White Feces Research Articles

The genetic basis of resistance to Enterocytozoon hepatopenaei (EHP) and White feces syndrome (WFS) in the whiteleg shrimp (Litopenaeus vannamei)

The microsporidian Enterocytozoon hepatopenaei (EHP) is a yeast-like intracellular fungus, that in the last decade has significantly contributed to major economic losses in the whiteleg shrimp (Litopenaeus vannamei) industry worldwide. In commercial ponds, EHP affected shrimp frequently also shows symptoms of White Feces Syndrome (WFS), characterized by floating white fecal strings, reduced feed consumption, and growth retardation. To elucidate the genetic basis of resistance to EHP + WFS, a challenge test was conducted using a pedigreed shrimp population from the Benchmark Genetics breeding program in Colombia. Out of the total genotyped animals, 1436 individuals from 47 families successfully passed quality control, underwent parentage analysis, had phenotypic records and were available for further analysis. Moderate heritabilities were estimated for binary survival to EHP + WFS using pedigree based (0.31 ± 0.04) and genomic analysis (0.41 ± 0.06). Furthermore, a low genetic correlation between body weight and EHP + WFS challenge test survival traits was observed, implying that genetic improvement of resistance to EHP + WFS can be achieved without compromising growth performance. The genome-wide association analysis showed little evidence for any major QTL, indicating that multiple genes with small effects collectively contribute to EHP + WFS resistance. Furthermore, cross validation analysis showed 0.54 ± 0.01 accuracy of prediction for genomic analysis and 0.49 ± 0.001 for the pedigree analysis, indicating the relevance of a genomic selection strategy for achieving genetic improvement for EHP + WFS resistance in L. vannamei.

The Effect of Water Quality on the Performance Growth of Vannamei Shrimp (Litopenaeus vannamei) at the Center for Brackish Aquaculture Fisheries

Vaname shrimp is one of the leading commodities of the aquaculture sector, with high production rates influenced by the rapid growth period and relatively short maintenance time, high stocking density production system, has a high appetite for food and has good resistance to disease. This study aims to assess the effect of water quality on the growth of vaname shrimp (Litopenaeus vannamei) in ponds. Water quality measured includes temperature, salinity, dissolved oxygen (DO), and pH, all of which play an important role in the growth and health of shrimp. The methods used in this study included periodic measurements of water quality parameters in the morning and evening in four ponds (A5.1, A5.2, A6.1, and A6.2), as well as observations of Average Body Weight (ABW), Average Daily Growth (ADG), and Survival Rate (SR) of shrimp. The results showed that ponds A5.1, A5.2, and A6.1 showed an increase in SR and biomass values, while A6.2 experienced a decrease in SR and biomass values caused by the outbreak of White Feces Disease. This is influenced by temperature, salinity, and DO parameters that are not in the optimal range for shrimp growth. Fluctuations in water quality parameters can significantly affect shrimp metabolism and health. Therefore, good water quality management, including water change cycles and sterilisation, is essential to prevent health problems and improve the growth of vaname shrimp. This study emphasises the need for attention to water quality in vaname shrimp farming to achieve optimal results.

Identification and Molecular Analysis of Hemocyanin as a Body Resistance Gene in Litopenaeus vannamei

Production of white shrimp (Litopenaeus vannamei) tends to decrease every year caused by diseases, one of which is White Feces Disease (WFD). Genetically, monitoring has been carried out on the parent characters of SPF (Specific Pathogen Free) shrimp imported from Hawaii and Florida with low genetic variation. If there is a threat such as disease caused by bacteria and the gene that codes for disease control or the body's resistance gene is missing, it allows the individual to become susceptible to disease. Gene that codes for body resistance in white shrimp is hemocyanin. Hemocyanin gene studies are needed as a first step in controlling disease in white shrimp. Method used is a descriptive method. Procedures carried out are sample collection, detection of WFD, molecular analysis of hemocyanin and data analysis. Results showed that healthy shrimp had hemocyanin while shrimp with WFD had very little or no amount of hemocyanin. Hemocyanin gene profile in healthy shrimp was also analyzed and there were 4 nucleotide change made changes to 4 amino acid. Changes in amino acids affect the stability of hemocyanin and cause polymorphism of hemocyanin. Phylogenetic analysis showed dendogram split into two clades between L. vannamei and P. monodon.

