Pacific White Shrimp Penaeus Vannamei Research Articles

Utilization of date seed meal in the diet of Pacific white shrimp (Penaeus vannamei): growth performance, body and fatty acid composition, biochemical parameters, and tolerance of salinity stress

Current study aimed to examine the effectiveness of date seed meal (DSM) in the diet of Pacific white shrimp (Penaeus vannamei). Shrimp were fed on diets containing different amounts of DSM including 0, 50, 100, 150, and 230 g/kg for a period of 8 weeks. Growth parameters and body proximate composition showed no significant differences among treatments (p > 0.05). Similarly, no notable differences were observed in hemolymph biochemical parameters in shrimp fed with different amounts of DSM compared with the control group (p > 0.05). The contents of whole body polyunsaturated fatty acids (PUFAs) including docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and total n-3 in P. vannamei fed diet containing 100 g/kg DSM were significantly greater than control treatment (p 0.05). Altogether, the results of this study showed that DSM could be utilized as a cheapest source of carbohydrate in the shrimp diet without depressive effects on its performance.

Effects of sodium chloride supplementation for Pacific white shrimp Penaeus vannamei diets, cultured in low salinity waters

The culture of Penaeus vannamei in low-salinity waters is a recent development in Brazilian Northeast. The purpose of this study was to investigate the effects of NaCl dietary supplementation on shrimp growth, survival, haemolymph osmolality and total hemocyte counts. In trial 1, earthen pond-reared shrimp ranging from 5 to 20 g were sampled at intervals for determination of haemolymph osmolality. Haemolymph osmolality was not influenced by the increased weight of shrimp. Juveniles shrimp (5-20 g) haemolymph osmolality were then evaluated 24 h after they had been transferred from pond water (0.5 ppt) to the seawater (35 ppt). Shrimp haemolymph osmolality increased with external salinity and ranged from 661.0 ± 25.2 mOsm/kg (D1) and 916.9 ± 40.1 mOsm/kg (D4). In trial 2, shrimp reared in low-salinity water (0.3-0.5 ppt) were distributed into five groups (control, D1, and treatments, D2, D3, D4 e D5) with four replicates. Diets consisted of the basal diet supplemented with 0 g/kg, 5 g/kg, 10 g/kg, 20 g/kg, and 40 g/kg of NaCl, respectively. After 22 days, differences in survival, final weight, specific growth rates (SGR) and absolute growth rate (AGR) among treatments were significant. However, there were no significant trends in haemolymph osmolality and shrimp total hemocyte counts within the five tested groups.

Biochemical screening and determination of bioactive components of commercially cultured pacific white shrimp Penaeus vannamei

Background: Marine waste is an extraordinarily renewable aid for the restoration of several valued metabolites with potential biological applications. Objectives: The investigation is planned to detect the biochemical components present in the prawn shell waste by qualitative, quantitative methods, to assess the antioxidant potential, and also to find the bioactive compounds existing in the prawn shell waste by gas chromatography-mass spectrometry (GC-MS) analysis. Materials and Methods: Penaeus vannamei shell wastes are collected, cleaned, dried, and powdered well. The bioactive compounds present in crude ethyl acetate extract of P. vannamei shell was determined by qualitative, quantitative, and GC-MS analysis. The free radical scavenging activity of the extract was studied by different in vitro antioxidant assays. Results: The bio-compounds such as carbohydrates, saponins, flavonoids, tannins, and quinones show the positive result by qualitative analysis. The higher tannin content 49.2 ± 0.084 mg/g was observed in the ethyl acetate extract of P. vannamei shell and the flavonoid was found to be 5.994 ± 0.044 mg/g. The GC-MS analysis of the P. vannamei shell shows the various numbers of bio-compounds. Some of the identified compounds are Timonacic which has the powerful antioxidant property, Octadecane, 3ethyl5(2ethylbutyl) is a good antifungal agent, Acetamide possesses antioxidant and anti-inflammatory property. The results of the in vitro assays revealed that P. vannamei shell extract possess significant antioxidant activity. Conclusion: The present study suggests that the effective utilization of prawn shell waste enhances biomedical research field for the development of the natural drug for many chronic diseases with no side effects and at the same time can reduce environmental pollution.

