Monodon Larvae Research Articles

Combating vibriosis in Penaeus monodon culture system by administration of endophytic Penicillium citrinum SW171 extract that confers better growth and protection

The black tiger shrimp, Penaeus monodon, has been a key species in the development and expansion of intensive shrimp aquaculture worldwide. The problem of disease susceptibility in P. monodon, particularly vibriosis caused by Vibrio harveyi, poses a significant threat and leads to substantial economic losses. To combat bacterial infections, researchers are exploring the antimicrobial potential of microbes from unique environments, like algicolous endophytes. In this study, we investigated the in vivo exclusion of Vibrio in P. monodon post-larvae using an extract from the endophytic fungus Penicillium citrinum SW171 (PCE), evaluating its impact on disease resistance, growth, and survival. Crude endophytic extract was administered both via feed and rearing water for 28 days before the challenge with V. harveyi. Treatment with PCE improved the water quality of rearing water by significantly reducing ammonia and nitrate levels compared to the control. This treatment notably decreased Vibrio colonies without substantial alteration in the overall microbial load of the rearing water. Moreover, the endophytic extract not only inhibited pathogens but also enhanced productivity, as evidenced by improved growth rates (1272 ± 20.8 and 1109.02 ± 28.4 mg) compared to the control (1026.02 ± 33.8 mg). Transcript levels of the immune-related genes i.e., anti-lipopolysaccharide factor (ALF), crustin, penaeidin, prophenoloxidase-activating enzyme (PPA), phagocytosis-activating protein (PAP), lysozyme-like, ferritin, haemocyanin, lectin, and survivin, were assessed in post-larvae using qRT-PCR. Extract treatment led to significant up-regulation of all genes except PPA, survivin and ALF. The cumulative survival rate of the group orally treated with PCE was 66.9 %, while that of water treatment was 64.5 %, significantly higher than that of the control group. The higher growth rate and post-challenge survival of P. monodon larvae point towards the immunostimulatory and antibacterial properties of endophytic P. citrinum extract which can be exploited in aquaculture for better production.

Automatic Penaeus Monodon Larvae Counting via Equal Keypoint Regression with Smartphones.

Today, large-scale Penaeus monodon farms no longer incubate eggs but instead purchase larvae from large-scale hatcheries for rearing. The accurate counting of tens of thousands of larvae in these transactions is a challenging task due to the small size of the larvae and the highly congested scenes. To address this issue, we present the Penaeus Larvae Counting Strategy (PLCS), a simple and efficient method for counting Penaeus monodon larvae that only requires a smartphone to capture images without the need for any additional equipment. Our approach treats two different types of keypoints as equip keypoints based on keypoint regression to determine the number of shrimp larvae in the image. We constructed a high-resolution image dataset named Penaeus_1k using images captured by five smartphones. This dataset contains 1420 images of Penaeus monodon larvae and includes general annotations for three keypoints, making it suitable for density map counting, keypoint regression, and other methods. The effectiveness of the proposed method was evaluated on a real Penaeus monodon larvae dataset. The average accuracy of 720 images with seven different density groups in the test dataset was 93.79%, outperforming the classical density map algorithm and demonstrating the efficacy of the PLCS.

Growth and Lipidomic Analyses of Penaeus monodon Larvae Supplemented With Aurantiochytrium limacinum BCC52274

Long-chain polyunsaturated fatty acids (LC-PUFAs) are essential for growth and health of larval marine animals. Marine animals have a limited capability for LC-PUFA synthesis, and the larvae must obtain LC-PUFAs from diet. The protist Aurantiochytrium limacinum (AL) is abundant in 22:6 n-3 (docosahexaenoic acid, DHA), 22:5 n-3 (docosapentaenoic acid, DPA) and 16:0 fatty acids, which qualifies it as an LC-PUFA source for feed application. Therefore, in this study, a common feed containing lower amounts of total LC-PUFAs, Thalasiosira weissflogii, was replaced with AL at graded proportions and supplied to Penaeus monodon larvae from mysis (M) 1 to post-larval (PL) 2 stages to supplement LC-PUFAs in the diet. After that, all shrimp from PL2 to PL12 were continuously reared and subjected to the same diet regime, which was a combination of Artemia and commercial dried feed. The AL-supplemented PL2 shrimp demonstrated marked accumulation of the key fatty acids present in AL—16:0, DPA and DHA. The supplemented larvae showed no difference in growth during the supplementation period from M1 to PL2; however, average body weight and biomass were increased in PL12 shrimp that were fed earlier with AL. Lipidomic analysis revealed that profiles of fatty acids but not lipid classes/subclasses in PL shrimp reflected the supplied diet. The main saturated fatty acid (SFA, 16:0) predominantly accumulated in acylglycerols, which are energy-reserve lipids, in PL2 shrimp. Both LC-PUFAs (DHA and DPA) were preferentially deposited in phospholipids or structural lipids. Furthermore, while the amounts of both LC-PUFAs increased along with the amount of supplied AL, that of the SFA did not. This suggests that LC-PUFAs were prioritized to be stored over SFA when both types of fatty acids were present in high amounts. This analysis substantiates the importance of LC-PUFAs and provides an insight into how different types of the dietary fatty acids were differentially accumulated in lipid classes and subclasses for their biological functions.

