Banana Shrimp Research Articles

Molecular authentication and discrimination between banana shrimp and Pacific white shrimp by duplex PCR-lateral flow dipstick (dPCR-LFD) system

Banana shrimp is easily substituted by Pacific white shrimp due to its relatively similar morphology and appearance. The duplex PCR-lateral flow dipstick (dPCR-LFD) system was developed to authenticate these two species based on the mitochondrial cytochrome b (Cytb) gene. Two pairs of species-specific primers were designed for dPCR amplification. The specificity was also tested toward nine marine species. The sensitivity of the method was also evaluated at the DNA range of 0.02 %-60 % of adulterated Pacific white shrimp DNA in DNA from banana shrimp. Several types of cooked samples under various conditions were also tested. The developed dPCR-LFD system could specifically differentiate banana shrimp from Pacific white shrimp. No cross-amplification was observed in the specificity test. The sensitivity test showed the detection limit of 0.02 % (0.01 ng) of Pacific white shrimp DNA. The cooking processes including boiling, frying, and steaming did not show any effect on the efficiency of the dPCR-LFD system. This technique could be therefore implemented for the authentication of banana shrimp and Pacific white shrimp products as well as further use for other seafood frauds.

Water quality and immunological response of banana shrimp (Fenneropenaeus merguiensis) co-cultured with green seaweed (Caulerpa lentillifera) in the laboratory

Co-culture of newly domesticated shrimp, F. merguiensis, and green seaweed, C. lentillifera, was conducted in six cement tanks to assess their impact on water quality and immunological response. Shrimp juveniles (14,3±0.3 mg) were stocked at a density of 50 shrimps/m2 and co-cultured with C. lentillifera at two initial stocking rates: A (0.1 kg/m2), B (0.2 kg/m2), and C (without seaweed) as a control treatment. All treatments were replicated twice, and the trial lasted eight weeks. The results of the experiment demonstrated that co-culturing F. merguiensis with C. lentillifera not only improves water quality, primarily nitrogen (TAN, NO2, NO3) and phospate (PO4-) compounds, but also on immunological parameters (THC, DHC, PA, and PO activity) assessed. Shrimp production indicators improve significantly (p<0.05) after seaweed treatments. Furthermore, C. lentillifera grows at a pace of more than 10% per day and is suggested for co-culture with shrimp at a density of 0.1 - 0.2 kg/m2.

Xenogeneic transplantation of spermatogonia from banana shrimp (Fenneropenaeus merguiensis) into white shrimp (Litopenaeus vannamei)

Banana shrimp (Fenneropenaeus merguiensis) is one of the famous shrimps for the consumer, while larvae of F. merguiensis for farming depend on wild-caught broodstock. On the other hand, white shrimp (Litopenaeus vannamei) is propagated from a culture broodstock and has a high growth rate. Currently, spermatogonia transplantation is one of the alternative methods to preserve and propagate the offspring of several vertebrates. Transplantation technology has not been reported in shrimp. This study provided information on the transplantation technique in shrimp using F. merguiensis as a donor and L. vannamei as a recipient. Spermatogonia were prepared from wild-caught F. merguiensis, 11–12 cm in length, and the cells were 8–10 µm in diameter. The spermatogonia were injected into postlarvae days 4, 9, and 16 of L. vannamei. The PKH-26 fluorescent signal was between the heart and hepatopancreas of the recipient 4 wk post-injection. In addition, the gonad of the recipient contained the proliferated donor germ cells in the gonad of the recipient after 4.5 month post-transplantation, determined by in situ hybridization with a VASA probe. The mature transplanted shrimps had dark spots on the gonad, similar to F. merguiensis's gonad. Then, the donor-derived offspring were achieved after the natural mating of transplanted shrimp. The donor-like morphology of F1 offspring was approximately 70.5%. When the genetics of F1 offspring were clarified and revealed, 2% of F. merguiensis, 28% of L. vannamei, and 70% of the hybrid between F. merguiensis and L. vannamei. The overall results indicated the successful establishment of spermatogonia transplantation in shrimp. The benefit of this work could apply to conserve or produce this shrimp in the future.

