Progress 08/01/10 to 07/31/12
Outputs
Target Audience: The target audience reached by our efforts include scientists, shrimp farmers, and other iondustry personnel such as feed and equipment manufacturers Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? Five graduates students performed their thesis or dissertation reseach under this program. How have the results been disseminated to communities of interest? Yes the results were disseminated in the scientific and industry communities by Journal articles and meeting presentations What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Selective breeding We evaluatedof resistance the TSV-selelect line to the Belize isolate of TSV. Mean survival after TSV exposure was 78% for select families whereas survival of Kona stock was 17% at day 21. Select family survival was from 31% - 100% Vibrio Characterization / Raceways The objectives of this project were to: (a) quantitate the density of the Vibrio bacterial community in relation to total bacteria in the shrimp raceways;(b)to develop a multiplex PCR assay for the identification of Vibrios of interest in aquaculture settings; and (c) to look at possible relationships between total Vibrios, V. parahaemolyticus and environmental limiting factors in the raceways. The proportion of Vibrio in the bacterial community varied throughout the growing season, staying at zero percent in all the tanks until the middle of June then hovering mostly between one and three percent. A few of the tanks had a brief increase in the number of Vibrios to five to eight percent. Although, the proportion of Vibrio to total Bacteria was higher in the high solids treatment, no significant difference was found between the means of the groups of high and low solids. At a 95% confidence level the significance level was greater than 0.05 or 0.208. Major Pathogen Transmission In this study we compared the effect of temperature on Yellow-Head Virus (YHV) in Litopenaeus setiferus to the effect on WSSV in L. setiferus. Studies have also shown that temperature near 33 ?C is effective in preventing disease, and reducing mortality from WSSV in L. vannamei. We compared the effect of temperature on pathology from YHV to that of WSSV in L. setiferus. We followed viral load of both viruses by qPCR. A total of 64 gulf white shrimp, Litopenaeus setiferus were divided into 4 groups of 16 and held at comparative high and low temperature. The viral dosage standard was .02 mL of viral homogenate per 5 grams of shrimp. All shrimp within the 31°C WSSV group were determined to be WSSV negative whereas the lower temperature WSSV groups were positive with 100% mortality. On the other hand all temperature groups of YHV ex[posed shrimp had 100% mortality. Although, previous studies have shown that temperature inhibits WSSV pathology, this suggests that that high temperature does not inhibit pathology from YHV. TSV and Within-Host Dynamics In this study we compared the net rate of replication of two TSV isolates (Texas 95 and Belize) of differing virulence within co-infected shrimp. We developed a quantitative SNP genotyping assay to measure net growth rates of each competing viral. The more virulent Belize TSV outcompeted the less virulent Texas TSV in the intrahost environment and therefore, possesses a within host selective advantage. Belize TSV exhibited a faster within host net reproductive rate than the less virulent Texas TSV. The more virulent Belize TSV generated a productive infection sooner in all susceptible host when compared to the less virulent Texas TSV and therefore, possesses a between host selective advantage. Prototype Production System Evaluation The purpose of this study was to compare chemoautotrophic-based biofloc systems to three heterotrophic-based biofloc systems in which different carbohydrates were used. Shrimp (6.8 g) were stocked at 300 m-3 into 16, 500-L tanks and grown for eight weeks. Four treatments were created: Autotrophic (T-A), Heterotrophic Sucrose (T-HS), Heterotrophic Molasses (T-HM), and Heterotrophic Glycerol (T-HG). The heterotrophic treatments were managed such that the C:N ratio of inputs (feed and carbohydrate) was approximately 25:1. The autotrophic treatment received no added carbohydrate. We found that nitrate-N was significantly greater in the T-A treatment (P ≤ 0.01) with virtually no nitrate accumulation in the heterotrophic treatments. 5-day biochemical oxygen demand (BOD the T-HM treatment; the T-A treatment had a significantly lower BOD5 versus any other treatment (P ≤ 0.04). Total suspended solids was significantly lower in the T-A treatment compared to any other (P ≤ 0.02). Shrimp growth rate was significantly greater in the T-A and T-HS treatments versus the T-HM treatment, and there was no significant difference in growth rate between the T-HG treatment and any other treatment. Microbial Community & Nutrient Cycling A total of 8 raceways were sampled. DOC increased in concentration over time and ranged from 13 to 76 mg/L. TDN increased over time with a drop off in the last week in all raceways except one and ranged from 4 to 44 mg/L. PON and POC varied and ranged from 0.3 to 57 mg/L and 12 to 241 mg/L, respectively. NH4 concentrations ranged from 0.00009 to 2 mg/L and fluctuated from week to week. NO2 varied throughout the experiment and ranged from 0.0002 to 9 mg/L. NO3 ranged from 0.004 mg/L to 28 mg/L. SRP ranged from 0.01 to 19 mg/L and increased over time except one raceway. Temperature ranged from 25.86 to 31.84 ?C in the morning and 27.03 to 33.82 ?C in the afternoon. DO ranged from 4.15 to 13.45 mg/L in the morning and 2.67 to 10.73 in the afternoon. pH ranged from 6.72 to 8.25 in the morning and 7.11 to 8.47 in the evening. Salinity ranged from 15.01 to 18.88 in the morning and 14.97 to 18.93 in the afternoon. Stable isotope analysis was run on the shrimp feed and shrimp tissue. The isotopic signatures (δ13C, δ15N) as well as the percent carbon (%C) and percent nitrogen (%N) of the shrimp feed and tissue were analyzed. The average δ13C of the feed was -23.6 per mil and the average δ15N was +5 per mil. The average δ13C of the shrimp tissue was -20.6 per mil and the average δ15N was +8.7 per mil. The average carbon concentration of the feed was 43.6% and average N concentration was 5.3%. The average C concentration of the shrimp was 43.6% and the nitrogen concentration was 12.7%.