Effect of Silver Nano Particle Microalgae Chlorella pyrenoidosa and Dunaliella salina on Growth and Survival of Penaeus monodon Larvae

Penaeus monodon is one of the most important farmed crustaceans. Its also known as Asia Tiger Shrimp because its carapace and abdomen are transversely banded with red and white. The use of synthetic antibiotic in aquaculture had caused problems related to health and environmental safety. Chlorella pyrenoidosa and Dunaliella salina are photosynthetic microalgae. Silver nano particle in microalgae C. pyrenoidosa and D. salina had synthesized and showed their growth stability. They offer a potency to be exploited to supported growth and survival of shrimp larvae. The objective of the study was the application of silver nano particle in microalgae C. pyrenoidosa and D. salina on P. monodon larvae. The research methodology was carried out by making microalgae C. pyrenoidosa and D. salina containing silver nano particle and used as feed of shrimp larvae. Observations were made on the growth and survival of shrimp larvae compared to both microalgae and common feed. The results showed that the P. monodon larvae have the higher growth and survival rate with microalgae C. pyrenoidosa at the beginning of their growth compared to D. salina. However, microalgae without nanosilver and common feed showed a better result for growth and activity of shrimp larvae.

A preliminary experiment on production of dsRNA by in-vivo and its application to tiger shrimp Penaeus monodon larvae for survival enhancement

RNA interference (RNAi) is one of the most recent tools against shrimp viral infection by gene constructs of dsRNA induction. This study aimed to produce dsRNA by in-vivo method and to analyse the effect of its application to tiger shrimp larvae. The dsRNA production was conducted by cloning of genes encoding VP15 and VP24 of WSSV into L4440 vector containing T7 promoter, then transformed to Escherichia coli and grew in LB media for mass production. The bacteria were in-activated using heat-killed bacteria method by immersion at 80°C for 5, 10, and 15 min. Before WSSV-challenge test, tiger shrimp PL-12 were vaccinated by immersion using in-activated bacteria in concentration of 1.3×108 cell/mL for 30 min as a treatment and without vaccination was as a control. The results showed the successful production of VP-dsRNA by in-vivo. In-activated bacteria was effective at 5 min, since dsRNA did not damage. Survival of larvae at 5 days post challenge (dpc) in VP15-dsRNA was relatively higher (28.3%) compared to control (24.4%), and application of VP24-dsRNA also showed higher survival (86.9%) compared to control (83.1%) at 10 dpc. The result implied that the application of dsRNA exhibited a sign of potential way to produce resistant larvae.

Effects of live microalgae and algae powder on microbial community, survival, metamorphosis and digestive enzyme activity of Penaeus monodon larvae at different growth stages

