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Consortium Research Update FY2004 |
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| The latest report from the USMSFP
Consortium December 2004 |
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| Highlights
and Accomplishments FY04 |
DURING
THE PAST YEAR, the USMSFP focused research
on four major objectives:
Stock Improvement, Disease Control,
Sustainable Culture Technologies,
and Product Quality and Markets.
In addition, the USMSFP assisted
industry directly under some of these
objectives by providing broodstock,
postlarvae, education and training,
and disease diagnostics. Following
are highlight thrusts and achievements
of the USMSFP conducted under each
major activity.
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| STOCK
IMPROVEMENT FY04 |
The
primary focus of the Stock Improvement
objective this year was to continue
to evolve the breeding program to
include new genetic lines to address
emerging industry issues, expand
the USMSFP gene pool, research the
genetic basis of disease (TSV) resistance,
and improve the efficiency of selective
breeding and performance evaluation
efforts. Pedigree tracking and analysis
of genetic diversity supported this
work in a timely manner, while genomics
research emphasized continued development
of the linkage map for L. vannamei.
Work on cryopreservation of male
gametes was also reinstated this
year, with positive results. Of particular
note was the production of the first
group of shrimp in the new Nucleus
Breeding Center at the Oceanic Institute.
This facility will greatly expand
the capabilities of the program by
providing increased hatchery and
maturation space, and the ability
to run different lines concurrently.
During FY04, the selective breeding
program successfully produced shrimp
from its TSV-Resistant (Task 1.2.1),
Growth (Task 1.2.2), Inbred (Task 1.2.3,
and Sentinel (Task 2.2.7) lines. The
Low Salinity line was redesignated
the TSV-Resistant line during FY04
since the last year salinity (2 ppt
vs 15 ppt) was found to have no effect
on family survival. It was deemed more
important to continue breeding this
line for TSV resistance to further
efforts on determining the genetic
basis of disease resistance. Growth
line evaluations emphasized testing
at commercial farm sites (Task 1.2.4.2).
In a collaborative agreement, Growth
line broodstock were shipped to Harlingen
Shrimp Farms (HSF), Texas, which produced
postlarvae for stocking into their
ponds, and shipment to Seafood Systems
Inc., Michigan, and WMC for testing
in superintensive production systems.
Although pond trials were terminated
after a TSV outbreak in Texas (see
below), ongoing superintensive trials
are currently highly successful. At
OI, similar (Batch 18) Growth line
animals achieved 1.7 grams/week through
18 grams total weight (Task 1.2.4.2).
This represents a mean estimated breeding
value (BLUP) for growth in this line
0.56 grams/week higher than the founder
stock, while the estimate for survival
(BLUP EBV) has increased by six percentage
points, from 70 to 76 percent (Task
1.5.1).
Research on the genetic basis of TSV
resistance continued with identification
of 12 expressed sequence tags (ESTs)
associated with TSV susceptibility
(Task 1.2.3.3). These ESTs will be
added to the linkage map to facilitate
the QTL for TSV resistance. Further,
four alleles associated with TSV resistance
and TSV susceptibility were identified
in the QTL mapping resource families
(Task 1.2.3.3). This information will
facilitate selection of the TSV-resistant
line. Disease challenges (Task 1.2.4.3)
indicated that the underlying mechanism
for survival against TSV is to prevent
reaching lethal loads rather than tolerate
them. This, together with findings
last year that salinity influenced
expression of TSV resistance in certain
families, hints at an immune-type functioning
which can be exploited with breeding
and/or stimulation. In fact, preliminary
evidence gained from cDNA libraries
of Kona line animals this year (Task
1.2.3.3) indicates TSV affects some
immune response genes and acts through
the protein synthetic machinery and
mRNA associated with cytoplasmic cytoskeletal
structures, a key theory advanced that
will be examined next year. Similarly,
efforts moved forward on development
of marker-assisted selection, with
identification of an additional 10
ESTs for the linkage map (Task 1.2.3.2).
