Iranian Journal of Fisheries Sciences
Volume:23 Issue: 5, Sep 2024

The  present  study  was  conducted  to  evaluate  the  dietary  effect  of  nucleotide  on  growth performance and intestinal microbial flora in Siberian sturgeon (Acipenser baerii). Four hundred fifty fish of A. baerii (39.77±10.24 g initial weight) were distributed into 15 tanks (300 L) and they were fed with different levels of nucleotide (Ascogen®) including 0.0 (control), 0.2 (diet 1), 0.4 (diet 2), 0.6 (diet 3), and 0.8 (diet 4) g kg -1 in triplicates for nine weeks. The fish were fed daily until apparent satiety. The results showed no significant differences in the final length and survival rate among the experimental groups (p>0.05). However, the final weight, weight gain, daily growth rate, specific growth rate, and condition factor were significantly enhanced in the groups fed with diet 3 and diet 4 (p<0.05). The count of intestinal lactic acid bacteria (LAB) was the same among the experimental groups (p>0.05), while the total count of the intestinal bacteria was significantly decreased compared to the control group (free from nucleotide) (p<0.05). In conclusion, most of the growth indices were improved in the fish fed with nucleotide at 0.6 and 0.8 g kg -1. However, the treated diets could not affect the intestinal LAB population in Siberian sturgeon.

It is well known that ammonia nitrogen is a major pollutant in aquaculture, which can have toxic effects on fish. When absorbed in toxic concentrations, ammonia nitrogen can enter the bloodstream of fish, affecting blood parameters, immune responses, and causing oxidative damage and neurotoxicity. Recently, a study was conducted to investigate the toxic effects of ammonia on the blood, liver, growth, tissue damage, and immune indices of Cyprinus rubrofuscus in the presence of formaldehyde bisulfite sodium (FBS). The study involved 360 C. rubrofuscus, which were randomly distributed among 24 aquaria with a ratio of FBS to ammonia set at 31mg/L:1mg/L. The experiment was conducted with 15 fish in 6 treatments and 4 repetitions until 50% mortality was observed. The growth, histology, hematology, immunity, liver enzymatic and biochemical features of the fish were studied, and the results were analyzed using one-way analysis of variance (One-Way ANOVA) and Duncan’s test. The study found that the blood, immune, and liver indices of koi fish changed in the presence of FBS. Additionally, adding FBS to aquarium water reduced nitrogen compounds in fish storage tanks, further reducing the nitrogen compounds in fish aquaria.

Caulerpa racemosa is edible marine green algae of the Caulerpaceae family. C. racemosa is consumed as a sea vegetable in many countries, especially Southeast Asian countries. In recent years, molecular studies caused some changes in the taxonomic positions of the members of the genus Caulerpa. It is necessary to accurately identify species of this genus based on modern molecular studies due to the consumption of some species and also the toxic effect of some other species of this genus. Some species of Caulerpa have already been reported from the southern coasts of Iran based on preliminary morphological studies. The purpose of this study was to collect and accurately identify the species of the genus Caulerpa in the coastal waters of the Persian Gulf and the Gulf of Oman in the southern coastlines of Iran. This study was based on the combination of molecular and morphological characteristics studies of the collected samples of this genus in this area. In the current article, the results obtained about the Caulerpa racemosa are presented. Samples of the genus were collected from different coastal areas of the Persian Gulf and seashores of Oman Gulf along the geographical borders of Iran and transported to the laboratory in cool conditions. After cleaning and washing, some of the cleaned samples were dried in silica gel and used for DNA extraction and thereof PCR process based on tufA gene. In addition, herbarium samples required for morphological studies were prepared and deposited in the herbarium of Agriculture and Natural Resources Research and Education Center of Hormozgan province. The results of this study relatively solve the confusion in Caulerpa racemosa- peltata complexity for Iranian members of the complex. In addition to morphological features, the current molecular investigation also helped to accurately identification of the members of this complex in the Iranian seashores of the Persian Gulf and Gulf of Oman. As a highlighted conclusion, the current research on Caulerpa species from the Iranian seashores of the Persian Gulf and Gulf of Oman resulted in resolving two species including Caulerpa sertulariodes (S. G. Gmelin) Howe forma farlowii (Weber-Van Bosse) Børgesen, which was resolved as Caulerpa selago (Turner) C. Agardh (Salehi Balashahri et al., 2021) and Caulerpa racemosa var. macrophysa also resolved as Caulerpa racemosa (Forsskål) J. Agardh.

