فصلنامه شیلات
سال شصت و ششم شماره 2 (تابستان 1392)

The present study was performed to elucidate the probable effects of replacing fish meal and fish oil with plant sources on growth performance، feed utilization indices and muscle fatty acid profile of rainbow trout. Fish with an average weight of 15±2 g were distributed into 12 (300 L) tanks (50 fish/tank) and reared for 60 days using different experimental diets. Fish oil fully replaced with a blend vegetable oil canola: linseed: safflower (40:30: 30، respectively) and fish meal was substituted by plant protein at three different levels of 40، 70، and 100%. The control diet contained fish meal and fish oil as the only sources of dietary protein and lipid. Results showed that replacement of 40% fish meal with plant protein did not have any negative effects on growth indices، feed utilization and proximate composition of trout muscle compared to control diet (P>0. 05). However، replacing 70 and 100% fish meal with plant protein resulted in significantly decreased final weight، feed conversion ratio، protein content of fillets، protein and lipid productive values and protein efficiency ratio (P<0. 05). Fish oil replacement with a vegetable oil blend resulted in significant increment of Vaccenic acid، Linoleic acid and Linolenic acid and significant decrease of Myristic acid، Palmitic acid، Oleic acid، Arachidonic acid، Eicosapentaenoic acid and Docosahexaenoic acid in the fillets (P<0. 05).

This study was conducted to investigate the effect of olive oil cake on growth and sensory evaluation of rainbow trout. Four practical diets containing 0 (control)، 5، 10 and 15% of olive cake (dried and well powdered) was formulated and fed to triplicate groups of fish. Two hundred and forty fish with average initial weight of 71. 3 ± 5 g were randomly distributed into 12 circular concrete ponds with 3m diameter and 1 m height. River water with flow rate 1L. Sec-1 was flowed; the water temperature and pH were 10 ± 3ºC، 6. 7-8. 1 respectively، during 70 days of experimental trial. The fishes were fed at 1-1. 5% body weight in three times daily (8، 12 and 18). The final weight، WG، SR، CF، SGR، BWI، FCR، HIS and body composition of trial fishes were indicated that to maximum 5% olive oil cake be replaced. The poor growth، feeding efficiency and body carcass composition was observed in treatment 4 with 15% olive cake inclusion and significant with other treatments (P<0. 05). The result of sensory evaluation showed that adding olive cake to the diet has not affected color (P>0. 05); however it has positive effect on small and taste as compare with control diet (P<0. 05) and caused diet palatability for fishes. Generally، it can be concluded that inclusion of 5% olive oil cake in diet of rainbow trout is useful.

In order to sustainable exploitation and conservation of biodiversity of riverine ecosystems، which have been exposed to considerable modifications caused by anthropogenic activities، it is necessary to understand the habitat requirements of the species inhabiting these ecosystems. Kordan River of the Namak Lake basin، originates from the highlands of the Alborz Province، and is one of the environments inhabited by the native Angora loach، Oxynemacheilus bergianus. This river has been exposed to anthropogenic activities such as agriculture، dam construction and ecotourism. Habitat requirements of this species and the impacts of anthropogenic effects were determined in 68 stations along the Kordan River. According to the best model selected based on the Akaike Information Criterion (AIC)، the variables including altitude، river width، flow rate and the size of the substrate material were determining factors for the presence of this species. Other models which were، also، suitable based on AIC values، showed that the altitude and river width are the most important independent variables affecting the presence of the species. Therefore، the anthropogenic activities being held in Kordan River and bringing up the changes in river width، depth، substrate and the flow rate، can affect the presence and distribution of Oxynoemacheilus in the mentioned river.

Abundance and diet of Oncorhynchus mykiss were examined in Madarsoo River in Golestan National Park. A total of 144 fish specimens investigated (with average Total length of 190mm and Total weight of 80g). Ephemeroptera was the most abundant of collected benthic invertebrates. The Ivelev index showed that Ephemeroptera، Gammaridae and Tricoptera were the most important food items for O. mykiss. Our result has indicated that species is the potential food competitor of fish species، Paracobitis malapterura، Neogobius melanostomus، Neogobius fluviatilis، Albunoides eichwaldii in Golestan National Park stream.

