Abstract

Two live feed relevant copepods for larval fish and shrimps, Pseudodiaptomus annandalei and Apocyclops royi, were predominant year-round in a tropical brackish fishpond system. The ponds environment is harsh concerning physicochemical properties; temperature 20–32 °C, salinity 15–23 besides abrupt salinity drops 15–9, frequent severe hypoxia, and poor nutritional seston quality. In 50 studies investigating several physiological endpoints, P. annandalei performs optimally within 18–32 °C and salinity 10–30 and A. royi within 24–32 °C and salinity 10–32. Most extreme, A. royi is reported in situ at salinity 50 and in the laboratory; it can adjust from salinity 20 to freshwater within just two generations when fed on Baker’s yeast. Both species and in particular A. royi have developed an outstanding capability to convert ingested seston with poor fatty acid composition into the necessary long-chained polyunsaturated fatty acids (PUFAs) characterizing their tissues. Hence, they self-enrich their bodies’ fatty acid profiles. Their physiological plasticity is likely a prerequisite for existing extensive mass production in the harsh pond environment. Moreover, A. royi exhibit additional traits, that is, high density tolerance qualifying also for intensive mass production suggesting it as the most promising live feed of the two species for fish and shrimp hatcheries.

摘要

在热带咸水鱼塘系统中， Pseudodiaptomus annandalei和Apocyclops royi是两种与活饲料相关的桡足类幼体鱼和虾的饲料。池塘环境理化性质恶劣；温度 20-32 °C，盐度 15-23，此外盐度突然下降 15-9，经常严重缺氧，营养浮质差。在调查多个生理终点的 50 项研究中，P. annandalei在 18–32 °C 和盐度 10–30 内表现最佳，A. royi在 24–32 °C 和盐度 10–32 内表现最佳。最极端的是，原位报道了A. royi在盐度 50 和实验室中；当以面包酵母为食时，它可以在短短两代内从盐度 20 调整到淡水。这两个物种，尤其是A. royi已经发展出一种出色的能力，可以将摄入的脂肪酸成分较差的浮游物转化为必需的长链多不饱和脂肪酸 (PUFA)，从而表征其组织。因此，他们自我丰富了身体的脂肪酸谱。它们的生理可塑性可能是在恶劣的池塘环境中大规模生产的先决条件。此外，A. royi表现出额外的特性，即高密度耐受性也适合集约化大规模生产，这表明它是这两个物种最有希望用于鱼虾孵化场的活饲料。