The map currently has 160 markers toward
the goal of 500 for a medium density
map. When completed, the linkage map
will allow the program to select based
on genotype.
Efforts also continued this year on
consolidating 15 years of pedigree
and performance information of the
program into an integrated, computerized
database (Task 1.5.1). Last year, breeding
records from 1989-2003 were harmonized,
linked, and recoded into a continuous
pedigree to allow rapid tracking of
ancestors and descendants of individual
shrimp. During FY04, performance data
from 1989-2004 were harmonized and
linked to the pedigree/BLUP/REML system.
About 60 percent of the data has been
incorporated, with over 90,000 individual
records from Batches 9 through 12 completed.
This information will be used next
year in conjunction with existing microsatellites
to conduct walk-back selection. This
will greatly improve selection intensity
for phenotypic traits by eliminating
the need to use physical tags for family
identification. The identification
of combinations of cryoprotectants
that improved freeze/thaw survival
and viability of L. vannamei sperm
(Task 1.1.2) also improved the outlook
for long-term preservation of genetic
material and improved breeding efficiency
in the future.
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| DISEASE
CONTROL FY04 |
Disease
research continued to take a proactive
approach to protect the industry
by improving the precision of diagnostic
methods and tools, and gaining insight
into the mechanisms and transmission
of TSV, WSSV, and others. Particular
attention this year focused on NHP,
due to continued industry concern,
and infectious myonecrosis virus
(IMNV), an emerging and significant
disease of L. vannamei that has not
been identified in the US, but has
been added to the USMSFP working
list of specific (C-1,2) pathogens.
Also of note this year was the multi-institutional
collaborative effort of the USMSFP
in Texas to discern the causes of
a TSV outbreak that occurred in early
June 2004, and in Hawaii with an
outbreak of WSSV.
FY04 was marked by emergence of both
TSV and WSSV on domestic farms. USMSFP
scientists were alerted to a TSV outbreak
on five farms in south Texas. A rapid
response effort was mobilized between
TAES, UAZ, GCRL, and Tufts that linked
closely with farmers, the Texas Parks
and Wildlife Department, USDA/APHIS,
and other Texas universities (Task
2.4.2.5). The USMSFP confirmed the
outbreak for state and federal agencies
and determined the serotype and genotype
of the isolate (Task 2.2.2). The isolate,
designated TSV-04, was deemed closed
in origin to Asian TSV strains. Asian
strains of the virus previously had
not been detected in the US. Efforts
are ongoing and directed toward continued
diagnosis (Task 2.4.2.5), and identifying
the origins of the outbreak through
epidemiological survey (Task 2.4) and
use of Shrimp Test 12®, the USMSFP
genetic marker kit (Task 4.1.1). These
efforts are testament to the attentiveness
and flexibility of the USMSFP to rapidly
respond to emergency needs of the industry,
while still maintaining strategic focus.
Of further significance was the finding
that TSV can be transmitted through
water (Task 2.4.31), and the techniques
developed during this study (Real-Time
PCR and use of a positively charged
filter system to concentrate the virus)
will help determine the lowest infection
concentrations.
A similar effort was mobilized in Hawaii
with the State and USDA/APHIS to confirm
a WSSV outbreak on one farm on the
island of Kauai. Collaborative work
with the Hawaii Department of Agriculture
(Task 2.2.2) found that of commodity
shrimp sampled from various supermarket
chains on the island, 73 percent were
positive for WSSV and 82 percent were
positive for IHHNV. Other achievements
with WSSV this year included the development
of a simple field diagnostic kit (Shrimple®),
and standardization of viral introduction
and challenge methodology for an anti-VP
28 immune sera (Task 2.2.1). Anti-VP
28 may prove useful as a theraputant
to combat WSSV infection. While challenge
studies indicate commercially available
stocks have been bred for good resistance
to TSV (survival up to 100 percent
for TSV-A, and 71 percent for TSV-C),
the outlook for breeding resistance
to WSSV (survival up to 31 percent)
does not appear as promising
(Task 1.2.4.1).
