Volume 75, Issue 1, 2023
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ItemReplacement of fishmeal by common cricket (Acheta domesticus) meal in diets for juvenile tilapia (Oreochromis niloticus)( 2023)The present study was to substitute fishmeal with domestic cricket (Acheta domesticus) meals in diets for tilapia (Oreochromis niloticus) farming. Productive performance was evaluated by two diets based on Pearson's square, the treatment T1 with 20% inclusion and treatment T2 with 35%, respectively, and a control T3 (commercial feed) performed in triplicate. Each treatment had ten organisms weighing 9+5 gr for 40 days. Initial biometry was performed, and after this, every five days until the end of the bioassay. The production and survival variables were evaluated; Finally, a proximal analysis of moisture, ash, lipids, and protein was carried out. According to the weight gain, the performance of the diets presented significant differences between the three diets. T2 diet results were similar to T3 (Control) due to tilapia being omnivorous and having excellent resistance and adaptability to different types of food. Therefore, the possible use of this food can be considered, favoring its economic impact on tilapia crops.
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ItemProduction and Growth Performance of Nannochloropsis oculata (Droop) Hibberd in the Helical Photobioreactor( 2023)Phytoplankton species preferred in marine fish farming are the primary food source in the larval and young stages of bivalve mollusks, along with some fish and shellfish larvae. For this reason, selecting the appropriate phytoplankton and production technique for feeding marine fish larvae is crucial. Nannochloripsis oculata microalgae species, widely used in rearing sea bream and sea bass larvae and feeding rotifers, has an essential place in our country. N. oculata microalgae species, which is used in rearing sea bream and sea bass larvae and feeding rotifers, was produced in a helical photobioreactor by applying a continuous production technique at 30 ‰ salinity, and its growth performance was aimed to be investigated. In the study, N. oculata was grown in a helical photobioreactor at 30‰ salinity by applying the continuous production technique for two weeks, and the daily cell number and specific growth rate were determined. The study was repeated three times. The supply of live feed for marine fish fry and hatcheries established for this purpose is one of the most critical problems. The latest technology in the production of microalgae, which is the primary link of the live feed chain in this sector, is continuous algae production in helical tubular reactors. The helical tubular reactor used in the study consists of a transparent hose system consisting of a completely tubular helical reactor designed for microalgae production. The helical tubular continuous production system offers more efficient and economically more convenient alternatives than existing production systems. One of the most essential advantages of this system is that the system can be designed without requiring significant capital. The continuous culture technique allows the application of long-term and safe algae cultures. With this system, besides providing continuity in production, the negativities in batch production can be eliminated with adequate light. Since the algae production with the continuous method in the spiral photobioreactor remains in the maximum growth phase for a longer time than the batch production, it is a system with high production efficiency and quality, and production capacity is guaranteed. In addition, the algae product harvesting in the continuous system ensures the daily harvesting of algae as much as half of the system volume. A helical reactor enables automation in algae production and high-quality production over long periods. In the study, the sowing density of N. oculata was determined as 1.068x106 ±0.006 cells/mL. Algin cell growth increased logarithmically during the first five days. From the 5th day to the 15th day, the increase in the number of cells was determined as 12.35x106±0.165 cells/mL at the highest and 8.76x106±0.709 cells/mL at the lowest. However, on the 13th day, it was determined that the increase in algin cells was 12.35x106±0.165 cells/mL, and the specific growth rate decreased by 0.189±0.016 divisions/day. As a result of the study, the number of cells of N. oculata algae 5-15 increased. It was determined that it increased 10 times between days. In this context, it was possible to harvest half of the reactor volume of algae daily at maximum cell density for long periods in the helical reactor
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ItemEffects of dietary guava leaf aqueous extract supplementation on growth, antioxidant capacity, and non-specific immunity in mud crab Scylla paramamosain( 2023)Mud crab (*Scylla paramamosain*) fed five different diets with varying concentrations of guava leaf aqueous extract (0 mg·kg^--1^, 80 mg·kg^--1^, 160 mg·kg^--1^, 320 mg·kg^--1^, and 640 mg·kg^--1^) for 30 days. Mud crabs in the 320 mg·kg^--1^ guava-leaf extract groups outperformed the control group in terms of survival rates (SR), weight gain rates (WGR), and specific growth rates (SGR). When compared to the control group, mud crabs in the 320 mg·kg^--1^ guava-leaf extract groups had significantly higher levels of lipase (LPS), pepsin, lysozyme (LZM), superoxide dismutase (SOD), acid phosphatase (ACP), and glutathione (GSH) (*P \< 0.05*). The amylase (AMS) activity was significantly decreased in all experimental groups (*P \< 0.05*). Malondialdehyde (MDA) content in the hepatopancreas of mud crabs in the 160 mg·kg^--1^, 320 mg·kg^--1^, and 640 mg·kg^--1^ guava-leaf extract groups were significantly reduced compared to the control group (*P \< 0.05*). Additionally, real-time PCR results illustrated that the expression levels of *GPx3*, *CAT*, and *JNK* were all considerably increased in the 80 mg·kg^--1^ guava-leaf extract groups compared to the control group (*P \< 0.05*). In the 160 mg·kg^--1^, 320 mg·kg^--1^, and 320 mg·kg^--1^ guava-leaf extract groups, the expression levels of *SOD* genes were considerably greater than the control (*P \< 0.05*), which was consistent with the level of SOD activity. *GST* and *P53* gene expression levels were significantly up-regulated in the 80 mg·kg^--1^, 160 mg·kg^--1^, 320 mg·kg^--1^, and 640 mg·kg^--1^ guava-leaf extract groups compared to the control group (*P \< 0.05*). Overall, the addition of 160 mg·kg^--1^-320 mg·kg^--1^ guava-leaf extract to the feed of *Scylla paramamosain* promoted growth, enhanced the activities of digestive and antioxidant enzymes, and strengthened immunity.