Genetic diversity and population differentiation of wild and domesticated banana shrimp Fenneropenaeus merguiensis: Applications for development of its breeding program

The basic information on genetic diversity is important for the construction of a breeding scheme leading to the sustainable farming activity of banana shrimp Fenneropenaeus merguiensis. Here, its genetic variability was examined (N = 584). Species authentication was performed by cytochrome oxidase subunit I (COI) polymorphism (N = 77). Microsatellite analysis revealed limited genetic diversity (average no. of alleles per locus, NA = 4.857-5.571) in the previous domesticated stocks. Subsequently, specimens from different geographic locations including Trat, Rayong, Chonburi, Pattani and Nakhon Si Thammarat on the Gulf of Thailand (east) and Trang and Krabi on the Andaman Sea (west) were genetically analyzed. Relatively high levels of genetic diversity (NA = 7.857–23.429) and heterozygosity (Ho = 0.500–0.733) were observed. Genetic differentiation was found between all pairwise comparisons (P < 0.001) except Trat-Nakhon Si Thammarat (P > 0.0071). Phylogenetic analysis allocated wild F. merguiensis to three groups, A (Gulf of Thailand), B (Trang) and C (Krabi). Admixture analysis did not reveal large mixing between different lineages of genotypes in each population. However, the Krabi population (west) mainly showed the eastern genetic lineage. A new domestication program was established by selecting shrimp from different genetic groups. High genetic diversity was found in founders (NA = 27.714 and AR = 14.137) and brooders of the second generation (NA = 24.571 and AR = 12.835). Currently, genome-wide association study (GWAS) of G2 shrimp exhibiting large and small sizes from four families is being carried out to analyze growth-related SNPs in this species.

Identification of an essential role against shrimp pathogens of prophenoloxidase activating enzyme 1 (PPAE1) from Fenneropenaeus merguiensis hemocytes

Prophenoloxidase (proPO) activating enzymes, known as PPAEs, are pivotal in activating the proPO system within invertebrate immunity. A cDNA encoding a PPAE derived from the hemocytes of banana shrimp, Fenneropenaeus merguiensis have cloned and analyzed, referred to as FmPPAE1. The open reading frame of FmPPAE1 encompasses 1392 base pairs, encoding a 464-amino acid peptide featuring a presumed 19-amino acid signal peptide. The projected molecular mass and isoelectric point of this protein stand at 50.5 kDa and 7.82, respectively. Structure of FmPPAE1 consists of an N-terminal clip domain and a C-terminal serine proteinase domain, housing a catalytic triad (His272, Asp321, Ser414) and a substrate binding site (Asp408, Ser435, Gly437). Expression of the FmPPAE1 transcript is specific to hemocytes and is heightened upon encountering pathogens like Vibrio parahaemolyticus, Vibrio harveyi, and white spot syndrome virus (WSSV). Using RNA interference to silence the FmPPAE1 gene resulted in reduced hemolymph phenoloxidase (PO) activity and decreased survival rates in shrimp co-injected with pathogenic agents. These findings strongly indicate that FmPPAE1 plays a vital role in regulating the proPO system in shrimp. Furthermore, upon successful production of recombinant FmPPAE1 protein (rFmPPAE1), it became evident that this protein exhibited remarkable abilities in both agglutinating and binding to a wide range of bacterial strains. These interactions were primarily facilitated through the recognition of bacterial lipopolysaccharides (LPS) or peptidoglycans (PGN) found in the cell wall. This agglutination process subsequently triggered melanization, a critical immune response. Furthermore, rFmPPAE1 exhibited the ability to actively impede the growth of pathogenic bacteria harmful to shrimp, including V. harveyi and V. parahaemolyticus. These findings strongly suggest that FmPPAE1 not only plays a pivotal role in activating the proPO system but also possesses inherent antibacterial properties, actively contributing to the suppression of bacterial proliferation. In summary, these results underscore the substantial involvement of FmPPAE1 in activating the proPO system in F. merguiensis and emphasize its crucial role in the shrimp's immune defense against invading pathogens.