Effect of dietary date seed meal as an alternative carbohydrate source on immune-related gene expression of Pacific white shrimp Penaeus vannamei

Current study aimed to examine the effect of dietary date seed meal (DSM) as an alternative carbohydrate ingredient on immune-related genes expression of Pacific white shrimp (Penaeus vannamei). A total number of 750 shrimp (4.0 ± 0.1 g) were randomly assigned into five experimental treatments, each with three replicates. Experimental diets contained 0, 50, 100, 150 and 230 g/kg DSM substituted for both wheat and rice flour. Shrimp were fed at a rate of 5% body weight three times daily and the mRNA expression of α2-macroglobulin (α2-M), lipopolysaccharide and beta-1,3-glucan-binding protein (LGBP), integrin β, and peroxinectin (PX) was studied on five shrimp per treatment after 8 weeks feeding trial. The results showed that replacement of DSM up to 100 g/kg in the diet of P. vannamei caused no significant changes in the expression of α2-M and integrin β, however both of these genes showed lower expression in shrimp fed diets containing 150 and 230 g/kg DSM compared to control group. Moreover, no significant differences were observed in the expression of PX and LGBP between shrimp fed diets containing different amounts of DSM and control group. These findings demonstrated that as an inexpensive source of carbohydrate, DSM could be substituted up to 100 g/kg for wheat and rice flour in the diet of farmed shrimp without suppressive effects on the immune status.

Isolation of the sex-determining gene Sex-lethal (Sxl) in Penaeus (Litopenaeus) vannamei (Boone, 1931) and characterization of its embryogenic, gametogenic, and tissue-specific expression

The Pacific white shrimp Penaeus vannamei is the most cultured shrimp species around the world. Because females grow larger than males, the culture of ‘only females’ is of great interest, but knowledge on sex determination and differentiation is required for producing only females. In an effort to obtain information associated with reproduction in P. vannamei, transcriptomic data from female gonads was generated, and partial sequences of a transcript were identified as Sex-lethal (Sxl). Its characterization indicated that, differently from other penaeids in which this gene has been isolated, there are six isoforms of the Sxl transcript in P. vannamei (PvanSxl 1–6). These isoforms result from alternative splicing at three splice sites (SS1, SS2, SS3). The first splice-site is unique to P. vannamei, as it has not been reported for other Arthropod species; the second splice-site (SS2) is common among crustaceans, and the third splice-site (SS3) is also unique to P. vannamei and when spliced-out, it is always together with SS2. All isoforms are expressed during embryogenesis as well as gametogenesis of both genders. The two shorter isoforms, PvanSxl-5 and PvanSxl-6, which result from the splicing of SS2 and SS3, were found mostly expressed in adult testis, but PvanSxl-6 was also expressed in oocytes during gametogenesis. During oogenesis, the second largest isoform, PvanSxl-2, which splices-out only SS1, and PvanSxl-4 that splices-out SS1 and SS2 were highly expressed. These two isoforms were also highly expressed during embryonic development. In situ hybridization allowed pinpointing more specifically the cells where the PvanSxl transcripts were expressed. During embryogenesis, hybridization was observed from the one-cell stage embryo to late gastrula. In the female gonad in previtellogenesis, hybridization occurred in the nucleus of oocytes, whereas in secondary vitellogenesis the transcript also hybridized cytoplasmic granules and cortical crypts. Finally, in situ hybridization corroborated the expression of PvanSxl also in the male gonad during spermatogenesis, mostly occurring in the cytoplasm from spermatogonia and spermatocytes.

