Vibrio Counts Research Articles

Human Activity as a Growing Threat to Marine Ecosystems: Plastic and Temperature Effects on the Sponge Sarcotragus spinosulus.

Human activities increasingly threaten marine ecosystems through rising waste and temperatures. This study investigated the role of plastics as vectors for Vibrio bacteria and the effects of temperature on the marine sponge Sarcotragus spinosulus. Samples of plastics and sponges were collected during July, August (high-temperature period), and November (lower-temperature period). Bacterial growth and sponge responses were analysed using biochemical biomarkers. The results revealed a peak in colony-forming units (CFU), particularly of Vibrio alginolyticus, on plastics and sponges in August, followed by a decrease in November. In August, CFU counts of Vibrio spp. were significantly higher in sponges with poor external appearance (characterized by dull coloration and heavy epiphytic growth) but returned to levels observed in healthy sponges by November. Microplastics were detected in the tissues of both sponge groups, with higher concentrations found in affected specimens. Biomarker analyses revealed increased lysozyme, glutathione S-transferase, catalase, and superoxide dismutase activities in healthy sponges during August, while malondialdehyde levels, indicating oxidative damage, were higher in affected sponges. In conclusion, affected sponges exhibited elevated CFU counts of Vibrio spp. and reduced antioxidant and detoxification responses under elevated temperatures. These findings suggest that combined impacts of plastics and warming may pose significant risks to S. spinosulus in the context of global climate change.

Effects of dietary synbiotic supplementation on digestive enzyme, total Vibrio count, and hepatopancreas of Pacific white shrimp, Penaeus vannamei challenged with Vibrio parahaemolyticus

ABSTRACT This study evaluated the effects of dietary synbiotics on enhancing digestive enzymes, reducing the overall bacterial count of Vibrio, and minimizing hepatopancreatic histological damage caused by V. parahaemolyticus in shrimp (Penaeus vanamei). The experiments involved administering different treatments, namely Bacillus NP5 (SBM), Pseudoalteromonas piscicida1Ub (SPM), and Bacillus NP5 and P. piscicida 1Ub (SBPM), incombination with the prebiotic mannan oligosaccharide (MOS). This study was conducted for 60 days, followed by a challenge test with Vibrio parahaemolyticus for 7 days. The results of the experiments showed that dietary synbiotic supplementation demonstrated better digestive enzyme activity and histology of the hepatopancreas compared to controls (p < .05). After the challenge test, it was found that the damage to the hepatopancreatic tissue of shrimps was less severe and the total vibrio count was lower in the synbiotic treatment, indicating a protective effect compared to the positive controls (p < .05). In conclusion, the use of dietary synbiotics had the potential to enhance digestive enzyme function and provide disease protection for Penaeus vannamei shrimp.

Molecular characterization and gene expression of pattern recognition receptors in brown-marbled grouper (Epinephelus fuscoguttatus) fingerlings responding to vibriosis infection

The pathogen recognition system involves receptors and genes that play a crucial role in activating innate immune response in brown-marbled grouper (Epinephelus fuscoguttatus) as a control agent against various infections including vibriosis. Here, we report the molecular cloning of partial open reading frames, sequences characterization, and expression profiles of Pattern Recognition Receptors (PRRs) in brown-marbled grouper. The PRRs, namely pglyrp5, tlr5, ctlD, and ctlE in brown-marbled grouper, possess conserved domains and showed shared evolutionary relationships with other fishes, humans, mammals, birds, reptilians, amphibians, and insects. In infection experiments, up to 50% mortality was found in brown-marbled grouper fingerlings infected with Vibrio alginolyticus compared to 27% mortality infected Vibrio parahaemolyticus and 100% survival of control groups. It is also demonstrated that all four PRRs had higher expression in samples infected with V. alginolyticus compared to V. parahaemolyticus. This PRRs gene expression analysis revealed that all four PRRs expressed rapidly at 4-h post-inoculation even though the Vibrio count was only detected earliest at 12-h post-inoculation in samples. The highest expression recorded was from V. alginolyticus inoculated fish spleen with up to 73-fold change for pglyrp5 gene, followed by 14 to 38-fold expression for the same treatment in spleen, head kidney, and blood samples for other PRRs, namely tlr5, ctlD, and ctlE genes. Meanwhile less than a 10% increase in expression of all four genes was detected in spleen, head kidney, and blood samples inoculated with V. parahaemolyticus. These findings indicated that pglyrp5, tlr5, ctlD, and ctlE play important roles in the early immune response to vibriosis infected, brown-marbled grouper fingerlings.

