NEW TECHNOLOGIES IN AQUACULTURE DEVELOPMENT (JOURNAL OF FISHERIES)
Year:2017 | Volume:11 | Issue:2 |Papers Count:10

One of the most important problems in hatcheries is Saprolegniasis. It can be cause of high mortality of eggs and reduce the efficiency of hatching. The objective of the present study was to determine the optimum level and effective exposure time of sodium chloride on fungal infection of Persian sturgeon eggs (Acipenser persicus). The study was conducted in three different time durations: early of April, late of April and early of May and at five different concentrations (1, 1. 5, 2, 2. 5 and 3%) and four various time exposures (15, 30, 45 and 60 min). Results indicated that eggs and larvae of Persian sturgeon were died when exposed to concentration of 3% at all exposure times. The level of 2. 5% sodium chloride was effective to control fungal infections but the newly-hatched larvae could not swim, implicating the negative effect of sodium chloride on Persian sturgeon embryo at the applied concentration. Amongst other concentrations of 1, 1. 5 and 2%, there was no significant different between the control and 1% sodium chloride (P>0. 05). Furthermore, no significant difference was observed between concentrations of 1. 5 and 2% (P>0. 05). Level of 2% sodium chloride at time exposure of 15 min showed the highest rate of efficiency and the lowest fungal infection rate. Amongst concentrations, larvae hatched mostly when exposed to concentration of 2% sodium chloride solution for 15 min.

The aim of this study was to investigate the effects of Galactooligosaccharide Prebiotics (GOS) on some growth factors (feed conversion ratio, specific growth rate, percent of body weight gain and feed efficiency coefficient), the expression of ghrelin gene and several bloody factor related to immune serum (total protein, albumin, globulin, lysozyme, alkaline phosphatase, agglutination and complement activation) in goldfish. Trial was performed randomly on three levels: 0. 5, 1 and 2% of the prebiotic and the control group. 15 fish with an average weight of 4. 88 ± 0. 28 gr per 500-liter fiberglass tank were storage and with the same condition for 6 weeks fed with different levels of GOS. The fish were biometry at the end of the period. The intestinal tissue samples to investigate the ghrelin gene expression after three and six weeks. None of the factors related to growth did not show significant differences among treatments (P˃ 0. 05). Also results of serum immune tests showed that the total protein, albumin, globulin, lysozyme, alkaline phosphatase, agglutination and complement activation under the influence of Galactooligosaccharide had significantly different between treatment and control groups (P˂ 0. 05) and the rate of the control group was lowest in all tests. RNA was extracted from intestinal tissue and cDNA was synthesized. By using Real Time PCR and with usage specific primers, ghrelin gene expression was examined and the results showed significant differences in both time sampling in the ghrelin gene expression (P˂ 0. 05). Increasing of GOS levels decreased relative ghrelin gene expression. This study showed that GOS with Level 1 and 2 percent in six weeks increased safety due to an increase in total protein, albumin, globulin, lysozyme, alkaline phosphatase, agglutination and complement activation in fish, but despite various reports of growth performance improvement, adding GOS to the diet would not make a difference in the growth and decreased gene expression levels of ghrelin, which triggers appetite and growth.

Six native and introduced species of fish in Parishan lake were examined for parasitic infestation in faculty of veterinary medicine of Kazeroon university. Native fish comprised Barbus luteus, Barbus grypus, carassius carassius, Mastacembelus mastacembelus and exotic fish consisted Cyprinus carpio (Common carp and Mirror carp). Seven monogenean species or genus including Dactylogyrus extensus, D. anchoratus, D. pavlowsky, D. carassobarbi, D. barboide, Gyrodactylus sp. and Mastacembelus sp. and three protozoan genus including Ichthyophthrius sp., Trichodina sp. and Myxobolus sp. were detected and identified. The consequences of research revealed that 75. 7 per cent of seventy examined fish were infected however 24. 3 per cent of them had no infection to monogeneans. Highest abundance of infection happened in summer by 88. 5 per cent and the lowest frequency of infection occurred in autumn by 60 per cent. Also the most raise of infection was established by Dactylogyrus extensus in Cyprinus carpio (29. 7 per cent) and the least amount of infection was registered by Dactylogyrus barboides and Dactylogyrus pavlowsky in Barbus grypus joinly (1. 4 per cent). There was no significant statistics relation between rate of infection and season (P=0. 132), risk of infection and weight (P=0. 201) and rang of infection between six under study species (P=0. 12).

Mugelidae enjoy the second ranking in finfish harvesting from Iranian beaches of Caspian Sea following Rutillus fressi katum Kaminski. In order to identify and determine the density of benthic macro-invertebrates in the intestine of wild mullet of Iranian coasts of Caspian Sea and determine the food intake preference of fish in the natural environment, samples were taken weekly during the fishing season in 2007 to 2009 in the spokes cooperatives in Anzali station, Kiashahr, Noshahr, Babolsar and Turkmens. Harvested mullets were transported to the laboratory immediately and their eaten macro invertebrates were determined exploring the gastrointestinal content. The results revealed that Rotalidae family was the highest percentage of consumed prey in Mugel cephalus of Gillian (148. 8± 270. 3) and Balanidae family was the highest percentage of consumed prey in Mugel cephalus of Mazandaran (282. 3± 1303. 7), respectively. Therefore, these baits are preferred for golden Mullet feeding.

