فهرست مطالب

  • Volume:11 Issue: 3, 2012
  • تاریخ انتشار: 1391/07/29
  • تعداد عناوین: 20
  • K. Amini, S. S. Siraj, B. Mojazi Amiri, S. A. Mirhashemi Rostami, A. Sharr, H. Hossienzadeh Page 440
    The Persian sturgeon (Acipenser persicus) is considered as an endemic sturgeon of the south part of the Caspian Sea and provides the highest Iranian caviar production. Due to overfishing, degradation of the rivers conditions of the natural reproductive habitats, the fish stocks is decreasing. The immature breeders do not response to hormonal therapy at the sturgeon hatcheries as most having PI (above 10) and large numbers of breeders caught and transported to the hatcheries were unable to reproduce. This study was attempted to find the effect of LHRHa implantation on oocytes maturation and spawning of Persian sturgeon. Broodstocks were caught from the southeast region of the Caspian Sea. The selected female broodstocks (PI>10) ranged in size from 24.0 to 37.5 kg were implanted with LHRHa cholesterol pellets at concentrations of 0 μg/kg (control), and treatments of 10, 15 and 20 μg/ kg (in three replicates. The results from this study indicated that females treated with LHRHa hormone implantation at 10, 15, 20 µg per kg body weight reached final maturation. These results were observed for all fish from treatment numbers 2 (15 μg/ kg) and 3 (20 μg/kg), however only one fish reached final maturation in treatment 1(10 μg/ kg). The current implantation of LHRHa was able to enhance breeders with PI above 10 to final maturation which under normal condition at sturgeon’s hatcheries this is not possible. The results suggested that final maturation can be achieved that lead to high fertilization (78.33% ±13.87, 68.33% ±4.16 in treatment 2 and 3, respectively) and hatching rates (85.3% ±9.07, 68.33% ±7.64 in treatment 2 and 3, respectively) and also total larvae production. Thus, the information from this study is very useful for artificial propagation of not-fully-matured females of Persian sturgeon at Sturgeon hatcheries especially in Iran.
    Keywords: Acipenser persicus, Broodstocks, LHRHa implantation, Artificial propagation, Fertilization, Hatching rates
  • S. Dehghan Madiseh, F. Esmaily, J. G. Marammazi, E. Koochaknejad, S. Farokhimoghadam Page 460
    Benthic invertebrates are a well-established target in environmental quality status evaluations. The AMBI (AZTI's Marine Biotic Index) was developed to determine the impacts and the quality status of soft-bottom marine benthic communities. The aim of this study was investigating multivariate pattern of benthic invertebrate community and application of AMBI (AZTI's Marine Biotic Index) for determining quality of health status in Khuzestan coastal waters. Seasonal samplings were collected from eight creeks over one year study by Peterson grab sampler, beginning from October 2005. All creeks are characterized by muddy bottom. According to sensitivity to environmental stress, macrobenthic animals classified into 5 ecological groups. Among 28 identified faunal groups the most abundant groups were polychaets, molluscs, crustaceans and nematodes, respectively. Two way ANOVAs showed only seasonal significant differences in mean abundance (P<0.05) and Margalef richness index values (P<0.05), while all of studied creeks shows similar biological characters based on benthic communities. According to annual mean of AMBI value all creeks were in ecological group III with slightly polluted condition, except for Darvish that was in unpolluted category. In the present study, although the number of species initially increased, but due to appearance of dominant species such as Capitella sp. and nematods (as opportunist species), diversity values reduced. In general, according to AMBI and Biotic index values, the most creeks are classified into unpolluted and slightly polluted categories except for Zangy, Doragh and Patil in summer and also Zangy and Bihad in winter which was in moderate to heavily polluted category. Different types of exploitation, industrial and shipping activities in this area could result in unbalanced to polluted status in benthic animals (as the best indicators in sediment quality assessment) so these results can be acceptable.