Most hatcheries use live microalgae and algae powder for artificial rearing; however, the effects of these different diets on the rearing process and bacterial communities is not clear. In order to investigate the effects of live algae and algal powder on the larval culture of Penaeus monodon. Two kinds of live algae (Chaetoceros muelleri, Thalassiosira weissflogii) and Spirulina powder were used to feed larvae in this study, and the effects on the environmental parameters of water, the digestive enzymes activity of larvae and the bacterial community from the zoea stage to the post larval (PL) stage were explored. The results revealed that feeding larvae with C. muelleri significantly improved the enzymatic activity of amylase and the survival rate of the larvae, and significantly reduce the concentrations of NH4-N, NO2-N and the quantity of Vibrio in the water (P < 0.05). Feeding with T. weissflogii significantly improved the enzymatic activity of lipase and pepsin, and the percentage of metamorphosis (P < 0.05). It suggested that adding live microalgae was beneficial in increasing the diversity of the bacterial community in larvae. Cyanobacteria and Patescibacteria were dominant bacteria in the algal solutions of C. muelleri and T. weissflogii. The entire rearing environment was dominated by two phyla: Bacteroidetes and Proteobacteria. Virgulinella fragilis, the bacteria present in the liquid of C. muelleri and T. weissflogii, accounts for a high proportion of bacteria in the rearing water at the zoea stage. The bacterial community in the zoea stage showed significant negative correlations with NH4-N and NO2-N (P < .05), whereas the bacterial community in the PL stage showed significant positive correlations with NH4-N and NO2-N (P < .05). Saprospiraceae and Microbacteriaceae in the water were significantly positively correlated with NH4-N and NO2-N (P < .05). Feeding larvae with C. muelleri and T. weissflogii and Spirulina powder could increased the abundance of Microbacteriaceae, Devosiaceae and Saprospiraceae at the family level, and increased the abundance of Pseudoalteromonas, Roseovarius and Nautella at genus level. In conclusion, feeding larvae with live microalgae could improve the percentage of metamorphosis and survival rates of larvae by improving the external water environment, enhancing digestion, and regulating bacterial community.

EKSTRAK BUAH MANGROVE (Sonneratia alba) PADA Artemia salina DALAM MENGHAMBAT INFEKSI Vibrio harveyi TERHADAP SINTASAN BENUR UDANG WINDU (Penaeus monodon) SECARA INVIVO

Vibriosis disease Vibrio harveyi often drops Penaeus monodon production on the traditional coastal ponds of North Kalimantan. The purpose of this study was to find out the active compound extract of Sonneratia alba fruit inhibiting the infection of Vibrio harveyi, which was tested on the larvae of Penaeus monodon in post larvae 12 through the bioerichment of natural feed Artemia salina. This study used an experimental method performed with a Completely Randomized Design (CRD) of 4 treatments and 3 replications. The results showed mangrove fruit extracts containing alkaloids, phenol hydroquinone, flavonoids, saponins, steroids and tannins. Artemia salina bioenrichment succeeded in increasing the survival of Penaeus monodon larvae 78.33% in treatment III (20 ppm). The results of water quality measurements indicate the range at the normal limit for the life of the Penaeus monodon larvae. Keywords : Penaeus monodon, Artemia salina, Vibrio harveyi, Extract Sonneratia alba

Black tiger shrimp larvae (Penaeus monodon) that received eggshell powder in diet exhibit decreasing of growth and survival rate

The objective of the present study was to investigate the effect of eggshell powder supplementation in diet on the growth and survival rate of black tiger shrimp, Penaeus monodon larvae. A total of 600 shrimp larvae (PL 12) was used with five treatment levels and four replications. The shrimp fed with 42% of crude protein, feeding frequency three times a day at 08.00; 14.00; 18.00 pm and 5% feeding rate. The dietary treatments were A (0%), B (3%), C (6%), D (9%) and E (12%) fed for thirty days. Results showed that the supplementation of eggshell powder in diet had a significant effect on weight gain, length gain, specific growth rate, and survival of black tiger shrimp larvae. Duncan's advanced test showed that the optimum dose of eggshell powder was found in treatment A (0% eggshell powder) with weight gain, length gain, specific growth rate, and survival rate at 0.0301±0,0013 g, 12.41±0,56 mm, 12.82±0,16 %/day, and 94.17±1,66%, respectively. Hence, it can be concluded that the supplementation of eggshell powder may decrease the growth and survival rate of black tiger shrimp larvae.