Rationally designed probiotics prevent shrimp white feces syndrome via the probiotics–gut microbiome–immunity axis

Increasing evidence infers that some complex diseases are attributed to co-infection with multiple pathogens, such as shrimp white feces syndrome (WFS); however, there is a lack of experimental evidence to validate such causal link. This deficiency further impedes rational design of probiotics to elicit desired benefits to shrimp WFS resistance. Herein, we validated the causal roles of Vibrio fluvialis, V. coralliilyticus and V. tubiashii (in a ratio of 7:2:1) in shrimp WFS etiology, which fully satisfied Koch’s postulates. Correspondingly, we precisely designed four antagonistic strains: Ruegeria lacuscaerulensis, Nioella nitratireducens, Bacillus subtilis and Streptomyces euryhalinus in a ratio of 4:3:2:1, which efficiently guarded against WFS. Dietary supplementation of the probiotics stimulated beneficial gut populations, streptomycin, short chain fatty acids, taurine metabolism potentials, network stability, tight junction, and host selection, while reducing turnover rate and average variation degree of gut microbiota, thereby facilitating ecological and mechanical barriers against pathogens. Additionally, shrimp immune pathways, such as Fcγ R-mediated phagocytosis, Toll-like receptor and RIG-I-like receptor signaling pathways conferring immune barrier, were activated by probiotics supplementation. Collectively, we establish an updated framework for precisely validating co-infection with multiple pathogens and rationally designing antagonistic probiotics. Furthermore, our findings uncover the underlying beneficial mechanisms of designed probiotics from the probiotics–gut microbiome–host immunity axis.

Etiological factors driving white feces syndrome in farmed Pacific whiteleg shrimp, Penaeus vannamei in Tamil Nadu, India

Etiological factors driving white feces syndrome in farmed Pacific whiteleg shrimp, Penaeus vannamei in Tamil Nadu, India

Ecytonucleospora hepatopenaei proliferate in Procambarus clarkii: A warning for crayfish and shrimp aquaculture

The pacific whiteleg shrimp (Penaeus vannamei) and the crayfish (Procambarus clarkii) are the most productive aquatic animals in the world. The prevalence of the microsporidium Ecytonucleospora hepatopenaei (EHP), an intracellular spore-forming unicellular parasite which leading retarded growth of P. vannamei, has caused severe economic losses in most shrimp farming country. In this study, we found that the wild P. clarkii, living in shrimp ponds with EHP outbreak, excreted white feces after temporary laboratory culture. The hepatopancreas (HP) of symptomatic crayfish exhibited a lighter color and severely atrophied. H&E-stain showed tissue lesions in both hepatopancreas and intestine, and clustered microsporidian spores were filled in the cytoplasm of the cells. PCR using EHPptp2 and two microsporidian-universal primers sets demonstrated the existence of EHP in the hepatopancreas, intestine and the white feces of P. clarkii. The EHP loads of 103–104 copies of EHPptp2/50 ng HPgDNA were detected by qPCR. Developing stages and mature spores of EHP were observed in hepatopancreas of P. clarkii through indirect-immunofluorescence assay (IFA) and transmission electron microscopy (TEM). Considering the large-scale cultivation of P. vannamei and P. clarkii, overlap farming areas between these two species as well as the ability of crayfish to crawl on land and water, our finding indicates the potential role of P. clarkii in the transmission of EHP, and it is an early warning for crayfish and shrimp farming.