The ameliorative roles of dietary mannan oligosaccharides and vitamin E on growth performance, intestinal microbes, and structure, flesh quality, nutrient efficacy and stress resistance of pompano, Trachinotus ovatus

The current study aimed to examine the effects of mannan oligosaccharides (MOS) and vitamin E (VE) on the growth, intestinal microorganisms, and structure, ammonia, and pathogen resistance of golden pompano, Trachinotus ovatus. Four diets were used: Control (un-supplementation), VE (0.01 % Vitamin E), MOS (0.4 % mannan oligosaccharide), and MOS+VE (0.40 %MOS+0.01 %VE) for 56-day. The results revealed a synergistic effect of MOS+VE on increments of growth rate of pompano. The total aerobic bacteria significantly increased in fish fed supplemented diets, with the highest counts was in fish fed MOS+VE. The Vibrio counts was significantly diminished in fish supplemented diets, with a minimal counts was in fish fed MOS+VE. Intestinal morphology (villus length, villus width, and villus surface area) of pompano fed MOS+VE and the mixture of MOS+VE significantly improved, with the best results observed in fish fed the combination (MOS+VE). Both MOS and VE enhanced protein and reduce lipid; however, fish fed combination (MOS+VE) had the highest performance in terms of protein content. The nutrient utilization (PER, PPV, LER and LPV) were significantly enhance in fish fed VE or MOS, but the highest of those values were in fish fed MOS+VE). Pompano can tolerate best against ammonia and pathogen, when supplemented with MOS and VE in their diet. The survival of fish fed MOS or VE were significantly higher under ammonia and pathogen infection, but insignificantly difference between them. It is recommended to add 4 g.kg−1 MOS and 0.1 g.kg−1 VE to the diet of pompano.

Influence of stocking density on the growth, immune and physiological responses, and cultivation environment of white-leg shrimp (Litopenaeus vannamei) in biofloc systems

Biofloc (BF) stands out as a promising system for sustainable shrimp farming. Optimizing various culture conditions, such as stocking density, carbohydrate source, and feeding management, is crucial for the widespread adoption of the BF system. This study compares the growth performance of white-leg shrimp (Litopenaeus vannamei) in culture ponds at low density (LD) with 50 organisms/m2 and high density (HD) with 200 organisms/m2. Post-larvae of white-leg shrimp were stocked for 16 weeks in both LD and HD groups. The LD group exhibited a superior survival rate, growth rate, and feed consumption compared to the HD group. The BF from the LD system recorded a significantly higher protein content (16.63 ± 0.21%) than the HD group (15.21 ± 0.34%). Heterotrophic bacterial counts in water did not significantly differ with stocking density. However, Vibrio count in water samples was higher in the HD group (3.59 ± 0.35 log CFU/mL) compared to the LD group (2.45 ± 0.43 log CFU/mL). The whole shrimp body analysis revealed significantly higher protein and lipid content in the LD group. In contrast, the total aerobic bacterial count in shrimp from the HD group was high, with the identification of Salmonella enterica ssp. arizonae. Additionally, Vibrio counts in shrimp samples were significantly higher in the HD group (4.63 ± 0.32 log CFU/g) compared to the LD group (3.57 ± 0.22 log CFU/g). The expression levels of immune-associated genes, including prophenoloxidase, transglutaminase, penaiedin 3, superoxide dismutase, lysozyme, serine proteinase, and the growth-related gene ras-related protein (rap-2a), were significantly enhanced in the LD group. Conversely, stress-related gene expression increased significantly in the HD group. Hepatopancreases amylase, lipase, and protease were higher in the LD group, while trypsin activity did not differ significantly. Antioxidant enzyme activity (catalase, glutathione, glutathione peroxidase, and superoxide dismutase) significantly increased in the LD group. The histological structure of hepatopancreas, musculature, and female gonads remained similar in both densities. However, negative effects were observed in the gills' histology of the HD group. These results suggest that increasing stocking density is associated with significantly negative biological, microbial, and physiological effects on white-leg shrimp under the BF system.

