جستجوی مقالات مرتبط با کلیدواژه "fatty acids" در نشریات گروه "شیلات"

In the present study, the amount of proximate composition (protein, lipid, moisture, and ash) and the profile (quantity and quality) of fatty acids and amino acids in different parts of bigeye ilisha (Ilisha megaloptera) including (backbone, head, abdominal fin and viscera, caudal fin and fillet) were measured. The results of proximate composition showed that the amount of these compounds in different parts differed significantly and in many cases, the amount of macronutrients in waste parts was higher than fillet. The results of the analysis of fatty acids showed that different parts of the bigeye ilisha contain high levels of lipids rich in omega-3 long chain polyunsaturated fatty acids (n-3 LC-PUFAs) and long chain monounsaturated fatty acids (LC MUFAs). Among PUFAs, EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) had the highest percentages compared to other polyunsaturated fatty acids. The highest amount of EPA and DHA was found in the abdominal fin and viscera, respectively, equal to 1.986 g/100g (13.61% of total fatty acids) and 5.124 g/100g (35.11%). The ratio of omega-3 to omega-6 fatty acids (n-3/n-6) was different in different parts of the body, and the highest ratio was 17.433 in the abdominal fin and viscera. The highest percentage of the total essential amino acids was also present in the abdominal fin and viscera (43.14%). The lowest percentage of essential amino acids with the amount of 39.66% was found in the caudal fin. The amount of all essential amino acids in all cuts of bigeye ilisha was significantly higher than the amount recommended by FAO/WHO. The results of the present study showed that different parts of bigeye ilisha can be an ideal source of long-chain polyunsaturated fatty acids and essential amino acids.

The molluscs of Persian Gulf and Oman Sea have high nutritional value with high levels of protein, amino acids and fatty acids. Little researches have been done on determining the nutritional value of the identified species. This study was carried out with the aim of evaluating the nutritional value of the sea snail Babylonia spirata in Kanarak Wharf.Thirty sea snails (with an average length of 22±1.12 mm and an average weight of 7.8±0.14 g) from the mud and sand beds of Kanarak wharf (Sistan and Baluchistan province) were kept in cold boxes with powdered ice and transferred to the laboratory. Body chemistry, fatty acids and amino acids compositions were used. The results showed that the amount of protein, lipid, ash, moisture, and dry matter was 18.75, 6.49, 3.30, 70.63 and 29.37% respectively. Total essential amino acids and non-essential amino acids were equal to 15.95 g of amino acids/mg.The nutritional value of snail amino acid content is 60.50% compared to egg. The highest amount of amino acid in snail tissue was isoleucine (4.23 mg/g tissue), valine (3.06 mg/g tissue), lysine (1.10 mg/g tissue) and phenylalanine (1.09 mg/g tissue), respectively. In the analysis of the content of fatty acid groups, it was found that the highest amount among saturated fatty acids was palmitic acid (13.40±0.04%), stearic acid (6.29±0.23%), and heptadecanoic acid (6.17±0.18%) respectively.Among monounsaturated fatty acids (MUFA), eicosenoic acid (EPA, 20.80±0.33%) and palmitoleic acid (PA, 12.16±0.36%) showed the highest amount, respectively. While the highest amount of long-chain unsaturated fatty acids was respectively related to linoleic acid (LA, 20.27±0.24%), linolenic acid (LNA, 10.23±0.25%) and arachidonic acid (ARA, 2.08±31%). Also, the amount of eicosasterenoic acid (ETA) and eicosapentaenoic acid (EPA) was reported as 1.10±0.01 and 1.07±0.23%, respectively.The results of this research showed that the presence of amino acids (isoleucine) and fatty acids (linoleic acid) content, gives more economic value to sea snail B. spirata