Transcriptome profiling of banana shrimp (Fenneropenaeus merguiensis) ovaries and testes: Insights into FoxL2.

The banana shrimp is found in the Pacific and Indian Oceans. Female shrimp are preferred for consumption because they are larger than males. Understanding the mechanism of sex differentiation is important for developing techniques to increase the number of female shrimp for economic benefits. This study investigates the reproductive development of F. merguiensis using transcriptome analysis. Sxl2, dsx, AGH, FEM-1, and Nrg-X2 were classified as essential genes for testes development during the juvenile stage. Several genes were required for both juvenile and adult male development. Additionally, the expression of several genes was shown to be required for juvenile and adult ovarian development, including SOP1, SOP2, Ptgr1, EST, Vgr, Vmol1, and TR-beta A. Interestingly, high levels of FoxL2 expression were observed in the testes, in contrast to previous studies in humans and other mammals. The binding of FoxL2 to the Vtg promoter was demonstrated in silico with the highest relative binding score (RS = 0.89) using the JASPAR program. Knock-down of the FoxL2 gene with dsRNA significantly suppressed FoxL2 at 2, 4, and 6 d. As a result, Vtg expression increased when compared with the control at 2, 4, and 6 d, indicating that FoxL2 plays an important role in Vtg expression in the ovary. Our findings highlight the role of FoxL2 in banana shrimp reproduction and provide valuable information on the genes associated with the F. merguiensis reproductive system.

Differentially expressed genes in the testes from early to mature development of banana shrimp (Fenneropenaeus merguiensis).

Banana shrimp (Fenneropenaeus merguiensis) is an economically important species in Thailand owing to the high value of globally exported frozen brine shrimps. However, the regulatory mechanisms governing spermatogenesis and testicular development in this species are poorly understood. High-throughput RNA sequencing was used to investigate the mechanisms and regulated genes involved in testis development using transcriptome profiling of juvenile and adult banana shrimp testes. Differentially expressed genes (DEGs) in these two libraries were identified and quantified to confirm gene expression. DEGs were found in 7,347 genes, with 4,465 upregulated and 2,882 downregulated. Some of these genes were designated as candidate genes, and six specific DEGs, including PRM1, SPATA20, Sry, SSRF, Sxl, and Tra-2c, were selected to confirm the reliability of the RNA-seq data using qPCR. Moreover, six non-DEGs were chosen based on testis-specific and regulatory genes that support a specific function in spermatogenesis and testis development in this species, including Dsx, Gfra2, IAG, Sox9, Sox13, and Sox14A. Furthermore, Sry, Sox14A, Sox14B and SPATA20 were identified in early stages (nauplius-postlarvae) of shrimp development to provide more information involving testes formation and development. The transcript data from this study could differentiate a group of genes required at the early and late stages of testis development and both sets of testis development. Therefore, this information would help in manipulating each stage of testicular development.

Biochemical analysis of candidate probiotic bacteria was isolated from the digestive tract of the Banana shrimp (Penaeus merguiensis)