Investigations of the involvement of Vibrio species with Ostreid herpesvirus-1 in mass mortality events in the Pacific oyster Crassostrea gigas

Pacific oyster mortality syndrome (POMS) in Pacific oysters Crassostrea gigas is defined by mass mortality with Ostreid herpesvirus I (OsHV-1). In this study the association of Vibrio species with oysters before, during and after POMS events was investigated at population level to clarify their involvement with OsHV-1 in mass mortality events in the Georges and Hawkesbury River estuaries, Australia. In the POMS affected Georges River estuary, three patterns were observed concurrently at different sites: i) Vibrio counts and OsHV-1 DNA concentrations increased in adults and spat as mortalities started then decreased as mortalities stopped ii) bacterial counts increased in spat but not in adults associated with mortalities due to OsHV-1 iii) bacterial counts increased in the absence of mass mortality or high concentrations of OsHV-1 DNA. Although almost half of the 120 bacterial isolates were identified as an unknown Vibrio species belonging to the Splendidus clade with two predominant biotypes (A and H), there was no association between biotype and mortality. Concurrently in the Hawkesbury River estuary, neither mortality nor OsHV-1 were found, Vibrio counts fluctuated significantly and of 84 isolates identified, V. alginolyticus, V. parahaemolyticus and unidentified Vibrio sp. dominated; only five Splendidus clade isolates were identified. However, when POMS emerged in the Hawkesbury River estuary, the Splendidus-clade isolate became the dominant bacterial species. Mortality also occurred there without OsHV-1 and the dominant bacteria then were V. alginolyticus and V. harveyi, but the Splendidus-clade isolate was not detected. None of the bacterial species were specifically associated with POMS, although the Splendidus clade isolate increased in prevalence after POMS emerged in the Hawkesbury River estuary. V. aestuarianus was not detected in this study. While the findings suggest that bacterial proliferation follows infection with OsHV-1 in POMS, this was not a consistent feature. The number and diversity of bacteria within oyster tissues varied over time, between estuaries, between sites within an estuary and were associated with flooding, growing height, the age of oysters, mortality and OsHV-1.

Lysin and Lytic Phages Reduce Vibrio Counts in Live Feed and Fish Larvae.

Vibrio species are naturally found in estuarine and marine ecosystems, but are also recognized as significant human enteropathogens, often linked to seafood-related illnesses. In aquaculture settings, Vibrio poses a substantial risk of infectious diseases, resulting in considerable stock losses and prompting the use of antimicrobials. However, this practice contributes to the proliferation of antimicrobial-resistant (AMR) bacteria and resistance genes. Our investigation aimed to explore the potential of biological agents such as bacteriophage CH20 and endolysin LysVPp1 in reducing Vibrio bacterial loads in both rotifer and fish larvae. LysVPp1's lytic activity was assessed by measuring absorbance reduction against various pathogenic Vibrio strains. Phage CH20 exhibited a limited host range, affecting only Vibrio alginolyticus GV09, a highly pathogenic strain. Both CH20 and LysVPp1 were evaluated for their effectiveness in reducing Vibrio load in rotifers or fish larvae through short-setting bioassays. Our results demonstrated the significant lytic effect of endolysin LysVPp1 on strains of Vibrio alginolyticus, Vibrio parahaemolyticus, and Vibrio splendidus. Furthermore, we have showcased the feasibility of reducing the load of pathogenic Vibrio in live feed and fish larvae by using a non-antibiotic-based approach, such as lytic phage and endolysin LysVPp1, thus contributing to the progress of a sustainable aquaculture from a One Health perspective.

Detection and quantitative microbial risk assessment of pathogenic Vibrio cholerae in a river used for drinking, domestic, fresh produce irrigation and recreational purposes

Cholera infection results from the ingestion of water or food contaminated with toxigenic Vibrio cholerae. This study evaluated the occurrence of toxigenic V. cholerae in Asata River, Enugu Metropolis, Nigeria, and estimated V. cholerae infection risks from use of the River water for drinking, domestic and recreational purposes. Vibrio was detected and quantified using membrane filtration technique and thiosulfate–citrate–bile salts–sucrose agar. Isolates were screened by PCR, using specific primers targeting the internal transcribed spacer (its) region between 16 and 23S rRNA and the cholera toxin (ctx) gene. Sequenced 16SrRNA gene amplicons of two selected isolates were used for phylogenetic analysis. Quantitative microbial risk assessment (QMRA) was conducted using the β-Poisson dose–response model. About 81% (58/72) of Asata River samples recorded Vibrio counts above 1.0 ×\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ imes$$\\end{document} 103 cfu/100 mL. Of the fifty Vibrio isolates screened, its was detected in 54% (27/50), out of which 74% (20/27) had the ctx gene of toxigenic V. cholerae. Evolutionary relatedness of the sequenced isolates to V. cholerae was revealed. The estimated risks of cholera infection in persons exposed to untreated Asata River water were above 0.5 for all the exposure scenarios, for both the rainy and dry seasons. The risks were highest (~ 0.9) for exposure via drinking water and annual risk of infection was deduced to have a probability of 1.0. Therefore, dependence on the untreated Asata River water for drinking, recreational, domestic and irrigation purposes may present a potential public health risk of cholera outbreak. We recommend increased monitoring and surveillance of River water for Vibrio abundance and that Asata River be protected from further degradation.