Levels of genetic diversity and inferred origins of Penaeus vannamei culture resources in China: Implications for the production of a broad synthetic base population for genetic improvement

Knowledge about the origins and relative levels of genetic variation available in domesticated strains can be used to develop robust synthetic populations for use in stock improvement programs, in particular, where wild stocks are unavailable or the target species is alien. Here, we undertook a case study of Pacific white shrimp (Penaeus vannamei) where we utilised neutral molecular genetic variation data, population structure, and genetic relatedness as an initial step towards producing a base line for a long-term family-selection breeding program in China. The objective was to capture and maximise genetic variation in the base population while at the same-time to control inbreeding levels. Genetic diversity in 1162 individuals from 36 breeding lines sourced from 22 hatcheries with domesticated broodstock available in China was assessed using seven microsatellite loci. Genetic diversity levels in the sampled lines were considered to be healthy, with a mean number of alleles (A) 5.85, ranging from 4.00 in B4 to 12.43 in T1, and mean allelic richness (Ar) 4.46, ranging from 3.35 in B4 to 6.69 in T1 breeds. Mean inbreeding coefficient (Fis) was 0.07 among the 36 lines indicating acceptable levels of inbreeding. Genetic differentiation between lines from different hatcheries was moderate, with a mean FST estimate of 0.09 among all pairs of hatchery lines. Bayesian assignment and phylogenetic analyses indicated that hatchery lines in China could be broadly divided into four groups: i) a line from North America (NA1), originally sourced from Mexico (north Sinaloa) and Ecuador, ii) two representatives of the Kona line developed in Hawaii (Oceanic Institute) (NA2,3), iii) a line developed in Thailand (Southeast Asia 1 (SA1)), and iv) a mixed group containing stocks that originated in Latin America (predominantly from Panama and Colombia) (LA; SA2; CN1,2; NA4,5). From these data, we argue that a complete 4 × 4 diallel cross (16 crosses) of the four subpopulations should be trialled in China to develop a base line for a family selection breeding program with optimal levels of genetic variation and a relatively low inbreeding coefficient.

Streptococcus penaeicida sp. nov., isolated from a diseased farmed Pacific white shrimp (Penaeus vannamei).

Strain CAIM 1838T, isolated from the hepatopancreas of a cultured diseased Pacific white shrimp (Penaeus vannamei), was subjected to characterization by a polyphasic taxonomic approach. On the basis of 16S rRNA gene sequence analysis, strain CAIM 1838T was most closely related to Streptococcus bovimastitidis 99.3 % and to other species of the Pyogenes clade of Streptococcus with lower similarity values. Average nucleotide identity values and the genome-to-genome distance of strain CAIM 1838T, as compared with the type strains, confirmed the separate species status with closely related species of the genus Streptococcus and were all below the thresholds to delimit a species, 93.1 and 49.4 %, respectively. The DNA G+C content was 38.1 mol%. Differential phylogenetic distinctiveness together with phenotypic properties obtained in this study revealed that strain CAIM 1838T could be differentiated from the closely related species. Based on these results it is proposed that strain CAIM 1838T represents a novel species in the genus Streptococcus, for which the name Streptococcus penaeicida sp. nov is proposed (type strain, CAIM 1838T=CECT 8596T,=DSM26545T), is proposed.

Biofloc based technology evaluation for nutrient dense culture system for nursery and grow-out farming of Pacific white shrimp Penaeus vannamei Boone, 1931

