فصلنامه شیلات
سال شصت و نهم شماره 3 (پاییز 1395)

In the present study was evaluated the effect of dietary phospholipid on growth performance, nutrient digestibility and lipase activity in rainbow trout. Diets were prepared with 20% fat base which 60% of the experimental fat diet included fat powder. Phospholipids added in two levels (5 and 15 g/kg diet). Control diet was made without phospholipid and fat powder. 135 rainbow trout in each tank with initial mean weight of 27.45±1.88g were fed with experimental diet twice daily for 8 weeks. At the end of the experiment, growth performance, some plasma factor, nutrient digestibility and lipase activity were studied. Results of growth performance including BWI, CF, SGR, HIS, FCR demonstrated no significant differences between treatments and control group. But visceral somatic index was significantly higher in control group among treatments. Triglyceride value was significantly higher in control diet although, cholesterol didn’t have significant differences. Nutrient digestibility was significantly different among treatments. Fat and protein digestibility were higher in control and phospholipid 15, respectively and the lowest value was observed in the diet phospholipid 5. Supplemental phospholipid increased lipase activity significantly. The most value of lipase activity was observed in phospholipid 15. It seems that phospholipid provides a better growth performance due to increasing nutrient digestion and improves some parameters at level of 15g/kg in diet containing fat powder in rainbow trout.

In this study the effect of different percentages of composition of silver carp surimi and Indian white shrimp mince on the improvement of shrimp nugget texture was evaluated. Research treatments were consisted of control (full fried shrimp), S100, M70S30, M50S50, M30S70 and M100.The samples were analyzed for chemical and physicochemical properties (moisture, fat, water holding capacity and pH), physical characteristics (viscosity, product yield and shrinkage), color indices and sensory evaluation. The highest and the lowest amounts of moisture were observed in the control andM70S30 treatments, respectively. The control showed the highest amount of fat and the M70S30 treatment showed the lowest amount of fat. There were no significant differences in water holding capacity and pH between the control and treatments. Results of color indices were different in both pre- and final fried nugget shrimp and the control showed the highest amounts of lightness, redness and yellowness in comparison with other treatments. The control and M70S30 showed higher general acceptance compared to the other treatments. The results indicated that the use of surimi with shrimp mince for shrimp nugget production is possible and the optimal combination was M70S30.

Chlorpyrifos is an organophosphate pesticide that is widely used to control the pests in agricultural fields. The aim of this study is to determine the effects of sublethal concentrations (0.1, 0.05 and 0.02 mg/l) chlorpyrifos on the liver enzymes activities and oxidative enzymes (superoxide dismutase and catalase) in common carp (Cyprinus carpio) on 1, 7, 14 and 21 days. The present results suggest that a significant increase in the activities aspartate aminotransferase (AST) and alanine aminotransferase (ALT) fish exposed to pesticide chlorpyrifos compared with a control group (p

This experiment was conducted to evaluate the effect of different levels of dietary astaxanthin on the productive performance and stress resistance of Indian mackerel (Rastrelliger kanagurta). The experiment was conducted in a completely randomized design with 120 of Indian mackerel (with average weight of 7.14±0.01g) in 4 treatments and 3 replicates (n=10 in each replicate) and included: control group without using astaxanthin and another groups (treatment 2, 3 and 4) the amounts of this supplement were 50,100 and 150 mg/kg food. After 60 days of feeding, each treatment was exposed to acute crowding stress for 24 h. The results showed that compared with the control treatments containing astaxanthin showed significantly increase in serum total protein (TP), lysozyme activity and significantly decrease in alkaline phosphatase (ALP) activity, alanine aminotransferase (ALT) activity and aspartate aminotransferase (AST) activity (except to treatment 4) at 24 h after the initiation crowding stress (P