Plastic pollution has emerged as a pervasive global concern, with plastic waste contributing to the generation of microplastic particles (MPs) that have now integrated seamlessly into the human food chain. Intriguingly, early life exposure to MPs in children may occur through breast milk. This preliminary involved the analysis of human breast milk samples collected from 15 healthy breastfeeding mothers of the fishing community (BMSF) with daily habits of sea-food consumption and 8 healthy breastfeeding mothers (BMSH) with no history of seafood consumption in the past month and analyzed using microscopy and micro-Fourier-transformed infrared spectroscopy. In the BMSF group, a total of 276 MPs while 49 MPs were found in the BMSH group, indicating a substantial difference in MPs presence. The most prevalent MPs in both groups were fibers and pellets which fell within the size range of 5 to 18 µm, with polyethylene, polyvinyl chloride, and polypropylene being the most frequently observed types. Statistical analysis revealed a significant difference in the abundance of MPs between the two communities (F=13.57, P=0.001; Mann-Whitney U test, p<0.05). These findings emphasize the urgent need for further research to explore the potential health implications of MPs exposure through breast milk, especially in economically disadvantaged and vulnerable communities’ i.e. pregnant women, lactating mothers and children, with high seafood consumption.

Screening of marine bacteria for developing new drugs is an emerging field in marine biotechnology. The purpose of this study was to investigate the diversity of sponge-associated bacteria from Kish and Larak islands (Persian Gulf) and to determine their antimicrobial, antioxidant, and cytotoxic activities. After sampling, bacteria were grown on the marine sponge agar medium. The isolated bacteria were characterized by polyphasic methods. The antimicrobial activity of the isolated bacteria was determined by the microdilution broth method. Cytotoxic activity was evaluated by MTT (3-4,5-dimethylthiazol-2yl-2,5-diphenyltetrazolium bromide) assay on human cell lines. Antioxidant activity was performed by inhibiting DPPH free radicals. Among 121 bacterial isolates, Vibrio and Bacillus genera were the dominant frequency. The minimum inhibitory concentration of the extracted metabolites was recorded in the range of 64 to 512 µg/mL. The IC50 of antioxidant activity varied from 73.42 to 670.90 µg/mL. The cytotoxic activity of the extracted metabolites ranged from 40.57 to 181.80 µg/mL against SW 480 cell line and 141.30 to 359.70 µg/mL against HepG2 cell line. The HL 15, HL 85, and HK 5 extracts showed less toxicity against human umbilical vein endothelial cells. The results of genetic identification based on the comparison of 16S rRNA gene sequence showed that the potent strains HL 15, HL 24, HL 85, HK 5, and HK 36 belonged to B. safensis, V. alginolyticus, V. rotiferianus, B. aureus and Pseudomonas paralactis, respectively. The present study provided a new understanding of the diversity pattern and biological activity of the bacteria associated with Haliclona oculata.

The g-type lysozyme is one of the three major diverse lysozyme types recognized in the animal kingdom including fish. Using the RT-PCR technique, a 555 bp cDNA fragment encoding a g-type lysozymewas isolated from the skin mucus of Ctenopharyngodon idella using homolog primes. The cDNA named Ci-Kh, codes for 185 amino acids with a predicted molecular weight of 20.49 kDa and theoretical pI of 9.13. The sequence consists of one cysteine residue with no predicted signal peptide. Domain analysis showed e-value of 3.74e-107 with the conserved domain of lysozyme-like superfamily (cd01021) between amino acid residues 12 to 184. Multiple alignment with the lysozyme genes from other fish species revealed that this protein have a goose egg white lysozyme (GEWL) domain containing two conserved catalytic residues (Glu73 and Asp97) and N-acetyl-D-glucosamine binding site (Glu73, Asp85, Asp97, Tyr100, His101, His102, Ile119, Tyr147, Asn148). Protein structure prediction software revealed a prediction of 58% and 42% of a-helical and random coils for the coding sequence of Ci-Kh, respectively.The 3D model of Ci-Kh revealed that this protein was mainly composed of five main helices and random coils. Phylogenetic analysis indicated that Ci-Kh matched the group of five grass carp g-type lysozyme transcript variants with 86-99% similarity. Among the five variants of this gene, Ci-Kh sequence had the highest and lowest genetic distance with C. idella variant X2 (8.6%) and X3 (1.1%) sequences, respectively. We conclude that Ci-Kh as a different variant of g-type lysozyme cannot be ruled out.