The concept of “biofloc technology” is changing the facet of intensive aquaculture with scope to attain high productivity in a sustainable manner. In biofloc, dense heterotrophic bacterial community is developed through C:N ratio manipulation, where the system becomes bacterial dominated rather than algae dominated and takes care of the wastes generated through in situ bioremediation. Protein is utilised in two ways; as feed for the shrimp and as microbial floc when the heterotrophic microbes convert the nitrogenous wastes into protein. It also promises a healthy rearing system, which is increasingly identified as one possible solution for disease problems especially those striking at early stages. The purpose of this study was to evaluate the effect of biofloc and periphyton technology (BPT) on the growth and immunomodulatory performance of Pacific white shrimp Penaeus vannamei during nursery and grow-out culture. The experimental BPT treatments with three tier substrate system with molasses as carbohydrate (CHO) source were compared with the conventional autotrophic system. Theimmunomodulation and cumulative percentage mortality upon challenge with pathogenic strain of Vibrio parahaemolyticus were assessed in the reared animals. We have successfully demonstrated the BPT based nursery and grow-out systems for P. vannamei with the advantage of providing significantly (p<0.05) better growth performance (27.6% improvement inaverage body weight, ABW) and feed utilisation (31% improvement in feed conversion ratio, FCR). A production level of 4-4.5 kg m-3 of water was achieved through this BPT system registering a significant improvement over the conventional system (p<0.05). The Cumulative percentage mortality following pathogen challenge was significantly lower (p<0.05) in the biofloc grown shrimps compared to that of the control group, thus showing better resistance to pathogenic challenge. Furthermore, the biofloc reared shrimp did exhibit significant improvement in non-specific immune response in terms of serum phenoloxidase activity and total haemocyte counts possibly suggesting potential immunostimulatory role of the biofloc associated heterotrophic bacteria. This eco-based technology as revealed through our studies brings substantial improvement in productivity, minimising water requirement, recycling in situ nutrients and organic matter in turn improvingfarm biosecurity, augmentation of natural food, improvement of FCR and better health of the cultured shrimp.

Evaluation of different probiotic strains for growth performance and immunomodulation in Pacific white shrimp Penaeus vannamei Boone, 1931

The use of antibiotics in aquaculture can prevent certain diseases, however, its use is highly restricted due to several environmental and human health problems like development of antibacterial resistance. Probiotics are widely used for improving production of aquatic animals by means of improving water quality as well as by nutritional and immune modulation in animals thus, helping in preventing diseases. The present study was aimed to evaluate different strains of probiotics viz., a commercial probiotic, Bacillus subtilis, Enterococcus sp., Lactobacillus casei, Lactobacillus rhamnosus, Saccharomyces cerevisiae and Saccharomyces boulardii on the growth, microbial load and immunomodulatory performance of the Pacific white shrimp, Penaeus vannamei. Seven probiotic feeds each containing 5 x 109 CFU ml-1 of respective probiotics kg-1 of feed were prepared by top coating on apellet feed containing 35% protein and duration of the experiment was 75 days. All of the 6 selected strains of probiotics except the commercial one influenced the growth significantly when fed to the shrimp, compared to control group. Specific growth rate (SGR), average daily growth (ADG) and survival rate were observed to be higher in probiotic fed groups. Maximum growth was recorded in S. cerevisiae fed groups (8.05±0.21 g), followed by B. subtilis (7.65±0.21 g), while the control animals showed an average growth of 4.85±0.49 g with percentage improvement in the range of 50-95% when compared to all other treatments. Totalheterotrophic count significantly (p<0.05) increased in the rearing water of B. subtilis treated group (8.995± 0.021 x 103 cfu ml-1) when compared to that of control (5.475± 0.003 X 103 cfu ml-1) and total vibrio load was greatly reduced in B. subtilis (1.42 ± 0.04 x 103 cfu ml-1) and S. cerevisiae (1.47 ± 0.01 x 103 cfu ml-1) treated water compared to control (4.265 ± 0.06 x 103 cfu ml-1). Nonspecific immunity in terms of total haemocyte count (THC) was found to be significantly (p<0.05) higher in B. subtilis (12.4±0.8 106 cells ml-1) treated group while higher (p<0.05) prophenoloxidase (pro PO) activity was recorded in S. erevisiae (0.132±0.001 units min-1 mg protein-1) and B. subtilis (0.130±0.002 units min-1 mg protein-1) treated groups. The probiotic effect was found to be beneficial for better growth and immunomodulation, which was however found to be strain-specific.