In nature, there are many types of bacteria that can act as probiotics. These bacteria can come from soil, water, plants or even the digestive tract of animals. This study aims to analyze the biochemical characteristics of probiotic candidate bacteria originating from the digestive tract of giant prawns. The method used is a descriptive explorative method to perform biochemical analysis of the types of probiotic bacteria derived from jerbung shrimp. The biochemical analysis included the Catalase test, Oxidase test, Urea test, Citrate test, TSIA, Methyl red, Voges-Proskaeurs, and sugar fermentation test (D-Glucose, Sucrose, Inositol, Manisitol. Laboratory analysis results showed that the isolated bacteria had morphological characteristics rod-shaped, gram-positive, does not produce catalase and oxidase enzymes, but can produce citric enzymes. These bacteria are acidic, capable of fermenting glucose, sucrose, inositol, and mannitol. The conclusion of this study, probiotic candidate bacteria from the test results showed compatibility with Lactobacillus sp bacteria.Keywords: isolation; probiotics; shrimp

Transcriptome profiling of gonad-stimulating factors in thoracic ganglia and a potential role of Indian hedgehog gene in vitellogenesis of banana shrimp Fenneropenaeus merguiensis

Shrimp reproduction is controlled by several factors. Central nervous tissues, especially thoracic ganglia and brain, are known sources of gonad stimulating factors (GSFs) in crustaceans, but the GSFs in shrimp have not yet been clarified. Hence, we aimed to characterize and study putative GSFs from thoracic ganglia of adult female Fenneropenaeus merguiensis. An analysis of thoracic ganglia transcriptome revealed 3224 putative GSFs of a total 77,681 unigenes. Only 376 putative GSFs were differentially expressed during ovarian developmental stages. Eight candidate GSFs were validated for their expression patterns in thoracic ganglia, including the Indian hedgehog gene. F. merguiensis Indian hedgehog (FmIHH) was then investigated for its role in vitellogenesis. The obtained full-length cDNA of FmIHH was similar to other crustacean IHHs rather than Sonic and Desert HHs. The FmIHH was dominantly expressed in thoracic ganglia, and its expression was significantly increased in the vitellogenic stages before being downregulated at the mature stage of ovarian development. Injection of the recombinant FmIHH (His-TF-IHH) protein stimulated vitellogenin expression in ovaries on day 3 and 7, and also increased the gonadosomatic index. In addition, crustacean hyperglycemic hormone expression and total sugar were significantly decreased in eyestalks and hemolymph, respectively, after injection of His-TF-IHH, while lactic acid was increased. Both total sugar and lactic acid were unchanged in ovaries of His-TF-IHH injected shrimp. These results suggested that FmIHH plays a crucial role in vitellogenesis and regulate sugar uptake during ovarian development.

Effectiveness of SNPs for Sibship Assignment in Farmed Banana Shrimp (Penaeus merguiensis)

Pedigrees are essential components in selective breeding programs to manage genetic diversity and obtain accurate genetic parameter estimates to ensure long-term response to selection in captive populations. High throughput and cost-effective sequencing technologies has offered opportunities of using single nucleotide polymorphisms (SNPs) to resolve penaeid shrimp pedigrees from mass spawning cohorts and communal rearing. Effects of SNPs for sibship assignment were investigated on 546 shrimp using two software programs, Colony and Sequoia. Assignment rates and accuracies using SNP subsets with six different minor allele frequencies (MAFs), four sets of SNPs, and five genotyping error rates were compared to the microsatellite-based pedigree established in a previous study. High MAFs and numbers of SNPs contributed to significant increases in assignment rates and accuracies, whereas genotyping error rates showed negligible impacts on assignment results. Sibship assignments achieved rates and accuracies of 98% and 83%, respectively, with a minimum number of 91 SNPs (average MAF ≥ 0.14), and the two different programs exhibited similar resulting patterns for different SNP subsets. High consistencies between SNP-based and microsatellite-based pedigrees showed that accurate pedigrees could be achieved by using SNPs and thus contribute to the long-term response to selection in farmed banana shrimp.

