Saturday, April 17, 2010

SHRIMP RESEARCH ACTIVITIES AT OCEANIC INSTITUTE

Dustin R. Moss*, Clete A. Otoshi, Steve M. Arce, Carrie M. Holl, and Robert N. Cantrell
Oceanic Institute, 41-202 Kalanianaole Hwy., Waimanalo, HI 96795 USA
dmoss@oceanicinstitute.org
Through the U.S. Marine Shrimp Farming Program (USMSFP), Oceanic Institute (OI) has established a selective breeding program to improve the performance of specific pathogen free (SPF) Pacific white shrimp, Litopenaeus vannamei. In addition, OI researchers have developed biosecure, super-intensive production systems within which selectively bred shrimp have been evaluated. During the past year, 44 full-sib families from OIs Growth Line were evaluated in a 75-m2, biosecure raceway at an initial density of 409 shrimp/m2-m3. Trial duration was 74 d and mean family performance data are presented in Table 1. Mean family growth and survival were poorly correlated (rP = -0.2); however, several families exhibited both fast growth and high survival. Heritability for growth was moderate (h2 = 0.40 0.12) and similar to past estimates. Acclimation of nitrifying bacteria was similar to past trials with nitrite concentrations spiking to 26.9 mg/L at day-25 before stabilizing and remaining relatively low for the remainder of the trial. The addition of fresh seawater to mitigate poor water quality was not necessary and this resulted in low water usage for this trial (163 L/kg of shrimp produced). Representative shrimp from all families were also evaluated in a per os TSV (Belize isolate) challenge at Gulf Coast Research Laboratory (GCRL). Mean family survival ranged from 2.8 to 88.9%. Family TSV survival was poorly correlated with family growth (rP = 0.08) and growout survival (rP = 0.08). Performance of several hybrid cross between Growth Line shrimp and shrimp with high TSV survival (TSV Line) yielded little evidence of heterosis for TSV resistance.
In addition to Growth Line shrimp, 46 full-sib families from OIs TSV-Resistant Line were evaluated in a 75-m2, biosecure raceway. Initial stocking density was 363 shrimp/m2-m3 and the trial was harvested after 69 d. Mean family growth and survival were poorly correlated (rP = 0.2). Despite the poor correlation between these traits, several families exhibited fast growth and high survival (e.g. ten of the 46 families ranked in the top 20 for both growth and survival). Heritability for growth (h2 = 0.38 0.18) was similar to the Growth Line estimate. Acclimation of nitrifying bacteria was excellent in this trial and may be due to a new, simplified startup procedure. Nitrite-N reached a maximum concentration of 7.3 mg/L before stabilizing and remaining relatively low for the remainder of the trial. Water usage was 219 L/kg of shrimp produced and was similar to the previous trial. Representative shrimp from 44 families were also evaluated in a per os TSV (Americas isolate) challenge at GCRL. Mean family survival ranged from 44 to 98%. As for the Growth Line, family TSV survival was poorly correlated with family growth (rP = 0.07) and growout survival (rP = -0.15). In 2010, OI scientists will continue to conduct research on the selective breeding of L. vannamei and further develop super-intensive shrimp production systems.

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