Effect of Chromolaena odorata as bioactive compound in artificial diet on survival rate of tiger prawn Penaeus monodon

The leaves of Chromolaena odorata can be used as alternative bioactive compounds to address high mortality in shrimp due to outbreaks of Vibrio sp. during both larval rearing and grow-out. The study aimed to determine the effect of Chromolaena odorata leaves on the survival and growth performance of tiger prawn Penaeus monodon larvae. Four different formulated diets with different concentrations of Chromolaena odorata leaves (1250 mg/kg, 1500 mg/kg, 1750 mg/kg) and a control (0 mg/kg) were fed to tiger prawns infected with Vibrio harveyi. Data were collected on total hemocyte count (THC), phenoloxidase (PO) and survival rate. One way ANOVA was applied for statistical analysis. The results show that Chromolaena odorata leaves were able to increase the immune response of tiger prawns infected with Vibrio harveyi. This was indicated by the increase in total haemocyte count (THC), phenoloxidase (PO) and survival rate with the values of 0.05 × 106 cells / mL, 0.05 and 84 %, respectively, for the formulated diet treatment with 1500 mg/kg feed. The increase in tiger prawn immune response led to increased resilience against Vibrio harveyi. As a result, survival rates of treated tiger prawns were higher than the control.

Water Pretreatment Affects the Bacteria Communities in Penaeus monodon Larvae Culture

Water Pretreatment Affects the Bacteria Communities in Penaeus monodon Larvae Culture

Efficacy of potential phage cocktails against Vibrio harveyi and closely related Vibrio species isolated from shrimp aquaculture environment in the south east coast of India

A diverse set of novel phages infecting the marine pathogenic Vibrio harveyi was isolated from shrimp aquaculture environments in the south east coast of India. Based on initial screening, three phages with a broad host range revealed that the growth inhibition of phage is relatively specific to V. harveyi. They were also able to infect V. alginolyticus and V. parahemolyticus that belonged to the Harveyi clade species from shrimp pond and sea coast environment samples. However, the impact of these phages on their host bacterium are well understood; a one-step growth curve experiment and transmission electron microscope (TEM) revealed three phages grouped under the Myoviridae (VHM1 and VHM2); Siphoviridae (VHS1) family. These phages were further molecular characterized with respect to phage genomic DNA isolates. The randomly amplified polymorphic DNA (RAPD), restriction fragment length polymorphism (RFLP) digestion with HindIII, and major structural proteins were distinguished by sodium-dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE) clearly indicated that all the phage isolates were different, even when they came from the same source, giving an insight into the diversity of phages. Evaluation of microcosm studies of Penaeus monodon larvae infected with V. harveyi (105 CFU mL−1) showed that larvae survival after 96 h in the presence of phage treatment at 109 PFU mL−1 was enhanced when compared with the control. The resolution in over survival highly recommended that this study provides the phage-based therapy which could be an innovative and eco-friendly solution against Vibrio disease in shrimp aquaculture and in the natural environment.

Transferable chloramphenicol resistance determinant in luminous Vibrio harveyi from penaeid shrimp Penaeus monodon larvae

Antibiotic-resistant luminous Vibrio harveyi strains isolated from Penaeus monodon larvae were screened for the possession of transferable resistance determinants. All the strains were resistant to chloramphenicol and the determinant coding for chloramphenicol resistance was transferred to Escherichia coli at frequencies of 9.50x10-4 to 4.20x10-4. The results probably suggest the excessive use of chloramphenicol in shrimp hatcheries to combat luminous vibriosis.

Transferable chloramphenicol resistance determinant in luminous Vibrio harveyi from penaeid shrimp Penaeus monodon larvae

Antibiotic-resistant luminous Vibrio harveyi strains isolated from Penaeus monodon larvae were screened for the possession of transferable resistance determinants. All the strains were resistant to chloramphenicol and the determinant coding for chloramphenicol resistance was transferred to Escherichia coli at frequencies of 9.50x10-4 to 4.20x10-4. The results probably suggest the excessive use of chloramphenicol in shrimp hatcheries to combat luminous vibriosis.

Characterization of Vibrio parahaemolyticus and its specific phage from shrimp pond in Palk Strait, South East coast of India

Phage therapy is an alternative and eco-friendly biocontrol agent to prevent and control multidrug resistant bacteria in the aquatic system. The aim of this study is to isolate and characterize the Vibrio parahaemolyticus and its potential lytic phage from Penaeus monodon growing-out by rearing in shrimp ponds in Palk Strait, South East coast of India. The conventional phenotypic characteristics and molecular identification was confirmed using 16S rRNA sequence and to determine the antibiotic resistant profiles. The V. parahaemolyticus phage was effective against V. parahaemolyticus through one-step growth experiments, phage survival was determined by long-term storage at various temperatures and pH. Further, transmission electron microscope (TEM) revealed that the lytic phage belongs to the Myoviridae family. The isolated lytic phage (VVP1) was more specific against N1A V. parahaemolyticus and was able to infect N7A V. parahaemolyticus, N3B and N13B Vibrio alginolyticus strains. Evaluation of microcosm studies with P. monodon larvae infected with V. parahaemolyticus showed the survival of larvae in the presence of phage treatment at 2.3 × 1010 PFU/mL−1 was enhanced when compared with the control. This study provides the application of phage as a useful strategy to prevent and eliminate or reduce shrimp pathogenic V. parahaemolyticus in the aquaculture system.

