BIOCHEMICAL RESPONSES DURING STARVATION AND SUBSEQUENT RECOVERY IN POSTLARVAL PACIFIC WHITE SHRIMP, PENAEUS-VANNAMEI

Postlarval shrimp, Penaeus vannamei Boone, 1931, were held individuall y in cages and exposed to two feeding regimes. One group was starved f or 12 d and then fed during the following 12 d. A second group was fed throughout the 24 d study. Four individuals were sampled from each of the two groups on Days 0, 1, 2, 4, 8, 12, 13, 14, 16, 20, and 24. Mol ting and growth among the starved-fed postlarvae stopped after 2 d sta rvation, while fed postlarvae increased significantly in size througho ut the 24 d study. Among the starved-fed postlarvae, water content inc reased rapidly in response to starvation. DNA and sterol concentration s increased significantly during starvation due to selective catabolis m of cellular components. After 12 d, RNA concentration was not signif icantly different between the fed and starved-fed postlarvae, but beca me significantly higher in the starved-fed postlarvae 48 h after feedi ng resumed. Triacylglycerol reserves were severely depleted during the first day of starvation, while protein concentrations began to decrea se after the second day of starvation. RNA, protein, and the polyamine s spermidine and spermine, when expressed as a ratio to DNA, decreased in response to starvation. Concentrations of all measured parameters in the starved-fed postlarvae returned to levels similar to those in t he fed group 8 to 12 d after feeding resumed, Results of this study su ggest that triacylglycerol provides energy during short periods of sta rvation, while protein is utilized during prolonged starvation. The ra tios of RNA:DNA, protein:DNA, spermidine:DNA, spermine:DNA, two uniden tified amine compounds, and percent water content are all useful indic ators of prolonged nutritional stress in postlarval P. vannamei.