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Newly developed mRNA vaccines induce immune responses in Litopenaeus vannamei shrimps during primary vaccination

See SA, Bhassu S, Tang SS, Yusoff K

Dev Comp Immunol, 2025 Jan;162:105264.
PMID: 39299363 DOI: 10.1016/j.dci.2024.105264

White spot syndrome virus (WSSV) causes highly destructive infection in crustacean aquaculture, often resulting in 100% mortality within a week. However, there is lack of studies addressing the safety issues of WSSV vaccines in shrimps. In this study, WSSV VP28 mRNA vaccines were developed using codon deoptimization approach. These vaccines were administered to Litopenaeus vannamei shrimps at various dosages to access their safety and the shrimps' immune responses using quantification PCR (qPCR). The findings of this study indicate that the expression level of codon deoptimized VP28 mRNA vaccines are lower compared to the wild type VP28 vaccines, as observed through a comparison of bioinformatic predictions and experimental results. Additionally, the total haemocyte count (THC) in shrimps injected with codon deoptimized VP28 vaccine was higher than those injected with wild type VP28 vaccines. Furthermore, the expression of immune-related genes differed between codon deoptimized and wild type VP28 vaccines. In summary, the results suggest that 0.01 μg codon deoptimized VP28-D1 mRNA vaccine is the most promising WSSV mRNA vaccine, displaying low pathogenicity and expression in shrimps. To the best of our knowledge, this research represents the first attempt to attenuate WSSV using codon deoptimization method and development of a potential mRNA vaccine for shrimp purpose. The study addresses an important gap in shrimp vaccine research, offering potential solutions for WSSV control in shrimps.

Matched MeSH terms: Aquaculture
Effects of some dietary crude plant extracts on the growth and gonadal maturity of Nile tilapia (Oreochromis niloticus) and their resistance to Streptococcus agalactiae infection

Kareem ZH, Abdelhadi YM, Christianus A, Karim M, Romano N

Fish Physiol Biochem, 2016 Apr;42(2):757-69.
PMID: 26643907 DOI: 10.1007/s10695-015-0173-3

A 90-day feeding trial was conducted on the growth performance, feeding efficacy, body indices, various hematological and plasma biochemical parameters, and histopathological examination of the gonads from male and female Nile tilapia fingerlings when fed different crude plant extracts from Cinnamomum camphora, Euphorbia hirta, Azadirachta indica, or Carica papaya at 2 g kg(-1) compared to a control diet. This was followed by a 14-day challenge to Streptococcus agalactiae. All treatments were triplicated, and each treatment consisted of 30 fish. Results showed that C. papaya extracts were the most effective at delaying gonadal maturation to both male and female tilapia, as well as significantly increasing (P < 0.05) growth performance compared to the control treatment. Similarly, dietary C. camphora and E. hirta extracts also significantly improved growth, while no significant growth effect was detected between the A. indica and control treatments (P > 0.05). Further, crude body lipid was lower in the C. camphora, E. hirta and C. papaya treatments, but was only significantly lower for the E. hirta treatment compared to the control. Meanwhile, none of the hematological or biochemical parameters were significantly affected, although plasma ALT was significantly lower for tilapia fed A. indica compared to the control. After the 14-day bacterial challenge, tilapia fed C. camphora supplementation had significantly higher survival, compared to the control, but was not significantly higher than the other supplemented diets. Results indicate that dietary C. papaya extract can significantly promote growth and delay gonadal maturation to both male and female tilapia, while C. camphora was the most effective prophylactic to S. agalactiae and may be a cost-effective and eco-friendly alternative to antibiotics.

Matched MeSH terms: Aquaculture/methods*
Fulltext Comparative analyses of response surface methodology and artificial neural network on medium optimization for Tetraselmis sp. FTC209 grown under mixotrophic condition

Mohamed MS, Tan JS, Mohamad R, Mokhtar MN, Ariff AB

ScientificWorldJournal, 2013;2013:948940.
PMID: 24109209 DOI: 10.1155/2013/948940

