NEW TECHNOLOGIES IN AQUACULTURE DEVELOPMENT (JOURNAL OF FISHERIES)
Year:2010 | Volume:4 | Issue:1|Papers Count:16

This research study was conducted in summer 2008 at Abzisytan Shrimp Aquaculture Hatchery Center in Bushehr, "Delvar" for 10 successive weeks (2 weeks for adaptation and 8 weeks for culture). The effects of dietary nucleotide at 5 levels of dietary including 0.0% (control), 0.15%, 0.25%, 0.35% and 0.5% were investigated on the growth performance, and Whole-Body composition of Epinephelus coioides, with average weight of 10.70±0.29 and length 47.8±0.14, and with fifteen juveniles stocked in each tank which were fed by experimental diet. The results showed that SGR had a maximum rate in a 0.35% whilst WG, W2 and CF had a significant difference compared with control treatment. The best value of growth parameters were observed at dietary level of 0.35% nucleotide. Level 0.15% of dietary nucleotide resulted in better whole-body composition. There was a significant difference between %15, %25 and %35 compared with control. It is concluded that dietary with nucleotide positively influenced growth and chemical body composition of Epinephelus coioides.

The present study aimed to investigate the reproductive biology and ovarian histology of female Greater lizardfish, Saurida tumbil (Family: Synodontidae) in the Iranian coast of the Persian Gulf (Bushehr province), from February 2007 to February 2008, conducted by regular monthly collections. The total length of females ranged from 26.1 to 58 cm and the weight ranged from 136 to 1550 g. Observations on the seasonal distribution of maturity stages and variations in seasonal fluctuations in the gonadosomatic index (GSI) confirmed recent findings that the spawning periods have two peaks, the first and the maximum was in May and the second and smaller peak was in October. It was found that female Saurida tumbil reach the first sexual maturity at 27 cm. Mean absolute and relative fecundity were 263162 and 273, respectively. The minimum and maximum ova diameter was 6.71m (stage 1) and 875.34m (stage 5). The curvilinear relationship between the fecundity and total weight of the fish was F=2657.8 W 0.6617. The mean of the sex ratio was 1:5 (M:F( This sex ratio was congruent with other studies. HSI and GSI fluctuations in females were similar.

The effects of dietary inulin on the growth performance and some hemolymph parameters of the Pacific white shrimp (Litopenaeus vannamei) were investigated for a 5-week feeding trial. The experiment, carried out in triplicate, was conducted in circular PVC tanks of 300 L capacity, filled with 200 L of seawater. Each tank was randomly stoked with 25 individuals of 3.20±0.02 g average weight. The shrimp was fed three times a day at 08:00, 14:00 and 20:00, in satiation form with dietary inulin level of 2%, and a blank feed (without inulin) as control. There were no significant differences  in weight increase percentage (BWI), specific growth rate (SGR), orbital carapace length gain, protein efficiency ratio (PER), food conversion ratio (FCR), survival and muscle chemical composition (moister, protein, fat and ash) as compared with control group  but daily feed intake was significantly higher in treatment. Hemolymph parameters were higher compared to the control group but it was not significant.

Response Surface Method (RSM) was employed for optimizing the temperature, enzyme quantity, and time in order to produce hydrolyzed protein from viscera of beluga Huso hoso. Then, the effects of three independent variables including temperature, time and enzyme quantity were investigated on hydrolization rate as a surface response. Based on the three-dimensional graphs, the optimum condition for temperature, time and enzyme quantity were determined to be 50oC, 120 min and 1%, respectively. The hydrolyzed protein, produced by Alcalase, contained 66% protein and 1.34% lipid. The results of this study revealed that the amount of lipid content dramatically decreased in hydrolyzed protein than in initial row materials.

This study was carried out to survey gill histopathology and total haemocyte changes in experimental vibriosis by Vibrio harveyi in white leg shrimp. For this order one group (30 post larvaes) 75-day old were examined. Shrimps were challenged by 30-minute bath method and with 109 cell/ml concentration of bacteria. Results from gill histopathology in diseased moribund shrimps showed necrosis, lamella fusion, edema, haemocyte infiltration in gill filaments and nodular haemocyte aggregations with melanized foci. Results from total haemocyte count in diseased moribund shrimps showed a significant decrease in this factor in comparison with control group.