Significant advances were also made
on other diseases of proximate concern
domestically, NHP and black gill. A
pair of monoclonal antibodies (Mabs
3D6 and 4A2) was developed for NHP
(Task 2.3.1.1) which have been licensed
for use in a commercially available
kit for rapid, pondside diagnosis of
the disease. A real-time PCR for diagnosis
was also developed (Task 2.3), and
a quantitative estimate of NHP virulence
made (Task 2.5). The time course of
NHP pathology was elucidated using
the chronic infection bioassay developed
last year. Unlike WSSV, no chronic
state in NHP infection was found, and
all animals died 50-55 days post-infection.
Cooperative work with farmers on identifying
vectors and/or reservoirs for NHP continued
(Task 2.4.2.1), although efforts were
thwarted due to an excess of rain during
the 2004 growing season and lowering
of pond salinity at evaluation sites.
The protozoan, Gymnodinioides inkystans,
was found to be a primary cause of
black gill (Task 2.5).
Underscoring the need to remain vigilant,
the USMSFP also prioritized efforts
on two diseases that are not present
in the US, but which have potential
to spread rapidly if diagnostic and
prevention methods are not in place.
IMNV, currently limited to northern
Brazil, was isolated and characterized,
and classical and molecular diagnostic
methods for the disease developed (Task
2.5.3.3). Molecular diagnostic methods
were developed for spiroplasmosis identified
last year caused by Spiroplasma penaeii
(Task 2.3.1.3), as well as a much needed
bacterial challenge model using Vibrio
penaeicidia to evaluate the efficacy
of therapeutants (antibiotics, immunostimulants,
disinfectants) in shrimp (Task 2.3.3).
The USMSFP also completed a final step
toward the treatment of disease. Cooperative
efforts with the Texas Fish Farmers
Association and the Center for Veterinary
Medicine (CVM) at FDA seek approval
of oxytetracycline (OTC) for treatment
of NHP. The target animal safety report
was completed and submitted to Phibro
Animal Health, Inc. (Tasks 2.6.1.1
and 2.6.1.2). Initial studies (Task
2.6.1.3) were also carried out toward
the approval of a second antibacterial
compound, Florfenicol, with Schering-Plough
Animal Health.
|
| SUSTAINABLE
CULTURE TECHNOLOGY FY04 |
| Research
on sustainable culture technologies
continued to focus on the development
of superintensive production systems
and methods to improve biomass loading
and cost-effectiveness. Researchers
continued to use the USMSFP economic
model developed last year to better
refine their estimates, and incorporated
the nursery phase into the model.
Work also continued to determine
the physiological effects of low-salinity
culture and methods to improve production
in earthen ponds.
Among the most significant achievements
this year was the dedication and commissioning
of the large-scale growout facility
at GCRL (Task 3.1.1.1.2). This facility
houses twelve 232 m2 linear raceways
which will be used as a test bed for
demonstration of and improvements to
USMSFP superintensive production methodology.
It is the first facility to offer replicated,
pilot-scale units for rigorous scientific
evaluation of the technology. During
the first two commissioning runs, shrimp
achieved a milestone of over 1 gram/week,
and design modifications were implemented
for better temperature and oxygen control.
Nursery trials in the system also tested
design improvements. Further such runs
will continue until a 4 kg/m2 milestone
density is achieved. The system will
then be used to test various hypotheses
to facilitate development of the technology
using the economic model as a guide.
Continued efforts on super-intensive
nursery and growout production of shrimp
yielded record results. Nursery runs
of 2-gram shrimp yielding up to 6.79
kg/m2 were achieved (Task 3.1.2.1),
a 28 percent improvement in harvest
density from last year due to implementation
of foam fractionation. A record 6.82
kg/m2 of 20.4g average animals was
also harvested in growout from the
prototype (282 m2) system at WMC in
only 113 days (average gain of 1.62g/wk)
at 80 percent survival (420/m2 stocking
density) when using USMSFP Growth line
animals (Task 3.1.1.1). This confirmed
results of this line obtained at OI.