Screening of probiotics bacteria from coral reef using co-culture method for controlling vibriosis in tiger shrimp (Penaeus monodon) larvae

&lt;p&gt;ABSTRACT&lt;/p&gt;&lt;p&gt;&lt;br /&gt;This study was carried out to obtain bacteria isolates from coral reef using co-culture method which potentially inhibit Vibrio harveyi growth. A total of 110 isolates were isolated from Acropora sp., Merulina sp., Hystrix sp., Poecillophora sp., Porites sp., and Haliophora sp., and were screened for their antagonistic activity against V. harveyi in in vitro and in vivo test. Five candidate probiotics (5H1 candidate probiotics isolated from Acropora sp., 11I and 11G isolates isolated from Hystrix sp. and 13B and 13G1 isolates isolated from Poecillophora sp., was able to inhibit growth of V. harveyi MR5339 RFR up to 101‒102 cfu/mL. Two isolates (13B and 13G1) were not pathogenic at concentration 106 cfu/mL bacteria and could increase of survival rate of tiger shrimp (Penaeus monodon) larvae in in vivo test. Survival rate of tiger shrimp larvae that treatment with 13B and 13G1 were 86,67% and 88,33%, and have a significant different with positive control (61,67%). Partial sequencing of 16S-rRNA showed that 13G1 isolate was similar to V. alginolyticus.&lt;br /&gt;Keywords: vibriosis, Vibrio harveyi, tiger shrimp, probiotic, coral reef&lt;/p&gt;&lt;p&gt;&lt;br /&gt;ABSTRAK&lt;/p&gt;&lt;p&gt;&lt;br /&gt;Penelitian ini bertujuan untuk mendapatkan bakteri probiotik asal terumbu karang dengan metode kultur bersama untuk pengendalian penyakit vibriosis pada larva udang windu (Penaeus monodon). Sebanyak 110 isolat berhasil diisolasi dari Acropora sp., Merulina sp., Hystrix sp., Poecillophora sp., Porites sp., dan Heliophora sp. dan dilakukan penapisan untuk melihat aktivitas kemampuannya melawan Vibrio harveyi MR 5339 RfR dalam uji in vitro dan in vivo. Sebanyak 56 isolat menghasilkan daya hambat terhadap V. harveyi MR5339 RfR pada metode kultur bersama. Lima isolat kandidat probiotik (isolate 5H1 diisolasi dari Acropora sp., isolat 11I dan 11G diisolasi dari Hystrix sp., serta isolat 13B dan 13G1 yang diisolasi dari Poecillophora sp.), mampu menekan pertumbuhan V. harveyi MR5339 RfR hingga 101–102 cfu/mL. Kedua isolat (13B dan 13G1) terbukti tidak bersifat patogen pada konsentrasi 106 cfu/mL dan mampu meningkatkan sintasan larva udang windu pada uji in vivo. Nilai sintasan larva pada perlakuan yang diberi kandidat probiotik 13B dan 13G1 berturut-turut adalah 86,67% dan 88,33%, namun berbeda nyata dengan kontrol positif (61,67%). Hasil analisis sekuen sebagian gen 16S-rRNA menunjukkan bahwa isolat 13G1 termasuk spesies V. algynoliticus.&lt;br /&gt;&lt;br /&gt;Kata kunci: vibriosis, Vibrio harveyi, udang windu, probiotik, terumbu karang&lt;/p&gt;

In vitro and in vivo study of acyl homoserine lactone degrading Bacillus against Vibrio harveyi

