saeed zahedi

In this study, the effects of different levels of biofertilizer containing phosphate solubilizing bacteria on aerobic digestion of Nile tilapia (Oreochromis niloticus) sludge were investigated in vitro under a completely randomized design. Three experimental treatments including aerobic digestion of Nile tilapia solid sludge without adding biofertilizer (control) and aerobic digestion of solid sludge with adding biofertilizer containing phosphate solubilizing bacteria (Pseudomonas putida strain P13 and Pantoea agglomerans strain P5) at levels of 0.1% and 0.2% were used in triplicate. The aerobic digestion containers with a capacity of 1 L (9 containers) were kept in a shaker incubator at 30ºC for 28 days. The results showed that the concentration of phosphate, potassium, and iron nutrients on the 14th day of the experiment in the biofertilizer treatments were significantly higher than the control, but their concentrations on the 28th day in the biofertilizer-0.1% treatment were significantly higher than other treatments )p<0/05). The manganese concentration on the 14th and 28th days in the biofertilized-0.1% treatment was higher than other treatments (p<0/05). The results of the present study indicated that the aerobic digestion of fish sludge for two weeks with adding biofertilizer containing phosphate solubilizing bacteria (P. putida strain P13 and P .agglomerans strain P5) by counting 107 of each bacteria per mL (CFU/mL) at 0.1% improved the release and dissolution of nutrients.

Aquaculture is a sustainable solution to respond to the increasing demand for animal protein and also, food security in the world, and today, in order to develop it, it is necessary to pay attention to the sustainable aquaculture approach (economically, socially and environmentally). The development of modern aquaculture systems has been greatly expanded in recent years and each of them pursues the goals of sustainable aquaculture in some way. In fact, modern aquaculture systems enable the achievement of sustainable aquaculture by maximizing the productivity of resources, reducing costs, appropriate production quantitatively and qualitatively, and a slight environmental effects. Among the systems introduced so far, recirculating aquaculture system, cages, aquaponics, biofloc and integrated multitrophic aquaculture systems are known as promising systems in aquatic production in the world that can be developed in Iran as well. In this review study, in addition to introducing and discussing the importance of these systems in sustainable aquaculture, the resulting opportunities and also, the challenges of developing these systems in the country are addressed

At present, many cold water fish farms in the country use reused water to produce fish, but the effects of its using on fish muscle quality are not well known. The aim of the present study was to compare the muscle quality of rainbow trout (Oncorhynchus mykiss) raised in two open and partial reuse water systems. For this purpose, young trout with a stocking density of 20 kg/m3 and a loading density of 1 L/min/kg of fish was studied in two an open system (100% make-up water) and a designed partial water reuse system (with a reduction of 80% make-up water and its replacement with the reused water) for 45 days. Four times of water recirculation caused an increase of 6.7 and 6.5 times in the amount of water total ammonia and total phosphorus compared to an open treatment, respectively. Crude protein, crude fat, pH and moisture percentage showed significant differences between two treatments. In contrast, there were no significant differences in water holding capacity, cooking loss, texture analysis (hardness, adhesiveness, resilience, cohesiveness, springiness, gumminess and chewiness) and color indices of L*, a* and b* between two treatments. Consequently, the reuse of water to the same extent as the present designed protocol does not have very obvious changes on many studied muscle quality factors of fish.