Publications
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2011
Citation:
Boube, I. 2011. Identification of transcriptomic pathways involved in Taura syndrome virus resistance in Litopenaeus vannamei.MS thesis. The University of Southern Mississippi. Hattiesburg, Mississippi, USA.
- Type:
Journal Articles
Status:
Published
Year Published:
2010
Citation:
Lotz J M 2010. Evolutionary principles applied to disease control and health management in shrimp aquaculture. Pp. 679 694. In Alday-Sanz, V. (ed). The Shrimp Book. Nottingham University Press. Nottingham.
- Type:
Journal Articles
Status:
Published
Year Published:
2010
Citation:
Ray AJ, Dillon, KS, Lotz JM. 2010. Water quality dynamics and shrimp (Litopenaeus vannamei) production in intensive, mesohaline culture systems with two levels of biofloc management, Aquacultural Engineering (2010), doi:10.1016/j.aquaeng.2011.09.001.
- Type:
Other
Status:
Published
Year Published:
2011
Citation:
Ray AJ, Lotz JM, Brunson JE, Leffler JW. 2011. Shrimp Sampling Method Improves Stocking Process. Global Aquaculture Advocate. July-August: 15.
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Progress 08/01/10 to 07/31/11
Outputs
OUTPUTS: 3.1.1.1.6 Microbial Community Characterization Although nitrification studies would be valuable, many bacterial species that are important in the oxidation of nitrite have yet to be cultured and are largely uninvestigated . Proper study of these organisms would require more resources and personnel than has been allowed for. It has been proposed that maintaining our focus on the ecology of pathogenic microorganisms is more within the scope and need of the overall project. The ratio of Vibrio spp. to total bacteria is being quantified and will be statistically analyzed along with raceway parameters and water chemistry in order to investigate the conditions that may increase bacterial load or select for potentially pathogenic Vibrio spp. 2.3.1.2.3 Vibrio Characterization Disease caused by bacteria in the genus Vibrio, often called Vibriosis, causes billions of dollars (U.S.) in losses to the seafood farming industry each year. Control of this group of pathogens, some of which also cause human disease, is therefore essential for economic stability, food safety and consumer confidence in aquacultured products. The objectives of this funding cycle were to: (a) quantitate the density of the Vibrio bacterial community in relation to total bacteria in the shrimp raceways; (b) to develop a multiplex PCR assay for the identification of Vibrios of interest in aquaculture settings; and (c) to look at possible relationships between total Vibrios, V. parahaemolyticus and environmental limiting factors in the raceways. Sample collection Eight aquaculture raceways were sampled each week throughout the growing season, from May 18, 2010 to August 9, 2010. Four randomly selected tanks had a higher rate of biofloc removal by varying flow through large settling tanks resulting in four high and four low solids systems. The 25-mL water and floc samples were gathered using sterile, 50 mL conical vials. After vortexing for 30 seconds, the samples were concentrated to 1.5 mL by centrifugation and stored at -20˚C. Bulk DNA (deoxyribonucleic acid) was extracted using the Qiagen DNeasy Blood and Tissue kit (Qiagen Corp., USA) with the following options. After thawing, samples were lysed overnight at 56˚C, vortexing occasionally with 180 uL buffer ATL and 40 uL proteinase K. After lysing, 4 uL of RNase A (100 mg/ml solution, Qiagen Corp., USA) was added with pulse vortexing and incubated for two minutes at room temperature as directed. Real-time qPCR Validated primer sets (Table 1) were chosen to amplify 16s rDNA (ribosomal DNA) specific to the Eubacteria, the Vibrio Genus and the thermolabile hemolysin (tlh) gene of V. parahaemolyticus. For specificity, the pre-optimized annealing temperatures were not altered. Real-time qPCR was performed on the extracted DNA using the LightCycler 480 system (Roche Diagnostics Corp., USA). The reactions were run in triplicate on 96 well plates using each primer set and SYBR Green 1 Master Mix or 480 Probes Master(Roche Diagnostics Corp., USA). Standard curves for the real-time absolute quantitation analysis were constructed using serial dilutions of known quantities of each primer product. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
DNA copy numbers for all the samples were calculated with the Roche LightCycler software using the absolute quantitation, Second Derivative Maximum method (Roche Diagnostics Corp., USA). The ratio of Vibrio to total bacteria for the triplicate samples was calculated, averaged and used for further analysis with PASW Statistics 18 (SPSS, Chicago, USA). The proportion of Vibrio in the bacterial community varied throughout the growing season, staying at zero percent in all the tanks until the middle of June then hovering mostly between one and three percent. A few of the tanks had a brief increase in the number of Vibrios to five to eight percent. Although, the proportion of Vibrio to total Bacteria was higher in the high solids treatment, no significant difference was found between the means of the groups of high and low solids (see Figure 1). At a 95% confidence level the significance level was greater than 0.05 or 0.208. Data for V. parahaemolyticus were collected but are still being analyzed and will therefore not appear in this report. All data collection for 2.3.1.2.3 Vibrio Characterization was stopped after August 9, 2010, because the raceways could not be maintained. The shrimp died of unknown causes preventing further work.
Publications
- No publications reported this period
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