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ItemVisioning the future of Aquaculture in Hawai‘i( 2023)The University of Hawai‘i Aquaculture Program and the National Oceanic and Atmospheric Administration’s (NOAA) Hawaiian Islands Humpback Whale National Marine Sanctuary (sanctuary) co-hosted "Ho‘olālā i ka mahii‘a o kēia mua aku", a workshop focused on visioning the future of aquaculture in Hawai‘i. The workshop offered an opportunity to bring diverse stakeholders together to facilitate a dialogue on issues regarding aquaculture in Hawai‘i and to build relationships to promote future collaborations. Topics of discussion included food safety and security - sustaining local communities by enhancing locally produced and consumed foods; stimulating job creation while conserving natural and cultural resources, existing and future aquaculture projects, considerations for project siting and national aquaculture policies. A Workshop Advisory Team (WAT) was formed to plan the workshop and was comprised of cultural advisors, community and stakeholder representatives, and state and federal agency representatives. The WAT identified a workshop process, content, and potential participants. The workshop was the first of a series of planned discussions and brought together cultural and fishpond practitioners, community members, farmers, business and food industry representatives, subject matter experts, state and federal agency representatives and marine resource managers. The first day of the workshop was an information-sharing day open to the public. The format included presentations and panel discussions with opportunities for questions and answers. Presentations were provided on topics including: • Historical context of aquaculture in Hawai‘i • Current aquaculture activities in Hawai‘i • A national perspective of aquaculture • The role of the Department of Land and Natural Resources in the oversight of aquaculture in the State of Hawai‘i. Panel discussions included: Native Hawaiian aquaculture practices; today’s open ocean aquaculture; and cultural and environmental considerations in aquaculture practices. The remaining two days of the workshop focused on identifying common ground among the diverse participants to stimulate value-based discussions among multiple stakeholder groups. The remainder of the workshop focused on the Appreciative Inquiry (AI) strategic planning process for invited participants. Appreciate Inquiry is a process that identifies areas of common ground within a diverse group and is highly effective in stimulating discussions based on shared values among multiple stakeholders through a series of iterative and interactive sessions. The "Ho‘olālā i ka mahii‘a o kēia mua aku" workshop provided an opportunity for diverse stakeholders to expand participation in aquaculture-related conversations that involve cultural, community, economic, and natural resource interests. By utilizing the Appreciate Inquiry strategic planning process, facilitators worked with participants to identify commonalities and shared values that promote relationship building and allow for future collaborations. Discussions served to share and increase participants knowledge of a variety of issues including food safety and security - sustaining local communities by enhancing locally produced and consumed foods; stimulating job creation while conserving natural and cultural resources, existing and future aquaculture projects, considerations for project siting and national aquaculture policies. Additionally, it was recognized that although the workshop was an important step in visioningthe future of aquaculture in Hawai‘i, ongoing discussions will have to include additionalcommunities and stakeholder representatives to engage others in the process. To that end, fishpond revitalization and restoration were recognized as an important issue for many participants and there was agreement that a follow-up workshop should be planned for fishpond practitioners and agencies to discuss obstacles and challenges to fishpond restoration. This workshop will serve as an important venue to continue sharing knowledge and experiences relative to engaging community members to provide input in considering the future of aquaculture in Hawai‘i. This report provides an account of "Ho‘olālā i ka mahii‘a o kēia mua aku" workshop, a historical context and information on current aquaculture activities in Hawai‘i, and supplemental information regarding aquaculture projects globally. The intent of the report is to provide transparency and share information more broadly with those who did not participate in the workshop.
