نشریه علوم و فنون شیلات
سال سیزدهم شماره 1 (پیاپی 45، زمستان 1402)

The aim of this study was to evaluate fish meal replacement by a bacterial single cell protein (IPL68) on growth performance, digestive enzymes activity (protease, lipase and α-amylase), gut histology and gut microbiota in rainbow trout fry (initial weight = 2.51 ± 0.55 g) for 6 weeks. Five diets were formulated with different bacterial SCP level (0:D1, 25:D2, 50: D3, 75:D4 and 100: D5 %) to replace fishmeal protein. At the end of the trial, body weight gain, specific growth rate, condition factor and hepatosomatic index showed the higher values than other diets with a significant differences (P<0.05). The food conversion ratio had the lowest and highest values in D3 and D5 diets, respectively, with a significant difference (P<0.05). The survival rate in all experimental diets was 100%. The highest activity of protease, lipase and α-amylase enzymes was observed in the intestines of fish fed with D3 diet, which showed a significant difference compared to D4 and D5 diets (P<0.05). The highest number of total bacteria and lactic acid bacteria was observed in diet D3, which was significantly different from other diets (P<0.05). The highest villus height (µm) and the ratio of villus height to crypt depth was observed in fish fed with D3 diet, which was not significantly different from D1, D2 and D4 diets, but showed a significant difference with D5 diet (P<0.05). Based on the obtained results, D3 diet can be suitable for the growth of rainbow trout fry compared to other diets.

The aim of present study was production of Fatir bread fortified with rainbow trout and silver carp meats and evaluation of its quality attributes during room temperature storage.

Different concentrations of cooked rainbow trout and silver carp meat (5, 10, 15, 20 and 25%) were added to the Fatir bread and sensory properties of prepared bread were measured. Then, selected treatments were stored for 9 days at room temperature and during this time the quality attributes were evaluated. 

Results of initial sensory evaluations were showed that the Fatir bread containing 5% of rainbow trout and 10% of silver carp were accepted. Results also demonstrated that the protein, lipid and moisture content of the bread were increased with addition of the fish meat. Fatir bread fortified with fish meat had higher TVB-N, peroxide and total viable bacteria during room storage period. In terms of flavor index, the control Fatir bread was acceptable until the end of the storage period, however, the breads fortified with fish meat were within the acceptable range until day 5.

Can be concluded that although fortified breads showed higher nutritional value, they had lower shelf life than control bread. Between fortified breads, the quality changes were lower in the bread containing rainbow trout meat.

Gobiidae family fishes play a significant role in coastal ecosystems with mud beds and mangrove ecosystems and also play a key role in the food chain in these areas. They are known as a heavy metal biomarkers. The aim of this study was to investigate the metals cadmium, lead and nickel in the muscle of two species including Cryptocentrus cyanotaenia in Hormoz Island and Boleophthalmus dussumieri in the Bandar Kamir. A total number of 30 fishes, samples for each species were collected from selected area and after biometrics and preparation and digestion steps to determine the concentration of nickel, cadmium and lead metals were analyzed by atomic absorption spectrometry. In this study, comparisons were made between the concentration of metals with a maximum of 13.10±1.88 and a minimum of 2.85±1.20 µg/g, respectively for  lead and cadmium in the muscle of B. dussumieri. The highest and lowest values ​​of 12.13±1.96 and 2.86±0.83 respectively were recorded for lead and cadmium in C. cyanotaenia muscle. By examining the correlation between the concentrations of metals in the muscle of the species, it was found that there is a positive and significant relationship between the concentration of metals in the muscle and their biometry (total length and total weight). The results showed that the studied Gobiidae family fish are suitable biomarkers for nickel, cadmium and lead metals.