The use of natural extracts as one of good antioxidant source is increasing to improve fish quality. The present study aims at investigating antioxidant effect of orange peel extract on the quality of common carp fillet during refrigerated storage (4°C). Fish fillets were treated by 0، 1 and 5 % concentration of orange peel extract، packed and then stored in refrigerator. Chemical parameters (pH، peroxide value (PV)، thiobarbituric acid (TBA) and total volatile bases nitrogen (TVB-N)) and sensory analysis (texture، odour، taste، color and total acceptance) were measured by panelists on 0، 3، 6، 9، 12 and 15 days. The pH value increased during storage that was more in control (p< 0. 05). The amount of PV، TBA and TVB-N were significantly increased in the all of treatments، so that the values of control، 1 and 5 % reached to 14. 8، 12. 2، 10. 2 meq o2/kg fish fat and 0. 99، 0. 78، 0. 59 mg malonaldehyde/kg fish flesh and 33. 3، 30. 5، 22. 6 mg N2/100 g fish flesh at the end of storage respectively. The increase of values in 5 % was less than other treatments (P< 0. 05). Results of sensory analysis indicated significant reduction in sensory characteristics of fillets during storage. According to results of this study، fillets treated by 5% extract are consumable until end of storage in comparison with other treatments.

Import of DNA into fish genome is generally inefficient. Therefore، one of the current challenges in fish tarnsgenesis is the development of efficient DNA delivery systems. Here we test using two bacterial proteins to target DNA to zebrafish ZF4 cell line genome. Agrobacterium tumefaciens، a soil bacterium، efficiently transfers DNA as a nucleoprotein complex to plant cells genome. Agrobacterium proteins VirD2 and VirE2 perform important functions in this process. We reconstitute this synthetic complexes consisting of the bacterial proteins VirD2، VirE2، and single-stranded DNA (ssDNA) in vitro، to test the potential of this approach to enhance gene transfer efficiency to zebrafish ZF4 cell line. Our result revealed that VirD2 and VirE2 improved the efficiency of DNA integration into zebrafish ZF4 cell line genome.

This study was carried out to identify، evaluate of the diversity and density of phytoplankton and zooplankton during the different seasons in 2009 and 2010 from Chahnimeh water reservoirs of Sistan in Zahak province. In survey of plankton community in the Chahnimeh reservoirs، 10 phylum and 34 geniuses of phytoplankton were obtained. In the seasonal comparison، most of phytoplankton geniuses were determined in spring with 18 geniuses and the least diversity obtained in winter with 7 geniuses. In spring، summer and autumn seasons، most of the geniuses to the phylum of Chlorophyta with 43472، 4085 and 68933 numbers in litter were determined respectively. In winter highest density of the phytoplankton obtained for phylum of Myzozoa with the 11293 number per litter and then the most of the density was counted for Chlorophyta with the 9517 number per litter. In the survey of zooplankton community of these reservoirs، 7 phylum and 22 geniuses were identified. The greatest diversity of zooplankton was determined with 22 geniuses in summer and the lowest were obtained in autumn with 3 geniuses. In spring the highest density of zooplanktons were counted to the phylum of Rotifera with the 1273 number per litter. In summer، autumn and winter seasons، the highest density of zooplanktons was to the Arthropoda with the 1056، 190 and 1064 number per litter respectively. In according to the results، the seasonal variations can be effect on variations of planktonic density and diversity in Sistan Chahnimeh Reservoir’s. Population growth and increase of diversity of phytoplankton and then zooplanktons community in spring season may be is due to the improve of environmental factors and source of production for phytoplankton.

The zebra cichlid Cichlasoma nigrofasciatum is a species famous for its behaviors of biparental care. This study was conducted to examine the effect of parental care and their size on the reproductive success of this fish. Hatching rate (HRs) has significant difference (p<0. 05) in four parental care treatment، 1. bi-parental، 2. female-only، 3. male-only and 4. no-parental care. Mean hatching rate was 94. 81، 93. 36، 86. 15 and 84. 44، respectively. There was no significant difference in HRs between female-only and bi-parental care as well as no-parental with male-only care. Also، there were significant positive correlations of egg numbers (ENs) but not HRs to standard lengths (SLs) of parent (p≤ 0. 01). These results suggest that reproductive success of this fish primarily depends on bi-parental care and greater size.

Import of DNA into fish genome is generally inefficient. Therefore، one of the current challenges in fish tarnsgenesis is the development of efficient DNA delivery systems. Here we test using two bacterial proteins to target DNA to zebrafish ZF4 cell line genome. Agrobacterium tumefaciens، a soil bacterium، efficiently transfers DNA as a nucleoprotein complex to plant cells genome. Agrobacterium proteins VirD2 and VirE2 perform important functions in this process. We reconstitute this synthetic complexes consisting of the bacterial proteins VirD2، VirE2، and single-stranded DNA (ssDNA) in vitro، to test the potential of this approach to enhance gene transfer efficiency to zebrafish ZF4 cell line. Our result revealed that VirD2 and VirE2 improved the efficiency of DNA integration into zebrafish ZF4 cell line genome.