    Keywords: AMBI, Contaminant assessment, Khur, e, Mussa creeks, Persian Gulf
  • S. M. R. Fatemi, S. M. B. Nabavi, G. Vosoghi, M. Fallahi, M. Mohammadi Page 475
    Cochlodinium polykrikoides was bloomed in the Persian Gulf for the first time in September 2008, started from the Strait of Hormuz and then spread out towards the northern parts covering most of the areas of the Gulf and lasted 8 months. In order to find out environmental conditions during the bloom, a monthly sampling program was carried out in seven surface stations in 2008-2009. At each station, three samples (triplicates) were collected for phytoplankton analysis and also one sample for environmental analyses, including salinity, chlorophyll a and nutrients. Blooms of C. polykrikoides were observed with a seawater temperature of 20.1 to 31.0 °C, salinity 37.0-40.1 ppt and nutrient concentration ranges during the bloom and red tide were 0.064-0.707 mg/l nitrate + nitrite and 0.001-1.66 mg/l phosphate, respectively. Maximum of C. polykrikoides abundance was measured 26 × 106 cells L-1 in October 2008. Kruscal wallis test demonstrated a significant difference in densities and chlorophyll-a in different months and seasons not in different stations. This study showed increase of temperature (>31.0 °C) stopped bloom and red tide due to C. polykrikoides in both the eastern and middle sampling stations but in the western stations was determined decrease in nutrient amounts as the major factor therefore increased nutrient of coastal waters, and environmental conditions could have efficacy the occurrence of this dinoflagellate.
    Keywords: Red tide, Cochlodinium polykrikoides, Environmental conditions, Nutrients, Persian Gulf
  • M. Fuat Gulhan, A. Duran, Z. Selamoglu Talas, S. Kakoolaki, S. M. Mansouri Page 490
    Cypermethrin is a potential toxic pollutant that directly threatens the aquatic ecosystems and environment. Propolis, a natural product collected from plants by honey bees has many functions, such as antimicrobial, antioxidant, and anti-inflammatory. This study attempted to detrmine some biochemical and microbiological parameters of rainbow trout fillets after exposure to propolis and cypermethrin. The results of the current study revealed that levels of malondialdehyde (MDA), lactic acid, total volatile base-nitrogen (TVB-N), total counts of psychrophilic, and mesophilic bacteria increased in cypermethrin groups (P<0.05), compared to control group. Furthermore, there were no significant differences in pH levels between groups. Additionally, levels of MDA, lactic acid, TVB-N, count of psychrophilic, and mesophilic bacteria in cypermethrin+propolis treated groups were significantly reduce in comparison to exposed groups with cypermethrin (P<0.05). The findings also showed that the fillet quality some biochemical and microbiologic functions of fishes could be changed in groups that exposed to cypermethrin by propolis.
    Keywords: Biochemical parameter, Cypermethrin, Microbiological parameter, Propolis, Oncorhynchus mykiss
  • A. G. Harli, OĞ, Lu Page 504
    This study was carried out to investigate the apparent digestibility coefficients (ADCs) value of protein, amino acid and energy and body amino acid composition of rainbow trout fed solvent extracted soybean meal (SBM) and full-fat soybean meal (FFS) partly replacing fish meal (FM) in diets. Five iso nitrogenous (average 50.36% crude protein) and energetic (4294 kcal/kg total energy) diets were designed in 5 groups in triplicates. Diet one as control group with 43% FM and 25% SBM, Diet 2 with 28% FM and 40% SBM, Diet 3 with 13% FM and 55% SBM, Diet 4 with 28% FM and 40% FFS, Diet 5 with 13% FM and 55% FFS. Diets were fed to trout fishes with 49 g initial body weight for 20 weeks at 8.8±0.45 ºC. It was found that ADCs of energy, protein and most amino acids particularly methionine and lysine and fish body muscle lysine levels, significantly decreased by increasing the amount of FFS and SBM in diets (P<0.05). On the other hand, valine, isoleucine, threonine, methionine, phenylalanine, lysine and histidine showed a decreasing tendency with the increasing proportion of SBM in fish body composition. It was concluded that increasing the SBM and FFS percent replacing FM in trout fish diet, caused reducing protein, amino acid and energy digestibility, compared with the control diet. However, it can also be concluded that the replacement of SBM was more efficient than the replacement of FFS as regarding growth, ADCs of protein and essential amino acid contents of O. mykiss.