Dietary Bromelain From Pineapple Extracts Enhanced Growth Performance and Modulated Stomach Microbiota Which Provided Longer‐Term Protection to Penaeus vannamei Against Acute Hepatopancreatic Necrosis Disease (AHPND) Caused by Vibrio parahaemolyticus

The emergence of acute hepatopancreatic necrosis disease (AHPND) caused by pathogenic strains of Vibrio parahaemolyticus (VPAHPND) had economically impacted shrimp farmers. There is great interest in using phytogenics as antibiotic alternatives in mitigating bacterial diseases. A 28‐day feeding trial using quadruplicate groups of Penaeus vannamei was conducted to evaluate the efficacy of bromelain (BM), a pineapple extract, on growth, gut microbiota, and resistance to AHPND. Dietary 1% or 2% BM enhanced growth of shrimp, which was significantly (P &lt; 0.05) higher at 2% BM compared to control (0% BM). In the first AHPND challenge, shrimp survival (mean ± SE) fed 1% or 2% BM were 84.8% ± 3.8% and 78.3% ± 2.5%, respectively, and significantly higher compared to the positive control group (69.6% ± 1.8%). Surviving shrimp were then regrouped into triplicates and fed the control diet for 14 days. This wash‐out period was used to determine if prior dietary BM had a longer‐term effect on shrimp health. In the second AHPND challenge, shrimp survival previously fed 1% or 2% BM was 71.1% ± 9.7% and 73.3% ± 3.8%, respectively, and significantly higher compared to the control group (51.1% ± 2.2%). Hepatopancreas showed less damage and harbored significantly lower Vibrio counts in shrimp fed BM‐added diets. Dietary BM modulated the stomach bacterial community and imparted the highest alpha diversity. At the phylum level, Proteobacteria, Actinobacteria, and Bacteroidetes were the main groups across treatments but with varying relative abundance. Luteolibacter, Paracoccus, Planctomyces, and Demequina were identified as the main contributors for the diversity differences observed among treatment groups. The relative abundance of Luteolibacter was significantly enriched and Vibrio bacteria significantly lowered in the stomach of the BM‐added groups. It was concluded that dietary BM induced modulation of the stomach microbiota of shrimp, which potentially enhanced its resistance to AHPND‐causing VP.

Dietary administration of yeast (Saccharomyces cerevisiae) hydrolysate from sugar byproducts promotes the growth, survival, immunity, microbial community and disease resistance to VP (AHPND) in Pacific white shrimp (Litopenaeus vannamei)

This study investigated the effects of yeast hydrolysate (YH) from sugar byproducts on various parameters in Pacific white shrimp (Litopenaeus vannamei). The study found no significant differences in water quality parameters across all treatment tanks, ensuring that the observed effects were not due to environmental variations. There were no significant differences in growth parameters between the control group and groups receiving YH at different dosages. However, the group given YH at 10.0 g/kg feed exhibited a notably higher survival rate and higher expression of growth-related genes (IGF-2 and RAP-2A) in various shrimp tissues. YH was associated with enhanced immune responses, including lysozyme activity, NBT dye reduction, bactericidal activity, and phagocytic activity. Notably, the 10.0 g/kg feed group displayed the highest phagocytic index, indicating a dose-dependent immune response. Expression of immune-related genes (ALF, LYZ, ProPO, and SOD) was upregulated in various shrimp tissues. This upregulation was particularly significant in the gills, hepatopancreas, intestine, and hemocytes. While total Vibrio counts remained consistent, a reduction in green Vibrio colonies was observed in the intestine of shrimp treated with YH. YH, especially at 5.0 and 10.0 g/kg feed dosages, significantly increased survival rates and RPS values in response to AHPND infection. The findings of this study suggest that incorporating additives derived from yeast byproducts with possible prebiotic properties obtained from sugar byproducts can lead to positive results in terms of enhancing growth performance, immunity, histological improvements, and resistance to V. parahaemolyticus, the causative agent of acute hepatopancreatic necrosis disease (AHPND).