Histological demonstration of gonad development in the banana shrimp, Fenneropenaeus merguiensis

The genetic diversity of the banana shrimp Fenneropenaeus merguiensis is at risk because of over-harvesting, which consequently reduces food security. This endangerment is exacerbated because this species is not commonly cultivated by farmers. Overall, these factors necessitate conservation of this shrimp species across its natural habitat. Information on the migration of primordial germ cells (PGCs) to form a gonad is essential for shrimp preservation techniques such as broodstock preparation, sex differentiation, and germ cell transplantation. In this study, histological analysis and in situ hybridization of vasa expression (from embryo to testis development) were used to demonstrate the movement of PGCs. Hematoxylin and Eosin staining and in situ hybridization with the VASA probe revealed that the PGCs migrated retrogradely along the midgut, colonizing the area between the hepatopancreas and heart, a region that becomes the genital ridge in the postlarval stage. External sexual organs appeared at approximately 4 months of age. Through real-time PCR, the expression of the vasa gene was detected early on postlarval day 7, whereas its abundant expression was detected in the ovaries and testes of adult shrimp. This study could help with the identification and monitoring of PGCs or spermatogonia in banana shrimp and facilitate the implementation of other germ cell-relevant techniques in the future.

Antibiotic residue analysis of tetracycline and chloramphenicol in banana shrimp (Fenneropenaeus merguiensis) from a traditional shrimp farming in Brondong, Lamongan

Banana shrimp is one of the potential export shrimp cultivated in Brondong, Lamongan. Antibiotic residues, including pollutants, can come from cultivation pond areas and environmental pollution. The antibiotics in shrimp are tetracycline groups (oxytetracycline, chlortetracycline, and tetracycline) and chloramphenicol. This study aims to determine the presence of antibiotic residues in banana shrimp and whether the quality of the shrimp has met health safety standards based on antibiotic residue analysis using estimated daily intake (EDI) and hazard quotient (HQ) calculations. Examination of antibiotic residues is carried out at the UPT. Quality Testing and Development of Marine and Fisheries Products in Surabaya. This study used an observation method by taking shrimp samples, measuring pond water quality parameters, and testing the content of antibiotic residues in the laboratory. The examination results showed that residues of the tetracycline and chloramphenicol groups were not detected in banana shrimp. Calculations of EDI and HQ cannot be performed because antibiotic residues are not detected. The HQ value is below one, which indicates a low-risk level category. Banana shrimp from a farming pond in Brondong, Lamongan is safe for human consumption.

The impact of farm practices and wild carriers on white spot disease in marine shrimp in Rayong Province, Thailand.

White spot disease (WSD) is a highly lethal and contagious viral disease in marine shrimp caused by the white spot syndrome virus (WSSV). White spot disease impacts the worldwide crustacean aquaculture sector, including Thailand. This study aimed to investigate the effect of farm management practices and wild carriers on WSD occurrence in grow-out marine shrimp farms in Rayong Province, Thailand. A longitudinal study was conducted using a structured questionnaire from June 2018 to June 2020. A total of 186 questionnaires for 186 ponds were collected from 15 shrimp farms. Univariate and multivariable analyses using generalized estimating equations were used to determine the risk factors associated with WSD. In addition, possible carrier samples (wild shrimp and wild crabs) were collected inside and outside farms to test for the presence of WSSV. Direct discharge of treated wastewater into farm ponds was statistically significant in the final model (p < 0.01), with an odd ratio (OR) factor of 0.097 (95% confidence interval [CI] of OR = 0.007-0.242). Pooled sampling for WSSV in wild shrimp and crabs showed that 48 out of 936 (5.13%) samples tested positive for WSD using nested polymerase chain reaction. The samples from banana shrimp, jinga shrimp, banded snapping shrimp, dwarf prawn, whiteleg shrimp, green tidal crabs, and mangrove crabs tested positive. Based on the findings of this study, we infer that the environment plays an important role in the spread of this disease. The results of this study will provide insights into the effective planning of disease control.