    Keywords: Rainbow trout, Oncorhynchus mykiss, Soybean meal, Full, fat soybean meal, Amino acid, Digestibility
  • F. Hasanpour, E. Hoseini, A. A. Motalebi, F. Darvish Page 518
    Studies were conducted to evaluate the effects of soy protein concentrate (SPC) and Xanthan gum (X) on physical properties of surimi prepared from Silver carp (Hypophthalmichthys molitrix) using various amount of soy protein concentrate (0, 5 and 10%) and xanthan gum (0, 0.25 and 0.5%) in fish paste during 3 months of frozen storage at -18ºC. Results obtained from folding test showed that the gel-forming ability of the gel treated with commercial blend (4% sorbitol+4% sucrose) was higher than the gels containing soy protein concentrate and xanthan gum (P< 0.05). Xanthan gum had a harmful effect on gel formation of surimi. The lowest expressible moisture values were reported for the gels containing 10% SPC and commercial blend (4% sorbitol+4% sucrose) that indicated the gels matrix had high water holding capacity (P< 0.05). During 3 months of frozen storage at -18ºC, gel-forming ability and water holding capacity of surimi were markedly decreased (P<0.05). Results of this studies demonstrated that the samples consisting commercial blend (4% sorbitol+4% sucrose) and 10 % SPC were more acceptable from the viewpoint of water holding capacity and gel forming ability, respectively.
    Keywords: Surimi, Soy protein concentrate, Xanthan gum, Gel, forming ability, Expressible moisture
  • T. Maghsoudloo, J. G. Marammazi, A. Matinfar, M. Kazemian, E. Paghe Page 531
    The present study was carried out in order to establish an economical effective diet for the pacific white shrimp in the southern part conditions of Iran. Three dietary energy levels (E1=262, E2=312, E3=362 Kcal 100 g-1 diet) and 6 ratios of fish meal (FM): soybean meal (SBM) [(P1= 100% FM+ 0% SBM), (P2= 80% FM+ 20% SBM),(P3= 60% FM+ 40% SBM), (P4= 40% FM+ 60% SBM), (P5= 20% FM+ 80% SBM),(P6= 0% FM+ 100% SBM)], 18 experimental diets were prepared. Completely randomized design was used to assign 54 polyethylene 300 litre round tanks provided by aeration and was stocked by 19 juvenile shrimp as 3 replicates to each treatment. Shrimps average weight was about 0.77 g at the start. After 56 days culture period, maximum growth and nutritional performance were observed in the P6E1 and P5E1 treatments. In addition, the highest survival rate of the shrimps was observed in the P1E1, P1E2, P3E3 and P5E3 treatments. Results indicated that protein, fat, fiber and ash contents of carcase were significantly affected by the treatments (P<0.05). Results of the present study suggest the replacement possibility of at least 80% of dietary fishmeal by soybean meal in the diet of pacific white shrimp in the conditions of southern part of Iran.