In this study (Winter, 2007), the trimethylamine (TMA) content in the muscle tissue of whole croaker(Otolithes ruber) in relation with bacterial load changes (psychrophiles and mesophiles bacteria) was monitored during iced storage for a period of 18 days (0, 3, 6, 9, 12, 15 and 18th day). Results showed that the concentration of TMA and bacterial load (psychrophiles and mesophiles), increased linearly during iced storage. TMA was not detected in the first storage day. The first detection was in the 3rd storage day. In this study, the best correlation was found between TMA and psychrophilic bacterial load (R2=0.91), these bacteria were also found to be the dominant microorganism during storage time. Initial concentration of TMA 1.36mg/100g finally reached 8.97mg/100g, while psychrophilic bacterial load reached more than 108cfu/g. The average TMA concentration (in the 15th day) was found to be more than the acceptable range.

In this study, 5 diets were formulated to examine the effects of replacing 0, 25, 50, 75, 100% canola meal with soybean meal on the growth performance of rainbow trout (Onchorhynchus mykiss). All of the experimental diets were iso-caloric and iso-nitrogenous. The experimental period was 63 days and used a total of 450 rainbow trout weighing 10 g, randomly assigned to 15 tanks (30 fish per tank). Three tanks were used for each diet. The approximate analysis of the carcasses was performed before initiation and after termination of the experiment. The result showed that replacement of soybean meal by canola meal did not have any significant effect on body moisture and crude fat among the fish fed the 5 different diets. However, it showed significant differences in crude protein and fiber. There was no significant difference in growth. This study showed that canola meal has the potential to replace a substantial level of soybean meal in diet for rainbow trout.

The effects of antibiotics and oxygen on the fertilizing capacity of unfertilized ova of (Salmo trutta caspius) during storage were studied in two separate experiments.  In the first experiment, egg batches were stored without oxygen. In the second experiment, egg batches were stored in the presence of two concentrations of antibiotics (1: 250IU penicillin +250mg streptomycin and 2: 500 IU penicillin +500mg streptomycin and3: 750 IU penicillin +750 mg streptomycin per ml of celomic fluid) and then were transferred to plastic bags with sufficient oxygen content and kept at (2-3C) using domestic refrigerator. The fertilizing assays were carried out at 0 (control), 4, 8, and 12 days post storage. The results of the present study revealed that the fertilizing capacity of stored eggs decreased with the passage of time. In the first experiment there was no significant difference between eggs fertilized after 4 days of storage compared to control (day 0), but after 8 days of storage a significant difference was observed . In the second experiment, the fertilizing capacity of egg batches stored for 4 days without antibiotics showed significant reduction compared to control. The highest fertilizing capacity of hatching was observed in day 0. Unlike concentration 0, other two concentrations (1 and 2) had no significant difference with control and each other. There was little difference in concentration 3 in fertilizing and hatching percentage. The resolute in day 8 of maintenance was similar to day 4. Fertilizing and hatching percentage in day 12 of maintenance with antibiotic 0 concentrations was very low. In spite of this, there was no significant difference in fertilizing percentage between two concentrations of 1 and 2 (77.61, 62.59) respectively with control and observed significant difference in concentration 3 with control. Also, injection of oxygen showed significant positive effects on fertility of eggs (60.44% eyeing rate) compared to egg batches stored without oxygen (7.11%).

Rapid growth, feed efficiency, growth performance and disease resistance are the most important concerns in industrial aquaculture. In some food ingredients, the role of gut flora in feed efficiency and host health has been shown. Different approaches to study intestinal microflora have been used to improve growth performance, nutrient digestibility, and stimulation of the immune response, survival and resistance in many animals. Prebiotics, classified as a non-digestible food ingredient, beneficially affects the host by selectively stimulating the growth, activating a limited number of bacteria, and reducing the number of harmful bacteria in the gastrointestinal tract. Such information on prebiotics in aquatic organism is still inadequate.

Otolithes ruber is one of the species studied in the project of "stock assessment of demersal resources by swept area method in the Sea of Oman in 1999_2000. A series of 4 research cruises were conducted by R/V Ferdows_1.The area which was studied was from Meidani (58o55' E) to Gwatre Bay (61o30' E) with a depth range of 10 to 100m.The studied area of 1164 Nautical square mile was divided into 5 sub regions (A,B,C,D&E) each covering 30 minutes width, each region was divided into 4 depth stratum: 10 to 20, 20 to 30, 30 to 50 and 50 to 100 meters . In each cruise, sampling was carried out for more than 90 stations using a bottom trawler. The seasonal and annual biomass for each region and stratum was estimated. The average annual biomass for the whole area was 775.26 tons and for each stratum of 10 to 20, 20 to 30, 30 to 50 and 50 to 100 meters were 420.54, 265.87, 46.22 and 42.64 tons respectively. It is clear  that the maximum biomass was found at the depth of 10 to 20 m. whereas the minimum was found at the depth of 50-100 meters. The annual average biomass for different regions of A, B, C, D and E was estimated as 82.35, 133.79, 175.36, 162.32 and 221.45 tons respectively.The total length and weight of 1694 specimens of O.ruber were measured. The total length ranged from 20.5 to 60.5 centimeters. Comparing distribution patterns indicated that the O. ruber inhabits mainly in front of Darak, from Gordim till Chabahar and Gwatre Bay. The seasonal parabolic equations of length _ weight relationship were studied. In this regard, there was no significant difference between seasonal b_value with others.