Mixotrophic metabolism was evaluated as an option to augment the growth and lipid production of marine microalga Tetraselmis sp. FTC 209. In this study, a five-level three-factor central composite design (CCD) was implemented in order to enrich the W-30 algal growth medium. Response surface methodology (RSM) was employed to model the effect of three medium variables, that is, glucose (organic C source), NaNO3 (primary N source), and yeast extract (supplementary N, amino acids, and vitamins) on biomass concentration, X(max), and lipid yield, P(max)/X(max). RSM capability was also weighed against an artificial neural network (ANN) approach for predicting a composition that would result in maximum lipid productivity, Pr(lipid). A quadratic regression from RSM and a Levenberg-Marquardt trained ANN network composed of 10 hidden neurons eventually produced comparable results, albeit ANN formulation was observed to yield higher values of response outputs. Finalized glucose (24.05 g/L), NaNO3 (4.70 g/L), and yeast extract (0.93 g/L) concentration, affected an increase of X(max) to 12.38 g/L and lipid a accumulation of 195.77 mg/g dcw. This contributed to a lipid productivity of 173.11 mg/L per day in the course of two-week cultivation.

Matched MeSH terms: Aquaculture/methods*
Biodiversity of chloramphenicol-resistant mesophilic heterotrophs from Southeast Asian aquaculture environments

Huys G, Bartie K, Cnockaert M, Hoang Oanh DT, Phuong NT, Somsiri T, et al.

Res. Microbiol., 2007 Apr;158(3):228-35.
PMID: 17350231

In the present study, samples of pond water, sediment and farmed species were collected at 12 fish and shrimp farms in Malaysia, Thailand and Vietnam to determine the biodiversity and environmental distribution of chloramphenicol-resistant (CmR) mesophilic heterotrophs in Southeast Asian aquaculture sites. Following isolation on Iso-Sensitest agar supplemented with 35mug ml(-1) Cm and dereplication using (GTG)(5)-PCR fingerprinting, 557 genotypically unique CmR strains were subjected to polyphasic identification. The 557 mesophilic heterotrophic CmR isolates represented 18 different genera largely dominated by the genera Escherichia (40.2%), Pseudomonas (11.7%), Acinetobacter (11.1%), Klebsiella (7.5%) and Bacillus (5.9%). A total of 439 CmR isolates were further assigned to 31 described species or species groups, mainly including organisms that have been associated with various human opportunistic infections such as Escherichia coli (n=219), Pseudomonas putida (n=47), Klebsiella pneumoniae (n=38) and Acinetobacter baumannii (n=23). Strains of Escherichia, and most notably, of E. coli, were the only common group of CmR heterotrophs irrespective of country, sample type or farm type. Together with other predominant but less widespread groups such as acinetobacters and pseudomonads, the results of this biodiversity study suggest that E. coli can be regarded as a potential indicator of Cm resistance in Southeast Asian aquaculture environments.

Matched MeSH terms: Aquaculture*
Chemometric techniques in distribution, characterisation and source apportionment of polycyclic aromatic hydrocarbons (PAHS) in aquaculture sediments in Malaysia

Retnam A, Zakaria MP, Juahir H, Aris AZ, Zali MA, Kasim MF

Mar Pollut Bull, 2013 Apr 15;69(1-2):55-66.
PMID: 23452623 DOI: 10.1016/j.marpolbul.2013.01.009

This study investigated polycyclic aromatic hydrocarbons (PAHs) pollution in surface sediments within aquaculture areas in Peninsular Malaysia using chemometric techniques, forensics and univariate methods. The samples were analysed using soxhlet extraction, silica gel column clean-up and gas chromatography mass spectrometry. The total PAH concentrations ranged from 20 to 1841 ng/g with a mean of 363 ng/g dw. The application of chemometric techniques enabled clustering and discrimination of the aquaculture sediments into four groups according to the contamination levels. A combination of chemometric and molecular indices was used to identify the sources of PAHs, which could be attributed to vehicle emissions, oil combustion and biomass combustion. Source apportionment using absolute principle component scores-multiple linear regression showed that the main sources of PAHs are vehicle emissions 54%, oil 37% and biomass combustion 9%. Land-based pollution from vehicle emissions is the predominant contributor of PAHs in the aquaculture sediments of Peninsular Malaysia.

