Volume 73, 2021
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ItemExpression analysis of three immune genes IL-8, IL-6 and IL-1β in the Japanese flounder (Paralichthys olivaceus)( 2021)Interleukin-8 (IL-8), Interleukin-6 (IL-6), and Interleukin-1β (IL-1β) are major immune-related genes that play important roles in the innate immune system of vertebrates. In this study, the expression levels of the three immune-related genes in eleven tissues of normal adult Japanese flounder (Paralichthys olivaceus) were examined using semi-quantitative RT-PCR at 13time points after challenge with Lipopolysaccharide (LPS). The results showed that the highest expression levels of the Japanese flounder IL-8 were detected at 12h in the spleen, 12h in the head kidney, and 24h in the liver after the challenge with LPS. Interestingly, the expression levels of IL-6 in the spleen and head kidney were highest at 48h. The liver had the highest expression level of IL-6 at 36h.The highest expression levels of IL-1β were detected at 3h in the spleen and 9h in the head kidney and liver. These results indicated that IL-8, IL-6, and IL-1β also played important roles in the immune response of the Japanese flounder at lower temperatures. The study provided a basis for further research on the immune mechanisms of IL-8, IL-6, IL-1β, and the production of recombinant IL-8, IL-6, or IL-1β used in Japanese flounder cultivation.
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ItemCharacterization, functional analysis and antibacterial activities of theromacin from the Akoya pearl oyster Pinctada fucata( 2021)The Akoya Pearl oyster Pinctada fucata is distributed over the coastal area of South China and is the most popular farming shellfish for seawater pearl production. Antimicrobial peptides (AMPs) could inhibit or kill pathogenic microorganisms. Theromacin has been proven to be an antimicrobial peptide, which plays an essential role in the body's immune system. The AMP gene to be identified was encoding theromacin in the pearl oyster Pinctada fucata (PoAP). The full-length PoAP cDNA contains 522 bp and consists of a 5’-UTR of 6 bp, an unusually long 3’-UTR of 749 bp, and an open reading frame (ORF) of 375 bp that encodes a 124 amino acid peptide with a molecular weight of 13.67 kDa and the theoretical isoelectric point of 9.25. Homology analysis of the deduced amino acid sequence of the PoAP with other known theromacin sequences by MatGAT software revealed that the PoAP shared 29.0%-46.8% similarity to the other known theromacin sequences. Signal P-N program showed that PoAP contains 33 amino acid signal peptides and a mature peptide located at amino acids 34-124; the mature peptide contains 12 cysteine residues and 13 alkaline amino acid residues with a molecular weight of 13.67 kDa and the theoretical isoelectric point of 9.25. The tempered program suggests that PoAP is a membrane protein with one transmembrane helix between amino acids 13 and 34. The PoAP gene was linked into prokaryotic vector pET-32α, and the PoAP fusion protein with 31 kDa molecular mass was successfully expressed in Escherichia coli BL21. Using His-Bind Purification Kit Protocol purifies the antimicrobial peptides recombinant protein and compares the bacteriolysis effect on Gram-positive and Gram-negative bacteria using the purified protein. The results show that PoAP proteins had a bacteriolysis effect on the Gram-negative bacteria but on Gram-positive organisms. The antibacterial peptides theromacin seem to play a crucial antibacterial function in the immune responses of pearl oysters.