In this study, the impact of marigold and spirulina, both in isolation and in conjunction with one another, was analyzed on several indicators relating to growth, immunity, survival, and levels of astaxanthin present in zebrafish tissue. 120 zebrafish were randomly allocated to 10 litre aquariums across four different treatment groups (with three replications in each group, each containing 30 fish). The control diet is based on the basic diet, the second treatment diet contains 25 g/kg of spirulina powder (SP) on the basic diet, the third treatment diet contains 25 g/kg of marigold powder (MG) on the basic diet, and the fourth treatment diet It also contains 25 grams of marigold powder (MG) and 25 grams of spirulina (SP+MG)/kg of the basic feed. At the end of the experiment, some immune indicators and astaxanthin were checked in the tissue. The results of this study show the significant effect of spirulina (SP), marigold powder (MG), and the combination of spirulina and marigold powder (SP+MG) on immunity, and astaxanthin. Especially the marigold and the combined treatment of spirulina and marigold showed better performance (P<0.05). respectively, SP+MG and MG treatment significantly increased total protein, lysozyme, and astaxanthin in fish tissue, and the highest amount of IgM was observed in MG treatment (P<0.05). However, no significant difference was observed in relation to growth and survival.

In this study, a comprehensive assessment of the occurrence and spatial distribution of heavy metals including Nickel, Lead, Zinc, Copper, Cadmium and Chromium, as well as, TPHs in the surface sediments of the coastal areas and far from the coast of the Persian Gulf in Bushehr and Khuzestan provinces were performed to identify the possible sources of sediment contamination and determining the degree of pollution. Eight pollution indices were used to evaluate the quality of sediments in terms of heavy metal and TPH pollution. The investigated areas could be distinguished by a significant degree of heavy metal pollution of Nickel, Cadmium and Zinc. High concentrations of Nickel and Zinc were observed in stations around Nakhiloo, Bushehr. The comparison of average pollution indices between regions showed that both Bushehr and Khuzestan provinces, respectively, with the average of contamination degree (CD) (20.25 and 22.11), modified contamination degree (MCD) (3.38 and 3.69), pollution load index (PLI) (31.17 and 57.57), potential ecological risk index (PERI) (353.54 and 349.39) have a significant degree and risk of Nickel and Cadmium pollution, especially in Nakhiloo area, Bushehr. Investigating the spatial fluctuations of the concentration of TPHs in two provinces showed an increasing trend from Bushehr to Khuzestan. However, areas were located in no pollution or low pollution zonation and were safe from the adverse biological effects of TPHs. Comprehensive and impressive strategies to control and reduce these pollutions, especially in polluted areas, should be considered, so that the sources of these pollutions be managed.

In the current study, fish-isolated protein (FPI) was extracted by alkaline pH method from the wastes of the head and fins of Siberian sturgeon (Acipenser baerii) and Iranian sturgeon (Acipenser persicus) and its composition, functional and structural characteristics were investigated. The results showed that the extraction efficiency according to the wet weight, the protein recovery of FPI, and the dry matter recovery of FPI from the Siberian sturgeon was higher than that of Iranian sturgeon. The results showed 91-94% protein in FPI of two species. The results did not show any significant differences between the proximate analysis and TVB-N (P> 0.05). The water absorption capacity, foaming capacity, and stability of FPI were shown at 30, 50, and 50%, respectively. The whiteness and transparency index of the FPI extracted was low. The results of particle size and zeta potential (P< 0.05) showed that the size of FPI particles in both samples is about a micron and they have a negative charge, so they can be easily used in colloidal systems. FTIR spectroscopy in both samples showed all the absorption peaks related to the main bonds of the protein structure. In general, considering the large amount of sturgeon waste in processing, and the amount of protein, functional properties, and nutritional value of FPI extracted from two species of sturgeon, there is the possibility of using them in human food and sports supplements.

Rainbow trout have found a good place in the household food basket due to their valuable nutritional properties. Therefore, supply in the form of hygienic packaging of this product due to CORONA pandemic in the country will be inevitable. This research has been done in order to provide intelligent packaging with the ability to detect microbial spoilage of rainbow trout. Fish fillet was packaged with H2S gas sensor based on FeCl3/Cellulose acetate. These packages were examined for total bacteria, temperatures swing, H2S producing bacteria and Escherichia coli (1×104 CFU/ml) during storage at 25 ° C for 3 days as well as storage at 4 ° C for 16 days. After imaging the correlation, the color changes of the sensor were calculated and evaluated as the color value. Sensor performance in terms of color change was significant (P <0.05) and the correlation between sensor color value and total bacterial growth in a 3-day period was 0.901. In order to accurately identify the growth of Escherichia coli, the correlation of Pearson color value and bacterial growth was equal to 0.932. Also, in the study the correlation between the color value with the number of total bacteria, temperatures swing bacteria and H2S producing bacteria were 0.835, 0.869 and 0.836, respectively. Using a sensor with a combination of iron (III) chloride and cellulose acetate to determine the microbial spoilage of rainbow trout can be used in the future as a consumer-centric quality control method that can be commercialized.