Matched MeSH terms: Aquaculture*
The effect of dietary cricket meal (Gryllus bimaculatus) on growth performance, antioxidant enzyme activities, and haematological response of African catfish (Clarias gariepinus)

Taufek NM, Aspani F, Muin H, Raji AA, Razak SA, Alias Z

Fish Physiol Biochem, 2016 Aug;42(4):1143-55.
PMID: 26886132 DOI: 10.1007/s10695-016-0204-8

This study was conducted to investigate the growth performance, biomarkers of oxidative stress, catalase (CAT), superoxide dismutase (SOD), and glutathione S-transferase (GST) as well as the haematological response of African catfish after being fed with fish feed containing different levels of cricket meal. The juvenile fish were assigned to three different treatments with isonitrogenous (35 %) and isoenergetic (19 kJ g(-1)) diets containing 100 % cricket meal (100 % CM), 75 % cricket meal (75 % CM), and 100 % fishmeal (100 % FM) as control groups for 7 weeks. The results indicated that a diet containing 100 % CM and 75 % CM improved growth performance in terms of body weight gain and specific growth rate, when compared to 100 % FM. The feed conversion ratio (FCR) and protein efficiency ratio (PER) did not differ significantly between all diets, but reduced FCR and increased PER were observed with a higher inclusion of cricket meal. A haematological examination of fish demonstrated no significant difference of red blood cells in all diets and white blood cells showed a significantly higher value in fishmeal-fed fish. On the other hand, haemoglobin and haematocrit significantly increased with increasing amounts of cricket meal in the diet. Antioxidant activity of CAT was higher in the 100 % CM group compared to fish fed other diets, whereas GST and SOD showed increasing trends with a higher incorporation of cricket, although insignificant differences were observed between all diets. These results suggest that cricket meal could be an alternative to fishmeal as a protein source in the African catfish diet.

Matched MeSH terms: Aquaculture/methods
Ingestion of food pellets containing Escherichia coli overexpressing the heat-shock protein DnaK protects Penaeus vannamei (Boone) against Vibrio harveyi (Baumann) infection

Sinnasamy S, Noordin NM, MacRae TH, Bin Abdullah MI, Bossier P, Wahid ME, et al.

J Fish Dis, 2016 May;39(5):577-84.
PMID: 26132358 DOI: 10.1111/jfd.12390

Feeding aquatic animals with bacterial encapsulated heat-shock proteins (Hsps) is potentially a new method to combat vibriosis, an important disease affecting aquatic animals used in aquaculture. Food pellets comprised of shrimp and containing Escherichia coli overexpressing either DnaK-DnaJ-GrpE, the prokaryotic equivalents of Hsp70-Hsp40-Hsp20, or only DnaK were fed to juveniles of the white leg shrimp Penaeus vannamei, and protection against pathogenic Vibrio harveyi was determined. Maintaining pellets at different temperatures for varying lengths of time reduced the number of live adhering E. coli, as did contact with sea water, demonstrating that storage and immersion adversely affected bacterial survival and attachment to pellets. Feeding P. vannamei with E. coli did not compromise their survival, indicating that the bacteria were not pathogenic to shrimp. Feeding P. vannamei with pellets containing bacteria overproducing DnaK (approximately 60 cells g(-1) pellets) boosted P. vannamei survival twofold against V. harveyi, suggesting that DnaK plays a role in Vibrio tolerance. Pellets containing DnaK were effective in providing protection to P. vannamei for up to 2 weeks before loss of viability and that DnaK encapsulated by these bacteria enhanced shrimp resistance against Vibrio infection.

Matched MeSH terms: Aquaculture/methods*
The influence of fish cage aquaculture on pelagic carbon flow and water chemistry in tidally dominated mangrove estuaries of peninsular Malaysia

Alongi DM, Chong VC, Dixon P, Sasekumar A, Tirendi F

Mar Environ Res, 2003 May;55(4):313-33.
PMID: 12517423

The impact of floating net cages culturing the seabass, Lates calcarifer, on planktonic processes and water chemistry in two heavily used mangrove estuaries in Malaysia was examined. Concentrations of dissolved inorganic and particulate nutrients were usually greater in cage vs. adjacent (approximately 100 m) non-cage waters, although most variability in water-column chemistry related to water depth and tides. There were few consistent differences in plankton abundance, production or respiration between cage and non-cage sites. Rates of primary production were low compared with rates of pelagic mineralization reflecting high suspended loads coupled with large inputs of organic matter from mangrove forests, fishing villages, fish cages, pig farms and other industries within the catchment. Our preliminary sampling did not reveal any large-scale eutrophication due to the cages. A crude estimate of the contribution of fish cage inputs to the estuaries shows that fish cages contribute only approximately 2% of C but greater percentages of N (32-36%) and P (83-99%) to these waters relative to phytoplankton and mangrove inputs. Isolating and detecting impacts of cage culture in such heavily used waterways--a situation typical of most mangrove estuaries in Southeast Asia--are constrained by a background of large, highly variable fluxes of organic material derived from extensive mangrove forests and other human activities.