Monitoring of microbial, water quality, and production performance of Litopenaeus vannamei on intensive pond in Bulukumba, South Sulawesi, Indonesia

The aim of the research is to monitor the dynamics of microbial number, water quality, and production performance in Pacific white shrimp (Litopenaeus vannamei) cultivation in Bulukumba, South Sulawesi Province, Indonesia, utilizing an intensive system. This research was carried out on seven Pacific white shrimp ponds over the duration of one maintenance cycle (84 days), from November 2019 to February 2020. Interestingly, the results showed that the highest total bacterial counts (TBC) were obtained in pond P3, namely in the range of 0.12-98.0×105 CFU/mL, the highest total Vibrio counts (TVC) were obtained in pond P5, namely in the range of 0.09-2.8×105 CFU/mL, luminous bacterial counts (LBC) were only found in ponds P1, P4, and P5 with the same range values, namely 0-100×103 CFU. The best performance of Pacific white shrimp production was found in pond P2, with a percentage of survival rate (SR) and productivity of 65 percent and 4074.5kg/ha, respectively, and the worst was found in pond P5, with a percentage of survival rate (SR) and productivity of 35 percent and 2583.66 kg/ha, respectively. Finally, the intense culture system used for Pacific white shrimp accumulates dynamics that may alter microbiology, water quality, and production performance.

Effect of dietary β‐glucan supplementation on growth performance, body composition, intestinal microbes, and capacity against pathogen of golden trevally (Gnathanodon speciosus, family Carangidae)

AbstractThe efficacy of dietary β‐glucan supplementation in golden trevally (Gnathanodon speciosus) was evaluated. The fish were fed five different diets supplemented with 0%, 0.05%, 0.10%, 0.20%, and 0.40% β‐glucan for 56 days. After 56 days of culture, survival was the highest when the fish were fed a 0.10% β‐glucan diet. Growth rates were higher in fish fed diets supplemented with all β‐glucan levels. Lymphocytes increased when the fish were fed a diet supplemented with 0.05% β‐glucan, and thrombocytes increased when the fish were fed 0.2% and 0.4% β‐glucan‐supplemented diets. The total aerobic bacteria count in the gut of golden trevally was higher (p &lt; 0.05) and the total Vibrio counts in the gut of golden trevally were lower (p &lt; 0.05) when the fish were fed any level of β‐glucan. Flesh protein content was higher and flesh lipid content was lower when fish were fed β‐glucan‐supplemented diets at levels greater than 0.1%. When challenged with Streptococcus iniae, fish fed diets containing 0.10% or 0.20% β‐glucan exhibited the highest survival rates. The current results suggest that supplementation with 0.05 to 0.2% β‐glucan in the diet would be beneficial for the culture of the golden trevally.

Marine actinomycete Streptomyces variabilis S26 as a biocontrol agent for vibriosis in shrimp larval rearing systems.

Indiscriminate use of antibiotics has led to the emergence of antibiotic-resistant microbes and the loss of natural flora in aquaculture systems necessitating the ban of many of these chemotherapeutants in aquaculture. Actinobacteria play a profound role in the biogeochemical cycling in the marine environment and represent the principal source of secondary metabolites with antimicrobial property. In the present study, 98 marine-derived actinomycete isolates were screened for antimicrobial activity against the common aquatic pathogens. A potent actinomycete isolate S26, identified as Streptomyces variabilis based on 16 S ribosomal RNA (rRNA) gene sequencing was then checked for the production of antibiotic in five different fermentation media and the one which showed maximum production was chosen for further study. Optimization of the fermentation medium for secondary metabolite production was carried out by response surface methodology (RSM) using DESIGN EXPERT. The analysis of variance (ANOVA) of the quadratic regression model demonstrated that the model was highly significant for the response concerned that is, antimicrobial activity as evident from the Fisher's F- test with a very low probability value [(P model>F) = 0.0001]. Of the 10 different solutions suggested by the software, the most suitable composition was found to be starch, 1.38%; soy powder, 0.88%; ammonium sulfate, 0.16% and salinity, 27.76‰. S. variabilis S26 cultured in the optimized production medium was applied in the Penaeus monodon larval rearing system and the total Vibrio count and survival rate were estimated. S. variabilis S26 treatment showed a significant reduction in vibrios and conferred better protection to P. monodon in culture system compared with control.