The WMC system has evolved to include
Aquamatsâ for enhanced nitrification
and vertical surface utilization by
shrimp, supplemental aeration, heating,
and water circulation pumps, a 25m3
bead filter for sludge removal, and
a supplemental oxygen injection system
all of which have proven to enhance
both biological and economic performance.
In fact, the economic model of production
is nearing feasibility levels generating
IRRs of over 25 percent and NPVs $1.0M
over initial outlays under these improved
scenarios. With further confirmation
of runs and testing of design improvements,
the systems should reach the business
planning stage within the next five
years.
Small tank trials (Task 3.1.1.2.1)
confirmed the usefulness of biofiltration
for solids removal and algal management,
but were less effective at nitrification
unless managed carefully. This suggests
it may be unnecessary in superintensive
systems to rely on biofilters for nitrification,
which is prevalent throughout the entire
production system, but rather modify
their use for sludge (solids) removal
and oxygen (algal) management. Collaborative
work between WMC and NSU (Task 3.1.1.3)
demonstrated that sludge volume can
be reduced by 21 percent with sequencing
batch reactor (SBR) treatment, and
that sludge salinity can be reduced
to 1 ppt with only three washes. These
results promise to significantly reduce
waste and provide sludge recycling
management strategies for both pond
and superintensive production systems.
Next year will incorporate use of a
prototype system at WMC and build it
into the economic model to assess impact.
Research on development of a semi-purified
research diet and diet attractability
came to fruition during FY04. A semi-purified
diet is now ready for use by the USMSFP
that yields as good biological performance
as the best commercial feeds currently
available (Task 3.1.3.2). Plans next
year are to incorporate tests of the
diet and ingredient manipulations in
replicated trials at super-intensive
production levels to begin development
of optimum diet formulations for these
systems. Based on previous attractability
research, a partial harvest diet was
also developed (Task 3.1.3.5) that
will be used in future studies in conjunction
with the partial harvest strategy,
introduced last year. If successful,
the partial harvest strategy can increase
biomass harvest without increasing
biomass load in systems, and yield
higher gross income and potential profits
for farmers. Research in small tanks
this year (Task 4.2.2) indicated total
biomass was increased by over 15 percent
under some conditions using the partial
harvest method. Plans are to test this
strategy in both pond and super-intensive
production systems. Other tests of
attractants yielded results that could
potentially increase growth and decrease
FCR by 10 percent, and leaching and
overall feed costs by 15 and 5 percent,
respectively (Task 3.1.3.5). Similarly,
the USMSFP completed the FDA market
report for Pegabindâ, a commercial
feed binder, that was shown to improve
feed stability and reduce pollution,
while reducing feed costs (Tasks 2.6.2.2).
Research also continued in earnest
on improving pond management strategies
(Task 3.1.5) and understanding the
physiology of low salinity shrimp culture
(Task 3.1.4). Of note was the testing
of a touted commercial organic feed
void of fishmeal and fishoil that yielded
16.0g shrimp (mean 2g/wk growth rate)
at an FCR of 1.1 in replicate earthen
ponds stocked at 25/m2, similar to
biological performance obtained in
the same shrimp fed a standard commercial
feed that contained squid meal (Task
3.1.5). Whether markets for organically
grown shrimp exist or not, this work
indicates the potential for reducing
dependence on marine products in the
future for industry sustainability
and perhaps market positioning.
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| PRODUCT
QUALITY AND MARKETS FY04 |
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Efforts to develop strategies to respond
to falling shrimp prices during FY04
focused on developing novel ways that
might have immediate impact to help
existing farmers remain competitive.
This included the provision of materials
to assist direct marketing efforts
of farmers, evaluation of partial harvest
strategies to optimize existing management
methods, and determination of the usefulness
of molecular tags to identify stocks
to provide broodstock producers a competitive
advantage in selling stocks.