    Keywords: Pacific white shrimp, Fish meal, Soybean meal
  • M. Moghim, E. J. Heist, S. G. Tan, M. Pourkazemi, S. S. Siraj, J. M. Panandam, R. Pourgholam, D. Kor, F. Laloei, M. J. Taghavi Page 548
    In order to have a sustainable management on Persian sturgeon as a highly commercial species in the South Caspian Sea, we need to identify its population structure and the level as well as its conservation status in their natural habitat. To develop a conservation program for this all Caspian Sea' sturgeon species it requires knowledge of its genetic diversity using reliable molecular marker to study population genetic structure. For these purposes, an enriched library was prepared based on a modified biotin-capture method. Approximately 1800 positive clones were screened for microsatellites in an Acipenser persicus genomic library. Of these 350 positively hybridizing clones were sequenced, and 81 clones were identified as having microsatellites with adequate flanking regions. We developed and tested 68 microsatellite primer pairs for Persian sturgeon. Out of 68 primer pairs developed, 11 pairs resulted in poor or no amplification, 13 were ambiguous, 6 were monomorphic, 20 were tetrasomic and 18 were octosomic in Persian sturgeon. While none of the markers showed disomic inheritance in Persian sturgeon and Russian sturgeon (A. gueldenstaedtii). Several of the markers appeared useful for studies stellate sturgeon (A. stellatus), ship sturgeon (A.nudiventris) and beluga (Huso huso). Nearly all the polymorphic pattern for ship, stellate and beluga displayed the simple banding patterns characteristic of disomic loci, while those for Russian sturgeon displayed banding patterns characteristic of tetraploid or higher polyploid levels. These markers may prove useful in a variety of future sturgeon population genetic studies in the Caspian Sea.
    Keywords: Persian sturgeon, Acipenser persicus, Caspian Sea, Microsatellite, Population genetic
  • F. Parafkandeh Haghighi, F. Kaymaram Page 559
    The present study was carried out during 2006-2007 along the southern Caspian Sea. The species composition showed that the common kilka, Clupeonella cultriventris caspia, is dominant species with 89% and then anchovy, C. engrauliformis, has shown only 8.7% while it was already dominant species in the past decades. The overall results indicated that common kilka was replaced with anchovy kilka as previous dominant kilka species due to invasion of Mnemiopsis leidyi to the southern Caspian Sea. Anchovy suffered greatly from M. leidyi so that the total catch dropped from 95000 mt in 1999 to less than 20000 mt in 2007. In our survey, 1415 fish specimens were collected randomly, including 221 anchovy, 281 bigeye and 913 common kilka. The mean length of anchovy was 117.8 ± 0.27 mm, while it was about 93.0 mm during 1995 to 1998 before the invasion of M. leidyi. Analysis of age classes indicated the mean age of 4.5 ± 0.04 years for anchovy, 3.6 ± 0.03 for common kilka and 4.6 ± 0.08 for big eye C. grimmi. According to the age and the length structure of the specimens in this study, it could be concluded that in recent years, young fish population of anchovy has been decreased in comparison with the last decade. The results showed that some biological characteristics of kilka population were affected by M. leidyi. Recently fishing activities take place in shallow waters where schools of kilka are in suitable density for fishing. According to our results, ctenophore occupied the anchovy habitat where it was mainly more than 50 m depth. The fishing has moved to areas with depths less than 50 meters where it was the main reason to change in species composition.
    Keywords: Age structure, Caspian Sea, Clupeonella, Species composition, Mnemiopsis leidyi
  • J. Pazooki, M. Masoumian Page 570
    Two hundred forty seven species of parasites from Iranian freshwater fishes are presented in this synopsis. The parasites were recorded from infestations in fish from different parts of the country and summarized according to host species, organs were the parasite infestations occurred, province, faunal region and reference numbers. The following aspects of parasite infestations were also discussed: records of the most predominant parasites, the richest regions of parasite fauna, records of parasites according to province and the most severely infected fish species and finally host specificity in terms of exotic or endemic fish.
    Keywords: Parasites, Freshwater, fish, Iran
  • Pei, Min Yang, Guang, Hai Jin, Yi, Xin Liu, Jing, Wei Li, Zong, Yun Hu Page 590
    To investigate the ontogeny of Perccottus glenii, embryonic, larval and juvenile development of P. glenii were examined under captive condition. The fertilized eggs with numerous oil droplets were orange-pink in color, prolate spherical in shape and had average length of 3.32±0.14 mm and width of 1.24±0.04 mm. From fertilization to hatching, the ontogenesis of the fish spent more than 200 h, and the process of embryonic development was divided into 25 stages based on the morphological characteristics. The newly hatched larvae, with well-developed swim bladder and pectoral fins, measured 5.07±0.18mm in total length. Initial feeding occurred at day 2 after hatching (AH) and the complete absorption of yolk sphere was observed 3 days after hatching. At day 40 AH, scales and vertical pigment were found to be appear. Scales covered the entire body and all fins were well developed 70 days AH, at which time the juveniles reached the young stage with a total length (TL) of 24.74±4.28 mm. At day 140 AH, The fry with a TL of 29.57±4.65 mm, were morphologically similar to the adults except for size.