Establishment of a TaqMan probe-based qPCR assay for detecting microsporidia Enterospora epinepheli in grouper.

Enterospora epinepheli is an intranuclear microsporidian parasite causing serious emaciative disease in hatchery-bred juvenile groupers (Epinephelus spp.). Rapid and sensitive detection is urgently needed as its chronic infection tends to cause emaciation as well as white faeces syndrome and results in fry mortality. This study established a TaqMan probe-based real-time quantitative PCR assays targeting the small subunit rRNA (SSU) gene of E. epinepheli. The relationship between the standard curve of cycle threshold (Ct) and the logarithmic starting quantity (SQ) was determined as Ct = -3.177 lg (SQ) + 38.397. The correlation coefficient (R2 ) was 0.999, and the amplification efficiency was 106.4%. The detection limit of the TaqMan probe-based qPCR assay was 1.0 × 101 copies/μL and that is 100 times sensitive than the traditional PCR method. There is no cross-reaction with other aquatic microsporidia such as Ecytonucleospora hepatopenaei, Nucleospora hippocampi, Potaspora sp., Ameson portunus. The intra-assay and inter-assay showed great repeatability and reproducibility. In addition, the test of clinical samples showed that this assay effectively detected E. epinepheli in the grouper's intestine tissue. The established TaqMan qPCR assays will be a valuable diagnostic tool for the epidemiological investigation as well as prevention and control of E. epinepheli.

Water profile of white shrimp (Litopenaeus vannamei) infected with white feces disease (WFD)

In mid-2021, shrimp farmer reported case of mass deaths in white shrimp (Litopenaeus vannamei) in Pasuruan Regency, reaching 2.6-3 kg/day in Kalianyar Village, Bangil District. To determine the main pathogenic bacteria that cause mass mortality and the composition of microbes on rearing media infected with certain diseases and healthy ones, this study observed the water profile of ponds which include microbial composition in it using next-generation sequencing (NGS) technology. The research was conducted by taking healthy shrimp pond water samples and infected shrimp pond water samples. These results generally indicate that the disease is similar to white feces syndrome (WFS). The results of the NGS test showed that the main causative pathogen is Vibrio vulnificus because its presence in infected pond water is quite dominant.

Enterocytozoon hepatopenaei (EHP) Infection Alters the Metabolic Processes and Induces Oxidative Stress in Penaeus vannamei

Enterocytozoon hepatopenaei (EHP) is highly contagious and can cause hepatopancreatic microsporidiosis (HPM), which is typically characterized by the slow growth of shrimp. In this study, the differences in histology, metabolism, oxidative stress and growth between healthy and EHP-infected Penaeus vannamei were analyzed using an EHP challenge experiment. Histology showed that EHP caused lesions in the hepatic tubules of P. vannamei, such as hepatic tubular atrophy and epithelial cell shedding, with mature spores. Meanwhile, white feces may appear when the infection is severe. Furthermore, the content of total protein, glycogen, ATP and glucose in the EHP challenge group was significantly reduced. The qPCR results showed that EHP infection changed the expression of key genes in glucose metabolism, among which hexokinase (HK), phosphofructokinase (PFK), pyruvatekinase (PK), citrate synthase (CS) and isocitric dehydrogenase (IDH) were significantly down-regulated, while phosphoenolpyruvate carboxykinase (PEPCK), fructose bisphosphatase (FBP) and glucose-6-phosphatase (G6P) were significantly up-regulated. Obviously, the expression of growth-related genes was disordered. Simultaneously, the antioxidant genes manganese superoxide dismutase (MnSOD), catalase (CAT), glutathione peroxidase (GPX), glutathione-S-transferases (GST) and nuclear factor E2-related factor2 (Nrf2) were up-regulated to varying degrees in the EHP challenge group, and EHP infection induced significant increases in the oxidative damage products lipid peroxide (LPO) and malondialdehyde (MDA). Ultimately, the shrimp weight of the challenge group was 6.85 ± 0.86 g, which was significantly lower than that of the control group (8.95 ± 0.75 g). Taken together, we speculate that EHP changes the substance metabolism and growth process by causing oxidative damage to the hepatopancreas, which may lead to the growth retardation of P. vannamei.