Vibriosis caused by Vibrio harveyi is still a bottleneck for the development of shrimp culture industry. As quorum sensing (QS) regulates the virulence of V. harveyi, interference of QS might offer opportunity for controling V. harveyi in shrimp culture. The aim of this study was to evaluate the ability of AHL-degrading Bacillus to interfere with the AHL production and the growth of V. harveyi in vitro and in vivo on Penaeus monodon larvae. Based on biochemical and molecular study, the AHL-degrading Bacillus was confirmed as B. subtilis STC. The results showed that AHL-degrading Bacillus affected (P 0.05) in all treatments. Yet, there was a trend that the higher of B. subtilis STC given, the smaller number of AHL available in the system. The survival rates of P. monodon larvae were significantly different (P<0.05) among treatments. The use of AHL-degrading bacteria, B. subtilis STC, at the concentration of 1x106 CFU.ml-1 improved the survival rate of P. monodon larvae up to 65.56% when infected by V. harveyi. Therefore, this AHL-degrading bacteria could be used as biocontrol agent against vibriosis in P. monodon larvae culture.

Isolation of probiotics bacterium from coral reef for controlling vibriosis in tiger shrimp (Penaeus monodon) larvae

&lt;p&gt;Pathogenic Vibrio, especially luminous Vibrio harveyi, could cause mass mortality in tiger shrimp culture. One of the technique to work against luminous Vibrio is, using probiotic bacteria to inhibit the luminous Vibrio growth. This study was carried out to obtain bacteria isolates from coral reef which potentially inhibit V. harveyi growth. A total of 110 isolates were isolated from Acropora sp, Merulina sp, Hystrix sp., Poecillophora sp, Porites sp and Haliophora sp., and have probiotic activity against V. harveyi in in vitro and in vivo test.Of the total 110 isolates, 54 isolates show the inhibiting zone. Two isolates(8A and 1C)were not pathogenic and have the most effective activity in inhibiting growth of V. harveyi and significantly reduced larval mortality in in vitro and in vivo test. Treatment using probiotics candidate have significant different survival rate (83.33%) compared with positive control (61.67%). The growth rate of lenght of larvae treatment with isolate of 8A (5.25%) and 1C (5.06%) show the significant different compared with positive control (3.54%). The growth rate of weight of larvae treatment withisolate of 8A (17.51%) and 1C (17.61%) show significant different compared with negative (15.27%) and positive control (14.69%).&lt;br /&gt;&lt;br /&gt;Key word: coral reef, probiotic, tiger shrimp, vibriosis, V. harveyi.&lt;/p&gt;&lt;p&gt; &lt;/p&gt;&lt;p&gt;&lt;strong&gt;ABSTRAK&lt;/strong&gt;&lt;br /&gt;&lt;br /&gt;Vibrio patogen, khususnya Vibrio harveyi berpendar, dapat menyebabkan kematian massal pada budidaya udang windu. Salah satu alternatif untuk menghambat Vibrio harveyi berpendar adalah dengan menggunakan bakteri probiotik yang dapat menekan pertumbuhan Vibrio tersebut. Penelitian ini bertujuan untuk mendapatkan isolat bakteri dari terumbu karang yang potensial menghambat pertumbuhan V. harveyi. Total 110 isolat diisolasi dari Acropora sp, Merulina sp., Hystrix sp., Poecillophora sp., Porites sp. dan Haliophora sp, dilakukan penapisan untuk melihat aktivitas kemampuannya melawan V. harveyi MR 5339 RfR dalam uji in vitro dan uji in vivo. Sebanyak 54 isolat teridentifikasi mampu menghasilkan zona hambat. Dua isolat (8A dan 1C) terbukti tidak bersifat patogen dan memiliki aktivitas probiotik melawan V. harveyi MR 5339 RfR pada uji in vitro dan in vivo. Tingkat kelangsungan hidup larva pada perlakuan yang diberi kandidat probiotik dari kedua isolat tersebut adalah 83,33%, dan menunjukkan hasil yang berbeda nyata dengan kontrol positif (61,67%). Laju pertumbuhan panjang larva yang diberi isolat 8A (5,25%) dan 1C (5,06%)menunjukkan hasil yang berbeda nyatajika dibandingkan dengan kontrolpositif (3,54%). Laju pertumbuhan bobot yang diberi isolat 8A (17,51%) dan 1C (17,61%) menunjukkan hasil yang berbeda nyata terhadap kontrol negative (15,27%) dan kontrol positif (14,69%).&lt;br /&gt;&lt;br /&gt;Kata kunci: probiotik, terumbu karang,udang windu, V. harveyi, vibriosis.&lt;br /&gt;&lt;/p&gt;

