Iranian Journal of Fisheries Sciences
Volume:24 Issue: 3, May 2025

This study aimed to examine the effectiveness of mangrove (Avicennia marina) leaf powder (MLP) in the diet of Pacific white shrimp (Litopenaeus vannamei). The shrimp were fed with diets containing different amounts of MLP including 0 (control), 25 (MLP25), 50 (MLP50), and 100 (MLP100) g/kg MLP for 13 weeks. The results showed a significant improvement in the growth performance and survival rate of the shrimp fed different levels of MLP compared to the control group (p<0.05). Diets containing up to 50 g/kg MLP revealed significantly higher amounts of lipids and linoleic acid (LA), alpha linolenic acid (ALA) fatty acids compared to those of the control diet, while the carcass of shrimp fed diets containing MLP showed significant higher contents of polyunsaturated fatty acids (PUFAs) compared to the control diet, particularly DHA and ARA compared to those of the control group (p<0.05). After 48 hours of exposure to both low (4) and high (10) pH stress, the shrimp fed with different levels of MLP showed higher survival than that of the control group. The results of this study demonstrated the positive effect of dietary MLP on shrimp growth performance and resistance to pH stress.

This study presents the purification and characterization of novel recombinant trypsin derived from banana shrimp (Fenneropenaeus merguiensis) expressed in E. coli Rosetta-gami. The enzyme was purified using nickel sepharose chromatography and characterized through spectrophotometric kinetic and thermodynamic analyses, circular dichroism, and spectrofluorimetry. The cDNA encoding the putative trypsin, comprising 801 base pairs, was successfully isolated from the hepatopancreas of F. merguiensis. Sequence alignment of amino acids indicated a high degree of similarity (92-95%) with trypsins from F. chinensis, P. vannamei, and F. mondon. The purified recombinant trypsin exhibited a molecular weight of 23 kDa as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Optimal enzymatic activity was observed at pH 8 and 50 °C, with the enzyme demonstrating stability within a pH range of 7-9 and retaining approximately 50% of its initial activity across a temperature spectrum of 40-70 °C. The calculated half-life of the recombinant trypsin was 21.72 minutes at pH 8 and 50 °C. Kinetic parameters for casein as a substrate were determined, yielding Km, Vmax, kcat, and kcat/Km values of 130.4 μg/ml, 0.0617 μg·min-¹.ml-¹, 131.8 min-¹, and 1.01 min-¹μg-¹, respectively. Traditional methods for extracting trypsin from marine sources are inefficient. However, by utilizing recombinant DNA technology, we have produced a trypsin derived F. merguiensis with unique properties, including thermal stability and alkaline pH tolerance, highlighting its suitability for biotechnological applications.

A study of growth and reproductive parameters of Octopus vulgaris in the Moroccan Mediterranean (between Fnideq and Jebha) was carried out based on size frequency data of a sample of 14919 specimens (7891 females and 7028 males) from fishing trawlers and artisanal boats during 2015-2019. Different methods of FISAT II software including Powell-Wetherall, ELEFAN I, Shepherd, and Modal Progression Analysis were tested. Based on the annual sex ratio, females were slightly more abundant than males (1.06:1.00). Mature females were most abundant between June and September. Throughout the year, 53% of the males caught were mature on average. Length L50% and Weight TW50% were 15.56 cm, 2602.16 g for females and 10.77 cm, 991.30 g for males respectively. Compared with those found by other authors in the Mediterranean and Atlantic, and after the most appropriate growth parameters were selected, the Von Bertalanfy equation was estimated to be L(t)=28.76 (1- e-1.06(t - 0.386)) for combined sex. The size-age data obtained using the direct method and Bhattacharya's approach were substantially similar. The study of size frequencies from commercial data, even for octopus, would be a useful substitute to estimate size-at-age data required for stock assessment and fishery management.