In this study, the effect of lack and phosphorus deficiency (dipotassium phosphate; K2HPO4) on the growth rate, biomass, biochemical content, and fatty acid profile of Desmodemus sp. was investigated for 14 days. Accordingly, Desmodesmus microalgae were grown in culture media containing no phosphorus (P0), 10 (P10), 20 (P20), 30 (P30), and 40 mg/liter (P40). The P40 treatment was considered as a control group that had the amount of phosphorus required in the standard culture medium BG11. Based on the results, the highest cell density, specific growth rate, and biomass production were simultaneously recorded in the P20, P30, and P40 treatments on the 14th day of culture, which showed a significant difference from the other two groups (P<0.05). In addition, the highest chlorophyll a was also recorded in these three groups, which showed a significant increase compared to the group without phosphorus (P<0.05). The lowest chlorophyll b was recorded in P0 (1.62 mg/L) compared to other experimental groups (P<0.05). The analysis of body composition showed the highest amount of lipid productivity (14.93 mg/liter per day) in P20 treatment, which has a significant difference with other experimental groups, except for P10 (13.17 mg/liter per day) (P<0.05). The highest protein productivity rate was measured in P30 and P40 groups (P<0.05) and the highest carbohydrate productivity rate (10.55 mg/L per day) was measured in P40 without significant difference with P30 (8.87 mg/l per day). The highest amount of saturated fatty acids was observed in P0 (47.66% of total fat) and the highest long-chain unsaturated fatty acids in P40 treatment (30.58% of total fat) without significant difference with P30 (29.33% of total fat). Based on the results, the concentration of 20 mg/liter of phosphorus is a suitable concentration for the cultivation of Desmodesmus sp. microalgae for the production of biofuel, while the concentration of 40 mg/liter of phosphorus is a suitable concentration for the cultivation of the microalgae for using in the food and aquafeed industries.

Bacteria are used directly by zooplankton as a food source. The purpose of this study is to use straw as a substrate for the proliferation of bacteria in geomembrane pools and its effects on the production and biochemical compositions of Artemia. One week before Artemia culture, the pools inoculated with Dunaliella sp. and straw (particles less than 200 microns) as follows: treatment 1= geomembrane pool containing Dunaliella sp. (one week of algae cultivation), treatment 2 = geomembrane pool containing Dunaliella sp. and 0.5 grams per liter of straw (one-week algae cultivation and adding straw from the second week), treatment 3 = geomembrane pool containing Dunaliella sp. and 0.5 g/l of straw (algae cultivation and adding straw from the first week) and treatment 4= geomembrane pool containing 0.5 g/l of straw (adding straw from the first week). Artemia was cultured for 18 days and fed based on a turbidity depth of 15 cm. The highest growth rate was observed at the end of day 18 in treatment 3 (P<0.05). The highest amount of protein was obtained in treatment 1 (P<0.05). The highest amount of biomass was observed in the control and T3 groups (P<0.05). The presence of straw in Artemia pools decreased EPA fatty acid by 5-7 times less than the control (P<0.05). Artemia can grow while feeding on environmental bacteria. Applying straw in Artemia cultivation can lead to an increase in PUFA fatty acids with 18 carbon chains.

Dunaliella salina microalgae is a unique eukaryotic microorganism that has a high range of tolerance against environmental fluctuations including salinity, temperature, and light. The aim of this study was to determine the growth factors and content of fatty acids in D. salina under salinity and ultraviolet conditions. The experiments were conducted at three different salinities (150, 200 and 250 ppt) under UVB and UVC irradiations in 3 replicates. Algae growth rate and total algae biomass were measured by counting the number of cells every alternate day for 11 days by hemacytometer. The fatty acids profile was measured by gas chromatography and the amount of total fat using a soxhlet device. The growth rate of algae in most of the treatments under high salinity stress, UVB and UVC irradiation was significantly lower compared to the control group (P≤0.05). The highest cell counts were detected in the control one (2.4 million cells/ml) and UVB-150 treatment (1.98 million cells/ml) on day 7. But despite the higher cell count in the control group, the highest fresh wet weight of algae was obtained in the UVC-200 ppt/salinity group. Substantial differences were detected in the fatty acids profile between the treatments (P≤0.05). Algae cultured under UVB-200 contained the highest PUFA-n3 (20.05%) and the sum of PUFA (32.05%), while the highest PUFA-n6 (13.96%) was found in the UVC-150 group. Algae cultured at 250 ppt salinity without UV irradiation had the highest level (52.75%) of saturated fatty acids (SFA). It was concluded that UV irradiations and high salinity suppresses the growth but improves the synthesis of polyunsaturated fatty acids.

Coenzyme Q10, as an antioxidant compound, has a role in the electron transport chain of the animal cell. To study the effects of this natural antioxidant on the quality and composition of the fish carcass; rainbow trout were fed by five dietary treatments containing 0, 25, 50, 100, and 200 mg/Kg of coenzyme Q10 during an 8-week feeding trial. The results showed that coenzyme Q10 increased the pH and decreased the peroxide value of carcass fish on the first day of keeping in the refrigerator. The carcass thiobarbituric acid index was not affected by coenzyme Q10 at different refrigerator storage times (P< 0.05). Dietary levels of coenzyme Q10 significantly improved the organoleptic properties of fish flesh. Feeding the fish with various diet levels of coenzyme Q10 elevated the total omega-3, eicosapentaenoic acid, docosahexaenoic acid, and long-chain polyunsaturated fatty acids in the carcass compared to the control group. Overall, the results of this study showed that using coenzyme Q10 in the levels of 100-200 mg/kg of diet improve rainbow trout carcass quality.