During FY04 the WMC continued to promote
the concept of “South Carolina Fresh
Seafood” through dissemination of
brochures, questioners, and outreach efforts
(Task 4.2.1), although impact has been
difficult to measure. The partial harvest
concept, which essentially amounts to heavy
stocking initially and cropping to maintain
an optimum biomass, was shown theoretically
to provide up to a 25 percent increase
in margin per acre per crop (Task 4.2.2),
with minimal cost to farmers or change
in existing farming practices. Efforts
to develop microsatellite tags to distinguish
stocks from eight different countries and
the USMSFP are currently ongoing (Task
4.1.1) to establish a baseline and evaluate
the effectiveness of the USMSFP genetic
marker kit, Shrimp Test 12â, to detect
allele differences between shrimp samples.
If successful, this strategy could be used
to certify stock origins and be used as
a marketing tool, or to screen stocks and
trace back origins for biosecurity reasons.
As indicated earlier, the marker kit is
currently being used to screen shrimp that
were infected with TSV-04 in Texas to either
exclude of confirm the origins of parental
stocks.
Industry Support
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| INDUSTRY
SUPPORT FY04 |
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During FY04, the USMSFP produced and distributed
103,500 selected stocks and potential
broodstock (Task 1.4.1) and 1,051,000
Kona-line animals for growout (Task
2.2.7) to 15 cooperating research,
academic, and industry partners. This
included distribution of 300 Growth
line broodstock animals to HSF for
production of postlarvae for biological
evaluation in high-density growout
ponds. This is the second consecutive
year Growth line broodstock have been
made available to industry under cooperative
research agreement. Another 13 students
graduated from the Shrimp Pathology
Short Course, yielding to date (1989-2004)
training of a total 455 individuals
(Task 2.1.2) from the USMSFP, US industry,
academia and government, and foreign
countries. The USMSFP also processed
and reported over 350 disease diagnostic
cases (Task 2.2) for consortium members,
and the domestic and international
shrimp aquaculture industry
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| INFORMATION
DISSEMINATION FY04 |
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The USMSFP commitment to information dissemination
to the domestic shrimp industry has been
reflected in its workshops, training
and coursework as well as the program’s
website, brochures and newsletter, Industry
Briefs. During FY04, quarterly issues
of Industry Briefs were published, doubling
last year’s output. Moreover, the
format and scope was broadened to include
articles targeting both the shrimp farming
industry and research partners, and more
timely and in-depth analysis of industry
issues. Readership is currently over
500 and restricted to only US researchers,
farms, and industry professionals. Work
was also completed on the US shrimp farmers
website directory. This directory includes
links to one-page, individual farm websites
created by the USMSFP as well as links
to farms with existing websites. The
intent is to provide farmers enhanced
market visibility and vendors easy access
to farms in specific geographic areas.
The USMSFP website, www.usmsfp.org, expanded
further this year to provide the latest
local and global news detailing market
trends and prices. The USMSFP has earned
a top ranking based on website traffic
on major search engines. The website
continues to provide a high level of
statistical and qualitative feedback
on industry trends and concerns as “headline
news.” The site consistently receives
inquiries from established and prospective
shrimp farmers, in addition to responses
from online surveys. A USMSFP brochure
was introduced this year which highlights
the vision and major objectives and accomplishments
of the program and benefits to industry,
while providing an overview of its members
and their activities.
In addition to its publications and website,
information is distributed by the USMSFP
through conference meetings and farm site
visits. In March 2004, the USMSFP was highly
profiled during the 2004 World Aquaculture
Society conference in Honolulu, Hawaii.
In addition to conducting a special USMSFP
anniversary session with question-and-answer
period, the USMSFP director also chaired
all 14 special sessions, which included
over 170 presentations. The director also
attended the Texas Aquaculture Association
conference and the meeting of the South
Carolina Shrimp Growers Association, and
provided shrimp farmers with an overview
of USMSFP activities, followed by discussions
of local industry needs and concerns, and
visits to individual farm sites. The USMSFP
brochure and other materials were provided
at these meetings.
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