The study investigated the effect of dietary supplementation with savory (Satureja hortensis) extract (SE) on stellate sturgeon (Acipenser stellatus) growth and health status. The fish with an initial body weight of 68.94±2.8 g were allocated randomly into 9 tanks, with a stocking density of 5 fish per tank and were fed with an un-supplemented diet (control, SE0), 1% SE (SE1), and 2% SE (SE2) for 8 weeks in freshwater. After 8 weeks, the feeding was stopped for 24 h and the blood samples were collected to measure immune parameters. The results showed that SE2 exhibited significantly higher values for final weight (164.67 g), specific growth rate (1.55 %/day), and weight gain (95.90 g) as compared to the SE0 (p<0.05). No statistically significant effects were noted among the experimental treatments in terms of the survival rate (p>0.05). The experimental diets significantly affect hematocrit and the highest level was observed in SE2. Total immunoglobulin, lysozyme, and ACH50 levels were significantly higher in the supplemented diets (p<0.05). The present study demonstrates that the administration of savory extract can improve the growth and immunity in stellate sturgeon.

β-glucans (BG) are widely used as an immunostimulant in aquatic animals through injection, feed, and immersion. The present study aimed to examine the consequences of dietary administration of yeast β-glucan on the immune response and susceptibility of Macrobrachium rosenbergii to the Vibrio parahaemolyticus infection. Experimental prawns (4.55±0.08 g) were fed a formulated commercial diet supplemented with commercial yeast BG at 0.0% (control), 0.1% (T1), 0.2% (T2), and 0.3% (T3). After the feeding trial of 75 days, a challenge test with V. parahaemolyticus (104 cfu/mL) was performed for seven days. No significant differences (p>0.05) were observed in terms of final weight, specific growth rate, and weight gain, but the prawns fed with 0.1% (T1) BG had the highest survival rates (100%). However, immune parameters, e.g. level of total hemolymph protein, albumin, globulin and hemocyte number, were found to be significantly higher (p<0.05) in prawns fed with 0.2% (T2) BG-supplemented diet. The total hemocyte count and total hemolymph protein, albumin, and globulin were reduced after the V. parahaemolyticus infection. The study's findings suggested that yeast BG can be used at 0.1% to 0.2% to enhance the immune response of juvenile M. rosenbergii and increase their resistance to V. parahemolyticus infection without upsetting the usual growth and survival.

The aim of this study was to determine the hemocyte type of medicinal leeches, Hirudo sulukii and H. verbana. It was also determined the fractions of hemolymph proteins in these leech species. According to the analyses, four types of hemocyte (prohemocyte, plasmatocyte, granulocyte, and eleocyte) were detected in two species. The prohemocytes have large nuclei, and their cytoplasm occupies a small area. The plasmotocytes are the most abundant hemocyte type. They are polymorphic cells and are found together as aggregations. The granulocytes are generally rounded in shape and typically have large granules in their cytoplasm. The eleocytes are the least found cells in hemolymph and have few granules in their cytoplasm. The areas of hemocyte types did not differ between the two species. Using polyacrilamid disc gel electrophoresis, it was determined that the hemolymph proteins of H. verbana were separated into 11 fractions or fraction groups. On the other hand, they were separated into 10 fractions or fraction groups in H. sulukii. In addition to qualitative differences, there were important quantitative differences between electropherograms of the two leech species. Therefore, these findings made a contribution to studies considering Hirudo sulukii as a new species different from Hirudo verbana.