As the most of the efforts for sex determination of the sturgeon fishes have focused on the 3 years old and older specimens, it seems that the sex determination is not practically possible in the younger sturgeons. In this study we have examined 12 one-year old and 12 two-year old cultured Huso huso (Acipenseriformes) gonads from Qom province aquaculture site to check the possibility of sex determination. Histology and H&E staining were performed and light microscope was used for sex determination and gonad staging. 25% of one-year old fishes were male and 41.66% were female and the gender of 33.33% of them was unknown. Among 2 year-old fishes, the percentage of sexes, for both males and females was equal to 41.66% and the sex of 16.6% of them was unclear. One-year old females have oogonia and primary oocytes and their gonad stage was suggested as stage (I). In the Two-year old females, oogonia, primary and secondary oocytes were observed and their gonad stage was suggested as (I - II). Gonad stage of both one-year old and two-year old males was determined as stage (I). Our results show that histology and light-microscopic observation can be used to sex determination of two-year old and one-year old belugas.

Present study aimed to investigate salinity effects histopathological of kidney in Asian Sea bass (Lates calcarifer). For this purpose, juvenile fish with an average weight of 34.36±0.41 g were evaluated for 30 days. After 14 days of adaptation, the experiment carried out with 4 treatments and 3 replicates including 15, 35 and 50 gram per liter and fresh water. 15 fish were randomly introduced in each of the 12 fiberglass 300-liter cylindrical tanks. Fish feeding time was twice daily. The daily water salinity decline ratio was 3 ppt. At the end of experiment, kidney tissue was sampled and the histopathological studies (except 50 ppt) showed some changes including hypertrophy and urina tract epithelial tubule, reducing the lumen and the melanomacrophage aggregation, leukocyte infiltration and necrotic cells. Overall, sea bass fish was demonstrated a suitable compatibility in response to different salinity levels. Results indicated that this species could tolerate salinity changes up to brackish water and high salinity water.

To evaluate the barriers and factors affecting on per capita fish consumption in Sari, a field research was done with the administration of a structured questionnaire to the consumers in Sari. 266 respondents were randomly interviewed with regard to their attitudes and perception about fish consumption in 1393. Initially, descriptive analysis (such as frequency, mean and standard deviation) was performed on the data. Then, Freedman Test was used for analytical purposes and to investigate the factors influencing fish consumption through multiple linear regression analysis. Findings showed that price and fish smell were the main barriers to fish consumption, and income, family size, and occupation were significantly correlated with fish consumption. Also, it was found that the nutritional value of fish was the most important motivation of fish consumption among the consumers. The results showed that, beliefs about fish price more than its inherent characteristics, were significant regarding consumption barriers. Finally, it was suggested that politics for costs reduction of the production of farmed fishes in order to cost reduction of fish, development of fishery products odorless such as fish fillet and nugget as well as organizing commercial campaigns for consumers should be considered by fishery industry and public health activists.

Oxidation plays an important role in diseases and reduction of fats and oil quality in food products during processing and storage. Fish processing industry produce a lot of waste including skin, head, viscera, liver, and etc. These wastes contain good amount of rich protein material that are normally processed into low market-value products, such as animal feed, fish meal and fertilizer. Present work was conducted to study the effect of protein hydrolysis condition on antioxidant activity of hydrolysate obtained from Schizothorax zarudnyi wastes. Pepsin was used for protein hydrolysis and DPPH radical scavenging power was used to evaluate antioxidant activity of hydrolysates Hydrolysis condition variables were as enzyme concentration (1, 2, 3, 4, 5 and 10 %), substrate concentration (3, 4, 5, 6 and 7 g), reaction temperature (35, 37, 39 and 42 ºC), and hydrolysis time (6, 24, 30, 48, 72 and 96 hours). The optimum conditions obtained were as follows: enzyme concentration of 5%, substrate amount of 5 g, temperature of 37 ºC and time of 72 hours, under which, DPPH radical scavenging activity of 50.06 % was obtained.