Prevention of white impurities in vaname shrimp (Litopenaeus vannamei) using noni fruit extract (Morinda citrifolia) in semi-intensive shrimp cultivation system

White vanamae shrimp is one of the superior commodities in aquaculture. Currently, the productivity of white vanamae shrimp has not yet reached its production target. So, it is necessary to increase the amount of production on a gradual scale carried out by the community. In shrimp farming activities, disease problems are often encountered. Namely is a white stool, white feces, or White Feces Disease (WFD). The clinical symptoms that arise when shrimp are attacked by White Feces Disease (WFD) are that the shrimp's appetite decreases, the shrimp's intestines change color to white and even look empty due to lack of food intake, white feces floating on the surface of the water, and the shrimp's growth becomes abnormal. This WFD disease can be caused by poor cultivation practices, unhealthy seeds, and poor water quality, causing the emergence of disease microorganisms such as Vibrio sp bacteria. One way to treat this disease is to provide alternative medicine, noni fruit extract. This research consisted of 3 noni extract treatments and consisted of 3 replications, namely Treatment A: 10 mL/L; Treatment B: 15 mL/L; Treatment C: 20 mL/L. The noni dose is given at the specified dose once daily for one month. The survival rate of shrimp increased to 86.7%.

The Influence of Adding Api-Api Mangrove Leaf Extract as an Immunostimulant on Vaname Shrimp Against Vibriosis Disease Caused by Vibrio parahaemolyticus Bacteria

Vanname shrimp cultivation is one of the most developed aquacultures in Indonesia and makes it one of the commodities with the highest foreign exchange inputs for the Indonesian state from the fisheries sector. Disease attack is one of the main causes of failure in vaname shrimp culture, especially disease attacks caused by Vibrio parahaemolyticus bacteria. Avicennia alba mangrove leaf extract is known to have active compounds that can act as antibacterial. This research was conducted by mixing Avicennia alba mangrove leaf extract with doses of 150 ppm (VA), 250 ppm (VB) and 350 ppm (VC) into commercial feed by re-pelletting. Positive control (KV+) treatment used commercial vitamins added to the feed. The vaname shrimp used was 60 days old with an average initial weight of 8.9 grams. The aquariums used were 15 pieces with a size of 60 x 30 x 40 cm and a volume of 54 liters of water. The white shrimp challenge test with Vibrio parahaemolyticus bacteria with a concentration of 106 Cfu/ml as much as 0.2 ml. The clinical symptoms of white vaname shrimp include pale white hepatopancreas, blackened tail, grippy swimming legs, necrosis in some parts of the body, necrosis of the tail, blackened and necrotic rectum, broken intestines that are partially brown and starting to turn white, empty intestines, presence of white feces. appears in the aquarium, decreased appetite, as well as not actively swimming. The results showed that Avicennia alba leaf extract had an effect on absolute weight growth (W), growth rate (GR), specific growth rate (SGR), survival rate (SR), total haemocyte count (THC) and phagocytic activity of white shrimp. The dose of 350 ppm VC treatment was the most influential dose as an immunostimulant in this study.