The feeding habits of Epinephelus coioides and E. bleekeri were studied from Oct. 2019 to Sep. 2020 in the northern Persian Gulf and the Oman Sea. According to the results of the stomach content analysis, pelagic and benthopelagic prey were predominant in two species, and bony fishes were the main food for both species. The results of the diet overlap index showed a high overlap for these species: 0.98 in the Persian Gulf and 0.99 in the Oman Sea. It was also found that 64.29% of the prey of E. coioides juveniles were from benthic communities, while 21.34% were from demersal communities. Additionally, it was estimated that 100% of E. bleekeri juveniles in two regions fed exclusively on benthic preys. The analysis comparing the length classes of E.coioides and food overlap revealed that there is a high overlap (0.99) in prey consumed between the Persian Gulf and  the Oman Sea, as indicated by the canonical correlation. The significance of the Wilks-Lambda test (p>0.05), also supports this finding. The results of the SIMPER analysis showed a high degree of uniformity in E.bleekeri between the Persian Gulf and the Oman Sea (86.92%). This suggests that the prey consumed in different length classes do not overlap between these regions. However, Leiognathus lineolatus is the main reason for this difference, accounting for 8.03%. Switching the feeding habits of the studied species from benthic and demersal prey to pelagic, semi-pelagic, and benthopelagic preys requires fisheries management of forage fish and control of fishing gear.

Population parameters of three dominant benthic fish (Bartail flathead, Spotfin flathead, and Rough flathead) were estimated during the period from April 2022 to October 2023; The specimens were caught as by-catch of shrimp bottom trawlers, and also in coastal stake nets. The b value of the total length and weight relationship for the Bartail flathead was 3.23 and for Spotfin and Rough flatheads were calculated as 3.33 and 3.29, respectively, which revealed a positive allometric growth pattern in all species. Von Bertalanffy's growth parameters including TL∞, K, and t0 were estimated at 56 mm, 0.5 (Y-1), and -0.27 for P. indicus; 40 mm, 0.6 (Y-1), and -0.25 for G. suppositus and 33 mm, 0.9 (Y-1), and -0.17 for G. scaber, respectively. The natural mortality (M) for the mentioned species was estimated (at 0.95, 1.17, and 1.61 per year), fishing mortality (F) was (1.16, 1.39, and 2.57 per year) and total mortality was (2.11, 2.56, and 4.18 per year), respectively. The exploitation coefficient (E) was estimated at 0.55 for the Bartail flathead, 0.54 for Spotfin flatheads, and 0.61 for the Rough flathead, which indicates the relatively high fishing pressure on these species in the region. To mitigate this pressure, it is recommended to reduce fishing efforts, install bycatch reduction devices on trawl nets, and increase monitoring of coastal stake nets in the region.

1,3-dibromo-5,5-dimethylhydantoin (DBDMH) is a broad-spectrum and efficient disinfectant used in aquaculture. The present study aimed to know if the response of antioxidative defense system was reversible under different concentrations of DBDMH exposure. The fish were exposed to subacute concentrations of 0.06, 0.3, and 1.5 mg/L for 16 days and then transferred to DBDMH-free water for 10 days. Results showed that SOD/CAT (except 0.06), GPx (only 1.5), GR (only 0.3), T-GSH (only 1.5), and content GSH/GSSG ratio (0.06, 1.5) significantly increased at 1 day after exposure. SOD, CAT, GPx, GR, and T-GSH were decreased in all the groups at 2 days. The recovery results showed that SOD (0.3), GST (all groups), T-GSH contents (1.5), and GSH/GSSG ratios (1.5) were significantly increased, and it suggested the damage produced by 0.06~1.5 mg/L DBDMH were irreversible. The current study suggests such antioxidant responses could be used as the ecological biomarkers for monitoring residual DBDMH in aquatic environments of tilapia ponds, which also provides an early warning of DBDMH for wild fish because of the persistent existence in the contaminated water.

This study investigated the seasonal variation in the nutrient composition of four groups (with different average weights) of cultured olive flounder (Paralichthys olivaceus) to determine the optimal season and harvest size. The yield of 1 kg olive flounder did not vary throughout the seasons. The texture of the muscle tissue, levels of crude lipids, and vitamin E content in the 1 kg fish were highest in April and lowest in August. However, the levels in the 2, 3, and 4 kg fish were lowest in April, during the reproductive period, and highest in December. The vitamin E content in the fish muscle may correspond with high levels of crude lipids, possibly influenced by the spawning period. The 4 kg group had lower levels of crude lipid, texture, and vitamin E content than other fish, potentially owing to repeated spawning. The optimal harvest size for olive flounder was 3 kg based on nutrient evaluation.