With the development of aquaculture in the marine fish sector, the identification of the nutrient composition required by larvae in the early stages of life has more considered. Despite the obvious importance of nutrition in the development of larvae of Sparidentex hasta, which is an economic species in aquaculture at; the south of the country, due to the small size and sensitivity to manipulation of marine fish larvae, little information is available about nutritional needs. Embryo and yolk sac compounds are affected by reproductive nutrition and according to the vital role of fatty acids in membrane permeability in the larval stage; it is possible to increase the survival rate of larvae by proper management of the fatty acid compounds required at the beginning of initial feeding (dry food or live food enrichment). In this study, samples were taken in three stages of gastrula, at the time of yolk sac uptake and three days after complete yolk sac uptake (beginning of active feeding). It was then stored in liquid nitrogen and -80 ° C freezer until laboratory work was performed using GC gas chromatography. The most abundant fatty acids were oleic and palmitic and there was a statistically significant difference in different stages of fatty acids (P<0.05). According to the results in SFA and PUFA up to larval stage, the trend was increasing, and in MUFA, oleic, it was a decreasing trend. The reduction of some fatty acids is because of energy consumption and further increase is for the role of storage, especially in membrane tissue. Therefore, the amount and ratio of fatty acids in the early stages of the life of the Sparidentex hasta determines the minimum larval requirement in the initial diet.

The aim of this study was to evaluate different filling media on some quality characteristics of canned rainbow trout. For this purpose, three groups of filler materials including salt water, tomato sauce and sesame oil were used to produce canned products. After three months of treatment at ambient temperature, the results showed that the highest amount of free fatty acids in the treatment of tomato sauce (0.93.0% of oleic acid) and the highest amount of thiobarbituric acid was recorded in the treatment of brine (0.131 ±0.003 mg malondialdehyde/kg) (p < 0.05). Results of trout meat fatty acids profiles revealed that there was no significant difference between the amount of docosahexaenoic acid (DHA), saturated fatty acids, and monounsaturated fatty acids between the treatments of tomato sauce and brine (p < 0.05). However, the highest total amount of polyunsaturated fatty acids (PUFA) was observed in sesame oil treatment (2.76 ± 2.63 g/100 g oil) (P <0.05). The highest level of PUFA in the filler medium was observed in the treatment of sesame oil (43.37 ±2.89 g/100 g oil) and the highest level of DHA was observed in tomato sauce treatment (2.39± 0.15 g/100 g oil). The colorimetric scores also showed that the highest L* levels were related to salt water treatment and the lowest values were related to tomato sauce treatment, and also the highest values of a* (18.32±0.72) and b* (35.90±0.42) were observed in tomato sauce treatment (p < 0.05). The highest results of sensory acceptance were recorded in the canned trout filled with tomato sauce compared to other treatments. According to the results of this study, tomato sauce is recommended as the best filling medium in canned rainbow trout.

The main focus for this study was to compare and evaluate the quality changes and to determine the shelf life of frozen Scomberomorus commerson fillet using quick and slow freezing methods. Scomberomorus commerson fillets were frozen by slow and quick freezing methods and kept in the freezer at -18°C for 180 days. Then proximate analysis, chemical test (Total volatile base nitrogen; TVN, Thiobarbituric acid; TBA), drip loss, fatty acids profile and sensory analysis were assessed. Generally, Ash content, TBA, and TVN, drip loss, SFA values were significantly increased during storage time where as the moisture, protein, fat, PUFA and MUFA were significantly decreased (P<0.05). The ratio of TVN, TBA and drip loss was found to be higher in slowly as against quickly frozen fish. The PUFA (19.71), MUFA (23.40) and ω3 (14.69) of the quick samples was higher than that of the slow samples (16.99, 22.64, 12.34%, respectively). Regarding sensory analysis, both samples were in acceptable condition but the quality of quick samples was better than slow frozen samples. The quick freezing method was generally much more influent on quality parameters than slow freezing method.