Microbiome analysis of Litopenaeus vannamei reveals Vibrio as main risk factor of white faeces syndrome

The diversity of the gut microbiota substantially influences the health of the host, including shrimps. White faeces syndrome (WFS) is a multifactorial shrimp disease that can cause severe financial losses in Litopenaeus vannamei aquaculture industry. WFS in shrimps is caused not only by the microsporidian Enterocytozoon hepatopenaei infection but also by gut microbial dysbiosis, specifically the Vibrio species. The objectives of this study are to explore the gut microbiota composition in L. vannamei shrimps and to gain insights into the genetic factors associated with the development of WFS. For this, PacBio Sequel II platform was utilized to obtain full-length sequencing of the 16S rRNA gene (V1-V9). Significant variations in the intestinal bacterial abundance were observed between healthy and WFS-affected shrimps. At the genus level, Candidatus Bacilloplasma, Photobacterium, Pirellula, Rhodobacter and Lactococcus are abundantly present in the healthy shrimps, whereas, Cyanobium PCC-6307, Staphylococcus, and Vibrio are overrepresented in WFS shrimp. V. parahaemolyticus was identified as the predominant species in WFS samples. Function prediction analysis revealed that shrimp samples affected by WFS exhibited decreased lipid metabolism pathways, while showing elevated nucleotide metabolism and glycan biosynthesis pathways. Additionally, exosome and bacterial toxin pathways are more commonly found in diseased samples than in healthy ones, suggesting the potential involvement of unfavourable gut flora colonization. Our study provides clear understanding of the gut microbial community, specifically at the species level, distinguishing between WFS and healthy shrimps. Additionally, it emphasizes the role of Vibrio in the development of WFS and underscores the significance of analysing the core genes related to pathogens in studying the etiology of the disease.

Investigation on extraction methods of garlic (Allium sativum L.) with activity against three strains of Vibrio causing disease in shrimp

Garlic (Allium sativum L.) is a plant with potent antibacterial activity that has been known for a long time. In this study, we extracted different extracts from garlic such as essential oil, polysaccharide, 5% acetic acid extract, ethanol extract, fractional ethyl acetate extract, fractional ethanol extract and fractional water extract to find the garlic extract with the best antibacterial activity against Vibrio parahaemolyticus, Vibrio vulnificus and Vibrio cholera, all species causing white feces disease and acute hepatopancreatic necrosis disease in shrimp. The results showed that ethanol extract and essential oil had antibacterial activity in all three strains and garlic essential oil inhibited all 3 strains of Vibrio with the highest sterile ring diameter of 80 ± 0 mm by fumigation method. The MIC and MBC values of both ethanol extract and essential oil showed better resistance to V. vulnificus than to V. parahaemolyticus and V. cholera. The ethanol extract had MIC = 8.33 mg/ml and MBC = 12.50 mg/ml and the essential oil had MIC = 0.03 μl/100 μl and MBC = 0.05 μl/100 μl. The results of the time-kill curve showed that both the ethanol extract and the essential oil were able to kill all three strains of Vibrio only after 24 hours when added to the bacterial medium, while tetracycline only inhibited V. cholera, V. parahaemolyticus during the first 8 hours and 24 hours for V. vulnificus.

Profiling of Microbial Community in Rearing Water of White Shrimp (Litopenaeus vannamei) Infected with White Feces Disease Syndrome

Shrimp farmers have reported mass mortality of white shrimp (Litopenaeus vannamei), reaching 2-3 kg/day in Gerongan Village, Kraton District, Pasuruan Regency in mid-2021. Preliminary analysis suggests that mass mortality was caused by bacterial diseases. Thus, to find out the main pathogen causing the mass mortality, the present study investigated microbial composition in rearing media of white shrimp (Litopenaeus vannamei) infected by the white feces disease (WFD) and healthy white shrimp using next-generation sequencing (NGS) technology. The research was conducted by collecting normal water samples and infected shrimp pond water samples. The results of the NGS assay showed that Vibrio vulnificus was found dominant in WFD-infected shrimp pond water, therefore was suspected to be the main cause of WFD.

