NEW TECHNOLOGIES IN AQUACULTURE DEVELOPMENT (JOURNAL OF FISHERIES)
Year:2012 | Volume:5 | Issue:4 (20)|Papers Count:16

This study was aimed to determine proximate composition and moisture percentage, as well as amino acid and fatty acid profiles of the three species common carp (Cyprinus carpio), kutum (Rutilus frisii kutum), and rainbow trout (Oncorhynchus mykiss). The amount of crude protein in rainbow trout was significantly higher (P<0.05) than the two other species but the ration of crude fat was significantly greater in common carp than others. Since the ratio of important fatty acids like EPA and DHA and also PUFA was nearly in the same quantity, and on the other hand, the proportion of ΣEAA to ΣNEAA was too low in all the three studies species, thus the consumption of cheaper species like common carp don’t have lower nutritional value for consumers due to its lower price and lower delicacy.

Mercury is a toxic element enters into the Caspian Sea that can accumulate in aquatic animals’ organ. The aim of this study was to evaluate the testis tissue changes and estimating spermatozoa motility of kutums. At first, by using in vitro culture, testis with 10-5, 10-6 and 10-7 M of Hgcl2 solution, incubated for 3 and 6 days and in second experiment, kutums spermatozoa motility evaluated, after exposing with 0, 0.01, 0.1, 1, 10, 100 and 1000 mg/l of Hgcl2 solutions. The harmful effects of mercury on spermatogenesis and testis structure, with the increasing of concentration and exposed time, increased. As the inhibition of spermatogenesis and necrotic germ cells were more visible in 10-5 M in 6th day. Sperm motility parameters decreased significantly (P<0.05), with the increasing of mercury concentration and spermatozoa stopped in 100 and 1000 mg/l. According to these results, amounts of injurious effects on testis and spermatozoa motility had direct relationship with time and mercury concentration, and continuous pollution in fish environment would have irreparable injuries in future.

In this experiment the effect of probiotic supplementation in diet of rainbow trout larvae was evaluated using Yeasure (0.1, 0.2 and 0.3 kg/metric tonn of diet), BelugatexI (2, 5 and 9×109 CFU/g food), Belugatex II (2, 5 and 9×109 CFU/g food) and a Mixture of these probiotics and a control group (with no supplemental probiotic) for 60 days. Eleven treatments in sixty days experimental period was performed on 3300 rainbow trout larvae (oncorhynchus mykiss) in three replication. Bioassyas were performed each 7 days interval along the experiment. Growth indicies was measured, including body length, feed conversion ratio (FCR), specific growth rate (SGR), condition factor (CF) and survaivability. The results of the experiment indicated that highest growth indices (Body weight, SGR and CF) and best FCR belong to groups fed standard diet supplemented with blugatex II probiotic (9×109 CFU Belugatex I/g food). And there was a significant statistical difference between treatments (P<0.05). All probiotic treatments cause better results in body weight gain, SGR, CF and FCR compared with control group. Benefical effects of lactic acid producing bacteria as supplement probiotic was proved in this study, thus using lactic acid bacteria as probiotic additive in diet of rainbow trout is recommended.

For optimum management in Laar Lake, limnological and biological parameters such as identification, density and distribution of zooplanktons were done during 6 months from June to October in 2006. Samples were taken by simple plankton net (55 µm mesh size) from various depth layers (0-5 m, 5-10 m, 10-20 m, 20-30 m, 30-40 m) and were fixed with formalin 4%. In the laboratory they were studied with inverted microscope. The order of Cladocera was predominant, and comprised 48.71% of population annually, predominate genera were Bosmina sp., Daphnia pulex, Daphnia longspina and embryonic Cladocerus. The order of Rotatoria comprised the second position with genera of Asplanchna sp., Collotheca sp., Notholca sp., Philodina sp., Polyarthera sp. and Syncheata sp. (percentage composition 41.81). Ciliophora order was represented by one genus, Tintinnidium sp., (percentage composition 6.21) was at third position, Copepoda with 3.12 percentage composition two genera Cyclops and Copepoda Naupli. In this survey, we distinguished 13 genera in 4 zooplanktonic orders. For the sampling all monthly, mean of dominant zooplanktonic density belonged to Cladocera order (6311.83±123.40 ind./m3) while they reached minimum in September by (1875±1475.12 ind./m3) Rotatoria were the second level with mean of 5411.66±115.39 ind./m3 reaching minimum with 4993.75±73.10 ind./m3 were in September. Non-parametric analysis Kruskal-Wallis test and Mann-Whitney test showed that there were statistical significant differences (P<0.05) between Zooplanktonic density in different stations and months, but there was not any statistical significant difference between different depths (P>0.05). Biological studies indicated that this reservoir has low potential for planktonic generation and due to geographical location of this dam, remarkable temperature differences can be observed in different years especially in fall and winter, which is biologically important.