STUDY OF PROBIOTICS ON THE SEED PRODUCTION OF BLACK TIGER SHRIMP Penaeus monodon

Currently, antibiotics are widely used in shrimp hatcheries to control bacterial infections. Appearance of antibiotic resistant pathogens and restriction on the use of antibiotics have led to the development of alternatives to antibiotics in hatchery systems. In light of this, an attempt was undertaken to investigate the effects of probiotics on the larval rearing of Penaeus monodon, compared with control tanks (without probiotics). The results showed that several issues significantly improved with administering probiotics in the experimental tanks compared with the tanks without probiotics. For example, the concentration of ammonia was estimated to be 1.25 mg/L that was less than half of what was measured in the control tanks. The size variation was observed more in the control tanks than in the experimental tanks. Moreover, the muscle gut ratio of PL15 was about 85 to 92% in the probiotic treated tank and 70 to 80% in the control tank during the eight cycles of production. The fouling organisms were more in the control tank compared to the experimental tanks. The average length of PL15 was maximum when reared in the experimental tanks compared to the control tanks. The final survival rate of PL15 from the control and experimental tank was 35 and 52%, respectively. The present investigation indicated that probiotics played an important role in the growth, survival and health status of P. monodon larvae.

Distribution and abundance of Heterocarpus reedi Bahamonde, 1955, Cervimunida johni Porter, 1903, and Pleuroncodes monodon (H. Milne Edwards, 1837), larvae off Coquimbo and Caldera, Chile

To better understand the population dynamics of fishery resource species, 160 zooplankton samples were obtained with a Bongo net at 40 oceanographic stations around Caldera and Coquimbo in October and December, 2005, and analyzed. All crustacean decapod larvae were sorted, and Heterocarpus reedi, Cervimunida johni, and Pleuroncodes monodon larvae were identified. For all three species, the highest abundances of early zoea were found in October in Coquimbo, whereas advanced larval stages were predominant in December. In Caldera, advanced larval stages of H. reedi and P. monodon, and early zoeas of C. johni were dominant during both sampling months. The frequency of occurrence of H. reedi larvae was similar during both sampling months in Coquimbo and greater in October in Caldera. The frequency of occurrence of the larvae of P. monodon and C. johni was greater in both areas in October. All the megalops captured in both zones and sampling months corresponded to a single morphotype, with morphological characteristics similar to the smallest P. monodon juvenile specimens. Based on the larval distribution and abundance of these three species, it is postulated that spawning occurs earlier in the Caldera area than around Coquimbo, mainly in areas near the coast, given the differences in abundance of the developmental stages.

Distribution of Pleuroncodes monodon larvae over the continental shelf of south-central Chile: Field and modeling evidence for partial local retention and transport

In situ and modeled spatial distribution of squat lobster ( Pleuroncodes monodon) larvae over the continental shelf off south central Chile (35–37°S) was analyzed along with currents and hydrography. We aimed to identify the main larval transport/retention characteristics in the study area, which constitutes the southernmost P. monodon fishing grounds embedded in the Humboldt Current System. We hypothesized that the main contribution to population renewal originates in the two persistent adult aggregations close to the nursery ground that occurs over a continental shelf terrace limited by two submarine canyons. Two extensive bio-physical field campaigns were carried out during the main 2001–2002 upwelling season field data indicated that larvae were released from late austral winter to spring from spots to the north and south of the nursery. Zoea I were found mainly below 50 m depth in southward-flowing waters, whereas older zoea dominated in northward flowing layers above 50 m. Larvae were circumscribed between the coast and the shelf break front and pelagic retention areas were identified over the widest shelf area. Megalopa and juveniles during March, were only found over the nursery area. Individual based simulations coupled to the output of a hydrodynamic model (climatological configuration) for the studied area, showed that the release sites close to the nursery made the largest contribution to recruitment. Sites further north could also contribute to recruitment if hatching occurred later in the upwelling season. The contribution of vertical behavior to larval success was also important, as was the former’s interaction with the site and time of larval release. Our results support the relevance of coastal circulation (affected by topography) on the persistence of P. monodon populations off southern Chile, and the modulation of temporal variability. These results might apply to other abundant species in the area.