Re-maturation of wild banana shrimp (Fenneropenaeus merguiensis) broodstock in tank

The amount of post spawning of F. merguiensis broodstocks were subjected to further culture for three months period and fed various diets under recirculation system. The aim of the study was to evaluate their reproductive performances and seed production parameters. The broodstocks were fed a fresh diet consisting of chopped squid and Nereis sp, combined with a maturation diet (Skretting-Crude Protein: 59%). After the three-month culture period, a total of 17 pairs of broodstocks (53.53 ± 7.0 g for females and 28 ± 2.39 g for males) were selected, ablated, and reared for another ten days. Reproductive performance of these broodstocks and the post-larvae produced were observed. Broodstock’s performance in terms of egg and nauplii production was comparable to that naturally matured (wild) brooders. The average nauplii production was 250,000 individuals, with a latency period starting on the third day after ablation, and 77% of the broodstocks spawned within the given period. Furthermore, larval survival was high and reaching up to 40% until Pl-10. In conclusion, banana shrimp broodstocks can be maintained for certain period while maintaining their reproductive performance, if the diets and environmental parameters are kept within favorable conditions.

Rapid sample preparation and low-resource molecular detection of hepatopancreatic parvoviruses (HPV) by recombinase polymerase amplification lateral flow detection assay in shrimps (Fenneropenaeus merguiensis).

Viral diseases are a major problem in shrimp aquaculture facilities as these diseases reduce growth rates, which inevitably lead to production and profit losses. Hepatopancreatic parvoviruses (HPV) are common diseases in shrimp that appear to be associated with high or low levels of replication in specific genetic lineages. Selective breeding may result in resistance to HPV and improved body traits such as body weight, meat yield and shrimp colour, facilitating shrimp farming. HPV virus titre is commonly determined by quantitative PCR (qPCR), which is a time-consuming method requiring laboratory equipment unsuitable for field implementation. The aim of this study was to develop a simple, robust, rapid and reliable method to detect HPV in low-resource environments. We developed a rapid shrimp HPV test that uses (1) a simple three-step sample preparation protocol, followed by (2) isothermal recombinase polymerase amplification (RPA) and lateral flow strip detection (LFD). Analytical sensitivity testing was performed in a background banana shrimp sample matrix, and retrospective testing of Fenneropenaeus merguiensis hepatopancreas tissues (n = 33) with known qPCR viral titres was used to determine diagnostic sensitivity and specificity. The rapid shrimp HPV test could detect as little as 35 genome-equivalent copies per reaction in homogenized F. merguiensis banana shrimp. Retrospective testing of stored tissues (n = 33) indicated 100% diagnostic sensitivity (95% confidence interval, CI: 86-100%) and 100% specificity (95% CI: 66-100%) for detection of HPV. The rapid shrimp HPV test could be completed in only 40 minutes, and required only homogenization pestles, some pipettors, and a small heating block for single temperature incubation at 39°C. Critically, our procedure eliminated the time-consuming purification of nucleic acids from samples and when combined with RPA-LFD offers a user-friendly HPV detection format that can potentially be performed on-site. Our approach represents a major step forward in the development of a simple and sensitive end-point method for quick determination of unfavourable HPV virus numbers in shrimp, and has great potential to advance on-site management of shrimps in aquaculture.

The effects of different stocking densities on nursery performance of Banana shrimp (Fenneropenaeus merguiensis) reared under biofloc condition