Many algorithms in machine learning, pattern recognition, and data mining are based on a similarity/distance measure. For instance, the kNN classifier and clustering algorithms such as k-means require a similarity/distance function. Also, in Content-Based Information Retrieval (CBIR) systems, we need to rank the retrieved objects based on the similarity to the query. As generic measures like Euclidean and cosine similarity are not appropriate in many applications, metric learning algorithms have been developed with the aim of learning an optimal distance function from data. These methods often need training data in the form of pair or triplet sets. Nowadays, this training data is popularly obtained via crowdsourcing from the Internet.  Therefore, this information may be contaminated with label noise resulting in the poor performance of the learned metric. In some datasets, even it is possible that the learned metrics perform worse than the general ones such as Euclidean. To address this emerging challenge, we present a new robust metric learning algorithm that can identify outliers and label noise simultaneously from training side information. For this purpose, we model the probability distribution of label noise based on information in the training data. The proposed distribution function efficiently assigns the high probability to the data points contaminated with label noise. On the other hand, its value on the normal instances is near zero. Afterward, we weight the training instances according to these probabilities in our metric learning optimization problem. The proposed optimization problem can be solved using available SVM libraries such as LibSVM efficiently. Note that the proposed approach for identifying data with label noise is general and can easily be applied to any existing metric learning algorithms. After the metric learning phase, we utilized both the weights and the learned metric to enhance the accuracy of the metric-based classifier such as kNN. Several experiments are conducted on both real and synthetic datasets. The results confirm that the proposed algorithm enhances the performance of the learned metric in the presence of label noise and considerably outperforms state-of-the-art peer methods at different noise levels.

In the present study, the effects of startup and addition of ammonium chloride (NH4Cl) and sodium nitrite (NaNO2) salts for 4 weeks before fish stocking on efficiency of biofilter for removal of total ammonia nitrogen (TAN) from water, survival rate, growth performance, ammonia metabolizing and urea cycle enzymes activities as well as mucosal immunity of African cichlid (Labidochromis lividus) fingerling. The experimental unit was a recirculating aquaculture system (RAS) with water holding capacity of 200 L in which 20 fingerling fish with average weight of 3.06±0.07 g were stocked and cultured for 30 days. The experimental groups included the RAS without startup and adding salts (control, group 1), startup of RAS before fish stocking (group 2) and startup RAS with adding salts (group 3). Water from each experimental unit was sampled after 0, 10, 20 and 30 days of fish stocking. The results showed that the TAN concentration in the groups 2 and 3 was significantly lower than the control group (P<0.05). Nitrate concentration in the groups 2 and 3 was higher than the control group (P<0.05). The highest nitrate concentration was observed in the group 3 (P<0.05). Growth performance including final weight, weight gain, specific growth rate (SGR%), daily growth index (DGI) and body weight increase (BWI%) were higher in the groups 3, 2 and control, respectively (P<0.05). The food conversion ratio (FCR) in the groups 2 and 3 was lower than the control (P<0.05). The activities of glutamate dehydrogenase, glutamine synthetase and ornithine carbamyl transferase enzymes in liver and muscle tissues increased in the control and group 2 compared to the group 3 (P<0.05). The total immunoglobulin, lysozyme and alternative complement pathway activity (ACH50) of skin mucus increased in the groups 2 and 3 compared to the control; the highest levels were observed in the group 3 (P<0.05). The findings indicate that the startup of RAS with the addition of salts before fish stocking can be an effective way to improve the efficiency of biofilter in converting water ammonia to nitrate, survival rate, growth performance and health of the fish.

Fish farming in recirculating aquaculture systems (RAS) has been expanding in the recent years, but the effects of water reuse are not well known. The aim of the present study was to compare the growth parameters, stress response and muscle stress- and growth- related gene expression of rainbow trout (Oncorhynchus mykiss) in open system (OS) versus water reuse system (WRS). For this purpose, young rainbow trout were studied in stocking density of 44 Kg/m3 and loading density of 1 L/min/Kg of fish in an OS (100% make-up water) and WRS (66% reused water) for 60 days. The results showed that water NH3 concentrations increased significantly in WRS compared to OS. In addition, final body weight in the WRS decreased by 6.5% compared to OS on day 60. No differences were observed between treatments in terms of fish length (total, fork, standard), specific growth rate and condition factor. In contrast, feed conversion ratio increased significantly in WRS respect to OS. Moreover, blood plasma cortisol levels as well as RNA expression of heat shock protein 70 (HSP70) in muscle increased significantly in WRS versus OS. However, no significant changes were found in muscle mRNA levels of insulin-like growth factor-1 (IGF-1) and myosin heavy chain (MHC) between the two treatments. In conclusion, water reuse protocol reduced some growth parameters, and induced measurable stress in fish in a manner not related to the expression of IGF-1 and MHC genes.