Dietary mannan oligosaccharides elevated growth performance, gut morphology, microbiota, body composition, feed and nutrient utilisation of pompano, Trachinotus ovatus

Pompano (Trachinotus ovatus) is a highly economical aquaculture species; however, intensive aquaculture of pompano is associated with pathogen infection, environmental stress, drug and chemical use, causing reductions in growth, survival and economic losses. Mannan oligosaccharide (MOS) is a prebiotic that has been reported to boost the growth and health of many species; however, no study has examined the effects of MOS on pompano. In the present study, the effects of dietary MOS levels on growth, body composition, intestinal microbiota, feed, and nutrient utilisation in juvenile pompano were investigated over an 8-week experiment. Five diets containing five levels of MOS (0.1%, 0.2%, 0.4%, 0.6%, and 0.8%) were fed to pompano (mean weight, 5.16 g±0.05). The results indicated that pompano fed 0.1–0.40% MOS in the diet had the highest growth performance (p ≤ 0.009), but fish fed 0.6–0.8% MOS had no impact on growth (p ≥ 0.056). MOS had no effect on the survival rate of pompano (p ≥ 0.327). The gut surface area increased in fish fed 0.1–0.4% MOS (p ≥ 0.011), but not in fish fed 0.6–0.8% MOS (p ≥ 0.102). Total aerobic bacteria (TAB) increased in fish fed 0.1–0.4% MOS (p ≤ 0.017), but TAB was not affected at 0.6–0.8% MOS (p = 0.315), whereas Vibrio count and ratio of Vibrio to TAB significantly reduced in fish fed any levels of MOS (p ≤ 0.024). Feed conversion ratio (FCR) significantly reduced (p ≤ 0.019), while feed conversion efficiency (FCE) significantly increased (p ≤ 0.014), when pompano were fed a diet containing 0.1–0.4% MOS. Protein in fish increased in fish fed a diet providing 0.1–0.4% MOS (p ≤ 0.011), but when adding higher levels of MOS (0.6% and 0.8%) to the diets, the protein content in fish did not change (p ≥ 0.072). Lipid content was significantly reduced in fish fed 0.1–0.4% MOS (p ≤ 0.035), but not at higher levels of MOS (p ≥ 0.085). The protein efficiency ratio (PER), lipid efficiency ratio (LER), and lipid productive value (LPV) boosted in fish fed diet containing 0.1–0.6% MOS (p ≤ 0.029). Protein productive value (PPV) increased in fish served diet containing 0.1–0.4% (p ≤ 0.008). Those values did not change with 0.8% MOS (p ≥ 0.137). MOS levels had positive correlations with growth performance, FCE, PER, PPV, LER, LPV and TAB (r ≥ +0.481, p ≤ 0.001), while MOS levels showed negative correlations with intestinal Vibrio and FCR of pompano (r ≥ −0.562, p ≤ 0.003). The optimal levels of MOS were 0.424% for pompano's lowest FCR, while the best MOS concentration was 0.375% for pompano’s maximal growth.

Efficacy of processing methods on the proximate composition and microbial loads in Senilia senilis (Linnaeus, 1758) in mangrove swamps of Iko estuary, southeast, Nigeria

