Physiological responses of early postlarval shrimp Farfantepenaeus paulensis to different salinities were evaluated. Growth, net growth efficiency (K(2)), oxygen consumption, ammonia-N excretion, protein, lipid, carbohydrate, ash and energy content were determined in postlarval stages PL VI-VII and PL XIII-XV at 5 per thousand, 15 per thousand, 25 per thousand and 34 per thousand. PL VI-VII and PL XIII-XV correspond, in the wild, to the penetration of postlarvae into estuarine zones and the adoption of benthic habits, respectively. Postlarvae were gradually acclimated to the various salinity levels in the stage PL VI-VII and were maintained there until reaching the stage PL XIII-XV. Although development time was not affected by salinity, growth was decreased at 34 per thousand. Oxygen consumption was less affected by salinity while ammonia-N excretion presented a negative correlation with salinity. In both stages, protein content was lower at 34 per thousand. In PL VI-VII, lipid was decreased at 5 per thousand, while no significant difference in lipid content was observed in PL XIII-XV. Carbohydrate and ash levels did not vary in function of salinity levels. Energy content was reduced in PL XIII-XV at 34 per thousand. Net growth efficiency (K(2)) between PL VI-VII and PL XIII-XV presented higher values at 15 per thousand and 25 per thousand, and the lowest at 34 per thousand. Enhanced energy expenditure due to osmoregulation was not detected as denoted by oxygen consumption rates. Nitrogen metabolism seems to play a key role in maintaining body fluids concentration in relation to medium salinity. It is concluded that the high degree of euryhalinity in these stages of F. paulensis may be an adaptation to ontogenetic events such as migration to estuarine areas. For aquaculture purposes, it is recommended to maintain these postlarval stages at salinities between 15 per thousand and 25 per thousand rather than 34 per thousand.

中文翻译：

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Farfantepenaeus paulensis Pérez-Farfante（甲壳纲、十足目、对虾科）早期虾苗在不同盐度下的生长、耗氧量、氨氮排泄、生化成分和能量含量

评估了早期虾苗 Farfantepenaeus paulensis 对不同盐度的生理反应。生长、净生长效率 (K(2))、耗氧量、氨氮排泄、蛋白质、脂质、碳水化合物、灰分和能量含量在 PL VI-VII 和 PL XIII-XV 阶段的后期幼体阶段测定为 5‰，15千分之二、千分之二十五和千分之三十四。PL VI-VII 和 PL XIII-XV 在野外分别对应于后期幼体进入河口区和采用底栖习性。后期幼体在 PL VI-VII 阶段逐渐适应各种盐度水平，并在那里维持直到达到 PL XIII-XV 阶段。虽然发育时间不受盐度的影响，但生长量下降了 34‰。耗氧量受盐度的影响较小，而氨氮排泄量与盐度呈负相关。在这两个阶段，蛋白质含量都较低，为 34‰。在 PL VI-VII 中，脂质减少了 5‰，而在 PL XIII-XV 中没有观察到脂质含量的显着差异。碳水化合物和灰分水平在盐度水平的函数中没有变化。PL XIII-XV 中的能量含量降低了 34‰。PL VI-VII 和 PL XIII-XV 之间的净增长效率 (K(2)) 呈现较高的值，分别为 15‰和 25‰，最低为 34‰。未检测到由于渗透调节引起的能量消耗增加，如耗氧率所示。氮代谢似乎在维持与中等盐度相关的体液浓度方面起着关键作用。结论是 F. paulensis 在这些阶段的高度广盐性可能是对个体发生事件的适应，例如迁移到河口地区。出于水产养殖的目的，建议将这些后期幼体阶段的盐度保持在 15‰和 25‰之间，而不是 34‰。