Stocking density (SD) is considered as a chronic stressor in aquaculture. The aim of the present study was to compare the growth performance, cortisol response and the mRNA expression of heat shock protein70 (HSP70) gene in rainbow trout (Oncorhynchus mykiss) reared at two common SDs of Iranian fish farms in an open system. For this purpose, young all-female rainbow trout were studied at two SDs of 24 (medium SD or MSD) and 44 (high SD or HSD) Kg/m3 and loading density of 1 L/min/Kg of fish for 60 days. The obtained results showed a decrease of mean final weight in HSD groups by 6.2% as compared to MSD. However, no differences were observed between treatments in terms of fish length (total, fork, standard). Furthermore, relative fin lengths (pectoral, pelvic, anal, dorsal and caudal) were similar in the two categories after two months of treatment. On the other hand, body weight gain (%), daily growth rate, specific growth rate and thermal growth coefficient were decreased significantly in HSD in comparison to MSD sets. In contrast, no changes were observed in fish condition factor. High SD caused an increase of coefficient of variance of weight and feed conversion ratio in respect to MSD. Blood glucose and cortisol levels remained unchanged between treatments. At last, muscle HSP70 gene expression at mRNA level increased significantly in HSD versus MSD. In conclusion, our results suggested that increasing the SD in allowable ranges in trout fish farming systems with no oxygenation might cause a stress in fish indicated by change in some studied growth parameters as well as increased HSP70 mRNA expression. Therefore, SD increase should be accompanied by proper management schemes as well as nutritional approaches aimed to relieve the related induced stress and to strengthen the fish immune system.

Iron, manganese, and aluminum are three abundant metals on earth and their concentrations have increased in aquatic environments as a result of natural and industrial activities. This study was undertaken to report the median acute toxicity (LC50) and accumulation of the sub-lethal concentration (10% 96-h LC50) of iron (Fe), manganese (Mn) and aluminum (Al) in kutum (Rutilus kutum) fingerlings. For the 96-h LC50, the fish were exposed to concentrations of 105, 111, 117, 123, 129 and 135 mg/l of Fe and 40, 45, 50, 55, 60, and 65 mg/l of Mn and 18, 22, 26, 30, 34 and 38 mg/l of aluminum for 4 days. For sublethal exposure, they were exposed to mediums with concentrations of 12.3, 5.4 and 2.9 for Fe, Mn, and aluminum, respectively. Metal concentrations were determined by atomic absorption spectrophotometry in the gill tissues. Probit analysis showed the 96-h LC50 values of 122.98, 54.39, and 28.89 mg/l for Fe, Mn, and aluminum, respectively. Sub-lethal tests were conducted with nominal concentrations of 12.3, 5.4, and 2.9 mg/l of Fe, Mn, and aluminum for four days, respectively. Significant accumulations were observed in gills for all tested metals as compared to the control groups in short-term exposure (P<0.05). Obtained results clearly show that aluminum is the most toxic metal among tested ones for kutum fingerlings and it has the highest branchial AF value during sub-lethal exposure.

Pourpose : A computer simulation was carried out to assess the following hypothesis: during the stance phase of a transfemoral amputee gait, forces of individual muscles of the transected limb are higher than those of the intact limb. Methods and Materials : With each muscle as an ideal force generator, the lower extremity was modeled as a linkage that hip and knee were its joints. Kinematic data of hip and knee joints were recorded by a motion analysis system.

Through an optimization approach, the forces exerted by muscles were determined so that the recorded hip and knee joint angles could be produced. Simulation results showed that the hypothesis is refuted.

Actually, the individual muscle forces of the prosthetic leg are lower than those of the intact leg. This is in line with studies that reported the hip torque of prosthetic leg is lower than that of the intact leg.