Matched MeSH terms: Aquaculture*
Fulltext Myxozoan pathogens of Malaysian fishes cultured in ponds and net-cages

Székely C, Shaharom-Harrison F, Cech G, Mohamed K, Molnár K

Dis Aquat Organ, 2009 Jan 28;83(1):49-57.
PMID: 19301636 DOI: 10.3354/dao01990

We describe new myxosporean species from Malaysian fishes cultured in pond farms and net-cages. Myxobolus omari sp. nov. and M. leptobarbi sp. nov. were found in the muscles of Pangasianodon hypophthalmus and Leptobarbus hoevenii, respectively, while plasmodia and spores of Thelohanellus zahrahae sp. nov. and Henneguya daoudi sp. nov. were detected in the gills of Barbonymus gonionotus and Trichogaster trichopterus, respectively. Plasmodia and spores found in these fishes differed from the known myxosporean species in respect of their morphology, tissue tropism and 18S rDNA structure. No major pathological changes were found, but in the future these species might pose a potential threat to more intensified fish culture.

Matched MeSH terms: Aquaculture*
Occurrence and distribution of endocrine-disrupting chemicals in mariculture fish and the human health implications

Ismail NAH, Aris AZ, Wee SY, Nasir HM, Razak MR, Kamarulzaman NH, et al.

Food Chem, 2021 May 30;345:128806.
PMID: 33352402 DOI: 10.1016/j.foodchem.2020.128806

The presence and distribution of endocrine-disrupting chemicals (EDCs) in the mariculture fish from Pulau Kukup, Johor of Malaysia have been studied along with the impact on human health. Six different species of mariculture fish were collected, due to their high consumption in the Asian region-especially Malaysia, to assess their levels of EDCs. The highest concentration of EDCs detected in the muscle was dexamethasone (2.37-15.84 ng/g) and (0.77-13.41 ng/g), in the liver was dexamethasone (<2.54-43.56 ng/g) and progesterone (2.23-9.78 ng/g), and in the reproductive organ are dexamethasone (<2.54-37.23 ng/g) and caffeine (0.21-18.92 ng/g). The human health risk assessment in the current study suggested that there is no potential risk to the consumer because the hazard index was below 1 (HI

Matched MeSH terms: Aquaculture*
Fulltext Household Engagement in Both Aquaculture and Horticulture Is Associated with Higher Diet Quality than Either Alone

Akter R, Yagi N, Sugino H, Thilsted SH, Ghosh S, Gurung S, et al.

Nutrients, 2020 Sep 04;12(9).
PMID: 32899764 DOI: 10.3390/nu12092705

The consumption of high-quality diverse diets is crucial for optimal growth, health, and wellbeing.
OBJECTIVE: This study assessed the diet quality of households by their type of engagement in homestead aquaculture and/or horticulture. Socio-demographic determinants of diet quality were also studied.
METHOD: Diet quality was assessed using a nutrient adequacy ratio (NAR), based on the preceding 7 days' dietary recall at the household level. Adult male equivalent units (AMEs) were used for age- and sex-specific intra-household distribution of household intakes. Mean adequacy ratios (MAR) were computed as an overall measure of diet quality, using NAR.
RESULTS: Better diet quality (mean ± SD) was associated with households engaged in both homestead aquaculture and horticulture (0.43 ± 0.23; p < 0.001) compared to only one type of agriculture (0.38 ± 0.20) or none (0.36 ± 0.20). Tukey's post-hoc test confirmed significant differences in diet quality between both and either engagement (0.05 ± 0.01, p < 0.001), both and no engagement (0.07 ± 0.01, p < 0.001), and either and no engagement households (0.02 ± 0.01, p < 0.001). Beyond farm production of nutrient-rich foods, generalized estimating equations showed that diet quality was influenced by the higher educational level and occupation of adult household members, higher daily per capita food expenditure, sex, family size and region.
CONCLUSIONS: Projects that promote and support household engagement in both homestead aquaculture and horticulture have the potential to improve the diet quality of households.