Abstract The effects of banana shrimp Fenneropenaeus merguiensis stocking density on water quality, growth performance, survival rate and body composition was assessed in a biofloc system with limited water exchange. The study was conducted for 32 days with an average larvae weight of 10 ± 0.85 mg in fiberglass tanks containing 120 L of water at four stocking densities. Five experimental treatments consisted of a control (density 1000 shrimps/ m3) with 50% daily water exchange and four biofloc treatments with limited water exchange (0.5% daily) at four stocking levels (1000 shrimps, T1; 2000 shrimps, T2, 3000 shrimps, T3 and 4000 shrimps, T4/ m3) were considered. According to the results, total ammonia nitrogen (0.99 mg/L) and nitrite levels showed higher amounts in the control compared with the other treatments (P&lt;0.05). Growth performance and survival rate (95.55%) in the biofloc treatment with a density of 1000 shrimps/ m3 were higher than the other treatments (P&lt;0.05). The proximate composition of shrimp body and biofloc produced in rearing tanks depended on the stocking density, so the shrimp body ash increased along with the enhancement of stocking density. The lowest amount of ash (31.53± 0.81%) and protein (26.38 ± 1.26) of bioflocs was observed in T1 treatment. The present study showed that stocking density affects the water quality, growth performance, survival rate and body composition of banana shrimp larvae in a biofloc system. More improved indices of water quality, growth performance and survival rate were observed with the least stocking density of 1000 shrimps/m3 in the limited water exchange system.

Effect of feeding different types of β-glucans derived from two marine diatoms (Chaetoceros muelleri and Thalassiosira weissflogii) on growth performance and immunity of banana shrimp (Penaeus merguiensis)

β-glucans are produced by many organisms and could be used as supplementary feed to enhance immunity and growth in some aquatic animals. This study aimed to compare the effectiveness of β-glucans derived from two marine diatoms (Chaetoceros muelleri and Thalassiosira weissflogii) as growth promoters and immunity enhancers in banana shrimp (Penaeus merguiensis). Shrimp were divided into 3 groups: the control group was fed without β-glucan; the second and the third group were fed with 2 g kg−1 of β-glucan derived from C. muelleri and T. weissflogii, respectively. Shrimp were fed over a 30-day period to determine growth performance (final weight, weight gain, average daily gain (ADG), and feed conversion ratio (FCR)) at day 15 and day 30, respectively. The immune parameters determined were total hemocyte count (THC), phenoloxidase activity (PO) and immune gene expression. Survival rates were measured after 14 days of the feeding trial and Vibrio parahaemolyticus infection (6, 24, 48 h post infection). There was no significant difference (P > 0.05) for growth stimulation of shrimps between the two types of β-glucans (C. muelleri or T. weissflogii). Notably, shrimps fed with β-glucans had a higher final weight, weight gain, and ADG (P < 0.05) than shrimps fed with the control diet, while FCR of shrimps fed with both β-glucans was lower when compared to the control diet. Immune parameters, THC, PO, and gene expression of anti-lipopolysaccharide factor (ALF) and crustin were significantly higher (P < 0.05) in shrimps fed with β-glucans, especially with β-glucans from C. muelleri than the control group both before and after V. parahaemolyticus infection. Expression of penaeidin 3 and peroxiredoxin genes was significantly higher in shrimps fed with β-glucans after bacterial infection. Histopathology of hepatopancreas revealed an increase in blasenzellen hepatopancreatic epithelial cells (B cells) after 14 days of feeding which remained higher following infection with V. parahaemolyticus. The survival rate of shrimps fed with the diet containing β-glucan derived from either C. muelleri (82.2%) or T. weissflogii (77.8%) after V. parahaemolyticus infection was significantly higher than for the control group (51.1%) (P < 0.05). In conclusion, we propose that feeding banana shrimps with β-glucans derived from marine diatoms either C. muelleri or T. weissflogii at a 2 g kg−1 diet can significantly improve their growth performance and immunity.