This study aimed to compare the growth and yield of shrimp in different farms of the Heleh (H1, H2, and H3) and Shif (S1, S2, and S3) shrimp farming complexes and investigate the correlation between stocking density, aeration rate, automatic feeder usage, culture period, and harvested yield. Statistical analysis was performed to compare means for average daily growth rate, mean body weight, final yield (ton), survival rate (SR %), feed conversion ratio (FCR), and specific growth rate (SGR) across different farms. The results showed significant differences (p<0.05) between different farms for the parameters under investigation in the Heleh shrimp farming complex, while for Shif, no significant differences were found between different farms for average daily growth rate, FCR, and SGR (p>0.05). However, significant differences (p<0.05) were observed in SR (%), mean body weight, and final yield between different farms in Shif. Further analysis using Pearson correlation showed a high correlation (R>0.9) between the production level and the stocking density, aeration rate, and culture period. While the production level increased with an increasing number of automatic feeders, no significant correlation was found between these two parameters. Additionally, a positive correlation was observed between the SR (%) and the stocking density and the number of aerators. These results provide valuable insights into the factors that influence shrimp growth and yield, which can be useful for the development of more efficient and sustainable shrimp farming practices in both Heleh and Shif shrimp farming complexes.

Sperm short-term storage at low temperatures provides an advantage to control artificial reproduction in fish. However, spermatozoa lose their potential for motility and fertilization during the storage period that may be associated with microbial growth. In the present study, we used Zebrafish (Danio rerio) sperm to investigate the effects of bacterial contamination on spermatozoa motility and viability during short-term storage. Spermatozoa retained better motility characteristics during the storage period when sperm was diluted with an extender compared to the undiluted sperm. Inoculation of sperm with bacteria decreased spermatozoa motility in a concentration-dependent manner. Through the storage period, spermatozoa motility was not affected in sperm inoculated with 103 CFU/mL Vibrio harveyi or Pseudomonas aeruginosa. A significant decrease in spermatozoa motility was observed in the sperm inoculated with 108 CFU/mL V. harveyi and with 105 CFU/mL P. aeruginosa at 3 h post-storage. Next, we determined the effective concentrations of gentamicin to preserve spermatozoa against bacteria during short-term storage. The spermatozoa motility was similar to that of non-infected sperm when 0.08–0.15 and 0.02–0.04 mg/mL gentamicin was added to the sperm inoculated with 108 CFU/mL V. harveyi or P. aeruginosa, respectively. At 24 h post-storage, spermatozoa viability was significantly decreased in the sperm inoculated with 108 CFU/mL V. harveyi or P. aeruginosa, while it showed an increasing trend of spermatozoa viability in bacterially infected sperm with gentamicin. The results showed the detrimental effects of bacteria on spermatozoa motility during short-term storage, and determined effective dose of gentamicin to preserve spermatozoa against V. harveyi or P. aeruginosa. This study provides valuable information to develop artificial reproduction in Zebrafish research centers.

Tilapia is an introduced fish for aquaculture that spreads across Indonesia’s water resources. The study aimed to determine the mitochondrial DNA COI sequence, the genetic distance and phylogenetic of tilapia from Lake Toba, Lake Ranau, and the Balai Riset Pemuliaan Ikan (BRPI) Sukamandi, West Java. Five individuals were collected from each site, either wild and culture tilapia; strains of blue tilapia and red tilapia resulting from genetic development at BRPI. Basic Local Alignment Search Tool nucleotide (BLASTN) indicated that Oreochromis mossambicus and O. niloticus exist in natural water resources and culture in Sumatra and Java; O. aureus exists in natural water resources of Lake Toba and Lake Ranau, however, O. Urolepsis is only present at the research center of BRPI. The phylogenetic tree indicated four different subclusters of O. niloticus, O. mossambicus, O. aureus, and O. urolepsis; however, all are still in the same cluster with a bootstrap value of 88%.