Matched MeSH terms: Aquaculture/statistics & numerical data*
Environmental effects on the oxygen consumption rate in juvenile Epinephelus fuscoguttatus (Forsskal, 1775)

Okomoda VT, Mithun S, Chatterji A, Effendy MAW, Oladimeji AS, Abol-Munafi AB, et al.

Fish Physiol Biochem, 2020 Aug;46(4):1497-1505.
PMID: 32378001 DOI: 10.1007/s10695-020-00807-7

This study was designed to optimize the culture conditions of juvenile Epinephelus fuscoguttatus (Forsskål, 1775) under laboratory conditions. To this effect, the rate of oxygen consumption was monitored as an index of stress under different temperature, salinity, pH, photoperiod, and urea concentrations. The result obtained after 12 h of exposure suggests the preference of the juvenile E. fuscoguttatus to a temperature range of 15-25 °C and salinity of 30 ppt. Based on this study, temperature was found to be the most lethal as 100% mortality was observed after 6 h in fish exposure to temperatures above the optimal (≥ 30 °C). However, the oxygen consumption rate was similar under the different pH, photoperiod, and urea concentration tested. It was concluded that water temperature was most critical in terms of respiration physiology of the juvenile E. fuscoguttatus given the range and levels of environmental factors tested in this study.

Matched MeSH terms: Aquaculture/standards*
Fulltext Resistance and resilience of small-scale recirculating aquaculture systems (RAS) with or without algae to pH perturbation

Mohamed Ramli N, Giatsis C, Md Yusoff F, Verreth J, Verdegem M

PLoS One, 2018;13(4):e0195862.
PMID: 29659617 DOI: 10.1371/journal.pone.0195862

The experimental set-up of this study mimicked recirculating aquaculture systems (RAS) where water quality parameters such as dissolved oxygen, pH, temperature, and turbidity were controlled and wastes produced by fish and feeding were converted to inorganic forms. A key process in the RAS was the conversion of ammonia to nitrite and nitrite to nitrate through nitrification. It was hypothesized that algae inclusion in RAS would improve the ammonia removal from the water; thereby improving RAS water quality and stability. To test this hypothesis, the stability of the microbiota community composition in a freshwater RAS with (RAS+A) or without algae (RAS-A) was challenged by introducing an acute pH drop (from pH 7 to 4 during three hours) to the system. Stigeoclonium nanum, a periphytic freshwater microalga was used in this study. No significant effect of the algae presence was found on the resistance to the acute pH drop on ammonia conversion to nitrite and nitrite conversion to nitrate. Also the resilience of the ammonia conversion to the pH drop disruption was not affected by the addition of algae. This could be due to the low biomass of algae achieved in the RAS. However, with regard to the conversion step of nitrite to nitrate, RAS+A was significantly more resilient than RAS-A. In terms of overall bacterial communities, the composition and predictive function of the bacterial communities was significantly different between RAS+A and RAS-A.

Matched MeSH terms: Aquaculture*
Microbial water quality and the detection of multidrug resistant E. coli and antibiotic resistance genes in aquaculture sites of Singapore

Ng C, Chen H, Goh SG, Haller L, Wu Z, Charles FR, et al.

Mar Pollut Bull, 2018 Oct;135:475-480.
PMID: 30301062 DOI: 10.1016/j.marpolbul.2018.07.055

Poor microbial water quality jeopardizes the health and safety of food produced by aquaculture farms. Three fish farms and transect sites in Singapore were assessed for microbial water quality and antimicrobial resistance determinants. Of the 33 multidrug resistant E. coli isolated from surface waters of the Johor Straits, 81.8% were ESBL producers. The relative abundance of sul1, qnrA and intI1 genes were higher in sediments than surface waters. Among the surface water samples, higher concentrations (10-1-101) of beta-lactamases (blaSHV, blaOXA, blaCTX-M) were detected in the transect sites. This study highlights a potential antimicrobial resistance transmission chain from environmental waters, to animal carriers and humans.