The aim of this study was to determine levels of heavy metals, cadmium and lead, in muscle tissue of Barbus sharpeyi, Barbus grypus, Barbus xanthopterus, Barbus luteus and Aspius vorax in Hour-Al-Azim wetland. For this purpose, samples have been taken randomly from 2 stations (Rofae’ and Shat-Ali). Muscle tissues which were sampled over the months, within the same year, were analyzed. Preparation and analysis of samples were performed by Moopam international standard method (atomic absorption) and then were compared with recommended international standards and guidelines for these heavy metals. The results showed that maximum levels of lead have been detected in Aspius vorax of Shat-Ali station (1.62 ppm) and minimum levels have been detected in Barbus grypus of Rofae’ station (0.5 ppm). For cadmium, maximum and minimum concentrations accumulated in Barbus xanthopterus and Barbus luteus of Shat-Ali station (0.09 ppm) and Barbus grypus of Shat-Ali station (0.02 ppm), respectively. Based on these results, some fish species in Hour-Al-Azim wetland were infected with high concentrations of lead and cadmium and, therefore, consumption of these species may have potential risk for human health and should be approached with consideration.

The present study was conducted to identify the parasitic infestation in two phases on Persian sturgeon, Acipenser persicus, larvae and fingerlings in the Shahid Dr. Beheshti Hatchery in spring & summer 2007. In the first phase of this study, a total of 300 specimens of larvae were collected on five days after the onset of exogenous feeding. The second phase was conducted with 300 specimens collected from five earthen ponds, which included 150 larvae collected one week after stocking and 150 fingerlings collected at the time of their release into rivers. The specimens under study were measured and their biometric characteristics were recorded. Wet slides from the external and internal surface were prepared and parasites were identified following standard methods. No parasites were observed in the sturgeon larvae on 5 days after the onset of exogenous feeding. However Trichodina reticulata were observed in the larvae in the first week (prevalence=20%-30%; Intensity range=2-10). At the time of their release into the river, in addition to Trichodina reticulata (prevalence=56.67%-100%; Intensity range=5-680) a Digenea Terematoda, Diplostomum spathaceum (prevalence=3.34%-6.67%; Intensity range=1-2) were also observed in the sturgeon fingerlings. Significant differences (T-test) were detected in the intensity of Trichodina reticulata during the first week after stocking in earthen ponds and the time of their release into river.

The aim of the study is to determine Staphylococcus's & Micrococcus's outbreak and to identify gram positive bacteria pathogen on elected rainbow trout farms in Mazandaran province.Today, Rainbow trout is the number one cold-water fish in the world. Bacterial diseases such as Streptococcus's, Staphylococcus's and Micrococcus's that are created by Gram positive coccid-shape bacteria are one of the most important diseases that cause high mortality in farmed fishes.In this study, 12 farms were selected. For sampling purposes 10 fishes were selected from each farm with clinical sings such as lethargy, darkening, exophthalmia, hemorrhages around the eye and base of the fins. Gram positive coccid bacteria were isolated from the cultures of kidney and liver. The Bacteria isolated from kidney, liver and spleen were cultured in Blood agar or TSA agar plates. Identification of bacteria was conducted by staining and biochemical tests. Staphylococcus was causedby: Staphylococcus epidermidis, Staphylococcus warneri, Staphylococcus chromogens and Staphylococcus cohnii that were identified in spring and summer. Micrococcus luteus was also isolated as causing Micrococcus in fall, spring and summer. Results showed that 44% of infected fish were suffering from Staphylococcus and 22/22% was suffering from Micrococcus.

In order to identify the fishes of qanats and standing rivers of Qae`nat County, a series of sampling was carried out in four subarea of this county (including: Nimbolook, Zirkooh, Zehan, and Central sub regions) during 2007-2008, which covered 67 qanats and 6 rivers. The samples were collected by net (mesh=2mm) and after fixation in 10% formalin, they were transferred to laboratory for further species identification. From 73 surveyed water resources, we observed fishes only in 22 qanat and 4 rivers. Identified species were: Capoeta fusca from Cyprinidae family and Gambusia holbrooki from Poeciliidae family. Capoeta fusca is a subendemic species and is geographically  found only in eastern parts of Iran.