The present research was conducted with the purpose of evaluating the effect of protexin probiotic commercial product on some growth parameters and body compositions of the Siberian sturgeon for 8 weeks. The experiment was performed using one control treatment and three experimental treatments with three replications. This commercial product was used at three levels of 0.5, 1 and 1.5 g/kg diet. The fishes were fed three times a day with 8-hour intervals. The results showed that this probiotic product had not statistical significant differences on feed parameters such as food conversion ratio (FCR), specific growth rate (SGR), body weight increase index (BWI) and condition factor (K) (P>0.05). The results was shown statistical significant differences on crude protein and lipid levels in the fish carcass (P<0.05). The highest crude protein levels were observed in experimental treatments 1 and 2 which had significant statistical differences with those of the control treatment and treatment 3 (P<0.05). The highest crude lipid levels were observed in the control treatment and treatment 3 and had significant statistical differences with those of experimental treatments 1 and 2 (P<0.05). This experiment revealed that protexin probiotic product did not have any statistical significant differences on the growth parameters of the Siberian sturgeon, but increased nutrition levels in the fish carcass which could be valuable for fish farmer in terms of improving the quality of its meat.

Damghan is located in Semnan province between Shahroud in the east and Semnan in the west. Today in study determination water quality, the presence of Macrobenthoses was taken into consideration as a supplementary index to identify the pollution through chemical methods. In resistance to pollution, Macrobenthics are vital index for freshwater environments. In this investigation To this respect Six stations were sampled by Surber samplers (35×35 cm) in a course of 70 Km from August 2009 to July 2010 the collected samples were fixed in 4% formaldehyde solution and then for assessment and study transferred to the laboratory. 18 families out of 11 species were identified which mostly belonged to: Diptera, Amphipoda, Trichoptera, Tricladida, Ephemeroptera. Index Family biological Hilsebhoff (equity 1), were used to for Evaluation of water quality in six springs. In based of our researches, among them, these two stations: fourth station (Absij Dibaj Spring) and fifth station (Abrendan Spring) have the highest cleanest water.

Temperature is a major factor affecting fish growth in natural environment. To survey water temperature on growth rate and survival 10500 specimen in 3 ponds with 700 m2 (3500 density each pond) including 46.7% catla (Catla catla), 35% Rohu (Labeo rohita) and 18.3% mrigal (Cirrhinus reba) were selected. Mean weight and total length of specieman were 0.3±0.01 gr and 23.6±0.75 mm in rohu, 0.1±0.01 gr and 33.26±0.35 mm in catla, 0.16±0.01 gr and 34.8±0.96 mm. samples carried out monthly biometry, mortality and temperature was record daily. Artificial feed was used. With decreasing temperature decreased feeding rate till stoped in Decamber, Junurey and Febrary. The results indicated maximum growth was occurred in Septamber (29.74±0.45), October (23.74±0.77) and Novamber (20.12±0.46) while mean weight, total and standard length were constant in Decamber (15.4±0.67), Junurey (10.21±0.48), Februry (11.21±0.78) and March (19.41±0.49). Survival rate was observed 80.6-95.71 in 10.19-29.71°C temperature in 3 ponds. In low temperature 7°C in Junurey and Maximum temperature 34°C in septamber was not observed mortality. Maximum growth rate was in Rohu Major Reason was in density rate, regarding this fish, survival in low temperature, it can be concluded that this fish are suitable culture in Khuzestan climate.

Carangid is the dominent group of marine fish stocks with the most variety of species that find in all habitats of Iranian Waters of the Persian Gulf. Therefore increased of knowledge about its early life history and spatial and temporal spawning is necessary. Survey and study on fish larvae in Iranian side of the Persian Gulf carried out in different habitats 15 years ago. Sampling was done by Bongo-Net plankton sampler with 500µ mesh size. Specimens were separated in three stages; Preflexion, Flexion, Postflexion and in two subfamily: Caranginae, Scomberoidini with Four genera: Scomberoides sp. Caranx sp., Alectis sp., and Alepes sp., Carangid larva was present in all month with high abundance in spring and winter and highest abundance in western coastal of Khuzestan than others coastal waters.

