Rayner Thomas Allan, Jørgensen Niels Ole Gerslev, Drillet Guillaume, Hansen Benni Winding
Department of Science and Environment, Roskilde University, DK-4000 Roskilde, Denmark; Institute of Marine Biology, National Taiwan Ocean University, Keelung 20224, Taiwan.
Department of Plant and Environmental Sciences, University of Copenhagen, DK-1871 Frederiksberg C, Denmark.
Comp Biochem Physiol A Mol Integr Physiol. 2017 Aug;210:1-6. doi: 10.1016/j.cbpa.2017.04.020. Epub 2017 May 5.
Changes in free amino acids (FAA) were investigated in the potentially important live feed and neritic copepod species Acartia tonsa during naupliar development. Total content of FAA in A. tonsa nauplii was around 17% of dry weight at first development stage, and declined to 6% for later stages. Relative to body-volume and biomass, the FAA content indicated possible volume-dependent changes. However, changes in FAA with osmolytic activity could not account for this decline in FAA content, but suggests that the decline reflected degradation of residual FAAs from the embryonic stage. Glutamic acid revealed the largest change in relative abundance during naupliar development and declined from 29.0% at first nauplius stage to 7.1% at later stages. The high FAA pool in early naupliar stages may be necessary for naupliar development due to an absence of feeding at first development stages. The high FAA content in early nauplii indicates that A. tonsa is a valuable source for nutritional energy for first-feeding fish larvae and should be further exploited for aquaculture purposes. Enhancements to FAA abundances in nauplii through manipulation of maternal diets could be of future interest, as copepod nauplii can contain a substantial pool of FAAs at first development stage.
在无节幼体发育过程中，对具有潜在重要性的活饵料和近岸桡足类物种——中华哲水蚤（Acartia tonsa）体内游离氨基酸（FAA）的变化进行了研究。中华哲水蚤无节幼体在发育初期FAA的总含量约为干重的17%，而在后期则降至6%。相对于体积和生物量，FAA含量表明可能存在与体积相关的变化。然而，FAA随渗透活性的变化并不能解释FAA含量的这种下降，而是表明这种下降反映了胚胎期残留FAA的降解。谷氨酸在无节幼体发育过程中的相对丰度变化最大，从第一无节幼体阶段的29.0%降至后期的7.1%。由于在发育初期无节幼体不摄食，早期无节幼体阶段较高的FAA库可能对无节幼体发育是必要的。早期无节幼体中较高的FAA含量表明中华哲水蚤是初摄食鱼类幼体营养能量的宝贵来源，应进一步开发用于水产养殖。由于桡足类无节幼体在发育初期可能含有大量的FAA，通过控制母体饮食来提高无节幼体中FAA的丰度可能是未来值得关注的方向。