White feces syndrome in Penaeus vannamei is potentially an Enterocytozoon hepatopenaei (EHP) associated pathobiome origin of Vibrio spp

White feces syndrome (WFS) is a commercially important disease in Penaeus vannamei (whiteleg shrimp) farming. The aetiology beyond the white or golden white midgut with mediocre growth performance producing a floating mass of white fecal strings in WFS-affected shrimp farms remains uncharted. To give WFS a perception of pathobiome, healthy P. vannamei shrimps were subjected to an enteric microsporidian Enterocytozoon hepatopenaei (EHP) infection along with Vibrio harveyi and V. alginolyticus in different combinations. Immune responses in haemolymph (total haemocyte count (THC), prophenoloxidase activity (proPO), respiratory burst activity (RBA), superoxide dismutase activity (SOD) and catalase activity (CAT)), plasma biochemical changes (aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP)) and digestive enzymes activity (alpha-amylase (AMY), lipase (LIP) and protease (PRO)) were assessed in the challenged shrimps at 5, 10 and 15 days post-infection (dpi). The microbial interactions between the EHP and Vibrio spp. have led to the formation of WFS in the challenged shrimps. The histological sections of the hepatopancreas revealed the presence of EHP along with colonized bacterial masses, leading to the formation of aggregated transformed microvilli (ATM) structures and increased sloughing of lipid vacuoles into the tubule lumen. A significantly decreased THC and increased proPO levels, dysregulated antioxidant system, prominent hepatic damage, reduced energy metabolism and higher lipid production were the key records supporting that EHP-associated WFS in P. vannamei is due to the pathobiome.

Microbial communities associated with Zoea-2 syndrome and White feces syndrome in P. vannamei farming

DATA REPORT article Front. Mar. Sci., 05 May 2023Sec. Marine Molecular Biology and Ecology Volume 10 - 2023 | https://doi.org/10.3389/fmars.2023.1120004

Phytoplankton Composition in White Shrimp (Litopenaeus vannamei) Pond Culture Infected White Feces Disease (WFD)

The aim of this study is to find out the composition and condition of phytoplankton in the white shrimp (L. vannamei) culture inffected by the white feces disease so that one of the indicators of the onset of the white feces disease can be known. This research uses descriptive methods. The observed parameters are the identification of species diversity, abundance, diversity index and dominance index of phytoplankton. The sampling was conducted at three locations, Tuban area, Situbondo area, Lamongan area. The results of the study showed observations in Lamongan area, the total abundance of phytoplankton was 473 cells/L. Situpondo areas abundantity of phytoplankton total was 633 cels/L and Tuban areas abundance was 887 cells/L. In Lamongan area, the diversity index was 1,009. In Situbondo areas diversity Index was 1,013. In Tuban area, diversity indexes were 1,082. In Lamongan area, a dominance index was 0.477. In Situpond area, it was obtained a domination index of 0.544. The genus that dominates the three ponds are Cyclotella and Navicula. At all three locations have high variety of species and abundance of the genus members of the filum Cyanophyta and Bacillariofhyta are detrimental, the genuses that are found are indicators of contaminated waters. The dominance of Cyanophyta (blue-green algae) is also an indicator of the White Feces Disease.

Tail fell syndrome impacts intestinal microbiota in porcupinefish (Diodon hystrix)

IntroductionFrequent disease outbreaks seriously affect porcupinefish (Diodon hystrix), which is a new aquaculture breed in China. Recently, a novel disease, termed tail fell syndrome (TFS) was increasingly observed in fish stocks, resulting in stalk ulceration, tail loss, ascites and white feces in the intestine. Intestinal microbiota homeostasis is crucial to host health because it influences host and environmental factors, and responds to various internal and external stimuli. However, changes in intestinal microbiota induced by TFS are yet to be elucidated.MethodsIn the present study, we analyzed and compared the intestinal microbiota of normal D. hystrix with TFS fish.ResultsThough microbiota richness and diversity were not affected by TFS, deviations in diversity indices increased and taxa distribution evenness decreased, suggesting TFS lowered microbiota community stability in D. hystrix. Furthermore, at the genus level, Brevibacterium, Mesorhizobium, Ochrobactrum, Ralstonia, Anaerococcus, and Alistipes abundances were significantly increased in TFS D. hystrix, plus, we observed significant decreases in Halomonas, Prevotellaceae_NK3B31_group, and Psychrobacter. Functional comparison predictions between normal and TFS D. hystrix revealed significantly altered pathways were mainly associated with metabolism (biotin metabolism, steroid hormone biosynthesis, flavonoid biosynthesis, biosynthesis of type II polyketide products, and steroid biosynthesis). Overall, the results revealed that TFS impacted intestinal microbiota composition and function in D. hystrix, which should expand our knowledge on diseases associated with porcupine pufferfish aquaculture.

