February 15-18, 2009 Washington State Convention Center Seattle ...

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OXYGEN CONSUPTION OF Litopenaeus vannamei JUVENILES IN A SUPER INTENSIVE
ZERO WATER EXCHANGE RACEWAY CULTURE
Luis Vinatea, Alfredo O. Gálvez*, Jesus Venero, John Leffler and Craig Browdy
Universidade Federal Rural de Pernambuco, Departamento de
Pesca e Aqüicultura, R. Dom Manoel de Medeiros
s/n, Recife-PE, CEP 52171- 900, Brasil
alfredo_oliv@yahoo.com
It was studied the rate of dissolved oxygen (DO) consumption of Litopenaeus vannamei (13.2±1.42 g) juvenile maintained in
a microbial flock raceway system at high density (1 shrimp/liter). Each of two groups of 6 4-liter cylinders was placed either
in the dark or under light conditions of an enclosed greenhouse. The cylinders were filled out with raceway water and sealed
without receiving aeration. Four shrimp were assigned to each of three cylinders maintained in the dark and to three cylinders
maintained in the light. The remaining cylinders did not receive shrimp (control). Initial DO was determined for each treatment
(4.1±0.13 mg O 2 /L). Thereafter, DO content was determined every 10 min for a period of 30 minutes with a polarographic
digital oxygen meter. The oxygen consumption for shrimp maintained in the dark was 1.38±0.42, 1.08±0.12 and 0.55±0.28
mg O 2 /L for the 10, 20 and 30 min readings, respectively. The oxygen consumption for shrimp maintained under light conditions
was 1.14±0.37, 0.80±0.23 y 0.79±0.14 mg O 2 /L for 10, 20 and 30 minutes respectively. The oxygen consumption rate
was significantly different (P≤0.05) at 10 and 20 min between shrimp maintained in the dark and those maintained under light
conditions. When oxygen consumption was analyzed over time in presence of light, there were significant (P≤0.05) differences
between 10 and 20 min and between 10 and 30 min (Table 1). Under dark conditions there were only significant differences
in oxygen consumption between 20 and 30 min. It was concluded that anoxic conditions would be reached in less than 1 hour
either during the day (sunlight) or at night (dark) in the accidental absence of aeration/oxygenation.