Matched MeSH terms: Aquaculture*
Occurrence of endocrine disrupting compounds in mariculture sediment of Pulau Kukup, Johor, Malaysia

Ismail NAH, Wee SY, Haron DEM, Kamarulzaman NH, Aris AZ

Mar Pollut Bull, 2020 Jan;150:110735.
PMID: 31784268 DOI: 10.1016/j.marpolbul.2019.110735

Endocrine-disrupting compounds (EDCs) such as hormones, pesticides, phenolic compounds, and pharmaceuticals compounds can cause adverse effects on humans, animals, and other living organisms. One of the largest mariculture areas situated in Pulau Kukup, Johor, Malaysia, is actively involved in exporting marine fish to other countries worldwide. This paper aims to provide baseline data on the level of EDC pollutants found in mariculture sediments in Malaysia since no reports have investigated this issue. Calculated samples recovered are between 50.39 and 129.10% at 100 ng/g spiking level. The highest concentration in the sediment samples was bisphenol A (0.072-0.389 ng/g dry weight) followed by diethylstilbestrol (<0.208-0.331 ng/g dry weight) and propranolol (<0.250-0.275 ng/g dry weight). Even though the concentrations of the targeted compounds obtained were low, their effects could become more evident longer term, which raises not only environmental health concerns but the potential risk to humans.

Matched MeSH terms: Aquaculture*
Metagenomic Analysis of the Effect of Enteromorpha prolifera Bloom on Microbial Community and Function in Aquaculture Environment

Sun F, Wang C, Chen H, Zheng Z

Curr Microbiol, 2020 May;77(5):816-825.
PMID: 31927597 DOI: 10.1007/s00284-019-01862-x

Enteromorpha prolifera blooms considerably affected coastal environments in recent years. However, the effects of E. prolifera on microbial ecology and function remained unknown. In this study, metagenomic sequencing was used to investigate the effect of E. prolifera bloom on the microbial communities and functional genes in an aquaculture environment. Results showed that E. prolifera bloom could significantly alter the microbial composition and abundance, and heterotrophic bacteria comprised the major groups in the E. prolifera bloom pond, which was dominated by Actinomycetales and Flavobacteriales. The study indicated that viruses played an important role in shaping the microbial community and diversity during E. prolifera bloom. These viruses affected various dominant microbial taxa (such as Rhodobacteraceae, Synechococcus, and Prochlorococcus), which produced an obvious impact on potential nutrient transformation. Functional annotation analysis indicated that E. prolifera bloom would considerably shift the metabolism function by altering the structure and abundance of the microbial community. E. prolifera bloom pond had the low ability of potential metabolic capabilities of nitrogen, sulfur, and phosphate, whereas promoted gene abundance of genetic information processing. These changes in the microbial community and function could produce serious effect on aquaculture ecosystem.

Matched MeSH terms: Aquaculture*
Fulltext Postbiotics Applications as Infectious Disease Control Agent in Aquaculture

Yao Ang C, Sano M, Dan S, Leelakriangsak M, M Lal T

Biocontrol Sci, 2020;25(1):1-7.
PMID: 32173662 DOI: 10.4265/bio.25.1

Aquaculture is developing so fast that infectious disease outbreak happens regularly. Antibiotic treatment results in development of antibiotic resistance pathogens, thus cause urgent action in searching of other alternative treatment method. Postbiotic was one of the explored strategies among various proposed alternatives. Due to its benefits in agriculture industry, it may be useful in aquaculture industry. Although many reviews were reported on other alternative strategies, the review on postbiotic in aquaculture is limited. This mini review provides an overview of different postbiotics as aquaculture disease control agents. Peptides and exopolysaccharides have antimicrobial properties against bacterial pathogens. Then, short chain fatty acids have both antimicrobial activities against bacterial pathogens and immunostimulating effects to aquatic organism. Vitamins, peptidoglycan and lipopolysaccharide are reported as immunostimulants. Finally, cell surface proteins and teichoic acid can act as vaccine.

Matched MeSH terms: Aquaculture/methods
Fulltext Gut Immune System and the Implications of Oral-Administered Immunoprophylaxis in Finfish Aquaculture

