract) and three treatments supplemented with Sargassum extracts 5, 10 and 15g/kg diet. The results showed that the highest final weight, weight gain, specific growth rate and condition factor were observed in fish fed with 15g/kg S. ilicifolium extract. Hemoglobin and MCH in fish fed with diets containing S. ilicifolium extracts showed significant difference compared to control group. The levels of triglyceride and cholesterol in fish fed with control diet were significantly higher than that of fed diets containing S. ilicifolium extracts (P<0.05). The highest proteases, amylase and lipase activities were recorded in Sargassum extract at 15g/kg diet. The results of this study showed that goldfish fed the diet containing 15g/kg S. ilicifolium had better growth performance and activity of digestive enzymes compared to other groups. Therefor the administration of 15g/kg of S. ilicifolium extract is recommended to use in goldfish diet.

The country's ornamental fish farming industry has been growing progressively and live spawning guppy is one of the top-selling ornamental fish in Iran and the world. Spirulina algae is rich in nutrients such as protein, amino acids, essential fatty acids and natural pigments and has many uses as a supplement for livestock, poultry and aquatic animals, especially ornamental fish. This research was conducted with the aim of comparing the effect of diets spirulina algae-supplemented and concentrate diets without spirulina algae on the reproductive and survival indices of guppy broodstock for 90 days. The rearing environment included glass aquaria under controlled conditions with an exposure time of 12 hours light and 12 hours of dark and a water temperature of 28 ± 1 °C. The four test groups included Treatment 1 (concentrate feed), Treatment 2 (concentrate feed with 5% spirulina algae), Treatment 3 (concentrate feed with 10% spirulina algae) and Treatment 4 (concentrate feed with 15% spirulina algae). Each treatment consisted of three replicates and five female and three male breeding specimens of Big Air Dumbo guppies imported from Thailand were kept in each replicate. The results showed the highest rate of relative fecundity (39.3±1.62) and productive larvae (150.0±2.65) and the lowest survival rate in the diet containing 15% spirulina algae supplement. During the breeding season, a significant difference in the survival rate of fish was observed with different treatments (p<0.05), such that the highest and lowest survival rates in female breeders were 93.33 ± 6.67 and 33.67 ± 6.67, respectively male breeders were observed 33.33 ± 0.0% and 88.88 ± 11.11 in treatments one and four, respectively. As a result, spirulina algae can be used as a suitable supplementary food in an environmentally friendly way in the diet in order to achieve optimal reproduction and survival in guppy ornamental fish.

This study was carried out to investigate the effects of macroalgae Padina australis and Gracilaria pygmaea extracts on growth performance and blood parameters of juvenile Common carp (Cyprinus carpio). Animals were randomly divided into four groups (initial weight 5 g); control group (basal diet without extracts), and three groups were fed with basal diet supplemented with 5 g/kg Padina australis, 5g/kg Gracilaria pygmaea and 2/5 g/kg Padina australis + 2/5 g/kg Gracilaria pygmaea for 8 weeks. Fish were hand fed to apparent satiation 3 times a day and for 8 weeks. Results showed that growth factors (final fish weight, specific growth rate, weight gain, condition factor and feed conversion) in fish fed with diet containing macroalgal extracts (Padina australis, Gracilaria pygmaea and Padina australis + Gracilaria pygmaea) was significantly higher than the control group. Hemoglobin level and the weight of hemoglobin in a red blood cell in fish fed with diet containing macroalgal extracts (Padina australis, Gracilaria pygmaea and Padina australis + Gracilaria pygmaea) was significantly higher than the control group. The control group had a higher level of triglycerides and cholesterol compared to the groups fed with diets containing macroalgal extracts (Padina australis, Gracilaria pygmaea and Padina australis + Gracilaria pygmaea).

The main purpose of this applied research which was carried out by a mixed-method (qualitative + quantitative) approach, was to identify and provide strategies for the development of entrepreneurial ecosystems and start-up businesses in the field of warm-water fish. The statistical population of the research in the qualitative part included 12 experts in entrepreneurship, business, and fisheries, who were selected by snowball sampling, and data were collected from them so the theoretical saturation was achieved. In the quantitative part, the statistical population consisted of experts in the field of fisheries and entrepreneurship from three categories of policymakers, decision-makers, experts, and activists in the field of warm water fish and fisheries operators, of whom 40 interviews and questionnaires were completed through convenience sampling method. In the qualitative part of the research, using the content analysis technique of the interviews, four dimensions of the SWOT model including strengths, weaknesses, opportunities, and threats were identified and it was provided to the respondents in the form of a questionnaire, and the data was collected from them. Based on the results of the quantitative part, strengths in the interior and weaknesses in the exterior environment were dominant. In other words, the development strategies of this ecosystem are within the range of competitive-diversity strategies or adaptive strategies. These strategies try to make the most of the available opportunities by reducing weaknesses. Finally, for the development of entrepreneurship and start-up businesses in the field of warm-water fish, a set of strategies in seven categories of inputs, production and producer, collection/processing, distribution/procurement, financial resources, market/customer, and human resources were proposed.

Infusoria are a group of aquatic organisms that are used to feed fish larvae. They are actually small forms of life in freshwater that include: Amoeba, Oglena, Green algae, Paramecium, Rotifer, Vertisella, and Invertebrates are small. Due to its small size, Infusoria can be used to breed newly hatched larvae of many aquarium fish species such as gourami and beta fish. Many home aquarium owners are naturally unable to provide enough infusoria to raise fish larvae. Infusoria can be grown by soaking any decomposing vegetative material such as lettuce and cabbage in an old, chlorinated, glassless water bottle. Depending on the temperature and light received, the infusoria begin to multiply within two to three days after planting. The water is initially cloudy due to the increase in the level of bacteria, but when the infusoria consume them, the water becomes clear. At this stage, infusoria are usually visible to the naked eye as small, white moving spots.