Alternate livelihood development for ‘Aila’ affected tribal people through aquaculture in Bali Island of the Sunderban, West Bengal, India

The concept of “biofloc technology” is changing the facet of intensive aquaculture with scope to attain high productivity in a sustainable manner. In biofloc, dense heterotrophic bacterial community is developed through C:N ratio manipulation, where the system becomes bacterial dominated rather than algae dominated and takes care of the wastes generated through in situ bioremediation. Protein is utilised in two ways; as feed for the shrimp and as microbial floc when the heterotrophic microbes convert the nitrogenous wastes into protein. It also promises a healthy rearing system, which is increasingly identified as one possible solution for disease problems especially those striking at early stages. The purpose of this study was to evaluate the effect of biofloc and periphyton technology (BPT) on the growth and immunomodulatory performance of Pacific white shrimp Penaeus vannamei during nursery and grow-out culture. The experimental BPT treatments with three tier substrate system with molasses as carbohydrate (CHO) source were compared with the conventional autotrophic system. The immunomodulation and cumulative percentage mortality upon challenge with pathogenic strain of Vibrio parahaemolyticus were assessed in the reared animals. We have successfully demonstrated the BPT based nursery and growout systems for P. vannamei with the advantage of providing significantly (p<0.05) better growth (27.6% improvement in average body weight, ABW) and feed utilisation (31% improvement in feed conversion ratio, FCR). A production level of 4-4.5 kg m-3 of water was achieved through this BPT system registering a significant improvement over the conventional system (p<0.05). The cumulative percentage mortality following pathogen challenge was significantly lower (p<0.05) in the biofloc grown shrimps compared to that of the control group, thus showing better resistance to pathogenic challenge. Furthermore, the biofloc reared shrimp did exhibit significant improvement in non-specific immune response in terms of serum phenoloxidase activity and total haemocyte counts possibly suggesting potential immunostimulatory role of the biofloc associated heterotrophic bacteria. This eco-based technology as revealed through our studies brings substantial improvement in productivity, minimising water requirement, recycling in situ nutrients and organic matter in turn improving farm biosecurity, augmentation of natural food, improvement of FCR and better health of the cultured shrimp.

Screening of pathogens from a biosecured pacific white shrimp (Penaeus vannamei) farm in Kattur, Tamil Nadu

Screening for presence of various pathogens were carried out in one of the biosecurity maintained shrimp farms in Kattur Village of Tamil Nadu. Sampled shrimps exhibited pinkish discolouration of the body, pale hepatopancreas and antennal cut indicating bacterial infection. Similarly, there was also large scale size variation and reduced growth compared to the days of culture. Samples were screened for bacterial and four (including three OIE-listed) viral pathogens. The samples were also subjected to histopathological investigations. Based on the biochemical tests, the isolated bacteria was identified as Vibrio parahaemolyticus. Metalloprotease gene-specific PCR further confirmed the isolates to be V. parahaemolyticus. PCR was carried out to further investigate the early mortality syndrome/acute hepatopancreatic necrosis disease (EMS/AHPND) strain status of these isolates and were found to be negative. The samples were found to be positive for white spot syndrome virus (WSSV) by second step PCR and infectious hypodermal and haematopoietic necrosis virus (IHHNV) by direct PCR. All these were negative for monodon baculovirus, yellow head virus and gill associated virus. Infection of samples by WSSV and IHHNV were further confirmed by histopathology. The finding of the present study indicated the reduction in growth and size variation due to bacterial infection by V. parahaemolyticus and viral infection by IHHNV. Though bisosecurity was maintained in the farm, the pathogens are suspected to be transmitted through the seed or improper pond preparation.