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ItemA comparison of the physiological responses to heat stress of juvenile and adult starry flounder (Platichthys stellatus)( 2021)Water temperature is the most important factor in fish farming as changes in water temperature cause physiological stress in fish. There have been few studies on physiological responses to high temperatures, which vary with aging. This study investigated the responses of juvenile and adult Platichthys stellatus to heat stress. Plasma cortisol, glucose, lactate, and lysozyme levels, antioxidant enzyme activities, and expression of heat shock proteins 70 and 90 (HSP70 and HSP90) of P. stellatus were determined at water temperatures of 16, 20, 24, 28, and 30°C. As a result, it was confirmed that several plasma parameters of adult were significantly higher than that of juvenile under heat stress. Plasma cortisol and glucose levels of adult were increased than juvenile at 24 and 28°C. Plasma lactate level of adult were higher than that of juvenile at 28°C. Comparisons of survival and physiological changes showed that juveniles have better thermal tolerance, resulting in a higher cumulative survival rate. Moreover, the relationship between thermal tolerance and HSP gene expression revealed that expression of HSP70 and HSP90 was significantly upregulated at 28°C in both juvenile and adult fish, and HSP70 expression was significantly higher in juvenile fish than in adult fish. It is judged that the adult's HSP70 activity was lower than juvenile, so the demand for plasma parameters for heat response was relatively high, whereas juvenile's HSP70 activity increased at 24 and 28°C, indicating a relatively stable value of plasma parameters. These results indicate that the thermal tolerance of juvenile fish is greater than that of adult fish, based on the differences in plasma parameters and HSP expression. These findings improve our understanding of age-related changes in P. stellatus during thermal stress and may help guide the management of fish farms.
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ItemEffect of Power Pump and Nozzle Diameter Microbubble Generator to Increase Oxygen Concentration in Aquaculture( 2021)Various types of microbubble generators for use in aquaculture facilities for aeration. The aeration system is essential for high-density shrimp cultivation. However, there is a blockage in the microbubble generator aeration system, and generally, aeration at high densities requires considerable electrical power. In this study, modifications were made to various diameter nozzles and various pump power for microbubble generators. This research was conducted to determine the best microbubble by comparing the nozzle diameter and pump power. To achieve this goal, three diameter nozzles are combined with three different powers with an airflow rate of 2.5 LPM. The best combination of 32.5 mm nozzle diameter and 160-watt pump power. Produce bubbles ranging from 5.6 – 82 μm, with an increased oxygen concentration time of 60 minutes.
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ItemFirst report of Iridovirus (ISKNV) infection in Israeli mariculture gilthead sea bream (Sparus aurata) at the Mediterranean Sea( 2021)Megalocytiviruses have caused mass mortalities in various farmed fish species, both edible and ornamental. Infectious spleen and kidney necrosis virus (ISKNV) belongs to this family of viruses and induces lethal diseases in cultured fish. Here, we publish the first report describing this epizootic virus affecting the sea bream (Sparus aurata) in the offshore mariculture farm located in the Mediterranean Sea in Israel. The infectious agent was diagnosed with histology analysis and was identified as ISKNV by PCR.
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ItemEntirely Farm-raised Snubnose Pompano (Trachinotus blochii) Under High Salinity in Saudi Arabia( 2021)Snubnose pompano (Trachinotus blochii), a species of economic importance in the Red Sea region, has shown aquaculture potential in Saudi Arabia. The unique environment of the Red Sea causes aquaculture systems to operate under high salinity (42‰–45‰), but there is a lack of information regarding the culture of snubnose pompano in these conditions. This study estimated the survival, growth, and farming costs of snubnose pompano in two production systems: indoor and outdoor tanks. The experiments were performed in triplicate in 2020–2021, with 100 sub-adult fish per production system. The survival rate, growth performance, natural sexual maturation, and farming costs were determined. The results indicated that snubnose pompano culture is feasible under high salinity conditions using the indoor production system considering the significant differences in survival rate and growth performance, although the outdoor system had lower feed and labor costs. After 550 days of rearing, the sub-adult fish weighed more than 1,100–1,200 g, and both males and females had sexually mature gonads. These results show that spawning can be induced in high salinity (42‰) conditions. This study was the first to successfully farm-raise snubnose pompano in Saudi Arabia. Our results can thus be used as a reference for related research and aquaculture development in the Middle East region.