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ItemSeasonal variation of phytoplankton in My Thanh River, Mekong delta, Vietnam( 2023)A study on the seasonal variation of phytoplankton composition was conducted at the upper, middle, and lower parts of the My Thanh River, which supplies an important source of water for aquaculture. Qualitative and quantitative samples of phytoplankton were collected monthly at both high and low tide. The results showed that a total of 171 phytoplankton (algae) species were recorded, belonging to 59 genera and 5 phyla. Diatoms were the most abundant group with the highest species number, followed by green algae. The other phyla possessed a lower number of species. The species composition was more diverse in the rainy season and at high tide at most of the sampling sites. The mean density of algae varied from 30,900-43,521 ind.L^-1^. The density of diatoms was higher in the middle and lower parts. At the same time, euglenoids displayed the highest density in the upper part, showing a difference in the dominant algae group under the influence of salinity. Salinity was found to be significantly positively correlated (p<0.01) with diatoms, whereas it was negatively correlated (p<0.05) with blue-green algae and euglenoids. The algae composition was quite diverse, with the H' index ranging from 2.0-3.3, showing the water quality was slightly to moderately polluted.
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ItemEffects of guar gum supplementation in high-fat diets on fish growth, gut histology, intestinal oxidative stress, inflammation, and apoptosis in juvenile largemouth bass (Micropterus salmoides)( 2023)The present study aimed to investigate the influence of guar gum supplementation in high-fat diets on the growth performance and intestinal oxidative stress, inflammation, and apoptosis of juvenile largemouth bass. Five isonitrogenous diets were prepared: a control diet (10% crude lipid, C), a high-fat diet (17% crude lipid, HF), and three high-fat diets supplemented with 0.3% guar gum (GG0.3), 1% guar gum (GG1), and 3% guar gum (GG3). Largemouth bass (3.1±0.2 g) were randomly assigned to fifteen tanks (30 fish/tank) and fed for 8 weeks. The results demonstrated that GG0.3 significantly increased specific growth rate (SGR) and increased feed conversion ratio (FCR) compared to HF (P < 0.05). For histology, high-fat diets containing guar gum significantly increased intestinal villus length, villus width, and perimeter ratio, compared with HF (P < 0.05). Compared with Control, HF significantly decreased reduced glutathione (GSH) contents and increased malondialdehyde (MDA) contents in the intestine (P < 0.05). Additionally, HF significantly increased the expression of interleukin 1β (IL-1β), tumor necrosis factor α (TNF-α), and cysteine-aspartic proteases 9 (Caspase 9) in the intestine (P < 0.05). Compared to HF, GG0.3 significantly decreased MDA contents, increased GSH contents, and downregulated the expression of IL-1β, TNF-α, and Caspase 3 than diet HF in the intestine (P < 0.05). These results suggest that guar gum can alleviate the adverse effects of high-fat diets on growth and gut health in fish.
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ItemEffects of vitamin C on transport of Penaeus monodon( 2023)The experiment simulated the logistical transportation of Penaeus monodon. It set four distinct gradient Vitamin C (Vc) addition levels, including 0mg/L, 111mg/L, 222mg/L, and 333mg/L, to investigate the impact of Vc on the anti-stress ability of P. monodon during transportation. And the survival rate following transportation and a 15-day interim rearing period were recorded. Moreover, the alterations in tissue structure and activity of the enzymes alkaline phosphatase (ACP), alkaline phosphatase (AKP), total superoxide dismutase (T-SOD), and total superoxide dismutase (T-AOC) were checked. The results showed that with the increase of Vc supplemental level, the survival rate of P. monodon after transportation and after 15 days of temporary rearing increased to varying degrees. ACP and AKP in the hepatopancreas increased first and then decreased. T-SOD activity in the 0mg/L group was the lowest and then decreased gradually. The activity of total antioxidant capacity (T-AOC) in the 0mg/L group was the lowest and then stabilized. The branchial tissue structure also changed. The branchial tissue blood cell disorder decreased, the diaphragm gradually narrowed, the cornered cortex gradually recovered, and the swelling decreased. In conclusion, Vc positively affects the survival rate of P. monodon after transportation and temporary cultivation and alleviates the stress of P. monodon. The amount of Vc added at about 333mg/Lin, the transportation of P. monodon could play a positive role. The experimental results provide primary data for the transportation of P. monodon.