Strategy for Developing Whiteleg Shrimp (Litopenaeus vannamei) Culture Using Intensive/Super-Intensive Technology in Indonesia

The Government of the Indonesian Republic has targeted an increase in the value of shrimp exports and production until 250% by 2024. Thus, a special strategy is needed to develop whiteleg shrimp (Litopenaeus vannamei) culture that can increase production but does not negatively impact the aquatic environment. For this reason, research was carried out to obtain a strategy for developing sustainable intensive/super-intensive technology of whiteleg shrimp culture in South Sulawesi Province, Indonesia. The activity was conducted in South Sulawesi Province from March to July 2021. The data were collected from questionnaires submitted to respondents or actors, namely whiteleg shrimp brackishwater pond managers and other stakeholders and structured observations on whiteleg shrimp ponds. The validity of the questionnaire was tested using Corrected Item-Total Correlation method and the reliability was tested using Cronbach’s alpha method. Another primary data source was obtained through Focus Group Discussion. Data analysis was undertaken using the Analytical Hierarchy Process method. The research results show that, of the 18 intensive/super-intensive technology of whiteleg shrimp farming businesses operating in Bulukumba, Je’neponto, and Takalar Regencies, only one whitleg shrimp farming business applies super-intensive technology. The main problems in intensive/super-intensive whiteleg shrimp culture are disease attacks, namely acute hepatopancreatic necrosis disease or early mortality syndrome and white feces disease and the inconsistent quality of seed. Among the four criteria studied, it was found that environmental factor criteria are the most influential in developing intensive/super-intensive technology of whiteleg shrimp culture. Among the seven alternative strategies, the order of priority of the alternative strategies is environmental protection of culture, management of culture areas, modern technological innovation, environmentally friendly culture technology, easy access to business and capital, improvement of human resources, and availability of pond facilities.

EFEKTIFITAS EKSTRAK MANGROVE Rhizophora apiculata (Tomlinson, 1986) DALAM MENGHAMBAT Vibrio parahaemolyticus PENYEBAB PENYAKIT PADA UDANG VANAME Litopenaeus vannamei (Boone, 1931)

Vaname (L. vannamei ) shrimp cultivation is currently experiencing problems, one of which is disease caused by Vibrio bacteria, especially V. parahaemolyticus. This type of vibrio is the cause of white feces disease and AHPND in shrimp. Disease control due to Vibrio can be done by utilizing plants that have active compounds as natural antibacterials that are environmentally friendly. Mangrove plants have several active compounds that have great potential as antibacterial. This study aimed to examine some parts of the mangrove plant R. apiculata in inhibiting the activity of V. parahaemolyticus. Three parts of the mangrove plant, namely: roots, stems, and leaves were extracted using methanol. The three extracts were tested for their antibacterial activity against V. parahaemolyticus by several tests such as phytochemical, sensitivity, zone of inhibition, best dose, and toxicity tests. The test results showed that R. apiculata mangrove stem extract had the greatest ability to inhibit V. parahaemolyticus with an effectiveness value of 15.85% with the best dose of 200 mg/L. Toxicity testing using vaname shrimp larvae extract showed that mangrove stems were non-toxic with an LC50 value of 2,155.5 mg/L.Keywords: White feces disease, AHPND, active compounds, extracts, antibacterials