Green water technology for the production of pacific white shrimp, Penaeus vannamei (Boone, 1931)

A study was conducted to assess the efficiency of green water culture strategy for production of Pacific white shrimp Penaeus vannamei (Boone, 1931) in high density polyethylene (HDPE) lined ponds (300 m2) for a period of 96 days. Green water from a broodstock fish pond was used for rearing shrimp in treatment ponds; whereas, filtered seawater was used for growing shrimp in control ponds, with both treatment and control in triplicates. Shrimp juveniles (specific pathogen free, SPF) of uniform size (1.74±0.46 g) were stocked at the rate of 100 nos. m-2 per pond. Feeding, water exchange, sampling and water quality analysis were done as per standard shrimp growout procedure. Shrimp health status and microbial load in culture ponds were recorded periodically. Water quality parameters did not show significant variations between control and treatment ponds. Enhanced growth, survival (19.7%) and biomass (23.3%) were observed in treatment ponds when compared to control. Significant reduction in bacterial population and improved shrimp health status were also noticed in treatment ponds. Green water culture technique reduced harmful bacterial population in culture ponds and enhanced shrimp growth, survival, health and production.

Effects of Alginate‐Derived Oligosaccharides on Immune Ability of Farm‐Cultured Shrimp Penaeus vannamei and Its Resistance to Vibrio harveyi

AbstractThis study was designed to examine the immunoregulatory effects of alginate‐derived oligosaccharides (ADOs) on farm‐cultured Pacific white shrimp Penaeus vannamei and its resistance to Vibrio harveyi. Total hemocyte count, superoxide dismutase (SOD) activity, bacteriolytic activity, phagocytic rate (PR), the average number of beads ingested per cell (ABPC), and the protective efficacy for P. vannamei challenged with Vibrio harveyi were determined. The study showed that the administration of ADOs at 1.0 g/kg of diet improved SOD activity, bacteriolytic activity, and PR by 25.2, 20.4, and 20.9%, respectively, 30 d after exposure. Total hemocyte count and ABPC showed no significant differences. The 96‐h survival of the shrimp reached 46.7% and 90.0% when they were challenged with V. harveyi at concentrations of 1 × 107 and 1 × 106 cfu/shrimp, which was significantly higher than that in the control group. The results obtained indicate that ADOs can act as an immunoregulant for P. vannamei.

Detection of viruses in the exotic shrimp Penaeus vannamei Boone, 1931 cultured in India

Pacific white shrimp Penaeus vannamei Boone, 1931, is a recently introduced species in India. P. vannamei samples, collected from various shrimp farms of Karnataka, India were subjected to polymerase chain reaction (PCR) based detection of whitespot syndrome virus (WSSV), hepatopancreatic parvovirus (HPV), monodon baculovirus (MBV), infectious hypodermal and hematopoietic necrosis virus (IHHNV), taura syndrome virus (TSV) and infectious myonecrosis virus (IMNV). Out of the 81 shrimp samples analysed, 41 samples (50.6%) were found positive for WSSV and four (4.9%) were positive for IHHNV. Among 41 WSSV positive samples, 20 (48.7%) samples were found positive for WSSV by 1st step PCR, while the remaining 21 (51.2%) samples were positive by nested PCR. WSSV positive samples were further confirmed by dot blot hybridisation assay. However, clinical signs/disease symptoms were not observed in any of the shrimp samples tested positive for the viruses.

Brain architecture of the Pacific White Shrimp Penaeus vannamei Boone, 1931 (Malacostraca, Dendrobranchiata): correspondence of brain structure and sensory input?

Penaeus vannamei (Dendrobranchiata, Decapoda) is best known as the "Pacific White Shrimp" and is currently the most important crustacean in commercial aquaculture worldwide. Although the neuroanatomy of crustaceans has been well examined in representatives of reptant decapods ("ground-dwelling decapods"), there are only a few studies focusing on shrimps and prawns. In order to obtain insights into the architecture of the brain of P. vannamei, we use neuroanatomical methods including X-ray micro-computed tomography, 3D reconstruction and immunohistochemical staining combined with confocal laser-scanning microscopy and serial sectioning. The brain of P. vannamei exhibits all the prominent neuropils and tracts that characterize the ground pattern of decapod crustaceans. However, the size proportion of some neuropils is salient. The large lateral protocerebrum that comprises the visual neuropils as well as the hemiellipsoid body and medulla terminalis is remarkable. This observation corresponds with the large size of the compound eyes of these animals. In contrast, the remaining median part of the brain is relatively small. It is dominated by the paired antenna 2 neuropils, while the deutocerebral chemosensory lobes play a minor role. Our findings suggest that visual input from the compound eyes and mechanosensory input from the second pair of antennae are major sensory modalities, which this brain processes.