    Keywords: Perccottus glenii, Early development, Invasive species
  • M. S. Rahman, M. Shahjahan, M. M. Haque, S. Khan Page 602
    Euglenophyte bloom is a common problem in most of the aquaculture ponds in Bangladesh. In the present study we conducted an experiment to control euglenophyte bloom for getting better fish production using duckweed (Lemna minor) and lime. The experiment was carried out using four treatments, i.e., ponds were supplied with duckweed (T1), lime treatment (T2), both duckweed and lime (T3) and without supply of duckweed and lime (T4). Rohu, catla, mrigal, silver carp and silver barb were stocked and their gut contents were analyzed monthly. The ranges of water quality parameters were analyzed within the productive limit during the experimental period. The mean abundance of euglenophyte was significantly highest in T4 (17.62 ± 1.97 × 104 cells/L), followed by T2 (2.96 ± 0.20 × 104 cells/L), T1 (1.94 ± 0.35 × 104 cells/L) and T3 (1.53 ± 0.42 × 104 cells/L). Gut content analysis revealed that considerable amount of euglenophyte were consumed by silver carp and silver barb, but not preferred by rohu, catla and mrigal. The gross yields of fish were 2133.37, 1967.76, 2816.52 and 1725.62 kg/ha/5 months in T1, T2, T3 and T4, respectively. The highest fish production in T3 and lowest fish production in T4 indicated the use of duckweed and lime is economically sustainable for controlling euglenophytes bloom, maintaining water quality and getting higher fish production.
    Keywords: Euglenophytes, Bloom, Duckweed, Production, Pond, Water quality, Lime
  • M. Raissy, M. Moumeni, M. Ansari, E. Rahimi Page 618
    The present study was aimed to evaluate the antimicrobial resistance and the presence of antibiotic resistance genes in Vibrios spp. isolated from seafood. A total of 72 isolates of Vibrio in 6 species including V. parahaemolyticus, V. vulnificus, V. alginolyticus, V. harveyi, V. mimicus and V. cholerae were examined. The results revealed that all isolates were expressing multiple antibiotic resistances. Of the 72 strains tested, 70 were resistant to ampicillin (97.2%), 60 to gentamycin (83.3%) and 56 to penicillin (77.7%). Eight strains were resistant to 4 antibiotic, 19 resistant to five antibiotics, 10 to six antibiotics, 34 to seven antibiotics and one to eight antibiotics. Results also revealed that 20 Vibrio strains (27.7% of total examined strains) contained one to three of the antibiotic resistance genes. StrB, tetS and ermB genes coding for streptomycin, tetracycline and erythromycin resistance were found in 18, 6, 5 isolates, respectively and Sulfamethoxazole resistance gene, sul2, was not detected in this study. Detection of resistance genes in Vibrio strains obtained from seafood is considered as a potential danger for consumers and also suggests that these resistance determinants might be further disseminated in habitats, thus constituting a serious health risks to human.
    Keywords: Vibrio spp., Antimicrobial resistance genes, Seafood, Persian Gulf
  • E. Rezaei, S. Vatandoust, M. Kazemian Page 627
    Traditional morphometric measurements and meristic counts were used to investigate the hypothesis of population fragmentation of Mash mahi, Aspius aspius taeniatus (Eichwald, 1831) among two fishing areas in southern Caspian Sea basin(Tonekabon:32 specimens and Sari:34 specimens). Univariate analysis of variance showed significant differences between the means of the two groups for 12 out of 26 standardized morphometric measurement and three out of nine meristic counts. In discriminant function analysis (DFA), the proportion of individuals correctly classified into their original groups was 82.1% and 61.2% for morphometric and meristic characteristics, respectively. Clustering based on Euclidean distances among groups of centroids using an UPGMA and also principal component analysis’ results (PCA) for morphometric and meristic data indicated that two samples of Mash mahi were distinct from each other in these regions, while there were a relatively high degree of overlap between two locations.