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ItemProfiles of cyclin B and cdc2 during ovarian and embryonic development in Exopalaemon carinicauda( 2023)Mitosis-promoting factor (MPF) is a complex formed by cyclin B (cyclin B) and cyclin-dependent kinase (cdc2). To investigate the role of MPF in the reproduction of Exopalaemon carinicauda, we cloned its full-length cDNA of the Ec-cyclin B and Ec-cdc2 genes. We analyzed their molecular characteristics and expression profiles during ovarian and embryonic development. The results showed that the Ec-cyclin B gene was 1194 bp long and encoded a 397 amino acid (aa) long protein. However, Ec-cdc2 was 900 bp long, which encoded 299 aa with a conserved cyclin binding motif PSTAIRE. The phylogenetic tree analysis showed that Ec-cyclin B had the highest homology with the cyclin B of Macrobrachium rosenbergii (81.06%). In comparison, Ec-cdc2 had the highest homology with the cdc2 of E. modestus (96.80%). Ec-cyclin B showed the highest expression in the ovary, whereas Ec-cdc2 was the highest in the hepatopancreas, followed by the ovary. In the five stages of ovarian development, Ec-cyclin B and Ec-cdc2 expression levels reach the highest at stage Ⅴ(p < 0.05). Overall, the expression of these two genes first increased and then decreased at different embryonic developmental stages. Therefore, these findings suggested that cyclin B and cdc2 played an essential role in the ovarian and embryonic development of E. carinicauda.
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ItemCharacteristics of the interferon regulatory factor IRF5 and its stimulation expression by Elizabethkingia miricola Infection in black-spotted frog (Pelophylax nigromaculatus)( 2023)Interferon regulatory factors (IRFs) have been confirmed as vital transcription factors for the immune system, which play a certain role in anti-infection defense, immune regulation, hematopoietic cell development, and maturation of the immune system. In this study, the cDNA of Interferon regulatory factor 5 (IRF5) was cloned from black-spotted frog, Pelophylax nigromaculatus, and termed PnIRF5. The results indicated, the full-length cDNA of PnIRF5 was 2090 bp, and a putative protein of 504 amino acids was encoded. The results of protein domain prediction suggested that PnIRF5 exhibited a DNA-binding domain (DBD), a middle region (MR), an IRF association domain (IAD), a virus activated domain (VAD), as well as two nuclear localization signals (NLSs). Phylogenetic analysis clustered PnIRF5 into the amphibian IRF5 subgroup in vertebrate IRF5 group. The results of qPCR show that PnIRF5 mRNA was expressed in all examined tissues, with higher levels were identified in the kidney, intestine, and lung. The gene expression of PnIRF5 was analyzed in kidney, spleen, and liver of black-spotted frog after challenged with Elizabethkingia miricola, and the maximum expression level of PnIRF5 in liver, spleen, and kidney were 1.80, 2.33 and 2.88 times that at 0 days post challenged, respectively. As indicated by the results, the PnIRF5 protein may take on critical significance in protecting black-spotted frog from E. miricola infection, and they may play a certain role in the immune response of black-spotted frog against bacteria.
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ItemStructure, sequence and phylogenetic analysis of the complete chloroplast genome of the brown algae Saccharina sp. ye-E (Laminariaceae: Phaeophyceae) from Sakhalin Oblast, Russia( 2023)For this investigation, the chloroplast genome of Saccharina sp. ye-E from Russia was uncovered and annotated with Illumina sequencing data to examine the phylogenetic relationship of Saccharina in Laminariaceae from a molecular biology perspective. Analysis of the structural characteristics, simple repeat sequence (SSR) loci, relative species differences, codon preference, and phylogenetic relationships was conducted. The results revealed that the chloroplast genome of Saccharina sp. ye-E had a length of 130,624 bp, containing 139 protein-coding genes (PCGs), 6 ribosomal RNAs (rRNAs) and 57 transfer RNAs (tRNAs) genes, and a total GC content of 31.1%. There were 15 SSR loci in the genome. Effective codon number (ENC) and codon adaptation index (CAI) both indicated the strong codon randomness and codon preference. The phylogenetic tree, based on the complete chloroplast genomes of 10 brown algae, showed that four species of Saccharina genus formed a clade, with Saccharina sp. ye-E and Saccharina latissimi having the most related genetic affinity. It is believed that the determination of the chloroplast genome of Saccharina sp. ye-E will be beneficial for future algal genetics evolution and systematic studies in the Laminariaceae.