Multidrug-resistant Salmonella can infect fish if reared in contaminated water or through manure in ponds that stimulate planktonic biomass. If the fish are not properly cooked, they can become a public health threat. Prior studies have reported the contamination of Salmonella in aquaculture products from marketplaces, however, our study determined the contamination of multidrug resistance Salmonella spp. through antimicrobial susceptibility in three fish (Labeo rohita, Oreochromis niloticus, Cyprinus carpio) from two retail markets in Lahore, Pakistan. A cross-sectional study was designed from June 2022 to August 2022 in two major fish markets in Lahore. Among 200 samples (L. rohita n= 80, O. niloticus n= 60, C. carpio n= 60), 16% were positive for Salmonella spp. with 3.12% of the isolates were resistant to 10 antibiotics, while 100% being resistant to at least two or more antibiotics. We detected high resistance to streptomycin (100%) and oxytetracycline (96.9%). Doxycycline and kanamycin followed a high resistance trend as well (87.5%). Moreover, lincomycin and trimethoprim (84.45%) resistance were also high in the Salmonella isolates. However, the lowest resistance was found against azithromycin (50%) and amoxicillin (40.6%). In addition, 100% of the Salmonella spp. isolates were multidrug resistant with seven different resistance patterns. Our study highlights the need to continuously monitor pathogens and restrict unnecessary drug use in aquaculture practices.

Five isonitrogenous and isoenergetic experimental diets of juvenile Pelteobagrus fulvidraco were formulated by replacing 0%, 15%, 30%, 45%, and 60% of fishmeal with cricket meal, named T0, T15, T30, T45, and T60, respectively. The experimental fish were cultured for 10 weeks. The results showed that with an increase in cricket meal content, the final body weight, weight gain rate, and specific growth rate of juvenile P. fulvidraco increased first and then decreased. The FBW, WGR, and SGR in T30 were significantly higher than those of T0, whereas the feed conversion ratio was significantly lower than those of T0 and T15. The hepatosomatic index in T30 was significantly higher than those of T0 and T15. The essential amino acid contents in juvenile P. fulvidraco muscle, arginine, and valine in T60 were significantly higher than those of T0. Compared with the T0, the content of glucose in the serum of T30, T45, and T60 had significantly increased, whereas the content of total cholesterol was significantly decreased. The activities of the serum superoxide dismutase and catalase in T30 and T60 were significantly higher than that of T0. In conclusion, these results suggested that replacing fishmeal with cricket meal has no effect on growth performance and muscle amino acid contents, and improves serum antioxidant capacity in juvenile P. fulvidraco.

Narrow-barred Spanish mackerel (Scomberomorus commerson) is one of the most important commercial fish species in the Persian Gulf and Oman Sea. Parasites of the genus Hysterothylacium (Ascaridoidea: Anisakidae) are common ascaridoid nematodes of fish-eating birds and sea mammals. The aim of this study is to identify morphological and molecular characteristics of the Hysterothylacium on S. commerson from April 2012 to December 2013. The morphological identification of Hysterothylacium specimens (n=10) was performed based on characteristic features, measurements and comparison with other publications. Larvae were counted, fixed in 70% ethanol and cleared in lactophenol for 48 h for identification. The molecular species description was based on a polymerase chain reaction (PCR) of sequences comprising ITS-1 and ITS-2. After the blast of nucleotide sequences, with the other recognized sequencing recorded in the GenBank, the most similarity was observed to Hysterothylacium persicum. Based on the morphological analysis and sequencing, the Hysterothylacium specimen was described as H. persicum. It is the first morphological and molecular identification of H. persicum in S. commerson from Iran. A combination of morphological description with a molecular technique seems to be the best practice for identifying anisakid larvae.