    Keywords: Aspius aspius taeniatus, Morphometric, Meristic, Caspian Sea, population differentiation
  • A. Samcookiyaei, M. Afsharnasab, V. Razavilar, A. A. Motalebi, S. Kakoolaki, Y. Asadpor, M. Y. Yahyazade, A. Nekuie Fard Page 644
    In this research the affect of A. hydrophila on pathogenesis of Crayfish A. leptodactylus was carried out. This study was designed in three groups as treatments and one group as control in triplicate with 20 Crayfish in each glass aquarium. The treatments have exposed to A. hydrophila. The concentrations of the bacteria in treatments were, and CFUmL-1 respectively. The untreated control group was disinfected by oxytetracyclin at concentration of 100 ppm for 24 hours. The haemolymph samples were withdrawn for measuring of THC and TPC within interval hours (2, 6, 12, 24, 48, 96, 144, 240 and 336). The Crayfish samples were then fixed in Davidson fixative. The results showed that the differences of THC value between treatment 4 (95.33±23.16) and control (1.13±.45) were significant (P<0.05) as well as control and treatments 3 (35.33±16.16) and 4 (95.33±23.16) during 2 initial hours. In case of THC the significant difference (P<0.05) was observed between control group (72.33±15.04) and treatment 3 (13.13±5.85) after 48 hours. During 240 hours, also the difference of THC value between control group (80.33±24.94) with treatment 2 (14.67±3.51) was significant (P<0.05). The finding of TPP value showed that there was no significant difference between control group and treatments in during mentioned times (P<0.05). The result of histopathology in heaptopancreas and gill sections showed that hemocyte aggregation and necrosis within pyknosis of nucleus. In lower concentrations of bacteria no pathological changes of heart were observed. In digestive tract no changes were appeared in treatments, but in concentration of 3×108 CFU ml-1 a low aggregation of hemocytes was revealed.
    Keywords: Astacus leptodactylus, Aeromonas hydrophilia, Total Hemocyte Count, Total Protein Concentration, Histopathology
  • H. R. Esmaeili, A. Gholamifard Page 657
    The scanning electron microscope was used to investigate the ultrastructures of the egg membrane surface (unfertilized egg) of an endemic cyprinid fish, Cyprinion tenuiradius Heckel, 1849. The eggs of this species were almost circular in shape, had a smooth surface and one type II micropyle consisting of the flat pit and a long canal in the animal polar region. The micropyle region was not flat, micropyle was circular or oval in shape and the micropyle canal was located in its center. Round or oval accessory pores were also observed in the pit around of the micropylar canal. The surface of zona radiata was smooth with a uniform distribution of almost round pores with lips.
    Keywords: Morphology, Fertilization, Cyprinion tenuiradius, Micropyle, Accessory openings
  • S. Taheri, A. A. Motalebi, A. Fazlara Page 666
    The effect of aqueous solutions of ascorbic acid (AA) on the rancidity development in Cobia (Rachycentron canadum) fillets during frozen storage was studied. Cobia fillets were treated with ascorbic acid (AA 0.25% and AA 0.5%) then stored at -18°C up to 6 months. Rancidity development was measured by several biochemical indices including free fatty acids (FFA), peroxide value (PV), and thiobarbituric acid (TBA) and complemented by the sensory analysis (odor, consistency and appearance). In addition, pH and expressible moisture (EM) were measured during 6 months storage. Proximate composition was also determined in the first day. TBA, PV and FFA levels increased on all treatments due to lipid oxidation. Ascorbic acid showed antioxidative effect on Cobia fillets during frozen storage as indicated by TBA, PV and FFA levels. Results showed that free fatty acid, primary and secondary oxidation products, EM and pH value of AA- treated samples were significantly lower than those of the control samples (P<0.05). A gradual decrease (P<0.05) in sensory analysis were observed as the storage time increased. Results of our investigation revealed that ascorbic acid retarded oxidative changes in frozen Cobia fillets whereas AA 0.25% was not as effective as AA 0.5% on oxidative stability. Best oxidation inhibition results on fish fillets were obtained when employing a 0.5% AA solution.