Stimulatory effect of peritrophin on vitellogenesis in female banana shrimp, Fenneropenaeus merguiensis

Glass bottom boat (Gbb) is a member of the transforming growth factor β family that plays several physiological roles in arthropods, including in reproduction. Recently, Fenneropenaeus merguiensis's Gbb (FmGbb) was demonstrated to play a stimulatory role in vitellogenesis of the banana shrimp, but potential partners of FmGbb have not been identified. Therefore, this study aimed to identify proteins that interact with FmGbb and characterize their gonad-regulating function. A yeast two-hybrid assay revealed three potential candidates: peritrophin (FmPT), polehole-like protein (FmPhl), and an uncharacterized protein. Expressions of FmPT and FmPhl were found mainly in the ovaries and significantly increased in the developing stages. However, in a GST-pull down assay, there was no protein–protein interaction between soluble recombinant glutathione-S transferase-fused FmPT (GST-rPT) protein and the recombinant FmGbb protein (His-TF-rgbb). The vitellogenesis stimulatory role of FmPT was then investigated both in vitro and in vivo. Ovarian explants treated with GST-rPT showed no significant change of vitellogenin (Vg) expression, but the injection of GST-rPT in ovaries and hepatopancreas of previtellogenic shrimp did induc Vg expression, suggesting a vitellogenesis stimulating activity of FmPT. Our findings show that FmPT has a novel role in vitellogenesis stimulation and has the potential to be developed as a gonad-stimulating bioproduct for use in shrimp aquaculture.

Biofloc as a Food Source for Banana Shrimp Fenneropenaeus merguiensis Postlarvae

AbstractThe aim of this study was to investigate the effect of different levels of wet biofloc on water quality and feeding, growth performance, survival, and body composition of banana shrimp Fenneropenaeus merguiensis. The experiment consisted of the control group (feeding 100% commercial feed and 50% water exchange per day without biofloc) and four treatments in which portions of the commercial feed were replaced by wet biofloc (T2: 25%, T3: 50%, T4: 75%, and T5: 100%) with limited water exchange. Postlarvae of banana shrimp (mean ± SD weight of 4.5 ± 0.68 mg, density of 5 postlarvae/L) were experimentally held in fiberglass tanks with 170 L of seawater with salinity of 28‰ for 30 d. An acceptable range of total ammonium nitrogen and nitrite nitrogen was maintained in rearing tanks with wet biofloc throughout the experiment despite minimal water exchanges, but total ammonium nitrogen and nitrite nitrogen were significantly higher in the control group. Postlarvae fed with 25% wet biofloc had significantly higher total biomass (222.36 g) and survival (76.27%) compared with the other treatments. A comparison of banana shrimp fed with 25% or 50% wet biofloc and those fed with 100% commercial feed did not show a significant difference in body composition. The highest levels of body ash (12.7% of dry weight) were obtained in banana shrimp fed with 100% wet biofloc. In general, it was found that up to 50% of commercial feed can be replaced with wet biofloc (developed under the conditions of this study) without compromising growth performance, survival, and carcass quality of banana shrimp postlarvae.

Gonad Quality of Banana Shrimp Male Broodstock Penaeus merguiensis (De Man, 1888) Fed Different Natural Diets.

A study was carried out to determine the maturation period, quality and quantity of sperms production in Banana shrimp male broodstock, Penaeus merguiensis fed different natural diets. The three different natural diets namely; squid, fish and shrimp flesh used in this study were obtained from known sources and fed to the tested shrimp in triplicate groups. Based on the results obtained, squid seem to be the most effective natural diet as it enhances the sperms maturation within 20 days. Feeding fish and shrimp flesh as diets for the Banana shrimp broodstock resulted in the observation of maturation in 22 and 24 days, respectively. Similarly, squid diet also recorded the highest (p = 0.002; p < 0.05) sperms count (58.6 to 74.5) as compared to fish diet (44.0 to 61.3) or shrimp diet (28.0 to 42.8). Also, feeding squid diet resulted in a higher percentage of live sperms with ranged between 97.75% to 98.80%. On the other hand, broodstocks fed fish and squid flesh was observed with ranges of between 96% to 97.86% and 92.54% to 96.06%, respectively. It was therefore concluded that squid diet was most effective to improve sperm quality, quantity and maturation period in male broodstock of P. merguiensis. Further study should be carried on the reproductive performance of broodstock fed with squid as diets and it effect on the performances of post larvae obtained.