Today, microalgae are considered as an important source for the production of biofuels and pharmaceutical products. However, the lack of an efficient and economical method for dewatering and harvesting their biomass is is an important challenge to achieve this goal. The important issue for choosing the harvesting method are species characteristics, final product value and energy consumption. Therefore, in this study, the effect of flocculation method with pH change technique (range 6 to 11) using sodium hydroxide and hydrogen chloride on harvesting efficiency, and fatty acid content of Dunaliella salina was tested. The results of this study showed that with the addition of sodium hydroxide and increasing the pH from 8.2 to 9.8, the flocculation process increased upwards from 18 to 90% and then remained constant until: pH 11. In contrast, increasing hydrogen chloride and creating an acidic environment up to: pH equal to 6 had no effect on clot stimulation. The highest coefficient of biomass concentration was observed in alkaline treatment with pH: equivalent to 9.8 which was 10 times the initial concentration (at pH equal to 8.2 the effect of alkaline pH induction technique and the centrifuge technique on the fatty acids content of biomass was tested. In the next stage, the effect of alkaline pH induction technique and the centrifuge technique on the fatty acids content of biomass was tested. The analysis showed that the percentage of lipid and fatty acids of harvested biomass were significantly different from each other. Based on the obtained results, the flocculation method by increasing the pH by 9.8 is a simple and relatively inexpensive technique with high efficiency and is suitable for harvesting Dunaliella salina microalgae for specific purposes.

In the present study, the effect of pre and post frying treatments on oil absorption and nutritional value of silver carp (Hypophthalmicththys molitrix) fillet were examined. Experimental treatments, including treatment 1 (control): normal frying; treatment 2: drying the fillets at room temperature before frying until reach a constant weight; treatment 3: normal frying, removing the oil from the fried fillet on a strainer in hot air until it reaches a constant weight; treatment 4: was the composition of treatment 2 and 3 (drying the fillets at room temperature before frying, normal frying and removing the oil from the fried fillet on a strainer in hot air until it reaches a constant weight; and the raw fillets were tested without frying. At the end of the experiment, chemical compounds, fatty acid profiles, and AI and TI characteristics of fish fillets were measured in various experimental treatments. The results of the study showed that the frying process caused significant changes in the chemical composition and the fatty acid profile of the fried fillets compared to the raw fillets. Examination of the fatty acids profile of fillet, as well as n-3/n-6 ratio and AI showed that these indicators increased due to normal frying compared to other experimental treatments. Also Frying reduces TI in frying experimental treatments. In general, it can be concluded that the total fat content of fish and the profile of its fatty acids can change during the frying process. Therefore, the use of pre-drying pre-treatment before frying and oil extraction in hot air after frying can be a way to reduce the oil adsorption by fried foods.

In this study, the effects of replacing fish meal with soybean meal on growth performance, feed efficiency, body composition, fatty acid profile and gut lactic acid bacteria of beluga sturgeon, Huso huso. Nine diets were formulated (40% crude protein) in which soybean meal was replaced by fish meal at 0 (control), 40 and 80% supplemented and with three multi-enzyme level 0, 1 or 2 g/kg of Kemin multi-enzyme. Fish were fed on experimental diets for 12 weeks at 1% body weight. Addition of soybean meal decreased growth performance and the effect was more pronounced when with increasing levels of soybean meal (P<0.05) and minimum final weight occurred at 80% of fish meal replaced by soybean meal. Body fatty acid composition was affected by dietary treatments. Fish fed the control diet; diets with enzyme supplementation (without the addition of soybean meal) as well as diets 4 and 5 (40% soybean meal; 0 or 1 g/kg enzyme) had the highest n-3 and eicosapentaenoic acid. In contrast, soybean meal at an inclusion level over 40% negatively influenced n-3 fatty acid. The lowest content of eicosapentaenoic acid and docosahexaenoic acid and n-3 fatty acid was observed in fish fed diets with 80% soybean meal without the inclusion of enzyme (treatment 7). Addition of soybean meal at both 40 and 80% replacement level regardless of enzyme supplementation increased the number of gut Lactococcus lactis, Lactobacillus carvatus, Pediococcus pentaseceous, Lactobacillus plantarum, total aerobic counts and total anaerobic counts. The highest number of bacterial counts occurred in diet containing 80% soybean meal with 2 g/kg enzyme (treatment 9) (P<0.05). The results of this study indicated that soybean meal with enzyme supplementation at 2 g/kg can substitute 40% for fish meal in commercial diets of great sturgeon.