Yersinia enterocolitica is the cause of yersiniosis in humans and its symptoms range from mild diarrhea to mesenteric lymphadenitis that may lead to appendicitis. In this study, the frequency and antibiotic resistance of Yersinia enterocolitica isolated from fish caught in Anzali wetland were investigated. Sampling was carried out for one year in four seasons from the autumn 2018 to the summer 2019 from four geographical directions: east, west, north and south, from different wetland levels. A total number of 91 fish were sampled from the body of these fish. Microbiological tests including biochemical tests, specific culture, and PCR were performed. In the specific culture method, 20 samples (21.97%) were contaminated with Yersinia enterocolitica. For the final confirmation of PCR, 20 samples were isolated from 14 samples (15.4%) containing specific culture method (6 Carp, 3 Anchovy, 0 Bream, 4 Pike Perch and 1 Pike) were infected with Yersinia enterocolitica. The chi-square test showed that there was no statistically significant difference between the various seasons (p >0.05), while there was a significant difference between fish species (p <0.05). Isolates from Yersinia enterocolitica using an antibiogram test of 10 antibiotics, the most susceptible isolates, Imipenem (92.8%), Kanamycin and Gentamicin (85.7%), Ceftazidime (78.57%). Cotrimoxazole and Nalidixic acid (71.4%) were the most resistant isolates to Ampicillin (64.28%), respectively. The results showed high levels of contamination of Yersinia enterocolitica, and indicative of potential dangers of Yersinia enterocolitica pathogenicity, especially in immunocompromised and susceptible individuals. Further studies on the pathogenicity of Yersinia enterocolitica in fish within the Anzali wetland and preventing sewage from entering the wetland are suggested.

Cyprinid herpes virus 3 (CyHV-3) is a significant threat to the production of common carp and koi, resulting in high mortality rates and posing a risk to the long-term sustainability of carp aquaculture. The presence of this disease in Iran has been confirmed by the veterinary organization and reported to OIE, with evidence suggesting its presence since 2021 in Iranian Koi and carp farms. Given the economic importance and rapid spread of CyHV-3, this review aims to provide a comprehensive summary of the current knowledge and research on the virus and its disease in Iran and worldwide.  The fish farmers and authorities in the country need to take necessary measures to prevent the spread of the disease and mitigate its impact on the aquaculture industry.

The European pilchard (Sardina pilchardus) plays a crucial role along the Algerian coast, forming a significant part of the local fisheries industry. However, overfishing has resulted in a decline in their population, which has had adverse effects on the fishery sector. This study was conducted to evaluate the current mortality rate and exploitation rate of the sardine S. pilchardus and investigate its growth and length-weight relationship along the Ghazaouet coast. A sample of 1576 specimens was collected from commercial purse seine catches on the western Algerian coast (Ghazaouet fishing grounds). The total length (TL) of the specimens ranged from 9.6 to 21.4 cm with an average of 14.6±1.86 cm, and the total weight (TW) varied between 6.2 and 57.8 g with an average of 25.4±9.57 g. The estimated growth parameters using the Von Bertalanffy approach have an asymptotic length L∞=21.26 cm, growth coefficient K=0.77 year-1, and age at zero length t0=-0.17 year. The results of the study showed that the length-weight relationship had an isometric growth (b=2.99) with a high correlation (r=0.95). The sex ratio showed no dominance between males and females (F+M/M=0.5). The instantaneous rate of total mortality (Z) was estimated to be 1.79 per year, with natural mortality (M) estimated at 0.65 year-1. Fishing mortality (F) and exploitation (E) were estimated at 1.14 and 0.64 year-1, respectively. Based on these results, the sardine stock in the southwestern Mediterranean Sea (western Algerian coast) is under higher fishing pressure. Consequently, it is imperative to implement management strategies that ensure sustainable levels of harvesting.

Age, growth, and reproductive traits of the South Caspian Spirlin in the southern part of the Caspian Sea basin, Tajan, River, were investigated. A comprehensive study was conducted on 663 specimens including 226 females, 297 males, and 140 unsexed individuals with a total length ranging from 25.88 to 121.66 mm. The specimens were collected using an electrofisher at monthly intervals. The female-to-male sex ratio was calculated as 1: 1.29. The growth rings on the scale were employed for age determination in this study. Both sexes exhibited only four age groups (0+ to 3+), with the 2+ age group dominating the population. Females consistently displayed larger sizes compared to males. The von Bertalanffy growth function yielded L t =123.90 (1- e -0.25(t+0.87) )  and L t =128.10 1- e -0.29 t+0.69  for males and females, respectively. Furthermore, the Fulton condition factor value was significantly higher in females than males. Notably, the maximum gonadosomatic index for both males and females coincided with the spawning seasons (May to August). Absolute fecundity varied from 290 to 1710 oocytes, with a mean of 793 oocytes. This study presents comprehensive data on the biological characteristics of the South Caspian Spirlin, providing valuable insights for fish stock assessment studies.