    Keywords: Cobia, Lipid oxidation, Ascorbic acid, Frozen storage
  • B. Unver, S. Kekilli Page 681
    In this study, the reproductive biology of chub population in Hafik Lake was investigated. 242 samples were caught between April and November 2009. The age of S. cephalus samples were found to range between I-VIII; in addition, 153 of them were female and 89 were male. Their fork lengths changed between 114-332 mm, and body weights were between 22.5 and 550.3 g. Male specimens were determined to reach sexual maturity at II and III age, while females reached at III and IV years of age. The smallest female individual at sexual maturity had 114 mm of fork length and 27.3 g, while the smallest male at sexual maturity had 118 mm of fork length and 24.2 g. The mean gonadosomatic index of male and female specimens were found highest in April (12.33, 8.02) and May (8.37, 4.64) and minimum in August (2.39, 1.22). Egg diameters of chub individuals were measured between 343 µm and 1900 µm. The egg number in per one gram ovary was maximum in August, and minimum in April and May. S. cephalus was determined to lay eggs in Hafik Lake towards the end of April, which continued until the end of July. Maximum fecundity in population was observed as 151302 in the specimen at the age of VI.
    Keywords: Chub, gonad development, Hafik Lake
  • S. Yelghi, S. A. Shirangi, R. Ghorbani, H. A. Khoshbavar Rostami Page 693
    The grey mullet fingerling were imported to Iran in 1997 from Hong Kong and in coastal fish pond of north part of Iran were successfully cultured in order to obtain broodstocks and induce artificial reproduction. Seasonal changes in serum concentrations of Testosterone, 17-β Estradiole (E2), 17-α Hydroxy Progesterone and also the level of calcium, Triglyceride and cholesterol in females grey mullet in captivity were measured by Radioimmunoassay or colorimetry, respectively. Investigating of sex steroids in different sexual maturity indicated that increasing of oocyte diameter and sexual maturity development serum testosterone was increased significantly (P<0.05). Although Biochemical parameters concentrations in blood serum of grey mullet diminished significantly until third stage of sexual maturity (P< 0.05), their level showed a rising trend at the fourth stage. A significant increase was observed in the serum protein and cholesterol concentrations (P<0.05), while, in contrast, serum Calcium ion and triglyceride levels didn’t have significant differences in third and fourth stages of sexual development (P> 0.05). These results suggest that the seasonal changes in serum lipids and gonadal steroids were associated with reproductive development. The data also support the hypothesis that the shortening photoperiod is a major factor in stimulating reproductive activity in striped mullet.
    Keywords: Mugil cephalus, Ovarian development, Sexual steroid hormones, Captivity
  • E. Zakipour Rahimabadi, S. Dad Page 704
    The study aims to determine the influence of frying (shallow and deep) with olive, canola and sunflower oil on fatty acid composition of silver carp. Frying by olive oil and canola oil increased the monounsaturated fatty acids (MUFA) significantly (p<0.05) that consequently decreased saturated fatty acids (SFA), polyunsaturated fatty acids (PUFA) and ω-3 fatty acids. Frying by sunflower oil increased PUFA significantly (p<0.05), which caused to decrease in SFA and MUFA. The ω-6/ω-3 ratio of control samples (0.224) after shallow fat frying and deep frying, increased to 1.287 and 0.615; to 2.290 and 1.538; and to 9.381 and 5.950 by olive oil, canola oil and sunflower oil, respectively. Results suggest that frying oil can change the fatty acid composition of fish. The changes are depending to the kind of frying oil and method of frying which used.
    Keywords: Frying_Fatty acid composition_ω 6_ω 3 ratio_Silver carp