The traditional uses of Senilia senilis by the inhabitants of Iko town, Eastern Obolo, Akwa Ibom State, Nigeria are enormous. A total of 250 samples of S. senilis was collected from the sampling site over a period of twelve (12) months and randomly subjected to four (4) different processing methods. Standard analytical procedures were used for proximate compositions and microbiological examination. Eleven (11) bacterial species and six (6) fungal species were isolated. Mean Total Heterotrophic Bacteria Count (THBC) of 1.72 × 105 cfu g−1 was recorded with least in shell (1.61 ± 1.7x105cfu g−1) and highest in gut (1.92 ± 2.1 × 105). Mean Total Vibrio Count (TVC) was 7.62 × 10−1cfu g−1 and followed the same pattern. Mean Total Coliform Count (TCC) was 3.33 × 101 cfu g−1 with least in flesh and highest in gut. Mean Total Salmonella Shigella (TSS) of 2.40 × 102 cfu g−1 was recorded and followed the same pattern. Mean Total staphylococcal Count (TSC) was 5.62 × 10−1 cfu g−1 with none on shell. Mean Total Fungal Count (TFC) was 3.33 × 104 cfu g−1 with least in shell and highest in flesh. THBC was low in fried (1.44 ± 0.43 × 104) and salted (1.43 ± 0.95b x104), TVC low in salted (1.15 ± 0.85 × 10), TCC low in salted (1.59 ± 0.42 × 10), while TSS and TSC were completely destroyed in frozen, fried and salted samples. TFC was low in salted (1.11 ± 0.09 × 104). Microbes were eradicated differentially across treatments. Proximate composition was mildly affected by the different processing. Generally, salting emerged first. However, a combination of some methods may produce a synergic effect.

Antibiotic Resistance in the Vibrio species isolated from the estuarine sediments of Uttara Kannada Karnataka

Vibrio species are the marine pathogenic bacterium which causes the health issues in the infected organisms. Antibiotic resistance in the Vibrio species is the threat to the human health by the transfer of the resistant gene in the human from the food chain. The present study was carried out to isolate the Vibrio species and to study antibiotic resistance from the sediments of two estuaries Kali and Aghanashini from Uttara Kannada, Karnataka. The sampling was done during low tide for the period of ten months from September 2021 to June 2022. The total vibrio count was observed in range between 3.86 to 4.83 Log X101 CFU/g. Vibrio parahaemolyticus, Vibrio alginolyticus, Vibrio navarrensis and Vibrio vulnificus were isolated and identified from the sediments. The identified Vibrio species were resistant to ampicillin and sensitive to chloramphenicol and tetracycline. Due the over use of antibiotics in the aquaculture and mariculture activities there is a possibility of organism to show multiple resistance towards the antibiotics.

Effect from Combinations of Yucca schidigera extract with Bacillus Strains on the Growth of White Leg Shrimp (Penaeus vannamei), Density of Vibrio sp., and on the Ammonia and Nitrite Content of Culture Water

The water quality including toxic gas parameters and Vibrio density is a serious problem in intensive shrimp culture. Yucca schidigera extract and Bacillus sp. are considered as a practical solution to improve the water quality. The aim of our study was to determine the effect of combination of Yucca schidigera extract and Bacillus spp. on total ammonia nitrogen (TAN) and nitrite contents, Vibrio count, and the growth performance of white leg shrimp (Penaeus vannamei). Shrimp (PL12) were assigned to seven treatments (triplicates) including treatments with combination of yucca extract and single strain of Bacillus (AY, B2Y, B3Y), combination of yucca extract and Bacillus consortium (ABBY), yucca extract only (Y), Bacillus consortium (ABB), and control treatment (C). Vibrio count was carried out by the spread plate technique every 7 days. TAN and nitrite contents were determined by using sodium nitroprusside, and sulphanilic acid with N-(1-naphthyl) ethylenediamine, respectively, at 24 hours and 168 hours after adding Bacillus strains and yucca extract. The shrimp growth parameters include the final biomass, final body weight (FBW, g), weight gain rate (WGR, %), survival rate (SR, %), and feed conversion ratio (FCR) were recorded after 5 weeks. The results showed that the water quality (0.073 – 0.179 ppm of TAN, 0.187 – 0.934 ppm of nitrite, and Vibrio count of 2.552 – 3.038 log CFU/ml) of tanks treated with combination of yucca extract and single strain of Bacillus (AY, B2Y, B3Y) or Bacillus consortium (ABBY), and Bacillus consortium (ABB) was significantly controlled compared to the control and yucca extract only treatments. The ABBY treatment most significantly improved the shrimp growth parameters (FBW, biomass, WGR, FCR, and SR – 0.424 ± 0.010 g, 40.202 ± 1.510 g, 14048.902 ± 328.756 %, 1.100 ± 0.040, and 94.667 ± 1.856 %, respectively) compared to the other treatments. Overall, our study concluded that the combination of yucca extract and Bacillus consortium could control water quality (0.036 – 0.105 ppm of TAN, 0.187 – 0.604 ppm of nitrite, and Vibrio count of 2.553 – 2.624 log CFU/ml), reduce 46.49% of FCR and significantly increase the growth performance (approximately 92.73% of FWB, 163.19% of biomass, 93.93% of WGR, 46.49% of FCR) of P. vannamei (PL12) with density of 100 individuals/100L.