Lee PT, Yamamoto FY, Low CF, Loh JY, Chong CM

Front Immunol, 2021;12:773193.
PMID: 34975860 DOI: 10.3389/fimmu.2021.773193

The gastrointestinal immune system plays an important role in immune homeostasis regulation. It regulates the symbiotic host-microbiome interactions by training and developing the host's innate and adaptive immunity. This interaction plays a vital role in host defence mechanisms and at the same time, balancing the endogenous perturbations of the host immune homeostasis. The fish gastrointestinal immune system is armed with intricate diffused gut-associated lymphoid tissues (GALTs) that establish tolerance toward the enormous commensal gut microbiome while preserving immune responses against the intrusion of enteric pathogens. A comprehensive understanding of the intestinal immune system is a prerequisite for developing an oral vaccine and immunostimulants in aquaculture, particularly in cultured fish species. In this review, we outline the remarkable features of gut immunity and the essential components of gut-associated lymphoid tissue. The mechanistic principles underlying the antigen absorption and uptake through the intestinal epithelial, and the subsequent immune activation through a series of molecular events are reviewed. The emphasis is on the significance of gut immunity in oral administration of immunoprophylactics, and the different potential adjuvants that circumvent intestinal immune tolerance. Comprehension of the intestinal immune system is pivotal for developing effective fish vaccines that can be delivered orally, which is less labour-intensive and could improve fish health and facilitate disease management in the aquaculture industry.

Matched MeSH terms: Aquaculture/methods*
Microalgal-bacterial granular sludge process for non-aerated aquaculture wastewater treatment

Fan S, Ji B, Abu Hasan H, Fan J, Guo S, Wang J, et al.

Bioprocess Biosyst Eng, 2021 Aug;44(8):1733-1739.
PMID: 33772637 DOI: 10.1007/s00449-021-02556-0

Microalgal-bacterial granular sludge (MBGS) process has become a focal point in treating municipal wastewater. However, it remains elusive whether the emerging process can be applied for the treatment of aquaculture wastewater, which contains considerable concentrations of nitrate and nitrite. This study evaluated the feasibility of MBGS process for aquaculture wastewater treatment. Result showed that the MBGS process was competent to remove respective 64.8%, 84.9%, 70.8%, 50.0% and 84.2% of chemical oxygen demand, ammonia-nitrogen, nitrate-nitrogen, nitrite-nitrogen and phosphate-phosphorus under non-aerated conditions within 8 h. The dominant microalgae and bacteria were identified to be Coelastrella and Rhodobacteraceae, respectively. Further metagenomics analysis implied that microbial assimilation was the main contributor in organics, nitrogen and phosphorus removal. Specifically, considerable nitrate and nitrite removals were also obtained with the synergy between microalgae and bacteria. Consequently, this work demonstrated that the MBGS process showed a prospect of becoming an environmentally friendly and efficient alternative in aquaculture wastewater treatment.

Matched MeSH terms: Aquaculture*
Selection and evaluation of Malaysian Bacillus spp. strains as potential probiotics in cultured tiger grouper (Epinephelus fuscoguttatus)

Yasin IM, Razak NF, Natrah FMI, Harmin SA

J Environ Biol, 2016 07;37(4 Spec No):791-800.
PMID: 28779739

A total of 58 Gram-positive bacteria strains were isolated from the marine environment and screened for potential probiotics for disease prevention and improving the productivity of tiger grouper Epinephelus fuscoguttatus larvae and juveniles. The bacteria were identified as Bacillus licheniformis, B. subtilis, B. circulans, B. sphaericus, B. cereus, Brevibacillus brevis, Corynebacterium propinquum, Leifsonia aquatica and Paenibacillus macerans. Only 24 strains showed antagonistic activities against four pathogenic strains; Vibrio alginolyticus, V. harveyi, V. parahaemolyticus and Aeromonas hydrophila, where two of the Bacillus strains, B12 and B45 demonstrated intermediate to highest level of inhibitory activity against these pathogenic strains, respectively. Further assessment by co-culture assay showed that Bacillus strain B12 exhibited a total inhibition of V. alginolyticus, while B45 strain displayed no inhibitory activity. Mixed culture of Bacillus B12 and B45 strains to outcompete V. alginolyticus was observed at a cell density of 10(7) CFU ml(-1). Molecular identification and phylogenetic tree analysis have categorized Bacillus strain B12 to the reference strains GQ340480 and JX290193 of? B. amyloliquafaciens, and Bacillus strain B45 with a reference strain JF496522 of B. subtilis. Safety tests of probionts by intraperitoneal administration of B12 and B45 strains at cell densities of 103, 105 and 10(7) CFU ml(-1) revealed no abnormalities and cent percent survival for healthy Epinephelus fuscoguttatus juveniles within 15 days of experimental period. Overall, the study revealed that Bacillus B12 strain possesses tremendous probiotic potential that could be used as a feed supplement in tiger grouper diets. ?

Matched MeSH terms: Aquaculture*

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