The habitat is one of the most important factors in species conservation. Since conservational plans can be set using habitat characteristics that are used by endangered species. Accordingly, the present study aimed to investigate the habitat requirements of Capoeta damascina in the Kordan River. This rivers flow in central part of the Alborz province. Along the river, three sampling stations were determined (up-, mid- and downstream). Samples were collected from the summer and the winter. Three fish samples were collected from each sampling station using electrocution. Totally, nine samples were collected. Sampling points were roughly located at a 100-m distance from each other. Environmental parameters were recorded at each station including water velocity, depth, water temperature, pH, width of the river, sediment texture, and diameter of boulders and total organic matter of sediment. Suitability indices were calculatedwith a maximum score of 1 for each environmental parameter and their average was calculated as habitat suitability index. General additive model was used to find a relationship between environmental parameters and suitability indices. Results showed that the downstream area of the river (third station) was the most favorable habitat for C. damascina. The present study may be used to assess suitability of habitats using indicating species in freshwater streams.

The insulin-like growth factors (IGFs) have a fundamental role in induction and improvement of growth in animals. Lysine and Leucine are limiting essential AA in fish, and it has been demonstrated that supplementation with them improves growth in different species. However, the specific effects of AA deficiencies in myogenesis are completely unknown. IGFs in muscle can affect the expression of components of the local IGF system. Thus, the response of all these genes to IGFs administration at two different times 6 and 18 hours in day 4 cultured myocytes of the same species was analyzed. Also, in this study, two isoforms of IGF-IRs were characterized in gilthead sea bream. Both IGFs increased the expression of IGF-I and IGFBP-5, but showed different effects on the receptors, with IGF-I suppressing the expression of both isoforms and IGF-II up-regulating IGF-IRb. Likewise, this study aimed to provide new information on the impact of Lysine and Leucine deficiencies in gilthead sea bream cultured myocytes in days 2, 4 and 8. Leucine deficiency did not cause significant differences in most of the molecules analyzed, whereas Lysine deficiency appeared crucial in IGFs regulation, decreasing significantly IGF-I, IGF-II and IGF-IRb mRNA levels. It demonstrates the importance of an adequate level of Lysine in fishmeal diet formulation for optimum growth.

In this research, effect of dietaryCichorium intybus powder on growth and survival indices of Litopenaeus vannamei was investigated during 6 weeks in Chabahar Fisheries Research Center. Therefore, Cichorium intybus powder was added to the starter feed of Havorash Company as four treatments including 0, 0.5, 1 and 1.5 percent. 540 post larvae with average weight 0.09±0.01 g were randomly distributed to four experimental groups (with 3 replicate) in 12 tanks with capacity 70 liter. In during experiment, 30 shrimps per every 10 days were randomly biometry from each treatment. During the feeding period, the shrimps were fed in 8:00 am and 20:00 pm based on 6 percent of body weight. At the end of experiment, growth and survival parameters and resistance post larvae to salinity (15 and 45 ppt) and formalin of (100 ppm) were investigated. The results showed that growth and survival of shrimps under Cichorium intybus treatment was higher than the control group, and the highest rate of growth, survival and feed conversion ratio belongs to shrimps fed with 1.5 percent of Cichorium intybus powder (p˂0.05). The highest resistance against environmental tensions recorded in shrimps fed with 1.5 percent C. I. In general the results showed that the use of Cichorium intybus powder at 1.5 percent make to significant increasing in the growth and survival ratio of vannamei shrimp and it can be used as a dietary supplement in the diet of this species.

Secondary metabolites of Enteromorpha intestinalis were extracted and their antioxidant effects evaluated. Crude extract was isolated using 96% ethanol at 60 °C for 2 h and then fractionated in order by solvents including hexane, chloroform, ethyl acetate, butanol and water. Extraction yield for crude extract was 3.17% and it varied between 4.07%-40.83% for fractions. Crude extract and fractions exhibited DPPH radical scavenging activity (22%-72%), ABTS radical scavenging (25%-62%), ferric reducing capacity (25%-82%) and total antioxidant activity (0.17-0.34 Abs) among which ethyl acetate fraction shoed the highest antioxidant activity throughout experiments. Besides, butanol (24 mg TA/ gr extract) and ethyl acetate (22 mg TA/ gr extract) fractions contained the highest amount of phenolic contents among crude extract and fractions. Overall, the results of current study revealed that ethyl acetate fraction of seaweed E. intestinalis possess the major bioactive compounds and may be utilized as an antioxidant in food industry.