Evaluation of a reliable non-invasive molecular test for the diagnosis of the causative agent of acute hepatopancreatic necrosis disease of shrimp

Acute hepatopancreatic necrosis disease (AHPND, also known as early mortality syndrome, EMS) has caused substantial mortality, up to 100%, in populations of penaeid shrimp cultured in SE Asia and in Latin America. The disease is caused by the bacterium Vibrio parahaemolyticus, which secretes binary toxins (PirAvp and PirBvp) resulting in the deterioration of the hepatopancreas tissue of infected shrimp. Diagnosis, screening, and monitoring of AHPND in shrimp populations involve sacrificing individuals to obtain tissue samples. This sampling method is undesirable when applied to valuable populations of broodstock. Here, we evaluated a non-invasive diagnostic method based on shrimp fecal samples that are analyzed by PCR. Small groups of Pacific white shrimp Penaeus vannamei were exposed to low levels of AHPND-bacteria and their feces were collected prior to any mortality observed (in the bioassays #1 and #2). Two protocols were evaluated. In one, DNA extracted from the fecal samples was directly analyzed by PCR. In the other, the fecal samples were cultured in TSB+ for 6h to enrich the bacterial populations, then the enriched bacterial broth was used for PCR analyses. Our results showed that the presence of V. parahaemolyticus could be detected both in fecal DNA samples and in the enriched bacterial broth, but the bands from the bacterial broth showed stronger amplification than the DNA; 12 strong positive in the enriched bacterial broth, but only 7 strong positive in the fecal DNA samples. Also, the AHPND bacteria present in the feces is infectious, determined by a bioassay of feeding specific pathogen free indicator shrimp with AHPND-feces (in the bioassay #3), and this proves that the AHPND can be transmitted through a fecal-oral route.

Enterocytozoon hepatopenaei (EHP) is a risk factor for acute hepatopancreatic necrosis disease (AHPND) and septic hepatopancreatic necrosis (SHPN) in the Pacific white shrimp Penaeus vannamei

The hepatopancreatic microsporidian Enterocytozoon hepatopenaei (EHP) is an emerging pathogen that affects cultured shrimp Penaeus vannamei in several SE Asian countries including China, Vietnam, Thailand, Indonesia, India and Malaysia. EHP infections are often accompanied by opportunistic infections of Vibrio spp. Laboratory challenges and a case control study were used to determine the effects of EHP infection on two Vibrio diseases: acute hepatopancreatic necrosis disease (AHPND) and septic hepatopancreatic necrosis (SHPN). To determine the effect of EHP on AHPND, two independent experimental infections were carried out. EHP-infected shrimp (EHP-AHPND group) and healthy shrimp (AHPND group) were challenged with 2.4×105CFU/mL of AHPND-causing Vibrio parahaemolyticus. The results of the experimental infections showed that EHP-AHPND group exhibited higher mortalities (60 and 44%) than the AHPND group (0 and 18%). The pathological effects of AHPND vs. EHP-AHPND groups were compared during the first 12h post infection, 57% of the EHP-AHPND group displayed severe hepatopancreas necrosis and sloughing, features characteristic of AHPND infection while only 11% of AHPND group showed these features. This indicated that EHP-infected shrimp have a higher susceptibility to AHPND infection. To determine the effect of EHP on SHPN, we reviewed the histopathology of samples collected where EHP is endemic; and a case control study was carried out to determine the association between SHPN and EHP. We compared individual shrimp displaying histological signs of SHPN with the shrimp from the same ponds without these signs. A strong association was found between SHPN and EHP, indicating that shrimp with EHP have an increased susceptibility to SHPN. These findings suggested that EHP infection is a risk factor for both AHPND and SHPN.