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ItemVariation of bacterial communities in black tiger shrimp (Penaeus monodon) with different growth performances( 2021)The intestinal bacteria of aquatic animals are closely related to their health and growth status. Penaeus monodon has become an important aquaculture species in the world because of its high nutritional value and market to demand. However, knowledge of bacterial communities on the growth phenotype of P. monodon is still limited. In this research, the bacterial community were comprehensively analyzed by using Miseq sequencing technology and bioinformatics. The results indicated that 29 phyla and 468 genera were identified by the taxonomic sequence. The data showed that the composition of microbial community was statistically different to fast-growing shrimps and slow-growing shrimps. There were significant differences in intestinal bacteria at the genus level. Lactococcus, Limnothrix, and Arthrospira had more abundance in the gut of fast-growing shrimps, which may promote the growth of P. monodon by affecting enzyme activities and improving immune response. Nautella, Shimia, Pseudoalteromonas, Aliiroseovarius, Albimonas, Tessaracoccus had more abundance in the gut of slow-growing shrimps. Nautella had the ability to express virulence by stimulated by environmental factors, thereby increasing the susceptibility to infection, which may have a negative impact on healthy growth of shrimps. Pseudoalteromonas, Aliiroseovarius and Shimia were related to the pathogenicity of shrimp, which may be an important factor affecting the growth of shrimp. Overall, this study demonstrates that the bacterial community associated with P. monodon was variation on different growth performance. These results can provide information on microbiome characteristics involved in the asynchronous growth of shrimp.
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ItemLysine requirement of the spotted scat Scatophagus argus (Linaeus, 1766)( 2021)The study aimed to determine the lysine requirement of young spotted scat Scatophagus argus (Linaeus, 1776) (average body weight = 10.7 g). The feeding trial was conducted for 8 weeks with 5 experimental diets which were isonitrogenous, isocaloric and isolipidic (35% CP, 18.3 MJ·kg-1, containing lysine levels as treatments containing equal dietary protein (35%) and lipid levels (5%) in 3 replicates. The lysine content was from 1.22 g to 1.94 g lysine·kg-1 dry diet (35 to 55 g·kg-1 CP) with an average content of 0.18 g lysine·kg-1 dry diet per treatment. Results showed that the growth rate, feed conversion and protein efficiency ratios were significantly highest at lysine level of 1.58 g·kg dry diet-1(45 g·kg-1 CP). Fish survival was not influenced by dietary lysine. Lysine requirement level for juvenile scat was estimated using quadratic regression of the percent weight gain (PWG) and specific growth rate (SGR) against dietary lysine level to have a mean value of 1.64 g·kg dry diet-1 (4.75 g·kg-1 CP).
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ItemReduction of Antibiotic-Resistant Bacterial Counts in a Mangrove-Riverine System in Capiz, Philippines - Preliminary Data( 2021)The anthropogenic impact of effluents and indiscriminate use of antibiotics in aquaculture promotes the emergence and proliferation of antibiotic resistant (ABR) bacteria. Comparative total bacterial and ABR counts were determined from 3 locations of the Cadimahan river of Capiz province, Philippines. The upstream station showed lower total bacterial but higher ABR counts, which is the inverse of the downstream station which showed higher total bacterial but lower ABR counts. The ABR counts accounted for 0.0173%, 0.0043% and 0.0002% of the total bacterial counts for upstream, midstream, and downstream, respectively, showing a strong inverse correlation of -0.84 in the Pearson correlation coefficient. This result suggests a remediating effect potentially mediated by microbial dynamics in the Mangrove-riverine system.
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ItemEffects of date (Phoenix dactylifera L.) kernel essential oil on growth performance and innate immunoassay in rainbow trout (Oncorhynchus mykiss) juveniles( 2021)This study aimed to investigate the effects of date (Phoenix dactylifera L.) kernel essential oil on growth and development performance parameters as well as phagocytic activity, respiratory burst activity, superoxide dismutase, lysozyme activity, and myeloperoxidase activity from immune parameters of rainbow trout (Oncorhynchus mykiss). The nutritional study was performed for 45 days to assess the effect of three concentrations (0.5, 1, and 2 mL kg-1) of date kernel essential oil in rainbow trout. β-citronellol, an important compound in many respects, was found 31.70% in date kernel oil. It has been determined that the addition of date kernel essential oil to rainbow trout feed decreases the feed conversion rate, increases the percent body weight gain, and the specific growth rate. It was observed that phagocytic activity, respiratory burst activity, and myeloperoxidase activity values improved in date kernel essential oil added groups, however, superoxide dismutase and lysozyme activity values were not affected. Consequently, date kernel essential oil can be act as a growth promoter, increase innate immunity, and cheap feed additive for the rainbow trout juveniles.
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