The present study was aimed to investigate the physicomechanical properties of biodegradable ternary films based on chitosan (CH) and starch (ST) at different ratios (100ST/0CH, 75ST/25CH, 50ST/50CH, 25ST/75CH and 0ST/100CH) via a simple casting method.The results showed that adding different ratios of chitosan (25-75%) to the control film (100ST:0CH)significantly reduced the moisture content, and elongation at break (EAB) and water vapor permeability (WVP) of the films, as the 75ST:25CH ratio has the lowest values; also, the solubility, tensile strength, contact angle and whiteness index of the films showed a significant increase compared to the control (p <0.05). FT-IR spectra of different films showed interactions through hydrogen bonding between the hydroxyl moieties of ST and amino moieties of CH in the blends, which enhanced the compatibility between the two polymers. On the other hand, the indicators related to the DSC test indicated that the thermal stability of composite films reduced after the addition of ST. SEM microstructural observations clearly demonstrated a re-organization of the surface of the two-phase films due to the presence of ST.The obtained results suggested the effectiveness of blending approach in improving the compatibility of polymers and overall functionality of films.

In the present study, the green tiger shrimp (Penaeus semisulcatus) processing wastes were hydrolyzed by alcalase in an enzyme-to-substrate ratio of 1: 100 under optimal conditions of temperature (55°C) and pH (7.5) for 16 hours, and the degree of hydrolysis was investigated. Also, the hydrolyzed sample during 300 minutes of hydrolysis, was fractionated by ultracentrifugal members having molecular mass cutoffs of 3, 10, and 30 kDa, and four peptide fractions were obtained. Then, the antioxidant activity (DPPH and ABTS free radicals scavenging activity) and the antihypertensive properties of hydrolysate and peptide fractions were measured at different hydrolysate concentrations. The degree of hydrolysis was the highest (31.86 ± 0.95%) at a hydrolysis time of 60 minutes. The results of DPPH radical scavenging activity showed that the peptidic fraction <30 kDa exhibited the highest scavenging activity compared to the other fractions (69.61 ± 0.15% at a concentration of 10 mg/mL). The highest rate of ABTS radical scavenging activity was also observed for the sample <30 kDa at a concentration of 2 mg/mL (99.38 ± 0.15%). Measuring the inhibitory activity of angiotensin-converting enzyme I (ACE-I) also revealed that although all samples could inhibit ACE (inhibitory activity between 12-53%), the highest inhibitory rate belonged to the peptide fraction <30 kDa (53.23%). In general, the results of this study showed that the peptides obtained from the hydrolysis of green tiger shrimp waste can be used as a natural antioxidant in the formulation of nutraceuticals.

Chitin is an important natural polysaccharide that is found in the cell wall of some organisms including crustaceans. The chitosan polymer, which is extracted from chitin, plays a very important role in the production of a wide range of materials used in food products. The present study aimed to extract chitin from the shell of the farmed shrimp Penaeus vannamei using the chemical method, through the steps of deproteinization, demineralization and deacetylation and using it as a natural coating with no negative effects, for protecting the covering of the fruits. To ensure the standard and determine the quality of the chitosan synthesized, FT-IR test was performed. Then, grape and strawberry fruits were covered by chitosan concentrations of zero (control sample), 0.2 and 0.5% as different treatments. During the two-month storage period at 0-4 degrees Celsius, and to control  of the changes in the fruits, the appearance quality factors in fruits were controlled weekly. Based on the results, the efficiency of chitin production from the shell was 58%, chitosan production from chitin was 84% and therefore, the efficiency of chitosan production from the shell was 48%, which is a suitable rate. The control samples of both fruits lost their appearance and shriveled in the first week of the test, and spoiled after three weeks. However, in bothe grapes and strawberries coated with dissolved chitosan with a concentration of 0.5%, the best antibacterial coating was created for the fruits and their appearance quality was maintained during the storage period of two months.