The rainbow trout (Onchorhynchus myksis) is a value fish and has been widely production for human consumption. The sexual developments of fish lead to reduce the somatic growth. Thus, production of sterile fish can be useful in aquaculture. Heat shock is a very effective way to optimizing the heat shock treatment time. Heat shocks were applied at different times after fertilization (range 10-28 min). Other parameters, in this paper were set as follows: temperature of shock=26°C, shock duration=10 min. the success of triploidy induction was determined by erythrocyte masurement. The results of statistical analysis indicates that the survival rates of treated groups, were lower than those of the control group (P<0.05). Nuclear volume showed a 2.17 times in triploids than diploid. The highest levels of triploid induction reached to 80% and were obtained at initiated 28 min after fertilization.

The present study investigated the effects of prebiotic inulin on the growth performance, survival, lactic acid bacteria population and body composition of common carp (Cyprinus carpio) juvenile. After acclimation, fish (initially average weight 6.25±0.12 g) were allocated into tanks (16 fish per tank) and triplicate groups were fed a control diet (27.7% protein and 7.15% lipid) or diets containing 0.5%, 1% and 1.5% inulin. At the end of trial growth factor, survival and body composition were assessed. At the end of study there were no significance differences in growth factor and survival rate between groups. LAB levels were significantly elevated in fish fed 1.5% dietary inulin. With the increase supplementation level of inulin, the mean value of protein increased, but the lipid carcass decreased (P<0.05). The result indicated that inulin in the level of 1.5% can improved geowth perfomance and survival carp juvenile.

The study was carried out during 2003-2004 as monthly. It is studied on effects of sand and gravel exploitation on fish abundance and species number of Tajan River. 3 stations were selected for sampling in this study. Fish community of Tajan river comprised 3 families Gobiidae, Cobitidae and Cyprinidae, among which the highest species number was observed in Cyprinidae (7 species). The highest and least abundance of fish were observed in station 3 (47%) and station 2 (11%), respectively. The dominant species of this river was Capoeta capoeta, which its abundance was 52.3%. The least and highest species number belonged to station 2 (3 species) and station 3 (9 species), respectively. Also, statistical analysis showed that the abundance difference between these 3 stations was significant and abundance and species number of fish were found in negative correlation with TSS, TDS and EC. Exploitation of sand and gravel had unfavorable influences on destabilisation of river substrate and fish habitats.

In accordance to evaluation of usage of Ceratophyllum Demersum on rate of growing as well as survival rate of Rainbow trout, four different diets were prepared that consist of 0%, 2%, 4% and 6% of the mentioned plant. This experience was tested with a three time repetition in a complete random model. The total number of all tested fish was 96 with the initial weight and length of 11.12±0.71 grams and 91.7±3.05 millimeters respectively. They were introduced to twelve aquariums considered the place of testing. In five weeks that the test occurred, some of the growing scales like Specific Growth Rate (SGR), Daily Growth Rate (DGR), Condition Factor (CF), Food Conversion Ratio (FCR) and Survival Rate (SR) for all diets were calculated. Results of data variance analysis presented that different diets did not show any significant differences in Survival Rate (SR) and Condition Factor (CF), however, meaningful differences in Weight (W), Specific Growth Rate (SGR), Daily Growth Rate (DGR) and Food Conversion Ratio (FCR) was observed (P<0.01) and also, after the test, the length of juveniles was proved to be dissimilar based on the diets (P<0.05). Based on the results, the diet No.3 consisting of 4% Ceratophyllum Demersum had the greatest effect on juveniles growing. Moreover, results of the Duncan’s comparative mean test demonstrated the maximum of 11 millimeter increase in length and 2.47 gram in weight with the growing scale amounts of 0.15, 1.36 and 0.74 for DGR, SGR and FCR respectively.

Regarding to the ecological and environmental importance of Garsoue River (adjusted to Gorgan Bay) as center of fish reproduction, specially roachand nursery zone, this study was carried out to investigate the accumulation of cadmium heavy metal in sediment and macro benthos collected from two stations of Bridge and Estuary of the river during one year at different seasons. In doing so, dry ashing of collected macro benthos samples was done by %5 Nitric Acid (HNO3) 5% and 1 N Choloridric Acid (HCL). Then, the concentration of cadmium heavy metal was assayed by GBC atomic re-absorption system. Water physiochemical parameters were determined by Hatch portable apparatus. Results indicated that maximum mean concentration of cadmium (0.17 ppm) in sediment was observed in Estuary region of the river at summer. Macro benthos samples collected from Bridge region of the river showed the highest concentration of cadmium (1.48 ppm) at autumn. Also, data obtained from cadmium concentration detected that mean content of cadmium is less than that of standard limit in river.