Reduction of Particle Size of Rhizoclonium riparium Protein Concentrate Improves Digestibility, Growth, and Feed Efficiency of Penaeus vannamei Post Larvae

The present study evaluated the effect of particle size (PS) of Rhizoclonium protein concentrate (RPC) on apparent digestibility coefficients (ADC) as well as on growth and feed efficiency of Pacific white shrimp (Penaeus vannamei) for a period of 30 days. Results showed that white shrimp could effectively digest Rhizoclonium protein concentrate in their diet. Average ADC values for dry matter (ADMD), crude protein (ADCP), and crude lipid (ADCL) were 71.1%, 84.4%, and 94.6%, respectively. A significant inverse relationship (p<0.05) was estimated between PS and ADMD (r=-0.66, p= 0.02). Particle size of 150 µm resulted in the highest final body weight (FBW), weight gain (WG), specific growth rate (SGR), feed conversion efficiency (FCE) and protein efficiency ratio (PER). All response parameters exhibited significant inverse correlations with particle size (p<0.05). In conclusion, digestibility of seaweed protein concentrate and its nutritive value could be improved by grinding it to an optimum size of 150 µm before dietary inclusion.

Reduction of Particle Size of Rhizoclonium riparium Protein Concentrate Improves Digestibility, Growth, and Feed Efficiency of Penaeus vannamei Post Larvae

The present study evaluated the effect of particle size (PS) of Rhizoclonium protein concentrate (RPC) on apparent digestibility coefficients (ADC) as well as on growth and feed efficiency of Pacific white shrimp (Penaeus vannamei) for a period of 30 days. Results showed that white shrimp could effectively digest Rhizoclonium protein concentrate in their diet. Average ADC values for dry matter (ADMD), crude protein (ADCP), and crude lipid (ADCL) were 71.1%, 84.4%, and 94.6%, respectively. A significant inverse relationship (p<0.05) was estimated between PS and ADMD (r=-0.66, p= 0.02). Particle size of 150 µm resulted in the highest final body weight (FBW), weight gain (WG), specific growth rate (SGR), feed conversion efficiency (FCE) and protein efficiency ratio (PER). All response parameters exhibited significant inverse correlations with particle size (p<0.05). In conclusion, digestibility of seaweed protein concentrate and its nutritive value could be improved by grinding it to an optimum size of 150 µm before dietary inclusion.

Methodological approach for the collection and simultaneous estimation of greenhouse gases emission from aquaculture ponds.

Global warming/climate change is the greatest environmental threat of our time. Rapidly developing aquaculture sector is an anthropogenic activity, the contribution of which to global warming is little understood, and estimation of greenhouse gases (GHGs) emission from the aquaculture ponds is a key practice in predicting the impact of aquaculture on global warming. A comprehensive methodology was developed for sampling and simultaneous analysis of GHGs, carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) from the aquaculture ponds. The GHG fluxes were collected using cylindrical acrylic chamber, air pump, and tedlar bags. A cylindrical acrylic floating chamber was fabricated to collect the GHGs emanating from the surface of aquaculture ponds. The sampling methodology was standardized and in-house method validation was established by achieving linearity, accuracy, precision, and specificity. GHGs flux was found to be stable at 10±2°C of storage for 3days. The developed methodology was used to quantify GHGs in the Pacific white shrimp Penaeus vannamei and black tiger shrimp Penaeus monodon culture ponds for a period of 4months. The rate of emission of carbon dioxide was found to be much greater when compared to other two GHGs. Average GHGs emission in gha-1day-1 during the culture was comparatively high in P.vannamei culture ponds.