Assessment of physiochemical properties and bacteriological diversity of Otamiri river in Owerri eastern Nigeri

The physiochemical and bacteria diversity of Otamiri River was analyzed using standard microbiological methods. A total of seventy two (72) water and twenty four (24) sediment samples were collected. The routine plate count revealed that the number of heterotrophic bacteria present ranged from 1.00E+06 Cfu/ml to 9.70E+06 Cfu/ml, fecal coliform count 2.00E+05 Cfu/ml to 9.00E+06 Cfu/ml, Salmonella/Shigella count 3.50E+05 Cfu/ml to 1.52E+07 Cfu/ml, Staphylococcus count 2.00E+05 Cfu/ml to 1.79E+07 Cfu/ml, coliform count 3.50E+05 Cfu/ml to 4.59E+08 Cfu/ml, Vibrio count 1.50E+05 Cfu/ml to 3.52E+07 Cfu/ml. Anaerobic bacteria count ranged from 2.00E+05 Cfu/ml to 2.85E+06 Cfu/ml. The proportion of bacteria isolated from the samples showed that Alcaligens faecalis had the highest 68(94.44), 24(100), followed by Lysinibacillus macrolides 54(75), 21(87.5) while Lactobacillus spp had the least in water sample 6(8.33), Klebsiella aerogenes had the least in sediment 6(25). Among the physiochemical parameters analyzed in the river water and sediment samples had values above the recommended standard by WHO. The samples biophysical parameters did not meet the standard recommended by WHO for portable water. Therefore, to prevent potential health risks, those who use river water for domestic purposes must appropriately cleanse it before use. The government of the day should devise ways of disposing solid waste and effluent rather than channel same into the river and enact strict laws that will punish individual, agencies and firms that indulge in such in order to protect natural bodies of water from pollution. Statistical analysis using analysis of variance Posthoc = Tukey Alpha (0.05) indicated that the mean bacteria counts between the sampling stations differ significantly at the 0.05 level.

“Antibiotic Resistance in the Vibrio species isolated from the estuarine sediments of Uttara Kannada Karnataka”

Vibrio species are the marine pathogenic bacterium which causes the health issues in the infected organisms. Antibiotic resistance in the Vibrio species is the threat to the human health by the transfer of the resistant gene in the human from the food chain. The present study was carried out to isolate the Vibrio species and to study antibiotic resistance from the sediments of two estuaries Kali and Aghanashini from Uttara Kannada, Karnataka. The sampling was done during low tide for the period of ten months from September 2021 to June 2022. The total vibrio count was observed in range between 3.86 to 4.83 Log X101 CFU/g. Vibrio parahaemolyticus, Vibrio alginolyticus, Vibrio navarrensis and Vibrio vulnificus were isolated and identified from the sediments. The identified Vibrio species were resistant to ampicillin and sensitive to chloramphenicol and tetracycline. Due the over use of antibiotics in the aquaculture and mariculture activities there is a possibility of organism to show multiple resistance towards the antibiotics.

Evaluation of a synbiotic formulation for water remediation in a shrimp pond.

In recent years, the use of probiotic bacteria has attracted the interest of the marine shrimp farming industry. However, there are certain limitations pertaining to the practical application of many commercially available probiotics. Here, a thoroughly screened optimal consortium of three indigenous sulfur probiotics was tested for antibiotic susceptibility and was found to be safe, with each culture being sensitive to all the tested antibiotics. Further, de-potash vinasse (DPV), an environmental hazard, was tested for its prebiotic potential, and its 1% (w/v) concentration was found to be effective for long-term viability (> 66days) of the probiotic cultures and safe for Artemia. The synbiotic formulation was tested first in a lab-scale microcosm setup successfully and subsequently tried on a shrimp farm; it was observed that the product was congruent to the efficiency of a commercial probiotic regarding almost all physicochemical parameters, sulfide, nitrate-N, nitrite-N, phytoplankton sustenance, Pseudomonas count, coliform count, and heterotrophic count. In addition, it was significantly efficient in maintaining pH, reducing ammonia-N and phosphate-P, Vibrio and Aeromonas count, and a net increase in the yield of shrimp biomass by 625kg, thus proving to be a better alternative than one of the already available remediation methods.