Aquarium fish production for the entertainment business sector is rapidly growing aquaculture industry. Most aquaculture production of ornamental fish in fresh water species. In the aquarium, which often host high frequency and density much higher than in normal conditions, parasite prevalence increases to some extent is to close the border of fatal. A total of 605 fish from 6 hatchery and rearing ornamental fish center in Mashhad such as zebra danio, guppies, Tiger Barb, Angel, platy, swordtail, Flower Horn, cichlid, Svartr, Blocks Moore, Gourami, Tetras, goldfish, Green Taylor and Parrot fish were sampled and tested. In this study, external parasites of skin, fins, gills and gastrointestinal tract were noted. The highest prevalence of parasites are Capillaria in Angel fishes (30%), Dactylogyrus in zebrafish danio (18%) and Trichodina in sword fish and Svartr (30%). Guppy, Tiger Barb, Angel and Flower Horan each with three distinct parasites, parasitic infections were highest pollution. Dactylogyrus have highest and Tetrahymna lowest dispersion among the fishes studied (as in 8 and 1 type of fish), respectively. Our findings revealed that the parasitic infections are very common among aquarium fishes. Although, no gross pathology was observed among infected fishes, but it is likely that in case of any changes in the environment, then parasitic infections could be harmful. Monitoring the health status of ornamental fish both in terms of trade with other countries and transfers between different provinces is one of the most important requirements in particular ornamental fish are fish health. Because the ornamental fish trade deal without health certificates will have negative effects on the sale and export of fish.

A comparative study was conducted on density and distribution of zooplankton in the Dam of Kardeh from April to March 2014. The samples were collected by Juddy net 55 microns. The maximum sampling depth (20 m) was showed in station 1 (Dam crest) during of spring. The specimens were fixed in formaldehyde (4%) and were identified and counted by inverted microscope. The population abundance of Rotatoria was showed with 62. 81 percent in a year which their dominant genera were Polyarthra, Syncheata and Keratella respectively. The frequency of Cladocera was 18. 51% and their dominant genera were Bosmina and Chdrus, respectively. The order of Cilliophora (14. 82%) with Tintinopsis, Ciliata and Didinium (3. 47%) were showed, respectively during year of 2015. In this study, 24 genera were identified from four plankton orders. The maximum average of zooplanktonic cell density was related to order of Rotifera in all months of sampling. Annual average of zooplanctonic total abundance was 922 ± 22 per liter, which, order of Rotifera was showed maximum density (394 ± 11 per liter) in the summer. Annual average frequency of Cladocera was 85 ± 21 in summer. In other hand, this average for Cilliophora was 137 per litter. Lowest frequency was related to copepod in all season while maximum frequency of them was showed 16± 4 per litter in summer. The maximum zooplanctonic frequency were showed in station 1 (Dams's crest) and 3 (end of the river), whereas, maximum average of zooplankton with cell density of 521± 45 per litter was calculated in summer. According to Non-parametric of kruskal-wallis and Mann-whieny test, there is significant different between stations and different months (P<0. 05), whereas there is no significant difference between depths. For seasons, summer showed significant difference with other three seasons (P<0. 05).

This study aimed to investigate the rally, the degree of toxicity and Compare petroleum hydrocarbons (PAHs) Benzo(ghi)perylane, Diben(ah)anthracene, Indeno(123cd)pyrene and Benzo(a)pyrene in fish tissue of common carp, pike, Karas, white, Lin and catfish Central West and East stations wetland and compare it with standard WHO (μ g / kg. dw20) was performed. PAHs measured by Gas Chromatography with detector (GC-FID) was carried out. Hydrocarbons Benzo(ghi)perylane were found in fish and plants. Benzo(a)pyrene in West and East stations Carp pond compared to the standard (WHO) significantly increased (μ g / kg. dw20) had (P<0. 05). The hydrocarbons in the gas station West, East and Central wetland showed significant differences (P<0. 05). Indeno(123cd)pyrene in central Aysshtgah catfish fish pond compared with the WHO showed significant increase (P<0. 05). Based on the results obtained Carp West and East stations wetlands from pollution as Benzo(a)pyrene and fish pond catfish Central Station in terms of pollution Indeno(123cd)pyrene from the point of view of health food unfit for human consumption.

In the present study, cold water fish gelatin with carboxy methyl cellulose was used to produce films. Because of its unique properties such as cost-effectiveness, availability and biodegradability, cold water fish gelatin has earned a special place in food packaging. In this research, improving mechanical properties of cold water fish gelatin films combined with carboxy methyl cellulose was investigated for the first time. Gelatin films of cold water fish with carboxy methyl cellulose at concentrations of 5%, 10%, 15% and 20% were prepared by a casting method. Mechanical properties were assessed according to the American National Standard ASTM D88210. Films were tested for mechanical properties and the results showed that increasing concentrations of carboxy methyl cellulose significantly increased Tensile Strength (TS) from 21. 04 MPa to 27. 74 MPa and significantly increased Young's Modulus from 1372. 83 kg/m2 to 1842. 87 kg/m2, but insignificantly decreased percentage elongation from 17. 69 to 15. 39. Examining absorption isotherm of the resulting composite films showed a reduction in single-layer moisture content, which had led to reduced equilibrium moisture of these films. Given biodegradability of these films and their improved mechanical properties by carboxy methyl cellulose, this kind of packaging can be used in various industries, especially food industry, as food covering in packaging foods and agricultural produce.